Name: ___________________________ Class: _________________ Date: __________
Chapter 02 1.
2.
3.
Your own scientific literacy would NOT be helpful in answering which of the following questions? a.
Should I take a cinnamon capsule every morning to help regulate my blood sugar?
b.
Should I spend the extra money to buy a particular pair of shoes that claims to help tone my leg muscles better than other athletic shoes?
c.
Will my cell phone cause me to have cancer?
d.
Which movie should I watch this weekend?
Which of the following would NOT be a situation where your own scientific literacy would be helpful in decision-making? a.
Should I send my child to a school that requires my child be vaccinated according to the vaccination schedule recommended by the Centers for Disease Control?
b.
Should I pay to store umbilical cord blood when my baby is born?
c.
Should I vote to support a new oil pipeline through a sensitive natural area?
d.
Is the space travel in Star Wars really possible?
Which of the following statements about the process of science is accurate? a.
Science is a systematic method designed to answer questions by evaluating evidence.
b.
Science attempts to solve a problem by evaluating the plausibility of only one solution without considering other possible explanations.
c.
Science does not use evidence and data collected to advance our understanding of natural and supernatural phenomena.
d.
4.
5.
6.
Science can answer all questions regarding the human experience and personal values.
Which of the following is LEAST likely to include unchecked bias when making scientific statements? a.
political groups
b.
religious groups
c.
marketing groups
d.
peer-reviewed scientific journals
Therapeutic touch (TT) is a type of “energy” medicine that involves the practitioner moving his or her hands over the energy field of the patient, without actually touching the patient, but redirecting the energy field to heal the patient. If a researcher were to design a survey of TT practitioners and their patients to determine the validity of TT, which of the following questions would NOT be helpful in determining the validity of the survey? a.
Is the researcher a regular TT practitioner or patient?
b.
Do the survey participants have a working relationship with the researcher or were they paid to participate?
c.
Are any non-TT patients included in the survey?
d.
How old is the researcher?
Which of the following would be a positive consideration when evaluating a researcher’s expertise regarding a particular scientific claim? a.
The researcher has an ideological, political, or religious belief that will be supported by the scientific claims being made.
b.
The researcher stands to make money if others accept the claims being made.
c.
The researcher stands to gain in prestige if others accept the claims being made.
d.
7.
8.
The researcher has a PhD, MD, or at least an MS and years of experience in the field in which he or she is making a scientific claim.
An individual claims to be able to detect the presence of graves in an old cemetery by using a “dowsing” or “divining” rod. The rod is a forked twig held in front of the individual as he walks across the cemetery. The “dowser” (person who is using the dowsing rod) claims that depending on which way the twig moves (up and down or side to side) he can determine if a grave is there and the gender and age of the individual buried at that spot. Which of the following would NOT help to evaluate if the dowser is a fraud? a.
It would help to know if the dowser had any previous knowledge of the cemetery.
b.
It would help to actually dig up the site to determine if the dowser’s predictions were accurate.
c.
It would help to at least use X-rays or some other means to examine what might or might not be buried in the ground.
d.
It would help to know the dowser’s age and affiliation with other dowsers.
Therapeutic touch (TT) is a type of “energy” medicine that involves the practitioner moving his or her hands over the energy field of the patient, without actually touching the patient, to redirect the energy field and heal the patient. Which of the following would be the first concept to investigate to help evaluate the claims of TT practitioners? a.
documentable and repeatable evidence that an external energy field actually exists for humans
b.
documentable and repeatable evidence that any existing energy field can be manipulated by merely passing hands over it
c.
documentable and repeatable evidence that TT practitioners can, without seeing or touching their subjects, actually feel the energy field of a patient
d.
documentable claims by TT practitioners and their patients that the patients thought they felt better after being treated by the TT practitioner even though there was no change in their diseases
9.
10.
11.
You are reading an article written by Neil Shubin et al. regarding the pectoral fin of Tiktaalik roseae in the peer-reviewed journal Nature. Dr. Shubin is a member of the National Academy of Sciences and is employed by The University of Chicago. This article represents a __________ literature presentation of __________ research. a.
primary; basic
b.
primary; applied
c.
secondary; basic
d.
secondary; applied
You are reading an article in Discover magazine about Tiktaalik roseae, the organism thought to be the link between fish and terrestrial tetrapods. The researcher that discovered Tiktaalik was publicly funded. This article represents a __________ literature presentation of __________ research. a.
primary; basic
b.
primary; applied
c.
secondary; basic
d.
secondary; applied
Scientists working for a major cosmetics company want to determine if a new face cream can reduce the number of fine lines and wrinkles on a person's face. This is an example of a.
applied research.
b.
basic research.
c.
meta-analysis.
d.
a cohort study.
12.
13.
14.
15.
Scientists at a major university are attempting to isolate a gene that slows the degeneration of collagen in skin. This is an example of a.
applied research.
b.
basic research.
c.
meta-analysis.
d.
a case-control study.
A research team funded by federal grants is studying the coevolution of pain receptors in grasshopper mice and the neurotoxic venom of scorpions (one of their primary food sources) to determine how the mice have adapted to the venom of their prey. This is an example of __________ research. a.
basic
b.
applied
c.
pseudoscientific
d.
random
A research team funded by a pharmaceutical company is studying the adaptation of grasshopper mice to the neurotoxic venom of scorpions in an attempt to determine how the mice’s adaptation could be used as a possible solution to pain management in humans. This is an example of __________ research. a.
basic
b.
applied
c.
pseudoscientific
d.
random
The federally funded Centers for Disease Control routinely collect and evaluate data regarding communicable diseases. This information helps
researchers make recommendations regarding vaccination schedules for children and adults. This is an example of
16.
17.
18.
a.
basic research.
b.
applied research.
c.
a case-control study.
d.
a cohort study.
A pharmaceutical company conducts trials on animals and cell lines to determine the safety of a new vaccine before performing clinical trials on adult human volunteers. This is an example of a.
basic research.
b.
applied research.
c.
a case-control study.
d.
a cohort study.
Which of the following examples indicates a situation where the researcher is MOST likely to have a possible bias regarding his or her work? a.
A researcher, funded by a pharmaceutical company, is testing the clinical effectiveness and safety of a new vaccine.
b.
A researcher, funded by a public grant, is testing the clinical effectiveness and safety of a new vaccine.
c.
A federally funded researcher is working on developing a genetically engineered microbe to quickly digest oil spills.
d.
A privately funded researcher is working on developing a genetically engineered and patented microbe to quickly digest oil spills. If successful, the microbe would be marketed worldwide.
You are reading an article in National Geographic regarding the evolution of humans. This would be an example of __________ literature.
19.
20.
21.
a.
primary
b.
secondary
c.
peer-reviewed scientific journal
d.
meta-analysis
Announcing “scientific” findings in a press conference before they have been published in an established scientific journal is an example of a.
primary literature.
b.
secondary literature.
c.
neither primary nor secondary literature because it has not yet undergone peer review to be primary literature, and secondary literature follows primary literature.
d.
both primary and secondary literature because it does not need to undergo peer review to be either primary or secondary literature.
The reliability of primary scientific literature is strengthened by the __________ process, in which the work is examined by other researchers in the same field. For instance, a scientific paper examining the evolution of tetrapods would be reviewed by other evolutionary biologists and paleontologists. a.
peer-review
b.
basic research
c.
applied research
d.
random research
Scientists analyzed 62 studies and determined that a strong physician recommendation for the HPV vaccine was a positive determining factor in whether or not parents chose to vaccinate their children. This analysis of various studies is referred to as
22.
23.
a.
meta-analysis.
b.
beta-analysis.
c.
secondary study.
d.
secondary analysis.
Based on the scientific evidence presented in more than 100 peer-reviewed, published research articles that evaluated millions of children, which of the following is NOT the reason for the observed increase of autism in the United States and other countries since the 1970s? a.
There is a heightened awareness of autism in society.
b.
More schools are screening more students for autism.
c.
People are generally more willing to label a broader range of conditions within the spectrum of autism disorders.
d.
The MMR vaccine is being more broadly administered, so more children are getting autism.
A researcher noticed that as the prevalence of cell phone usage increased between the years of 1998 and 2010, so did the number of individuals diagnosed with autism. He decided that cell phone usage by expectant mothers was causing autism. Which of the following would be the first step in evaluating his assumption? a.
The researcher should develop a clearly testable and falsifiable hypothesis.
b.
The researcher should carefully design a reproducible experiment.
c.
The researcher’s experiment should include thousands of participants from all gender, socioeconomic, racial, and ethnic groups both with and without autism.
d.
The researcher should use a small sample size (20 participants) of autistic children and their mothers to support the hypothesis.
24.
25.
The graph below shows which of the following?
a.
There is a strong correlation between the sale/consumption of organic food and the number of individuals diagnosed with autism between 1998 and 2007.
b.
The increased consumption of organic food has led to an increase in the rate of autism between 1998 and 2007.
c.
Consuming organic food causes autism.
d.
There is strong evidence that a cause-effect relationship exists between the consumption of organic food and the development of autism.
Thomas’s foot began to swell after he was stung by a scorpion. Thomas’s friend said his mom had an old, trusted herbal poultice remedy that would absorb the venom from the foot, reduce the swelling, and heal the foot. Thomas allowed his friend to place the herbal poultice on his foot before going to bed that night, and the swelling was gone in the morning. Which of the following can be concluded about the herbal poultice remedy?
26.
27.
a.
The poultice definitely worked because the swelling went down.
b.
The poultice definitely did not cause the swelling to go down.
c.
It is very likely that the poultice caused the swelling to go down.
d.
There is not anything that can be concluded about the effectiveness of the poultice remedy.
When Lori was diagnosed with breast cancer, the doctor recommended a lumpectomy followed by radiation therapy. Lori underwent the prescribed treatment recommended by the doctor. However, she also continued to eat lots of fruits and vegetables, walk three miles every day, and practice daily yoga. Within about three months, Lori was cancer-free. Afterward, Lori told everyone that her healthy lifestyle had helped to cure her. Is this conclusion reasonable given the circumstances? a.
No, a healthy diet and exercise regimen can never help cure cancer.
b.
No, there are too many confounding factors to know exactly what happened.
c.
Yes, the healthy diet and exercise regimen definitely helped to cure her.
d.
Yes, this evidence very strongly supports the hypothesis that a healthy diet and exercise regimen probably helped to cure her.
The fact that the onset of autism symptoms typically occurs at about the same age children receive many of their vaccinations, including the MMR, is an example of an observed a.
correlation but not necessarily evidence of a cause-effect relationship.
b.
correlation and strong evidence of a cause-effect relationship.
c.
cause-effect relationship supported by empirical evidence.
d.
cause-effect relationship but not necessarily a correlation.
28.
29.
30.
Which of the following is NOT a reason to scientifically evaluate the plausibility of claims made by a psychic who states that a missing child is alive and located in a particular area of the countryside months after the child went missing? a.
Precious time to search for the child could be lost.
b.
Manpower could be wasted looking in a location when there is no scientific evidence indicating the child might be there.
c.
It could cause additional and unnecessary grief when the new hopes and expectations of the parents are dashed.
d.
There is anecdotal evidence suggesting that psychics can predict the location of missing children.
Rick has high blood pressure and decides to try an herbal supplement recommended by his friend. Which of the following questions should Rick ask first to scientifically evaluate his friend’s recommendation before he begins taking the herbal supplement? a.
Has this herbal supplement been studied in a clinical trial by trained medical professionals?
b.
If this supplement was studied, who paid for the study?
c.
If this supplement was studied, how many people were included as patients in the study?
d.
What are the credentials of the team investigating the supplement?
Although it seems contradictory, real science does not intend to “prove” a hypothesis to be true. This is because a.
all true hypotheses will be rejected by the scientific method because they can be proven false.
b.
future experiments or discoveries may provide data that refute the hypothesis.
c.
science is a human endeavor, and like all human endeavors, it is limited by human understanding.
d.
the scientific method is limited to examination of the natural world.
31.
32.
33.
Developing a scientific understanding of a natural phenomenon typically begins by a.
observing a quantifiable natural phenomena.
b.
proving an answer.
c.
making a prediction.
d.
testing a hypothesis.
Sue has twin baby boys and is trying to decide whether to have them vaccinated against chicken pox or to take them to a “chicken pox party” where they can be naturally exposed to other children who currently have chicken pox. Which of the following would be the first relevant question for Sue to research before making her decision? a.
Are there any peer-reviewed, scientific studies of observable and quantifiable claims regarding the chicken pox vaccine or chicken pox parties?
b.
Do any relevant studies make testable and falsifiable predictions related to a clearly stated hypothesis?
c.
Are the relevant studies well designed and described with large sample sizes and minimization of bias, and have the results been reproducible?
d.
Are there a lot of parents on the Internet endorsing the chicken pox parties?
When determining whether a claim about a new cleansing juice diet is scientific or pseudoscientific, which of the following is NOT a helpful question to ask yourself? a.
What are the credentials and possible bias or agenda of the person(s) making the claim?
b.
Has the claim been published in a peer-reviewed, reputable scientific journal?
34.
35.
c.
Does the scientific study purporting to support the claim meet the standards of the scientific method?
d.
Are there a lot of people, including celebrities, endorsing the product as a healthy weight-loss method?
A popular post on the Internet states that hugs “transfer energy” between participants, giving them an “emotional lift.” Which of the following is a scientific approach to evaluating the claim of “energy transfer” during hugs? The hypothesis for the experiment would be as follows: if one person hugs another, the person receiving the hug will have more measurable energy after the hug. a.
First, develop a method of physically measuring the amount of energy available in a human being. Divide hundreds of subjects randomly into two groups, huggers and non-huggers. The available energy in the individuals of each group would be measured, the individuals would then hug (or not), and then the energy levels are measured again. The experimenter should not know which group is the hugging or nonhugging group to avoid expectation bias. The experiment should be repeated numerous times before analyzing the data.
b.
The researcher would need some people willing to hug someone else and fill out a survey stating how they felt before and after the hug. This should be repeated several times.
c.
The researcher would need some people willing to keep a daily log of how they feel during the day, how many hugs they get, and which days they feel the best at the end of the day.
d.
The researcher would need some people willing to complete a scientifically developed life history hugging survey. Through the survey, participants will document their own life histories of hugs (average number of hugs per day and how long they lasted) and emotional well-being. Once the survey is completed, the researcher will collate and evaluate the evidence. He or she should repeat this with a few different groups of people.
In the fall of 2012, a veterinarian from Texas issued a press release stating that her team of scientists had completed a five-year DNA study confirming the existence of “Sasquatch” or “Bigfoot.” Which of the following statements, if true, would lend support to her claims?
36.
37.
a.
She released her findings in a press conference prior to any peer review of her findings.
b.
There are no corresponding lines of documented physical evidence (fossil record, historic record, undisputed clear picture or video, or evidence that the environment could support a breeding population of large primates in the areas where they have been reported) to support her claims.
c.
The paper is published in an online source that consists of one issue with only this one paper (the full paper is for sale), and this new online publication is owned by the veterinarian.
d.
She consulted experts in the field of human genomics and made her DNA samples available to them for analysis.
Announcing “scientific” findings in a press conference before they have been published in an established scientific journal suggests a.
there may be reason to question the validity of the results or conclusions.
b.
that the results were too ground-breaking to wait for or need peer review.
c.
there is no reason to question the validity of the results.
d.
that the media has scientifically determined the results to be valid and repeatable.
A scientific paper that combines results from several cohort studies and a case-control study would be considered a(n) __________-analysis. a.
meta
b.
beta
c.
omega
d.
pseudo
38.
39.
40.
Observational studies that follow a particular group of individuals over a certain time period are __________ studies. a.
case-control
b.
meta-analysis
c.
beta-analysis
d.
cohort
If the Centers for Disease Control’s recommended vaccination schedule is delayed, the children who do not receive their vaccines on schedule a.
are just as well protected from diseases as they would be if they were on schedule.
b.
experience a decreased risk of contracting disease than they would experience if they were on schedule.
c.
experience no change in protection from diseases as they would experience if they were ahead of schedule.
d.
experience an increased risk of disease.
Which of the following situations might present a logical reason for accepting a scientific claim made by a person who did not have appropriate credentials for making that claim? a.
The claim could be supported by other nonbiased and credentialed scientists who have conducted similar research and arrived at the same conclusion, and the claim has been peer-reviewed.
b.
The claim could be supported by many other noncredentialled people who share the same ideas.
c.
The claim could be supported because the person really, truly believes what he or she is saying is accurate from his or her own personal experiences.
d.
The claim could be supported because certain celebrities have endorsed the idea presented by this particular researcher.
41.
42.
43.
Scientific studies that compare patients with a disease to those without the disease are referred to as a.
case-control studies.
b.
clinical trials.
c.
cohort studies.
d.
in vitro studies.
Which of the following would NOT be a reason for a peer-reviewed paper to be retracted by its publisher as untrue or inaccurate? a.
The author has made a clear error in the scientific process.
b.
It has been shown that the author plagiarized someone else’s work.
c.
It has been discovered that the author violated ethical guidelines or was involved in other scientific misconduct.
d.
Other researchers have published work that appears to contradict the paper in question.
A scientist publishes a paper in a peer-reviewed journal; this paper is later retracted. Which of the following (if found to be true) is NOT a legitimate reason for the retraction? a.
The study involved only 12 participants, but sweeping conclusions were made by the author. These participants were not randomly sampled; they were picked specifically for their symptoms. Furthermore, there was no control group.
b.
The findings could not be replicated, and there were many peerreviewed studies, including millions of participants that found no evidence for the claims of the original paper.
c.
The primary author of the paper received large amounts of money as a paid expert for lawyers who were suing companies based on the author’s claim. The author would also benefit financially in other ways, such as patents on alternative products.
d.
44.
45.
Although the findings were not replicated by other researchers, some studies indicated that the original paper might suggest a valid line of reasoning and warrants further investigation.
You discover that a holistic treatment called “ear candling” involves putting the end of a wax-coated cloth cone (a “candle”) into your ear and lighting it on fire, letting it burn to within about four inches of your face, and then repeating with a new candle. This process is supposed to remove tension, anxiety, and stress from your body. Which of the following statements or questions would be most helpful in scientifically evaluating these claims? a.
Your great-aunt used ear candling on all of her children and grandchildren, and they have all lived long and healthy lives.
b.
Have there been any studies that measured the feelings of well-being in individuals before and after ear candling?
c.
Ear candling has been used for centuries by many different cultures to cure earaches, reduce stress, and promote general well-being.
d.
Have there been any reproducible, peer-reviewed studies that compared ear candling in individuals who have ear infections with those who do not have ear infections?
According to the Centers for Disease Control (CDC), by the end of September 2014, roughly 8,000 cases of whooping cough had been reported in California for that year; more than 250 patients (mostly infants and young children) were hospitalized, with 58 of them requiring intensive care. Several other childhood diseases that were once common but then eradicated through high vaccination rates have returned since the antivaccination movement grew in the 1990s. The epidemiological data collected by the CDC indicates this resurgence of childhood diseases is most likely the result of a.
reduced herd/community immunity.
b.
reduced vaccine effectiveness.
c.
increased virulence of the pathogens causing these diseases.
d.
simply the increased number of people present in the United States.
46.
The figure below, based on data collected by The National Institute of Allergy and Infectious Diseases, graphically illustrates that as
47.
a.
increasingly more individuals in a community are vaccinated against a particular pathogen, future outbreaks of the disease are limited to fewer individuals because fewer people will become infected and then pass it on.
b.
individuals in a community become ill, increasingly more individuals either become ill or think they are becoming ill as they find out about the illness from friends, family, and the media.
c.
increasingly more individuals in a community are vaccinated against a particular pathogen, future outbreaks of the disease are limited to fewer individuals because fewer people think they can become ill. Just the idea of vaccines protecting from disease will make people think they are protected so they will not experience any symptoms.
d.
a population of individuals is infected with a particular pathogen, more and more people will become infected. This is beneficial because everyone will always survive, and their offspring will be immune to any future infections.
The figure below, based on data collected by The National Institute of Allergy and Infectious Diseases, graphically illustrates that a disease is less likely to spread to vulnerable members of a population if most of the population is immunized against the disease. This phenomenon occurs because
a.
when fewer individuals in the population are likely to become infected, fewer people are able to spread the disease, and the vulnerable members of the population are less likely to come in contact with contagious individuals.
48.
b.
if more individuals in the population become infected, fewer people are able to spread the disease, and the vulnerable members of the population are less likely to come in contact with contagious individuals.
c.
if more individuals in the population become infected, more people are able to spread the disease, and the vulnerable members of the population are less likely to come in contact with contagious individuals.
d.
when none of the population is immune to the disease, no one will contract the disease and therefore pass it on to the vulnerable members of the population.
In 1999, the United Kingdom began a meningitis vaccination program for children up to age 18. The graph below shows that post vaccination program, the number of adult meningitis cases is
a.
strongly correlated with the number of childhood meningitis cases; this appears to be related to the increased vaccination rates in children.
49.
b.
not correlated with the number of childhood meningitis cases; there appears to be no relationship to the increased vaccination rates in children.
c.
weakly correlated with the number of childhood meningitis cases; there appears to be no relationship to the increased vaccination rates in children.
d.
strongly but negatively correlated with the number of childhood meningitis cases; this is caused by the increased vaccination rates in children.
The graph below shows that after the childhood vaccination program was initiated in the United Kingdom in 1999, the annual number of meningitis cases in children
a.
decreased to nearly zero by 2004, as did the meningitis rate for adults.
b.
increased to over 700 in 1999 before slowly decreasing in 2000, as did the meningitis rate for adults.
50.
c.
did not decrease or increase; there was also no change in the meningitis rate for adults.
d.
decreased to zero by 2000, as did the meningitis rate for adults.
CDC’s HPV Vaccine Impact Monitoring Project evaluated data from over 10,000 biopsy specimens collected between 2008 and 2014. The proportion of cervical precancers due to HPV types 16 and 18 decreased from 55 percent to 33 percent in women ages 18–39 who had been vaccinated with the HPV vaccine. Additionally, precancers among unvaccinated women declined due to HPV-16/18. This decline is likely due to __________ immunity, which occurs when a significant proportion of a population has developed immunity to a disease. a.
individual
b.
herd
c.
natural
d.
vaccination
51.
Why would it be beneficial for you to be scientifically literate when choosing whether to purchase expensive workout apparel that claims to reduce muscle fatigue and promote circulation better than other brands of apparel?
52.
What is a first step an individual should take when beginning to assess a “scientific” claim made by another person?
53.
A large biotech company would like to market a microbe that will help clean up oil spills in the ocean by actually consuming and detoxifying the oil. Would this research be basic or applied? Explain your answer.
54.
Cheryl searches the Internet for information regarding the use of a particular herbal supplement because she has heard claims that it will help her safely build muscle while losing fat. During her search she comes across a site that claims to have evidence to support those claims. What questions should Cheryl ask herself as she peruses the site?
55.
Evaluate the following paragraph and determine whether the treatment method is most likely based on science or pseudoscience. Provide a brief explanation of your answer. “The symptoms of your cold are similar to those of mercury poisoning, so mercury should be the remedy you use. Of course, you should dilute it by using one part mercury to one trillion parts of pure water. This one allnatural remedy will treat all of your symptoms. You can trust this method because it is a very widely used system of medicine in the world, and its popularity is growing. Babies and pregnant women can use this method with no adverse effects, and it works in harmony with your immune system.”
56.
The graph below illustrates the predicted number of meningitis cases with or without herd immunity after the initiation of the meningitis vaccination program in the United Kingdom in 1999. Write a short paragraph comparing the observed number of cases to the predicted number of cases. Assess the predictive value of the model used to generate the graph and how this relates to the prediction of the number of cases that would exist without herd immunity.
57.
How does the HPV vaccine stimulate immunity in an individual human? Be sure to accurately include the following terms: antibodies, infectious organism, immune system, vaccine, virus.
58.
Your best friend, Joe, is selling a new apparatus he claims will generate “alkaline water” (having pH levels greater than 8) that you can drink in your own home. Joe also claims that drinking “alkaline water” will decrease your risk of getting cancer, lower your blood pressure, lower your blood sugar, improve your digestion, balance your body’s energy, and generate a sense of well-being. You can own your own machine for just $2,500 plus shipping and handling! Which of Joe’s claims are scientific and which are pseudoscientific? Include rationale, such as which claims could be tested in a lab, and describe why it is important to question Joe’s claims.
59.
In 2015 in the United States, the dietary supplements industry, including herbal remedies and energy drinks, grossed somewhere between 12 and 24 billion dollars in sales. The FDA regulates the safety and manufacture of conventional, pharmaceutical drugs before they are marketed to consumers. However, the companies that produce dietary supplements are responsible for evaluating the safety and purity of their own products before these are marketed to consumers. The FDA is responsible only for taking action against any adulterated or misbranded dietary supplement product after it reaches the market and consumers. The FDA will also issue warnings about a product after adverse reactions have been reported. Your friend, Vivian, is selling a fruit juice that contains a “secret, proprietary blend” of herbal ingredients. Vivian tells you that this fruit juice cured her dad’s migraine headaches, so you should use it to cure your migraines and to quit taking the medicine prescribed by your doctor. Write at least three steps you should take before you decide to follow Vivian’s advice about the juice.
60.
Why is it necessary to receive a new flu vaccine each year?
61.
You see a blog post on social media stating that this year’s flu vaccine is not very effective against the current strains of flu. The post urges readers to avoid the vaccine because it might actually give you the flu. What steps should you take and what types of information should you consider when evaluating this statement before deciding whether to get vaccinated with this year’s flu vaccine? Be sure to include examples of primary versus secondary literature.
62.
Between 1997 and 2007, mobile cell phone subscriptions have steadily increased from 18 users per 100 inhabitants to roughly 97 users per 100 inhabitants in developed countries. During this same time, diagnosed cases of autism have also steadily increased from around 50,000 to 250,000. Your friend decides that cell phones must cause autism. Briefly describe what your response would be to your friend’s conclusion, indicating any possible relationship(s) that may or may not exist.
63.
Medical researchers at the University of Sydney in Australia examined data from several cohort studies and several case-control studies regarding links between vaccines and autism. Overall, these studies included more than 1.25 million children from four different countries and vaccines for five different diseases. The paper concluded that there is no link between vaccines and autism. This work was published in the peer-reviewed journal Vaccine, and the researchers at the University of Sydney had no conflict of interest with the vaccines or the treatment of autistic children. Briefly describe this type of study and research (including if it is basic or applied research) and evaluate the strength of the researchers’ claim that no link exists between vaccines and autism. List four lines of evidence to support your assertion.
64.
A friend tells you that vaccines, in general, are not safe and that no one is keeping track of the side effects and dangers associated with vaccines. Your friend has decided that he will not be vaccinated and will not have any of his children vaccinated. You want to encourage your friend to reconsider his views, so you share with him that there are actually various organizations continually testing and evaluating vaccines for effectiveness, safety, and side effects. Summarize three ways this occurs.
65.
Which of the following texts are examples of primary literature and which are examples of secondary literature? a.
primary
b.
secondary __ 1. Biology Now 3e, your textbook __ 2. review articles found in peer-reviewed scientific journals __ 3. Journal of the American Medical Association, a peer-reviewed scientific journal __ 4. Science, a peer-reviewed scientific journal __ 5. National Geographic, a popular magazine about science and the world __ 6. Discover, a popular magazine about science __ 7. Popular Science, a popular magazine about science
__ 8. The Proceedings of the 15th Annual Meeting of the Society for Integrative and Comparative Biology, a publication of peerreviewed presentations at a professional meeting
66.
Indicate which of the following examples are most likely “real science” and which are most likely “pseudoscience.” a.
real science
b.
pseudoscience __ 1. This herbal remedy must work because people have used it for thousands of years and it always makes them feel better. __ 2. Facilitated Communication works only when everyone in the room believes it will work. __ 3. When this herbal remedy was given to 1,500 individuals who suffer from high blood pressure, 75 percent of those individuals experienced a decrease in their blood pressure. This was compared to a decrease in the blood pressure of 35 percent of the 1,500 individuals who were given the placebo. Another 1,500 participants in the study were given the standard blood pressure medication, and 73 percent of those individuals experienced a reduction in their blood pressure. __ 4. Dr. Simoncini insists on his website that cancers are actually fungal infections that can be cured by increasing the pH of the human body. He will gladly cure your cancer for 500,000 euros. __ 5. A researcher at The Baylor College of Medicine publishes peerreviewed research indicating that immunotherapy can help fight certain types of cancer. __ 6. The Journal of the American Medical Association publishes a peer-reviewed article showing a link between certain strains of the Human Papilloma Virus (HPV) and cancers of the urogenital tracts in both females and males.
Answer Key Chapter 02
1. Answer:
D
2. Answer:
D
3. Answer:
A
4. Answer:
D
5. Answer:
D
6. Answer:
D
7. Answer:
D
8. Answer:
A
9. Answer:
A
10. Answer:
C
11. Answer:
A
12. Answer:
B
13. Answer:
A
14. Answer:
B
15. Answer:
B
16. Answer:
B
17. Answer:
D
18. Answer:
B
19. Answer:
C
20. Answer:
A
21. Answer:
A
22. Answer:
D
23. Answer:
A
24. Answer:
A
25. Answer:
D
26. Answer:
B
27. Answer:
A
28. Answer:
D
29. Answer:
A
30. Answer:
B
31. Answer:
A
32. Answer:
A
33. Answer:
D
34. Answer:
A
35. Answer:
D
36. Answer:
A
37. Answer:
A
38. Answer:
D
39. Answer:
D
40. Answer:
A
41. Answer:
A
42. Answer:
D
43. Answer:
D
44. Answer:
D
45. Answer:
A
46. Answer:
A
47. Answer:
A
48. Answer:
A
49. Answer:
A
50. Answer:
B
51. Answer:
It would benefit me to understand how to evaluate the claims to “reduce muscle fatigue” and “promote circulation” because there may be no scientific evidence supporting the claim that the more expensive clothes do this or are any better at doing this than a less expensive brand. I would waste my money if the less expensive brand does these things just as well as the more expensive brand.
52. Answer:
A first step toward assessing the strength of a person’s scientific claim is to check her credentials. Does the individual have a degree, such as a PhD or MD, and is her degree in a field directly related to the area in which she is asserting expertise? It would be suspicious if the individual has a PhD in business and is making health claims about a new cancer drug.
53. Answer:
This would be applied research because the scientific knowledge is being applied to a human/environmental issue with potential commercial application. There is the potential for bias on the part of the researcher if he or she stands to benefit either financially or professionally from the findings.
54. Answer:
What evidence does the site share? If there was a study, where was the study conducted? Who paid for the study? Is there a description of the study readily available for me to read? Most important, was the study published in a peer-reviewed scientific journal or in primary literature? Additionally, she would want to ask if the site is trying to sell a product.
55. Answer:
This treatment is most likely based on pseudoscience. The statement uses scientific-sounding terminology without applying the scientific method/process. Although it would be possible to design an experiment to test a hypothesis with clearly measurable, testable, and falsifiable predictions, no such experiment has been mentioned, and no results have been presented. Overstated conclusions are presented as fact. Just because a method is “all natural,” “widely used,” or “growing in popularity” does not mean that it is effective or has been scientifically evaluated and peer-reviewed.
56. Answer:
Comparing the number of predicted cases with herd immunity to that of observed cases demonstrates a very close correlation between the two data sets. Assuming that the vaccination program successfully generated herd immunity in the population, we can deduce that the model used to make the predictions is accurate. If the model can accurately predict the number of “meningitis cases with herd immunity,” then it can likely also accurately predict the number of “meningitis cases without herd immunity.”
57. Answer:
A vaccine containing proteins found on the surface of the HPV virus is injected into the muscle of an individual. When the individual's immune system encounters these proteins, the immune system will begin to produce antibodies that recognize these proteins. If the individual is subsequently exposed to the HPV virus, his or her immune system is already primed with antibodies to attack the invading virus.
58. Answer:
First of all, the pH of the water produced by the machine could be tested to determine the actual pH; this would be a testable scientific claim. Another claim that could be tested is that it will lower your blood pressure and blood sugar. The claim that it will lower your risk of getting cancer would require more time to test, but could possibly be tested. If you wanted to test how much it improves your digestion, you would need to determine how to measure that improvement. All of these testable things would also require testing on many people to support or not support Joe’s claims. Joe’s claims that it will “balance your body’s energy and generate a sense of well-being” are vague and nondescript claims that would be extremely difficult if not impossible to test, so these are probably pseudoscientific claims. It is important to question or test Joe’s claims because the machine is expensive, and even if it really does make “alkaline water,” it might not actually be good for you.
59. Answer:
1) Try to discover what is in the “secret, proprietary blend” because you might be allergic to one of the ingredients. 2) Look up the product to see if there are any health warnings (like from the FDA) that have been issued regarding the product or its ingredients. 3) Consult secondary literature to gain a basic understanding of the product and any claims associated with it. 4) Consult primary literature to discover if there are any peerreviewed scientific studies investigating the effectiveness and safety of the product and its ingredients. 5) Check to see who conducted and paid for any published studies regarding the product.
60. Answer:
A new flu vaccine is needed each year because the flu virus changes (mutates) rapidly, and the strains each year usually differ from the previous year.
61. Answer:
Some of the things I should consider before making my decision would include the following: Is my friend a trained physician? What do reliable secondary scientific sources (e.g., WebMD) say about the vaccine? What do peer-reviewed scientific articles (primary sources might include CDC articles and definitely the Journal of American Medical Association) say about the vaccine, and is there any benefit other than preventing this year’s flu? Although this year’s vaccine might not prevent me from getting the flu this year, might it prevent my getting a flu that develops in the future? Is there any peer-reviewed, scientific evidence that getting the flu vaccine will actually give me the flu?
62. Answer:
I would tell my friend that although there seems to be a positive correlation (as one variable has risen, so has the other) between the use of cell phones in the developed world and the occurrence of autism, this data does not establish a cause-effect relationship between the two variables. There could be many other things influencing the autism rate. Someone would need to conduct scientific experiments to demonstrate a cause-effect relationship between these two variables.
63. Answer:
This type of study is a meta-analysis that combines, analyzes, and evaluates the results from multiple studies. The researchers’ conclusion is supported with solid science. First, the research team appears to have the appropriate credentials for investigating claims regarding vaccines and autism. Second, the study meets the standards of real science by including various lines of evidence and large sample sizes. Third, the study has been reviewed by other researchers specializing in the field of vaccines and then published in the primary literature. Fourth, there is no evidence of a conflict of interest; the researchers are not trying to sell us something or support a nonscientific belief.
64. Answer:
1) New vaccines are extensively tested on animals and/or cell lines before clinical trials on adult human volunteers even begin. Only if the vaccine is safe and effective will the U.S. FDA approve it for commercial sale. 2) Even after approval, every facility manufacturing vaccines is inspected by the FDA, each vaccine batch is tested for safety, purity, and potency, and anyone can report a vaccine adverse reaction to the Vaccine Adverse Event Reporting System (VAERS). 3) Before a vaccine is added to the official list of recommended immunizations, all of the data regarding that vaccine is reviewed by the Advisory Committee on Immunization Practices (ACIP) and then again by the director of the Centers for Disease Control (CDC).
65. Answer:
1.
B
2.
B
3.
A
4.
A
5.
B
6.
B
7.
B
8.
A
1.
B
2.
B
3.
A
4.
B
5.
A
6.
A
66. Answer:
Name: ___________________________ Class: _________________ Date: __________
Chapter 03 1.
2.
3.
The subatomic particles that possess a single negative charge and surround the nucleus are the a.
isotopes.
b.
protons.
c.
neutrons.
d.
electrons.
Nitrogen has seven protons, seven neutrons, and seven electrons. What is the atomic mass of nitrogen? a.
0u
b.
7u
c.
14 u
d.
21 u
The opioids shown here have what common chemical feature?
a.
They are all compounds.
4.
5.
b.
They are all elements.
c.
They are all isotopes.
d.
They all have the same structure.
In Figure 3.17, when researchers modified fentanyl to make NFEPP, what single change was made to the structure of the molecule? a.
An amino acid was replaced.
b.
An atom was added.
c.
A hydrophobic region was added.
d.
A double bond was created.
The bonds connecting the atoms in the following molecule are __________ bonds.
a.
polar, hydrogen
6.
b.
polar, covalent
c.
nonpolar, ionic
d.
nonpolar, covalent
Which one of the following images illustrates both hydrogen bonds and covalent bonds? a.
b.
c.
d.
7.
8.
O2, also referred to as atmospheric oxygen, is formed by a covalent bond between two oxygen atoms. This type of bond involves oxygen atoms a.
releasing protons.
b.
releasing electrons.
c.
sharing protons.
d.
sharing electrons.
Atoms in a single molecule of methane, CH4, share electrons. Methane is formed by __________ bonds joining __________ atoms. a.
hydrogen; two
b.
covalent; five
9.
10.
11.
c.
ionic; five
d.
ionic; two
The chemical reaction that represents photosynthesis is 6 H2O + 6 CO2 → C6H12O6+ 6 O2. What are the reactants? a.
H2O and CO2
b.
C6H12O6 and CO2
c.
H2O and O2
d.
C6H12O6 and CO2
The subatomic particles that possess a single negative charge, surround the nucleus, and are lost or gained by atoms called ions are the a.
isotopes.
b.
protons.
c.
neutrons.
d.
electrons.
Sodium chloride (table salt) is formed when positively charged sodium ions and negatively charged chloride ions are chemically attracted to each other. This attraction is best described as a(n) a.
hydrogen bond.
b.
ionic bond.
c.
covalent bond.
d.
solution.
12.
13.
14.
15.
In the chemical reaction that forms hydrogen peroxide (H2O2), hydrogen and oxygen share electrons, creating __________ bonds between the atoms. a.
covalent
b.
peptide
c.
hydrogen
d.
ionic
Ionic bonds __________, whereas covalent bonds __________. a.
form between the same two elements; form between different elements
b.
hold together compounds that do not dissolve in water; hold together molecules that dissolve in water
c.
hold together oppositely charged atoms; hold together atoms that share electrons
d.
consist of atoms with partial charges; consist of atoms with full positive and negative charges
When calcium (Ca2+) and chloride (Cl-) interact with one another, they bond using __________ bonds. a.
hydrogen
b.
peptide
c.
covalent
d.
ionic
Hydrogen and oxygen atoms are held together within an individual water molecule by __________ bonds. a.
hydrogen
b.
peptide
16.
17.
18.
19.
c.
polar covalent
d.
ionic
Which of the following is likely to participate in ionic bonding? a.
Li+
b.
H2 O
c.
He
d.
C6H12O6
Individual water molecules orient toward each other because of the __________ bonds that form between them. a.
covalent
b.
peptide
c.
hydrogen
d.
ionic
Which of the following is correct about hydrogen bonds? a.
Individually, they are very strong.
b.
They form between neighboring oxygen atoms.
c.
They do not involve binding with a hydrogen atom.
d.
They form due to partial positive and partial negative charges on atoms.
Which of the labeled areas of the water molecule in the following image possesses a partial negative charge?
20.
a.
A only
b.
B only
c.
C only
d.
A and C
If iodide ions (I-) were dissolved in water (as pictured here), they would be attracted to
a.
A only
21.
22.
23.
b.
B only
c.
C only
d.
A and C
Neighboring water molecules are held together with hydrogen bonds because a.
partially negatively charged oxygen atoms and partially positively charged hydrogen atoms on separate water molecules are attracted to one another.
b.
the hydrogen and oxygen atoms within a single water molecule share electrons equally.
c.
the oxygen and hydrogen atoms that participate in hydrogen bonding share electrons within a single valence shell.
d.
ionic interactions repel water molecules from hydrophobic oils that may be present in a solution.
Ice floats on water because a.
the crystal structure of ice is more regular than that seen in liquid water.
b.
the distance between water molecules in ice is greater than in liquid water.
c.
the cool temperature of ice reduces the extent of molecular motion relative to liquid water.
d.
when ice forms, the hydrogen bond in the water molecule becomes nonpolar; ice behaves like oil.
When sodium chloride (Na+Cl-) is dissolved in water, the sodium ion is a.
attracted to the hydrogen atoms of water molecules.
b.
repelled by the oxygen atoms of water molecules.
24.
25.
26.
c.
attracted to other sodium ions that are being dissolved.
d.
attracted to the oxygen atoms of water molecules.
A sample of pure water is analyzed for the atoms present. Which of the following would be the correct percentages of atoms present in the sample? a.
25.0 percent oxygen, 75.0 percent hydrogen
b.
50.0 percent oxygen, 50.0 percent hydrogen
c.
33.3 percent oxygen, 66.6 percent hydrogen
d.
66.6 percent oxygen, 33.3 percent hydrogen
Oil and water do not mix well because a.
water is polar and oil is nonpolar.
b.
only identical molecules of the same chemical can easily mix.
c.
water has hydrogen bonds and oil is polar.
d.
water and oil are covalently bonded.
You are given an unknown substance and asked to determine whether it is polar or nonpolar. The easiest way to do this would be to a.
determine whether the compound is held together by hydrogen bonds.
b.
determine the number of electrons in the compound’s outer shell.
c.
mix the compound with an ionic substance to see whether its bonds can withstand the pressure.
d.
determine whether the compound dissolves in water.
27.
28.
29.
30.
In making her morning tea, Dorothy drops a sugar cube into the hot water. She stirs the mixture but no longer sees the sugar cube at the bottom of her mug. In this scenario, the sugar is a.
nonpolar.
b.
the solvent.
c.
an acid.
d.
a solute.
In making her morning tea, Dorothy drops a sugar cube into some hot water. She stirs the mixture but no longer sees the sugar cube at the bottom of her mug. Based on her observation of sugar dissolving in hot water, she can properly conclude that the sugar is a.
hydrophobic.
b.
nonpolar.
c.
hydrophilic.
d.
inert.
A carwash attendant offers to treat Martin’s windshield with a protective agent. This substance coats the glass, causing beads of water to easily roll off during a rain shower. Which of the following must be correct about the protective agent? a.
It resists temperature changes well.
b.
It must be an acid.
c.
It is a polar substance.
d.
It must be hydrophobic.
The pH scale measures the a.
amount of water in a solution.
31.
32.
33.
34.
b.
likelihood that a solution will evaporate.
c.
concentration of hydrogen ions in a solution.
d.
number of atoms found within a molecule.
An acid is a polar substance that dissolves in water and a.
becomes nonpolar.
b.
leaves behind an OH- ion.
c.
accepts hydrogen ions from the solution.
d.
donates hydrogen ions to the solution.
After adding a small amount of Solution A to Solution B, the pH of Solution B declines from 8 to 3. Solution A must contain a.
a salt.
b.
a base.
c.
water only.
d.
an acid.
When ammonia (NH3) is dissolved in a solution, it accepts hydrogen ions from its surroundings. Ammonia is therefore a(n) a.
base.
b.
isotope.
c.
salt.
d.
acid.
A solution with a pH of 3 is
35.
36.
37.
a.
acidic.
b.
basic.
c.
nonpolar.
d.
neutral.
Of the following values, which indicates the most basic pH? a.
5
b.
7
c.
8
d.
10
Which of the following solutions has the highest concentration of free H+ ions? a.
pH 1
b.
pH 4
c.
pH 7
d.
pH 14
As shown in the following figure, the highest concentration of free hydrogen ions is found in
38.
a.
household ammonia.
b.
lemons.
c.
human blood.
d.
stomach acid.
According to the following figure, which of the following has a lower concentration of hydrogen ions?
39.
a.
milk.
b.
oranges.
c.
antacids.
d.
baking soda.
The most basic solution in the following figure is
40.
a.
seawater.
b.
borax.
c.
baking soda.
d.
tomatoes.
The most acidic solution in the following figure is
41.
a.
stomach acid.
b.
lemons.
c.
oven cleaner.
d.
pure water.
A solution with a pH of 4 is __________ acidic than a solution with a pH of 5. The solution with the pH of 4 has a __________ concentration of hydrogen ions than the solution with a pH of 5. a.
more; higher
b.
more; lower
42.
43.
44.
45.
c.
less; higher
d.
less; lower
Carbon atoms are bound to each other by __________ bonds. a.
ionic
b.
polar
c.
hydrogen
d.
covalent
Carbon’s prominence in living systems can be explained by the fact that a.
it forms weak reversible bonds.
b.
it bonds with up to three other atoms.
c.
carbon-based molecules can form long chains and rings.
d.
it does not form small molecules.
Which of the following is an organic compound? a.
water (H2O)
b.
methane (CH4)
c.
ammonia (NH3)
d.
carbon dioxide (CO2)
Astronauts returning from outer space studied samples taken from their lunar landing. They found that one of their samples was coated with organic compounds. Which of the following statements must be correct?
46.
47.
48.
a.
The compounds must be covered with ammonia (NH3) and water vapor.
b.
The samples must lack water but contain DNA.
c.
The samples must contain carbon atoms.
d.
The specimen must lack water, pesticides, and added hormones.
Carbon is an example of a(n) a.
compound.
b.
macromolecule.
c.
element.
d.
amino acid.
The central element found in organic molecules is a.
calcium.
b.
carbon.
c.
silicon.
d.
sodium.
Which of the following statements is true of proteins, carbohydrates, and nucleic acids? a.
All three are used to store genetic information.
b.
None of these macromolecules mixes well with water.
c.
Each of these molecules is built from a common set of monomers.
d.
All of these molecules are primarily used as energy-storage molecules.
49.
50.
51.
52.
A researcher in a laboratory tests a food item and identifies protein in it. The food item must also contain a.
glucose.
b.
lipids.
c.
amino acids.
d.
nucleotides.
Macromolecules are typically formed by repetitively adding small monomers together. Which macromolecule is properly matched with the appropriate monomer? a.
polypeptide—amino acid
b.
nucleic acid—amino acid
c.
polysaccharide—nucleotide
d.
triglyceride—cholesterol
A disaccharide consists of two a.
sugars.
b.
hydrocarbons.
c.
fatty acids.
d.
amino acids.
Nucleotides a.
are the building blocks of proteins.
b.
are involved in every chemical reaction in the cell.
c.
form physical structures such as hair.
d.
are the building blocks of nucleic acids.
53.
54.
55.
56.
The genetic material found in all living things is made of building blocks called a.
nucleotides.
b.
monosaccharides.
c.
phospholipids.
d.
steroids.
Which of the following are composed of the same monomers? a.
proteins and DNA
b.
RNA and cellulose
c.
starch and cellulose
d.
cholesterol and sucrose
Which of the following is the largest in size? a.
glucose
b.
protein
c.
carbon atom
d.
nucleotide
Which of the following could be built solely from glucose molecules? a.
fatty acids
b.
DNA
c.
oils
d.
starch
57.
58.
59.
A scientist has assembled 1.0 gram of protein, lipid, carbohydrate, and nucleic acids in separate tubes. They add each of these samples to a calorimeter, a device that determines the amount of energy present in the sample. Based on the role of these molecules in the body, predict which test tube will produce the most energy. a.
nucleic acids
b.
proteins
c.
carbohydrates
d.
lipids
Laura’s supervisor provides her with lipids, carbohydrates, proteins, and nucleic acids and asks her to determine their chemical components. Which of the following elements would she NOT expect to find in these items? a.
carbon
b.
iron
c.
hydrogen
d.
nitrogen
We use soap to clean ourselves better than we could with water alone. Soaps contain phospholipids that are responsible for the cleansing action. Based on this, predict which of the following materials would be needed to produce soap. a.
proteins
b.
triglycerides
c.
carbohydrates
d.
nucleic acids
60.
61.
62.
How many different amino acids are used to build proteins? a.
90
b.
20
c.
19
d.
4
Antibodies are an important class of human proteins that function in immune defense. If scientists fragmented antibodies under laboratory conditions, what chemical building blocks would they recover? a.
monosaccharides
b.
phospholipids
c.
amino acids
d.
nitrogenous bases
Based on these macromolecule images, what is a shared feature?
a.
They are all polar compounds.
b.
They are all organic compounds.
c.
They are all nonpolar compounds.
d.
They are all acidic compounds.
63.
Nitrogen has an atomic number of 7 and an atomic mass number of 14. Using the following image, describe the location and number of protons, neutrons, and electrons in nitrogen.
64.
Lithium, with an atomic number of 3, has a tendency to lose electrons when it chemically bonds to another atom. What type of chemical bonds does lithium usually form with other atoms? Explain how you determined your answer.
65.
During a study session, a biology classmate holds up a bottle of water and mentions that there are both hydrogen bonds and covalent bonds found within the liquid. Explain your classmate’s statement by describing the types of bonds that are found within the bottle of water.
66.
The bonds within an individual water molecule and between separate water molecules explain the special properties of water. Describe the type of bond within individual water molecules and the type of bond between separate water molecules. Then, list two unique properties of water.
67.
After giving a baby a bath, a parent applies baby oil to the child’s skin. How does the baby oil help the baby’s skin to retain moisture throughout the day? Explain the chemical basis of water retention in this example.
68.
Gina makes vinaigrette dressing with olive oil and vinegar and then shakes the jar vigorously. For a few minutes it appears as if the oil and vinegar have mixed. Then she notices the two liquids separating from each other. Describe why these two liquids do not stay together even after vigorous mixing.
69.
The pH value of pure water is 7.0. When Ralph measures the pH of rainwater in his neighborhood, he finds the pH value is 6.0. Which of these solutions has a higher concentration of hydrogen ions? What is the difference in the hydrogen ion concentration?
70.
Stomach acid has a pH value of 1.5–2.0. Antacids have a pH value of 10.5. Antacids are a common medication used to reduce the “burning” effect of stomach acid moving back up into the esophagus (the tube that carries food to the stomach). Describe how antacids affect the concentration of free hydrogen ions to provide relief from “heartburn.”
71.
There are four major classes of macromolecules found in living systems, and each uses a carbon skeleton as its structural backbone. Why is carbon regularly assembled to make important biological molecules?
72.
Indicate the basic subunits used to build each of the four major classes of macromolecules.
73.
Label each of the images as the subunit for a carbohydrate, protein, or nucleic acid. List two shared features between these subunits.
74.
A piece of genetic material has been isolated from an asteroid. Researchers are trying to determine if this is composed of RNA or DNA. Describe one criterion that could be used to determine if this is DNA or RNA.
75.
Match the type of bond associated with each description. Terms may be used more than once. a.
covalent
b.
hydrogen
c.
ionic __ 1. A positively charged sodium ion is attracted to a negatively charged chloride ion to form table salt. __ 2. Carbon shares electrons with oxygen atoms in a carbon dioxide molecule. __ 3. a weak electrical attraction that holds individual water molecules together __ 4. an unequal sharing of electrons within an individual water molecule
__ 5. Some structure in a protein molecule is due to weak electrical attractions.
76.
Use the molecule of ethanol shown in the following image to match the numbers with the questions they answer. Numbers may be used more than once. a.
0
b.
1
c.
2
d.
4
e.
8 __ 1. __ 2. __ 3. __ 4. __ 5.
77.
How many covalent bonds are indicated? How many valence electrons are in each carbon atom? How many electrons is the oxygen atom sharing? How many valence electrons are in each hydrogen atom? What is the total number of carbon atoms?
Using the following answer choices, match each characteristic with its macromolecule class. a.
lipids
b.
carbohydrates
c.
nucleic acids
d.
proteins __ 1. __ 2. __ 3. __ 4. __ 5. __ 6. __ 7.
participate in nearly every chemical reaction in living systems store and transmit genetic information speed chemical reactions act as short-term energetic molecules form the major framework of biological membranes exhibit various levels of structure function in energy storage and structural support
__ 8. used to create steroid molecules like cholesterol
Answer Key Chapter 03
1. Answer:
D
2. Answer:
C
3. Answer:
A
4. Answer:
B
5. Answer:
B
6. Answer:
A
7. Answer:
D
8. Answer:
B
9. Answer:
A
10. Answer:
D
11. Answer:
B
12. Answer:
A
13. Answer:
C
14. Answer:
D
15. Answer:
C
16. Answer:
A
17. Answer:
C
18. Answer:
D
19. Answer:
B
20. Answer:
D
21. Answer:
A
22. Answer:
B
23. Answer:
D
24. Answer:
C
25. Answer:
A
26. Answer:
D
27. Answer:
D
28. Answer:
C
29. Answer:
D
30. Answer:
C
31. Answer:
D
32. Answer:
D
33. Answer:
A
34. Answer:
A
35. Answer:
D
36. Answer:
A
37. Answer:
D
38. Answer:
C
39. Answer:
B
40. Answer:
A
41. Answer:
A
42. Answer:
D
43. Answer:
C
44. Answer:
B
45. Answer:
C
46. Answer:
C
47. Answer:
B
48. Answer:
C
49. Answer:
C
50. Answer:
A
51. Answer:
A
52. Answer:
D
53. Answer:
A
54. Answer:
C
55. Answer:
B
56. Answer:
D
57. Answer:
D
58. Answer:
B
59. Answer:
B
60. Answer:
B
61. Answer:
C
62. Answer:
B
63. Answer:
The atomic number tells us the number of protons, whereas the atomic mass is the sum of protons and neutrons. Therefore, nitrogen has seven protons, seven neutrons, and seven electrons. In the diagram, students should demonstrate that there are seven protons and seven neutrons in the atomic nucleus. The seven electrons should be drawn in the shells.
64. Answer:
When lithium loses electrons it becomes positively charged and participates in ionic bonding. Since lithium is positively charged, it will interact with negatively charged atoms.
65. Answer:
Your classmate is correct in their assessment of the bonds in the water. Within a water molecule, the hydrogen and oxygen atoms are held together by covalent bonds. Hydrogen bonds attract neighboring water molecules due to partial positive and partial negative charges on the hydrogen and oxygen atoms, respectively.
66. Answer:
Individual water molecules are held together by polar, covalent bonds. These bonds involve an unequal sharing of electrons that cause water molecules to have slightly positive and slightly negative ends. Hydrogen bonds are the relatively weak attractions that occur between the slightly negative end of one water molecule and the slightly positive end of another water molecule. The combination of the polarity of water molecules and the hydrogen bonds between them lead to the following properties of water mentioned in the textbook: water acts as the “universal solvent” capable of dissolving many substances, ice is less dense than liquid water, and water is a liquid at room temperature.
67. Answer:
Because the oil is hydrophobic and the water is hydrophilic, the two substances do not mix well. Coating the baby’s skin with baby oil surrounds the skin with a thin barrier that helps to prevent the loss of moisture since the two substances do not interact with each other. The two fail to mix because they do not share the same charged nature. Although water is electrically neutral, the oxygen and hydrogen ends of the molecule possess partial charges. The baby oil, on the other hand, is held together by nonpolar covalent bonds, so it has no partial charges.
68. Answer:
Oil is a nonpolar, hydrophobic substance that does not dissolve easily in water. Vinegar is a hydrophilic substance that is soluble in water. Hydrophobic and hydrophilic substances do not mix well and will separate as a result. Oil is also a less dense substance than vinegar and will rise to the top of an oil and vinegar solution.
69. Answer:
The rainwater has a 10-fold increase in the concentration of hydrogen ions when compared to pure water.
70. Answer:
Antacids are a base and bases remove free hydrogen ions from a solution. In the case of heartburn, highly acidic stomach acid is causing damage and pain. By adding antacids to the solution, the pH is raised as free hydrogen ions are accepted by the antacids (the solution becomes more basic) and the burning sensation is relieved.
71. Answer:
All of the major biological molecules (macromolecules) of living systems are organic molecules. As such, these molecules are formed using a carbon skeleton. This element is a central player because of its small size and need for four covalent bonds. Carbon readily participates in covalent bonding with other carbon atoms, forming single, double, and triple bonds. Carbon-carbon bonds may also branch or form rings. The carbon-carbon bond is also quite stable, which ensures the integrity of biological molecules in living systems.
72. Answer:
Carbohydrates are composed of monomers called monosaccharides. When amino acids are joined by peptide bonds, they form proteins. Nucleic acids such as DNA and RNA are built from nucleotide monomers. Lipids are not constructed in the same manner as the other three classes of macromolecules. This diverse class of macromolecules does not share a common monomer.
73. Answer:
The top image is a nucleotide, and the bottom image is an amino acid. The shared features between the two is the presence of covalent bonds and of carbon.
74. Answer:
The genetic material could be tested to see whether it was single stranded, which would indicate RNA, or double stranded, which would indicate DNA. The researchers could also look at the chemical structure of the nucleotides to see whether the sugar is ribose (RNA) or deoxyribose (DNA).
75. Answer:
76. Answer:
77. Answer:
1.
C
2.
A
3.
B
4.
A
5.
B
1.
E
2.
D
3.
C
4.
B
5.
C
1.
D
2.
C
3.
D
4.
B
5.
A
6.
D
7.
B
8.
A
Name: ___________________________ Class: _________________ Date: __________
Chapter 04 1.
2.
3.
Which of the following is a part of accepted cell theory? a.
Every living organism is composed of one or more cells, and all living cells have membrane-enclosed organelles.
b.
All living cells arise from preexisting cells, and all living cells have membrane-enclosed organelles.
c.
All living cells have membrane-enclosed organelles.
d.
Every living organism is composed of one or more cells, and all living cells arise from preexisting cells.
Select the smallest and most basic unit of life. a.
cell
b.
genome
c.
DNA
d.
nucleotide
Living organisms maintain a constant internal environment by sensing and responding to their internal conditions. This stable maintenance of internal conditions is known as a.
homeostasis.
b.
evolution.
c.
reproduction.
d.
sensation.
4.
5.
6.
7.
DNA is one of the features common to all known forms of life; it is used to a.
protect the outer membrane of cells.
b.
transfer information from parents to their offspring.
c.
obtain energy from the environment.
d.
sense changes within the environment.
The roots of a sunflower plant growing downward while the shoot grows upward and the flower turns toward the sun are examples of what characteristic of all living organisms? a.
They reproduce using DNA.
b.
They evolve through time.
c.
They make their own energy.
d.
They sense the environment and respond to it.
A species of butterflies gradually becomes darker in color over many generations; this is an example of which characteristic of living organisms? a.
They reproduce using DNA.
b.
They obtain energy from the environment to support metabolism.
c.
They can evolve as groups.
d.
They sense the environment and respond to it.
Which of these characteristics of living organisms are present in viruses? a.
composed of one or more cells
b.
can evolve as groups
c.
maintain energy from their environment
d.
obtain energy from their environment
8.
9.
10.
Adenine (A), thymine (T), guanine (G), and cytosine (C) are the __________ building blocks for DNA; they are organized in different combinations to code for all of the proteins needed to accomplish everything the cell does. a.
carbohydrate
b.
nucleotide
c.
protein
d.
lipid
Which of the following accurately describes viruses? a.
They are small, cellular infectious agents that are only capable of reproducing when inside a living cell, and they can attack plants as well as animals.
b.
Each is typically a piece of genetic material encased in proteins, and they can reproduce on their own.
c.
They can attack plants and animals, and each is typically a piece of self-replicating genetic material encased in a protein envelope.
d.
Typically a piece of genetic material encased in proteins; they are small, noncellular infectious agents that are only capable of reproducing when inside a living cell such as those of plants, animals, or bacteria.
Some antibiotics used to treat bacterial infections kill the bacteria by chemically punching holes in the cell wall of the bacteria, by preventing the bacteria from replicating their DNA, or by many other actions that ultimately cause cell death. Why do these antibiotics not work to kill viruses and cure people of viral infections? a.
Antibiotics cannot kill a virus because viruses are not living cells with cell walls to puncture, nor do they have the structures necessary for autonomous reproduction.
b.
Viruses are too virulent to be killed by those antibiotics.
11.
12.
13.
c.
Viruses are too quick for the antibiotics to work.
d.
Viruses mutate at a rate faster than the rate at which antibiotics can kill them.
Living cells have an intact phospholipid bilayer that separates the cell from its external environment; this structure is commonly referred to as the a.
nuclear envelope.
b.
protein coat.
c.
cell wall.
d.
plasma membrane.
Liposomes form spontaneously from __________ and are important because __________. a.
DNA; they provide a rigid structure to support the cell
b.
phospholipid monolayers; these phospholipid monolayers provide a stable barrier between the internal and external environments
c.
rigid cell walls; they provide support for the living cell and a barrier between the external and internal environments
d.
phospholipids and water; they provide a barrier between an external environment and an internal environment
An experiment mixed oil (lipids), organophosphate-containing detergent in water, and copper ions to act as a catalyst for a chemical reaction. Membranes budded off from the oil in this mixture. Which of the following is a reasonable and possible explanation of the experimental results? a.
The chemical reaction caused the organophosphates from the detergent to chemically combine with lipids from the oil to form phospholipids. The hydrophilic tails lined up toward each other with their hydrophobic heads pointing out toward the water; this configuration formed a phospholipid bilayer that pulled into a liposome.
14.
15.
b.
The chemical reaction caused the organophosphates from the detergent to chemically combine with lipids from the oil to form phospholipids with hydrophilic heads and hydrophobic tails. The hydrophobic tails lined up toward each other with their hydrophilic heads pointing out toward the water; this configuration formed a phospholipid bilayer that pulled into a spherical liposome.
c.
The copper ions permanently combined chemically with the lipids to form phospholipids. The hydrophilic tails lined up toward each other with their hydrophobic heads pointing out toward the water; this configuration formed a phospholipid bilayer that pulled into a liposome.
d.
The copper ions permanently combined chemically with the lipids and phosphates to form phospholipids. The hydrophilic tails lined up toward each other with their hydrophobic heads pointing out toward the water; this configuration formed a phospholipid bilayer that pulled into a liposome.
Phospholipids are large organic molecules with a hydrophilic, polar phosphate head connected to hydrophobic, nonpolar fatty acid tails. These molecules arrange themselves to form a mostly impermeable barrier between the fluid inside a liposome and its external environment by lining up a.
hydrophilic head to hydrophilic head, with the tails all facing outward from the center line of the membrane.
b.
hydrophobic tails facing each other at the center line of the membrane, with the hydrophilic heads facing outward, away from the center line of the membrane.
c.
hydrophobic tails facing hydrophilic heads.
d.
hydrophilic tails facing hydrophobic heads, with every other tail facing outward from the center line of the membrane.
Which of the following statements best describes the differences between the nuclear envelope and the plasma membrane? a.
The nuclear envelope consists of two concentric phospholipid bilayers, while the plasma membrane is only one phospholipid bilayer. Both membranes are selectively permeable.
16.
17.
18.
b.
The nuclear envelope consists of two concentric phospholipid bilayers, while the plasma membrane is only one phospholipid bilayer. Neither membrane is selectively permeable.
c.
Both membranes consist of two concentric phospholipid bilayers, are selectively permeable, and have pores.
d.
Both membranes consist of two concentric phospholipid bilayers, and neither is selectively permeable or has pores.
The permeability of a phospholipid bilayer membrane for a particular substance can be increased with help from transport a.
carbohydrates.
b.
phospholipids.
c.
receptors.
d.
proteins.
During the process of __________, water diffuses across a semipermeable membrane from an area where water is more concentrated to an area where water is less concentrated (it moves along the water concentration gradient). a.
osmosis
b.
active transport
c.
endocytosis
d.
pinocytosis
Cells naturally, without using energy, respond to changes in water concentration through the process of a.
endocytosis.
b.
osmosis.
19.
20.
21.
c.
phagocytosis.
d.
active transport.
The plasma membrane of some white blood cells contain __________ proteins that bind with proteins of cells such as bacteria that have invaded the human body. a.
channel
b.
receptor
c.
diffusion
d.
carrier
If the concentration of sugar molecules in water on side A of a selectively permeable membrane is 5 percent, and the concentration of sugar molecules in water on side B of a selectively permeable membrane is 15 percent, the water molecules will a.
mostly move from side B to side A because the water concentration is higher on side “B.”
b.
mostly move from side A to side B because the water concentration is higher on side “A.”
c.
mostly move from side A to side B because the water concentration is higher on side “B.”
d.
not move at all because the water concentrations are isotonic.
A screen door allows breezes to enter and aromas to exit but keeps out insects. Its function most resembles a.
the cytosol.
b.
the plasma membrane.
c.
the ER lumen.
d.
22.
23.
a ribosome.
Cheryl is in a lab attempting to prepare a slide of cow blood for observation in a wet mount. She places a small drop of the blood on a slide, adds a drop of 3 percent salt solution, and then covers all of it with a coverslip. After returning to her desk, she observes the slide with her microscope and notices that all of the red blood cells (RBCs) do not look like the nice round donut-shaped cells in her lab manual. Instead, the RBCs look very shriveled up. Her lab partner, Derek, has also made a slide, but the RBCs on his slide do look like the ones in the lab manual. Derek used a 0.9 percent salt (physiological saline) solution but the same vial of blood. The most plausible explanation for the appearance of the blood cells on Cheryl’s slide is that the a.
saline she used was hypotonic to the RBCs; this resulted in net water movement into the RBCs by osmosis.
b.
saline she used was isotonic to the RBCs; this resulted in no net movement of water into or out of the RBCs.
c.
saline she used was hypertonic to the RBCs; this resulted in net water movement out of the RBCs by osmosis.
d.
RBCs were hypertonic to the saline; this resulted in net water movement into the RBCs by osmosis.
Dialysis tubing is a selectively permeable membrane that can be filled with a solution to simulate a cell. A piece of dialysis tubing has been filled with a cloudy white solution of 5 percent starch, 5 percent egg albumin (protein), and 5 percent glucose (a small sugar) dissolved in water to simulate a cell. This simulated cell is weighed and then placed in a beaker of pure water. After soaking in the beaker solution for one hour, the simulated cell is once again weighed. Over time, the weight of the simulated cell can be expected to a.
increase because the cell is hypotonic to the beaker solution and water will enter the simulated cell through osmosis.
b.
decrease because the cell is hypertonic to the beaker solution and water will leave the simulated cell through osmosis.
24.
25.
c.
increase because the solution in the beaker is hypotonic to the simulated cell and water will enter the simulated cell through osmosis.
d.
decrease because the solution in the beaker is hypertonic to the simulated cell and water will leave the simulated cell through osmosis.
The following figure shows a beaker divided into two compartments by a semipermeable membrane that allows the passage of water molecules, but prevents the passage of sugar molecules. Assume that each sugar molecule represents a percentage point of sugar dissolved in the solution. Over time, the solution volume on the left side of the figure would __________. This is because the solution on the left side of the figure is __________ relative to the solution on the right.
a.
increase; hypertonic
b.
decrease; hypertonic
c.
decrease; hypotonic
d.
increase; hypotonic
Which of the following statements most accurately describes a selectively permeable membrane? a.
Solutes always move across a selectively permeable membrane from a region of higher concentration to a region of lower concentration.
b.
Charged molecules are always excluded from crossing the membrane.
26.
27.
28.
c.
All substances require specific transport proteins to pass through the membrane.
d.
Certain solutes move freely across the membrane by simple diffusion, while others require transport proteins; some substances are completely excluded from crossing the membrane.
If a bottle of perfume were spilled in the corner of a large lecture hall, the students sitting near that corner of the room would very quickly smell the perfume. Over time, the students sitting in the far corner of the room would smell the perfume. What phenomenon will have occurred to the perfume molecules that have entered the air? a.
osmosis
b.
facilitated diffusion
c.
active transport
d.
simple diffusion
A scientist is observing a membrane through which water and some small hydrophobic molecules can freely pass along a concentration gradient from high to low. However, some sugar molecules are too large to pass through the membrane either way without the assistance of passive transport proteins. Additionally, small Na+ ions and some proteins can pass through the membrane against the concentration gradient, but both require the assistance of active transport proteins. What general type of membrane are they observing? a.
impermeable
b.
impenetrable
c.
semipermeable
d.
completely permeable
Which of the following substances can pass through the plasma membrane by simple diffusion and facilitated diffusion?
29.
30.
a.
water (H2O)
b.
sodium ions (Na+) and hydrogen ions (H+)
c.
oxygen (O2) and carbon dioxide (CO2)
d.
sugars and amino acids
Ross places carrot sticks into a jar of water and refrigerates the jar overnight. The next day the carrot sticks are crisp and crunchy. The most likely explanation of why they became crunchy after soaking in water is that the water was __________ to the carrot cells, resulting in the net movement of water __________ the cells. a.
hypertonic; into
b.
hypotonic; out of
c.
hypertonic; out of
d.
hypotonic; into
Why would hydrophilic substances such as sodium ions (Na+), hydrogen ions (H+), sugars, and amino acids be unable to simply diffuse across a plasma membrane? a.
They readily mix with the hydrophobic tails that form the core of the phospholipid bilayer.
b.
They are repelled by the hydrophilic heads of the phospholipids that form the phospholipid bilayer.
c.
They do not readily mix with the hydrophobic tails forming the core of the phospholipid bilayer; therefore, they must move across by facilitated diffusion.
d.
They do not readily mix with the hydrophobic tails forming the core of the phospholipid bilayer; therefore, the only way they can move into the cell is by endocytosis.
31.
32.
33.
An amoeba, a protozoan that moves by pseudopodia, approaches a smaller protozoan and extends its pseudopodia (extensions of cytoplasm in plasma membrane) around the smaller protozoan. Once the amoeba’s pseudopodia completely surround the other protozoan, the amoeba’s plasma membrane pinches off by folding back into the amoeba and creates a vesicle containing the smaller protozoan. This vesicle is now within the amoeba itself and will soon fuse with other vesicles containing digestive enzymes. This is an example of a.
pinocytosis.
b.
exocytosis.
c.
facilitated diffusion.
d.
phagocytosis.
A white blood cell (WBC) encounters bacteria in a scrape on the knee of a child who has fallen off a bicycle. The WBC’s job is to take the bacteria inside itself and destroy it. If the bacteria are too large to be transported via transported proteins, how will the WBC most likely take them in? a.
exocytosis
b.
pinocytosis
c.
facilitated diffusion
d.
phagocytosis
A protein molecule, transferrin, that is embedded in the plasma membrane recognizes iron molecules and causes the plasma membrane to fold in around the iron and take it into the cell. This is an example of a.
exocytosis.
b.
diffusion.
c.
receptor-mediated endocytosis.
d.
pinocytosis.
34.
35.
36.
Which of the following would be likely to move through a plasma membrane by simple diffusion? a.
water (H2O), carbon dioxide (CO2), and oxygen (O2)
b.
polysaccharides, large protein molecules, and low-density lipoprotein particles
c.
bacteria and yeast
d.
sodium ions (Na+), hydrogen ions (H+), sugars, and amino acids
Neurotransmitters are chemicals that are released by nerve endings. These chemicals are often large and unable to pass through the membrane, so the nerve cell packages them in a vesicle that can fuse with the plasma membrane. The inside of the vesicle opens to the outside of the cell, releasing the neurotransmitters. This type of transport of cellular products is called a.
pinocytosis.
b.
receptor-mediated endocytosis.
c.
exocytosis.
d.
phagocytosis.
Cells lining blood vessels can form vesicles outside of the cell that can fold into the cell, taking in fluids from the outside environment. This is an example of a.
pinocytosis.
b.
receptor-mediated endocytosis.
c.
exocytosis.
d.
phagocytosis.
37.
38.
39.
40.
A factory with an office that controls the information sent to separate rooms for each of the manufacturing and shipping processes would be analogous to a a.
virus.
b.
prokaryotic cell with a nucleus.
c.
prokaryotic cell without a nucleus.
d.
eukaryotic cell with a nucleus.
The enzymes needed to perform photosynthesis in plant cells are closely associated with a.
chloroplasts.
b.
smooth ER.
c.
mitochondria.
d.
lysosomes.
Prokaryotes and eukaryotes are primarily distinguished by the absence or presence of a.
ribosomes.
b.
plasma membranes.
c.
organelles.
d.
cell walls.
Mitochondria are required for a.
photosynthesis.
b.
export of proteins.
c.
mitosis.
d.
41.
42.
43.
cellular respiration.
Martin observes a wet mount slide preparation using the compound light microscope in the lab room. He observes layers of cells that have a definite, rigid, rectangular shape; there appears to be a nucleus in all of the cells and there are many oval-shaped green structures that seem to be moving around inside of the cells in an orderly fashion. What general cell type is he most likely observing? a.
prokaryotic and plant
b.
prokaryotic and animal
c.
eukaryotic and plant
d.
eukaryotic and animal
Ribosomes are very small nonmembranous structures that can either exist freely in the cytoplasm or be embedded in the rough endoplasmic reticulum of a cell. They are associated with the synthesis of a.
lipids.
b.
proteins.
c.
nucleic acids.
d.
carbohydrates.
The smooth endoplasmic reticulum a.
manufactures steroid (lipid) hormones.
b.
produces the energy needed to run chemical reactions in the cell.
c.
converts sunlight into chemical energy.
d.
stores water, nutrients, and enzymes.
44.
45.
46.
47.
The Golgi apparatus a.
stores the cell’s genetic material.
b.
sorts proteins and lipids and sends them to their final destination.
c.
captures energy from sunlight and sends it to the mitochondria.
d.
manufactures lipids and hormones.
The boundary that surrounds the contents of the nucleus is called the a.
plasma membrane.
b.
nuclear envelope.
c.
nuclear pore.
d.
cytoskeleton.
Which of the following statements is true of chloroplasts? a.
They produce proteins used by other parts of the cell.
b.
They capture energy from sunlight.
c.
They give an animal cell its shape.
d.
They contain an entire copy of a cell’s genetic material.
Human muscle cells need large amounts of ATP to function in the movement of the body, which is why __________ are especially abundant in muscle cells. a.
mitochondria
b.
ribosomes
c.
vacuoles
d.
lysosomes
48.
49.
50.
In plants, the epidermis layer functions like a covering of skin to protect the leaf, while vascular bundles carry water and nutrients through the leaf. The palisade mesophyll layer is responsible for most of the photosynthesis that occurs, while the spongy mesophyll layer underneath it aids in the exchange of gases (CO2 and O2) and water vapor. In which leaf tissues would one expect to find the highest density of chloroplasts? a.
epidermis
b.
vascular bundles
c.
spongy mesophyll
d.
palisade mesophyll
Which of the following would be the best analogy for the function of the Golgi apparatus? a.
the machine that assembles a product
b.
a worker in a factory who places labels on products and then packs them into a shipping box
c.
the garbage truck that hauls away the wastes produced as a product is made
d.
the blueprints for making the product
Select the observation that supports endosymbiotic theory. a.
Nuclear envelopes have small openings called nuclear pores.
b.
Plant cells and many prokaryotes have cell walls surrounding the plasma membrane.
c.
Eukaryotic organisms can be either unicellular or multicellular.
d.
Mitochondria and chloroplasts contain DNA just like prokaryotic cells.
51.
52.
53.
A solid waste (garbage) transfer facility that sorts and breaks down garbage into recyclables and waste to be thrown away in the landfill would be a suitable analogy for which cellular organelle? a.
smooth ER
b.
rough ER
c.
lysosome
d.
nucleus
The flexible poles providing structure to a soft-sided tent most closely resemble the a.
endoplasmic reticulum in a bacterial cell.
b.
Golgi apparatus in a plant cell.
c.
cytoskeleton in an animal cell.
d.
nucleus in a eukaryotic cell.
The endoplasmic reticulum (ER) is a single membrane continuous with the nuclear envelope and a series of interconnected sacs throughout the cell. Why might it be beneficial to the cell for the ER to be continuous with the nuclear envelope? It might be beneficial for the ER and nuclear envelope to be connected because it a.
takes less energy, DNA, carbohydrates, and phospholipids for the ER to synthesize centrioles.
b.
is easier for messages to get from the nucleus to the ER where proteins and lipids are made for the cell; this would require the use of less energy.
c.
would make it easier for the nucleus to actually carry out cellular respiration.
d.
would make it easier for the ER to carry out photosynthesis.
54.
Using what you know about cell theory and viruses, explain why viruses are not alive.
55.
When scientists such as J. C. Venter and Daniel Gibson engineer a cell constructed with synthetic DNA in the laboratory, do they challenge accepted cell theory? If so, which part of cell theory do they challenge? Briefly explain your answer.
56.
Examine the following infographic. Are all bacteria (prokaryotes) likely to be 3 µm in length and all protozoans (eukaryotes) likely to be 500 µm in size? Support your answer using information from the infographic.
57.
How are prokaryotic and eukaryotic cells similar? How are these two cell types different?
58.
Label the plasma membrane in the following image. Use the following terms: cellular environment, external environment, plasma membrane, hydrophilic heads, hydrophobic tails, energy, CO2, amino acid, and transport proteins.
59.
The following figure depicts a transport protein in a plasma membrane. The dark blue molecules represent sodium ions being transported out of the cell. Is the transport of the sodium ions active or passive? Support your answer by describing evidence that is visible in the figure and stating its significance regarding your answer.
60.
The following figure depicts transport proteins in a plasma membrane. Molecules are moving through the plasma membrane. How are the molecules moving across the membrane? Is this transport active or passive? Support your answer by describing evidence that is visible in the figure and stating its significance regarding your answer.
61.
Examine the following photo. This photo shows low-density lipoprotein (LDL) particles bound to receptors on the outside of a plasma membrane. Suppose you view the same cell later and notice that the LDL particles are now enclosed in vesicles inside of the cell. What would you propose as the explanation for how the LDL particles arrived in their new location? Support your explanation.
62.
Explain the process through which cells lining blood vessels bring in pockets of fluids from the bloodstream. Is this process specific or nonspecific?
63.
If a white blood cell is approximately 18 µm in diameter, which of the cell types or viruses seen in the following infographic would it be large enough to engulf? Describe the process the white blood cell would use to engulf another cell.
64.
What additional structures would the cell shown here need to become a plant cell?
65.
There are cells in the human pancreas that produce insulin, a protein hormone that is important in the regulation of blood sugar levels. Once the pancreas cells have produced the initial peptide (small string of amino acids) component of insulin, it must be finished, packaged, and shipped out of the cell. Which organelles would likely be involved in this process of finishing, packaging, and shipping of a protein hormone? Include a brief, general description of what happens to the hormone at each organelle and the plasma membrane.
66.
Indicate which cell in the figure below is the plant cell and which is the animal cell. Label all cellular structures 1–12. Include a brief description of each structure’s function with its label.
67.
Match the following cellular structures with their primary function. a.
photosynthesis
b.
regulates what moves in and out of a cell
c.
structure and support for a cell
d.
site for lipid and hormone manufacture
e.
site for protein production
f.
enzymatic breakdown of large molecules
g.
assemble proteins
h.
cellular respiration
i.
water and solute storage
j.
location of DNA
k.
internal organization and structural support
l.
directs protein and lipid products to their final destinations __ 1. __ 2. __ 3. __ 4. __ 5. __ 6. __ 7. __ 8. __ 9. __ 10. __ 11. __ 12.
central vacuole nucleus cytoskeleton mitochondrion ribosomes rough endoplasmic reticulum smooth endoplasmic reticulum Golgi apparatus lysosome plasma membrane cell wall chloroplast
Answer Key Chapter 04
1. Answer:
D
2. Answer:
A
3. Answer:
A
4. Answer:
B
5. Answer:
D
6. Answer:
C
7. Answer:
B
8. Answer:
B
9. Answer:
D
10. Answer:
A
11. Answer:
D
12. Answer:
D
13. Answer:
B
14. Answer:
B
15. Answer:
A
16. Answer:
D
17. Answer:
A
18. Answer:
B
19. Answer:
B
20. Answer:
B
21. Answer:
B
22. Answer:
C
23. Answer:
C
24. Answer:
A
25. Answer:
D
26. Answer:
D
27. Answer:
C
28. Answer:
A
29. Answer:
D
30. Answer:
C
31. Answer:
D
32. Answer:
D
33. Answer:
C
34. Answer:
A
35. Answer:
C
36. Answer:
A
37. Answer:
D
38. Answer:
A
39. Answer:
C
40. Answer:
D
41. Answer:
C
42. Answer:
B
43. Answer:
A
44. Answer:
B
45. Answer:
B
46. Answer:
B
47. Answer:
A
48. Answer:
D
49. Answer:
B
50. Answer:
D
51. Answer:
C
52. Answer:
C
53. Answer:
B
54. Answer:
Cell theory states that all living things are made of cells, and cells arise from preexisting cells. Viruses do not have the cellular organelles and structures needed to maintain life, metabolize nutrients, or reproduce on their own. Viruses are not cells, so they cannot be alive.
55. Answer:
The engineering of such a cell is a challenge to the “all cells arise from preexisting cells” portion of cell theory because a new cell has been generated without dividing a preexisting cell into two new cells. OR: The process does not challenge cell theory because the DNA is actually a copy of a preexisting cell’s DNA, and therefore it actually does arise from a preexisting cell.
56. Answer:
There are likely to be sizes of prokaryotic bacteria and eukaryotic protozoans other than those shown for the bacterium, E. coli, and the protozoan, Amoeba proteus. Human cells are eukaryotic and come in many different sizes. Even viruses (which are not actually alive) come in different sizes. This would lead one to think that bacteria and protozoa would also be different sizes.
57. Answer:
All cells contain DNA as a genetic material, ribosomes to synthesize proteins, and a plasma membrane to separate the internal cytoplasm from the external environment. Only eukaryotic cells possess membrane-enclosed organelles and a membrane-enclosed nucleus. Eukaryotic cells are much larger and more complex than prokaryotic cells.
58. Answer:
(1) external environment (2) cellular environment (3) energy (4) transport proteins (5) plasma membrane (6) hydrophilic heads (7) hydrophobic tails (8) CO2 (9) amino acid
59. Answer:
The sodium ion transport depicted is active transport. The illustration indicates that the concentration of sodium ions is higher on the outside of the cell than it is within the cell. Whenever a substance is moved into or out of a cell against the concentration gradient, it typically requires the input of cellular energy to accomplish active transport.
60. Answer:
The molecules are moving across the membrane by facilitated diffusion. The molecules are moving through membrane proteins and with the concentration gradient from high to low, and there is no evidence that energy is being used; this is a passive transport system.
61. Answer:
The most likely way the LDL particles entered the cell was through receptor-mediated endocytosis. The receptors on the plasma membrane that bound the LDL particles were probably specific for the LDL particles. The membrane began to fold into a pocket inside of the cell and eventually pinched off, forming a vesicle there.
62. Answer:
Cells lining blood vessels would form pockets of fluids from the bloodstream through the nonspecific process of pinocytosis. Pinocytosis happens when the plasma membrane folds into the cell, forming a vesicle that is filled with whatever fluids and solutes happen to be around the cell at the time.
63. Answer:
The white blood cell (WBC) is larger than rhinovirus, influenza virus, measles virus, E. coli bacterium, and red blood cell. Therefore, it would be large enough to engulf them. The WBC would phagocytize the cell or virus by lining up beside it and folding its own plasma membrane around the other cell or virus. This fold would extend inward into the cell and pinch off as a vesicle.
64. Answer:
This prokaryotic cell would need a double membrane–enclosed nucleus that contains the DNA. This cell would also need a variety of membrane-enclosed organelles such as the mitochondria, endoplasmic reticulum, Golgi apparatus, a large central vacuole, and some chloroplasts. Plant cells and many prokaryotes, including the bacterium shown here, have a cell wall that surrounds the plasma membrane.
65. Answer:
The insulin would be finished by the rough ER, budded into a transport vesicle, and transported to the Golgi apparatus, where it might undergo further modification as it moves through it. At some point, a transport vesicle containing the insulin will bud off the Golgi apparatus, which will have chemically tagged it to be destined to hook up with the plasma membrane. Once it arrives at the plasma membrane, the membrane of the vesicle fuses with the plasma membrane opening to the outside of the cell and releases the hormone through exocytosis.
66. Answer:
The cell on the left is the plant cell. The cell on the right is the animal cell. (1) nucleus (location of DNA) (2) rough endoplasmic reticulum (site for protein synthesis) (3) smooth endoplasmic reticulum (lipid hormone synthesis) (4) Golgi apparatus (transports protein and lipid products to final destination) (5) lysosome (enzymatic breakdown of large molecules) (6) small vacuole (transporting proteins and lipids, shown in animal cell only) (7) mitochondrion (cellular respiration) (8) cytoskeleton (organization and structural support) (9) plasma membrane (regulates what moves in and out of cell) (10) cell wall (structure and support for plant cell) (11) chloroplast (photosynthesis) (12) large central vacuole (water and solute storage)
67. Answer:
1.
I
2.
J
3.
K
4.
H
5.
G
6.
E
7.
D
8.
L
9.
F
10.
B
11.
C
12.
A
Name: ___________________________ Class: _________________ Date: __________
Chapter 05
1.
2.
The following illustration indicates that photosynthesis and cellular respiration are both complementary and balanced. An excess of sugars produced fossil fuels like coal and petroleum; this suggests that in the past,
a.
the amount of photosynthesis exceeded the amount of cellular respiration.
b.
sugars were only one of several products of photosynthesis.
c.
reduced carbon-rich molecules could be produced independently from the photosynthetic process.
d.
the energy released from respiration must have exceeded the energy used in photosynthesis.
Chemical reactions that break down lipids are a.
catabolic.
3.
4.
b.
anabolic.
c.
metabolic.
d.
respiration.
The chemical 3-(3,4-dichloro-phenyl)-1,1-dimethylurea (DCMU) blocks the movement of electrons at the point indicated by the black, downwardpointing arrow in the following figure. Which of the following would be an immediate effect of treating a chloroplast with this drug?
a.
Water molecules would be split at a faster rate.
b.
The amount of NADPH produced by the light reactions would increase.
c.
A proton gradient would not be created, so ATP could not be made.
d.
The production of water would increase.
The Krebs cycle functions to
5.
6.
7.
a.
accept electrons and hydrogen ions from energy carriers.
b.
transform carbon from carbon dioxide into sugar.
c.
use energy from sunlight to split water molecules.
d.
transfer chemical energy from pyruvate to energy carriers.
The reaction sugar + oxygen > carbon dioxide + water + ATP is part of a.
photosynthesis.
b.
cellular respiration.
c.
the Krebs cycle.
d.
the Calvin cycle.
Cells contain the molecule GTP (guanosine triphosphate). Would this molecule be useful as an energy carrier (similar to ATP)? a.
no, because it does not contain the adenosine necessary for storing energy
b.
no, because it contains fewer phosphate groups than ATP
c.
yes, because it contains a nitrogenous base just like ATP
d.
yes, because it contains the same number of phosphate groups as does ATP
In the reaction C6H12O6 + 6 O2 > 6 CO2 + 6 H2O, the six CO2 molecules are examples of a.
substrates.
b.
products.
8.
9.
10.
c.
enzymes.
d.
reactants.
Which of these molecules carries the most energy? a.
ADP
b.
ATP
c.
free phosphate
d.
NAD+
After an enzyme catalyzes a reaction there is a(n) __________ in the concentration of __________. a.
increase; reactants
b.
increase; the enzyme
c.
decrease; the enzyme
d.
increase; products
Glycolysis is an anaerobic process, indicating that the glycolytic reactions a.
require no oxygen.
b.
produce molecular oxygen.
c.
produce ATP.
d.
produce citric acid.
11.
12.
13.
14.
Photosynthetic organisms capture energy from sunlight and convert it into chemical bonds by forming a.
sugars.
b.
enzymes.
c.
work.
d.
substrates.
The capture and use of energy by living organisms involves numerous chemical reactions. Collectively these processes are known as a.
metabolism.
b.
respiration.
c.
anabolic reactions.
d.
catabolic reactions.
The first law of thermodynamics states that a.
metabolic reactions must be balanced.
b.
the flow of energy connects living things to their environments.
c.
energy cannot be created or destroyed.
d.
systems tend to become more disorderly.
The role of water in photosynthesis is to a.
provide a phosphate group to ATP.
b.
capture light energy and transfer it to the electron transport chain.
15.
16.
17.
c.
provide electrons to the chlorophyll.
d.
combine with carbon dioxide (CO2) to make glucose.
Which of the following is a similarity between photosynthesis and respiration? a.
Neither is a metabolic process.
b.
They are both metabolic processes.
c.
Neither is an anabolic process.
d.
They are both mainly anabolic processes.
The Krebs cycle produces a.
NADH, ATP, and FADH2.
b.
water and carbon dioxide.
c.
ADP and NADP+.
d.
acetyl CoA and sugars.
The enzyme rubisco is important to the process of a.
catabolism.
b.
fermentation.
c.
glycolysis.
d.
carbon fixation.
18.
19.
20.
21.
Which of the following is either consumed or synthesized in virtually every cellular reaction? a.
sugars
b.
enzymes
c.
DNA
d.
ATP
The energy required for life processes must be extracted from an organism’s a.
nucleus.
b.
environment.
c.
predators.
d.
biosynthesis.
In a human cell, a.
one enzyme usually catalyzes more than five different chemical reactions.
b.
nearly all chemical reactions are catalyzed by enzymes.
c.
enzymes must be constantly replaced as they are used up in the reactions that they catalyze.
d.
enzymes are only found in the nucleus.
Which of the following molecules carries electrons to the electron transport chain of oxidative phosphorylation? a.
ATP
22.
23.
24.
b.
NADH
c.
CO2
d.
ADP
Some kinds of drain cleaners use enzymes rather than strong, more dangerous chemicals. These enzymes must be able to a.
catalyze a catabolic reaction.
b.
raise the energy of the reaction that clears the clog.
c.
create energy that can be used to break up the clog.
d.
catalyze an anabolic reaction.
Which of the following statements comparing photosynthesis and cellular respiration is accurate? a.
Photosynthesis is a catabolic pathway, whereas cellular respiration is an anabolic pathway.
b.
Water is formed during photosynthesis but broken apart during cellular respiration.
c.
Both photosynthesis and cellular respiration require electron transport chains.
d.
Both photosynthesis and cellular respiration produce CO2 as metabolic end products.
Examine the following illustration. Which statement best summarizes the contribution of photosystem I (PS I) during photosynthesis?
25.
a.
PS I provides the initial energy boost to the electrons on their way to photosystem II (PS II).
b.
PS I energizes electrons that initially accumulate within the thylakoid space and eventually drive ATP synthesis.
c.
PS I energizes electrons that are transported by NADPH to the Calvin cycle and will eventually reduce the carbon in CO2.
d.
PS I regulates the transmembrane passage of protons through the thylakoid membrane.
In many organelles, groups of different enzymes are located on membranes in close proximity to each other because a.
attaching enzymes to the membrane prevents the cell from losing them to the surrounding environment.
b.
when enzymes are in close proximity, each one can catalyze more than one type of reaction.
c.
these enzymes are involved in the same metabolic pathway, and keeping them closer together increases the efficiency of the pathway.
d.
all enzymes must act in groups to position substrates in the proper orientation to produce the product.
26.
27.
Which of the following is a product of the light-dependent reactions of photosynthesis? a.
water
b.
carbon dioxide
c.
oxygen
d.
glucose
The following image diagrams the action of an enzyme. Notice that the enzyme is depicted as being more tightly wrapped around the substrates in step 2 than it is in step 1. Why is this?
a.
When a substrate locks into the active site of an enzyme, the enzyme changes shape to mold itself around it.
b.
Generally, the size of a substrate is larger than the size of the active site into which it must fit. When the substrate enters the active site, the active site must stretch to fit.
c.
Before catalysis can occur, a substrate must change its shape so that it fits into the active site of the enzyme more precisely.
d.
Most active sites are only designed to hold one substrate. In this image, two substrates enter the active site, creating a tighter fit.
28.
29.
30.
31.
Photosynthesis and cellular respiration are both complementary and balanced, but the early history of life on Earth showed increasing oxygen concentrations. This indicates that a.
both photosynthesis and respiration were occurring at approximately the same levels.
b.
neither photosynthesis nor respiration were occurring.
c.
the amount of photosynthesis exceeded the amount of cellular respiration.
d.
the amount of cellular respiration exceeded the amount of photosynthesis.
A plant cell is mutated so that ATP synthase no longer functions. Which process will be affected? a.
photosynthesis only
b.
respiration only
c.
both photosynthesis and respiration
d.
neither photosynthesis nor respiration
What is the importance of photosynthesis to organisms other than plants? a.
All other organisms require carbon dioxide for life processes.
b.
The sugars made during photosynthesis are the direct building blocks of DNA.
c.
All cells must contain chloroplasts in order to survive.
d.
Photosynthesis captures energy that other organisms access when they ingest or absorb nutrients from photosynthetic organisms.
Enzymes can catalyze a reaction only if they
32.
33.
34.
a.
encounter a molecule of ATP.
b.
have a phosphate bound to their active site.
c.
have both products in their active site at the same time.
d.
encounter a substrate that fits their active site.
When ATP breaks down into ADP and a phosphate group, a.
energy is absorbed by ADP and transferred to enzymes.
b.
energy is released and can power cellular activities.
c.
ADP becomes the active site in an enzyme.
d.
the energy in the broken bond is transferred to the phosphate group.
The three stages of cellular respiration (in order) are a.
photosynthesis, glycolysis, and oxidative phosphorylation.
b.
glycolysis, the Krebs cycle, and oxidative phosphorylation.
c.
glycolysis, fermentation, and the Krebs cycle.
d.
photosynthesis, the Krebs cycle, and fermentation.
The energy carriers NADPH and NADH differ structurally. Functionally they are a.
quite similar; each is produced in catabolic pathways and used in anabolic pathways.
b.
quite similar; each is produced in anabolic pathways and used in catabolic pathways.
c.
somewhat different; NADPH is produced from catabolic processes, whereas NADH is used in anabolic processes.
d.
35.
36.
37.
somewhat different; NADH is produced from catabolic processes, whereas NADPH is used in anabolic processes.
In the reaction H2O + CO2 + carbonic anhydrase > H+ + HCO3-+ carbonic anhydrase, carbonic anhydrase is a(n) a.
reactant.
b.
product.
c.
enzyme.
d.
active site.
Which of the following statements describes the function of the lightdependent reactions in photosynthesis? a.
As electrons move through the light-dependent reactions, they release energy that is used to concentrate protons inside the thylakoid.
b.
As electrons move through the light-dependent reactions, they directly catalyze the formation of ATP.
c.
The light-dependent reactions release CO2 from glucose.
d.
The light-dependent reactions capture and store the electrons given off by NADPH.
A given enzyme a.
can be used for many different kinds of chemical reactions.
b.
is permanently changed during a chemical reaction.
c.
has a special site where the products bind before the reaction begins.
d.
increases the rate of a particular reaction.
38.
39.
40.
Plants and animals use different energy storage molecules, yet they both use the same mechanism to metabolize their stored energy. How can plants and animals both be successful, even though they use different energy storage molecules? a.
The internal components of plant and animal cells are identical.
b.
The first law of thermodynamics says that all cells have the same energy transfer system.
c.
The breaking of chemical bonds in a storage molecule results in the transfer of energy, regardless of the molecule that is stored.
d.
All organisms have the same enzymes to catalyze their energyproducing reactions.
A chemical reaction that uses ATP to build cellular components is a.
catabolic.
b.
anabolic.
c.
photosynthetic.
d.
respiration.
As an energy carrier, ATP differs from NADPH in that a.
ATP transfers energy through phosphorylation, whereas NADPH donates electrons and hydrogen ions.
b.
ATP transfers energy through redox reactions, whereas NADPH uses phosphorylation.
c.
NADPH is involved in a larger variety of chemical reactions than ATP.
d.
NADPH is made by photosystem I, whereas ATP is made by photosystem II.
41.
42.
43.
44.
In photosynthesis, the carbon used to make sugars is a.
provided by enzymes.
b.
provided by carbon dioxide.
c.
extracted from DNA.
d.
oxidized to make sugars.
A worker is paid every two weeks. She uses some of this money to pay for essentials and puts the remainder of her money in a savings account at a bank. The money the worker saves is analogous to the a.
conversion of ADP and free phosphate into ATP.
b.
conversion of ATP into ADP and free phosphate.
c.
way electrons are used to pump protons across a membrane.
d.
way enzymes catalyze chemical reactions in a cell.
During exercise, the increase in respiration rate and heart rate are driven by the need to replenish the oxygen used to support a.
lactic acid fermentation.
b.
carbon dioxide synthesis in the lungs.
c.
oxidative phosphorylation in muscle cell mitochondria.
d.
the Calvin cycle of photosynthesis.
The events of the Calvin cycle a.
use ATP and NADPH to produce sugars.
45.
46.
47.
b.
move electrons from photosystem II to photosystem I.
c.
move light-energized electrons to photosystem II.
d.
absorb light from the light reactions.
What type of reactions release energy by breaking down molecules? a.
catabolic
b.
anabolic
c.
photosynthetic
d.
dehydration synthesis
If the mitochondria of a cell did not produce an inner membrane, the mitochondria would be unable to a.
maintain the proton gradient required for ATP production.
b.
capture ATP from the sun.
c.
perform catabolic reactions.
d.
perform glycolysis.
Carbon dioxide is one product of a metabolic process, which occurs in both plants and animals. This process is called a.
catalysis.
b.
glycolysis.
c.
respiration.
d.
photosynthesis.
48.
49.
50.
51.
Which step of cellular respiration occurs outside the mitochondria? a.
glycolysis
b.
Krebs cycle
c.
Calvin cycle
d.
electron transport chain
Which of the following events in a cell would require ATP? a.
passive movement of molecules through the cell membrane
b.
linking together amino acids to form a protein
c.
breaking a carbohydrate into individual sugar subunits
d.
splitting a lipid molecule into smaller parts
Each time a person takes a breath, they are bringing in the oxygen needed to stay alive. The ultimate source of the oxygen used by all aerobic organisms comes from a reaction that breaks down a.
carbon dioxide.
b.
ATP.
c.
water.
d.
NADPH.
For each of the following characteristics, determine if it applies to photosynthesis, cellular respiration, or both. a.
photosynthesis only
b.
cellular respiration only
c.
both photosynthesis and cellular respiration
d.
neither photosynthesis nor cellular respiration __ 1. __ 2. __ 3. __ 4. __ 5.
52.
produces carbon dioxide produces sugars used by plant cells used by animal cells produces light energy
Determine whether each statement is an analogy for an anabolic pathway or a catabolic pathway. a.
anabolic
b.
catabolic __ 1. A worker uses individual bricks to build a wall. __ 2. In a popular video game, an ax is used to chop trees into individual blocks of wood. __ 3. In a popular video game, individual blocks of material are used to build objects. __ 4. An individual invests money in the stock market. __ 5. An individual spends money on a new car.
53.
For each of the following characteristics, determine if it applies to the lightdependent reactions or the light-independent reactions of photosynthesis. a.
light-dependent reactions
b.
light-independent reactions __ 1. __ 2. __ 3. __ 4.
produces oxygen gas produces sugars uses energy carriers produces energy carriers
__ 5. uses water __ 6. uses carbon dioxide
54.
The sequential reaction pathway A > B > C > D is dependent on enzymes for each separate step. The enzyme that has C as a substrate becomes nonfunctional. Explain how this affects the metabolic pathway shown.
55.
Excess carbon dioxide in the atmosphere is increasing climate change. How do photosynthesis and cellular respiration relate to this issue, and how can we use this knowledge to help decrease this problem?
56.
Explain how an increase in body temperature may affect the activity of enzymes with human cells.
57.
Support or refute the following statement: Cells would not be able to survive unless anabolic and catabolic processes occurred in linked reactions.
58.
Photosynthesis and cellular respiration are linked metabolic processes in the sense that the products of one feed into the other. What are the products of each metabolic process that feed into the other?
59.
Is the burning of wood most representative of anabolism or catabolism? Explain.
60.
A hypothetical chemical forms a permanent bond between the phosphates in ATP. How would this affect the cell?
61.
Two students are debating whether switching energy production from fossil fuels to traditional biomass would reduce carbon dioxide emissions. Explain the role of photosynthesis in storing carbon dioxide in these two energy sources. What is the total energy consumption shown for these two energy sources?
62.
What products are produced by the light-dependent reactions of photosynthesis? Of these products, which are by-products that are released to the atmosphere? Which products are used by the Calvin cycle?
63.
Defend the following statement by discussing the importance of the products of photosynthesis: The evolution of photosynthesis was an essential event for the evolution of life as we know it.
64.
List the energy carriers in a cell. Which energy carrier is most important to the cell, and why?
65.
Two students are discussing the importance of glycolysis in human cells. One student states that the main function of glycolysis is to produce ATP.
The other states that the main function is to produce NADH. Which student is correct?
66.
A mutation in a plant cell produces rubisco enzymes that can only bind O2 (and not CO2). What would be the outcome of this mutation?
67. In the following image, compare the energy sources that rely on photosynthesis with the energy sources that do not rely directly on it.
68.
List the three stages of cellular respiration. If the mitochondria in a eukaryotic cell are damaged, which of the three stages of cellular respiration would be impacted?
Answer Key Chapter 05
1. Answer:
A
2. Answer:
A
3. Answer:
C
4. Answer:
D
5. Answer:
B
6. Answer:
D
7. Answer:
B
8. Answer:
B
9. Answer:
D
10. Answer:
A
11. Answer:
A
12. Answer:
A
13. Answer:
C
14. Answer:
C
15. Answer:
B
16. Answer:
A
17. Answer:
D
18. Answer:
D
19. Answer:
B
20. Answer:
B
21. Answer:
B
22. Answer:
A
23. Answer:
C
24. Answer:
C
25. Answer:
C
26. Answer:
C
27. Answer:
A
28. Answer:
C
29. Answer:
C
30. Answer:
D
31. Answer:
D
32. Answer:
B
33. Answer:
B
34. Answer:
D
35. Answer:
C
36. Answer:
A
37. Answer:
D
38. Answer:
C
39. Answer:
B
40. Answer:
A
41. Answer:
B
42. Answer:
A
43. Answer:
C
44. Answer:
A
45. Answer:
A
46. Answer:
A
47. Answer:
C
48. Answer:
A
49. Answer:
B
50. Answer:
C
51. Answer:
1. 2. 3. 4. 5.
B A C B D
52. Answer:
1. 2. 3. 4. 5.
A B A A B
53. Answer:
1. 2. 3. 4. 5. 6.
A B B A A B
54. Answer:
A will still be converted to B, which will still be converted to C. However, D will not be produced because the enzyme that produces D is not functional.
55. Answer:
Photosynthesis takes in carbon dioxide; respiration produces it. If we increase the number of photosynthetic organisms, we could decrease the concentration of carbon dioxide in the atmosphere.
56. Answer:
Enzymes are typically proteins, and the shape of proteins is affected by an increase in temperature. In the case of an enzyme, an increase in temperature may change the shape of the enzyme and affect its ability to catalyze chemical reactions. The function of an enzyme is based on its shape.
57. Answer:
This statement is true because anabolic processes need the energy released from catabolic processes.
58. Answer:
Photosynthesis produces oxygen and sugars that are then used in cellular respiration. Cellular respiration produces carbon dioxide that is then used in photosynthesis.
59. Answer:
Burning wood releases energy and breaks down larger molecules into smaller components. Therefore, the burning of wood represents catabolism.
60. Answer:
The cell would not be able to break the bond between the last two phosphates and would not be able to use ATP to power cellular processes.
61. Answer:
Fossil fuels, such as oil and petroleum, were created when ancient organisms used photosynthesis to capture energy from sunlight. Part of the process of photosynthesis is the production of sugars from carbon dioxide. Traditional biomass, including wood and agricultural fuels, also relies on photosynthesis as a way to capture light energy and store it as chemical energy that is released when these materials are burned. The total energy consumption from fossil fuels and traditional biomass is 87.3 percent.
62. Answer:
The products of the light-dependent reactions of photosynthesis are oxygen gas and the energy carriers ATP and NADPH. Oxygen gas is a by-product that diffuses into the atmosphere. The energy carriers are used in the Calvin cycle to help convert carbon dioxide into sugars.
63. Answer:
Photosynthesis produces oxygen, which allows other organisms to conduct cellular respiration rather than fermentation. This allows these organisms to produce much more ATP. Photosynthesis also produces sugars, which are used as an energy source by other organisms.
64. Answer:
The energy carriers are ATP, NADPH, NADH, and FADH2. ATP carries the most energy.
65. Answer:
The second student is correct. Although glycolysis does produce some ATP, the NADH produced by glycolysis will be used by the electron transport chain to produce much more ATP. Therefore, the bulk of the ATP produced is due to the production of NADH rather than ATP directly in glycolysis.
66. Answer:
This plant would not be able to produce sugars in the Calvin cycle because they would not bind the carbon needed to produce the sugars.
67. Answer:
Nuclear power (2.2%) does not rely on photosynthesis, along with some aspects of modern renewable energy, including hydropower (3.7%). The other sources derive at least some, if not all, of their energy either directly or indirectly from photosynthesis.
68. Answer:
The three stages of cellular respiration are glycolysis, the Krebs cycle (or citric acid cycle), and oxidative phosphorylation. If the mitochondria are damaged, the aerobic stages that occur in mitochondria, the Krebs cycle and oxidative phosphorylation, would be impacted.
Name: ___________________________ Class: _________________ Date: __________
Chapter06 1.
2.
3.
Which of the following pairs of processes encompasses the entire eukaryotic cell cycle? a.
G1 phase and mitosis
b.
G1 phase and G2 phase
c.
interphase and metaphase
d.
cell division and interphase
A pool of cells is treated with a chemical that halts progress through the cell cycle at the G1 phase. In which stage of the cell cycle would most cells be found? a.
metaphase
b.
interphase
c.
anaphase
d.
cytokinesis
The G0 phase of the cell cycle is distinguished by a.
the failure of cells to divide following telophase.
b.
a doubling of chromosomes.
c.
an absence of preparation for DNA synthesis.
d.
the appearance of a metaphase plate.
4.
5.
Which numbered region in the image indicates the part of the cell cycle when DNA replication occurs?
a.
Region 1
b.
Region 3
c.
Region 4
d.
Region 5
According to the image, during which phase of the cell cycle does the cell complete preparations for cell division?
6.
a.
Region 1
b.
Region 2
c.
Region 3
d.
Region 4
According to the image, which phase of the cell cycle produces daughter cells?
7.
8.
a.
Region 1
b.
Region 2
c.
Region 5
d.
Region 6
What are the stages of interphase? a.
G0, G1, and G2
b.
S1, S2, and G0
c.
G0, G1, and S
d.
G1, S, and G2
Which of the following statements about cell division is correct?
9.
10.
11.
a.
It is the process by which organisms reproduce and grow.
b.
It is no longer necessary once an organism reaches maturity.
c.
In all cells it occurs in two sequential stages: mitosis and meiosis.
d.
It is the process by which fertilization occurs.
In animals, the outcome of meiosis is the a.
creation of genetically identical offspring.
b.
protection of cells from cancer.
c.
production of eggs and sperm.
d.
regulation of the progression through the cell cycle.
The process of cell division is different for prokaryotic versus eukaryotic cells because a.
prokaryotes have a single circular chromosome.
b.
prokaryotic cells have multiple linear chromosomes.
c.
prokaryotic cells are larger than eukaryotic cells.
d.
prokaryotic DNA resides within a nucleus.
The processes of mitosis, meiosis, and binary fission all a.
generate offspring cells through asexual reproduction.
b.
occur in both eukaryotic and prokaryotic cells.
c.
are used to produce daughter cells.
d.
generate clones.
12.
13.
14.
15.
A researcher is recording the process of bacterial cell division using timelapse microscopy. Which of the following processes would be observed? a.
meiosis
b.
mitosis
c.
binary fission
d.
either meiosis or mitosis, depending on the growth conditions
Which of the following is associated with mitosis? a.
sexual reproduction
b.
equal distribution of chromosomes
c.
prokaryotic cells
d.
binary fission
Some daughter cells are described as clones. For this description to be appropriate, the daughter cells must a.
result from sexual reproduction.
b.
belong to a multicellular organism.
c.
contain a set of DNA that is identical to that of the parent cell.
d.
have been produced by meiotic cell division.
In animals, which of the following distinguishes meiosis from mitosis? a.
Mitosis is used for the repair of cells, whereas meiosis creates cells for sexual reproduction.
b.
In mitosis, single loops of DNA are copied, whereas meiosis involves multiple linear chromosomes.
c.
Meiosis is a form of asexual division, whereas mitosis is a form of sexual division.
d.
16.
17.
Mitosis occurs in prokaryotic cells, whereas meiosis occurs in eukaryotic cells.
Which of the following is a difference between binary fission and mitosis? a.
replication of the genetic material
b.
breakdown of the nuclear envelope
c.
cell growth before division
d.
asexual versus sexual reproduction
The process shown in this figure could produce two __________ cells.
18.
a.
identical skin
b.
genetically unique sperm
c.
cloned red blood
d.
identical prokaryotic
What similarities exist between mitosis and binary fission? a.
Both processes require the separation of circular DNA molecules.
b.
Both processes involve the replication of more than one piece of DNA.
c.
Both processes include the equal distribution of DNA to daughter cells.
d.
19.
Both processes occur in bacterial cells.
The circular region near the center of the illustrated replicated chromosome represents a
Fig. 6.5
20.
a.
chromatid.
b.
centromere.
c.
centriole.
d.
homologous chromosome.
A replicated chromosome consists of __________ sister chromatid(s). a.
one
b.
two
c.
four
d.
six
21.
22.
23.
24.
The chromosomes in a homologous pair a.
both came from the organism’s mother.
b.
both came from the organism’s father.
c.
do not line up together during meiosis.
d.
consist of one maternal and one paternal chromosome.
Select the correct order of mitotic cell division stages. a.
prophase, anaphase, metaphase, telophase
b.
anaphase, metaphase, telophase, prophase
c.
prophase, metaphase, anaphase, telophase
d.
telophase, prophase, metaphase, anaphase
The centromeres split and the sister chromatids separate during which phase of mitosis? a.
prophase
b.
telophase
c.
anaphase
d.
metaphase
An actively dividing cell has six chromosomes. How many sister chromatids are present within this cell at the end of G2 phase? a.
0
b.
3
c.
6
d.
12
25.
26.
27.
28.
Chromosomes are lined up at the middle of the cell during the __________ portion of cell division. a.
metaphase
b.
anaphase
c.
interphase
d.
telophase
When examining the rapidly dividing cells of a fish embryo, a researcher notices a cell that seems to contain two nuclei. The middle of the cell is pinched inward. This cell must be in __________ of mitosis. a.
prophase
b.
telophase
c.
metaphase
d.
anaphase
Which of the following would promote a cell to advance through the G2 checkpoint? a.
The cell lacks necessary nutrients.
b.
The genetic information has been duplicated.
c.
The cell is too small in size.
d.
A chromosome has been damaged.
Which of the following is NOT a factor that influences a cell’s progression through the cell cycle? a.
gametes
29.
30.
31.
b.
cell cycle regulatory molecules
c.
hormones
d.
growth factors
Cells that demonstrate anchorage independence a.
exist in G0.
b.
are primed to become metastatic.
c.
closely monitor their progression through the cell cycle.
d.
are benign tumors that are of little concern.
Cancers are groups of cells that divide rapidly and uncontrollably. Thus, cancer cells a.
are always in the G0 phase.
b.
never enter the cell cycle.
c.
have a relatively short G1 phase.
d.
are stuck at the metaphase plate.
Which of the following is a possible consequence of disabling the G2 checkpoint in the cell cycle? a.
Damaged DNA would be immediately replicated and passed on to the two daughter cells, giving rise to helpful, new alleles.
b.
Incompletely replicated DNA may be passed to the two daughter cells; these cells could be lacking specific genes or chromosomes and would likely not survive.
c.
The cell cycle would pause if cell size or nutrient supply is inadequate, DNA is damaged, or DNA replication is incomplete.
d.
The cell cycle would simply skip mitosis and go directly to G1 to start over.
32.
33.
34.
Ana Soto and Carlos Sonnenschein found evidence that nonylphenol interferes with the G1 checkpoint in the cell cycle of human breast cells. A possible consequence of disabling the G1 checkpoint is that the cell a.
may begin to replicate DNA before it is ready or allow damaged DNA to be replicated and then continue dividing inappropriately. If unchecked, this cell division could continue to form a potentially cancerous tumor.
b.
will immediately enter into mitosis without replicating its DNA during S phase. The cell will not be able to survive because it will have too few chromosomes.
c.
will complete mitotic separation of its replicated DNA but will not complete cytokinesis.
d.
life cycle will stop before DNA replication and separation can occur. This dead cell will become a potentially cancerous tumor.
Which of the following cell types can be produced by meiosis? a.
skin
b.
muscle
c.
pancreatic
d.
sperm
During meiosis I, the chromosome number is reduced to haploid by separating a.
each sister chromatid into two different daughter cells.
b.
one of each homologous chromosome pair into two different daughter cells.
c.
each sister chromatid into four different daughter cells.
d.
one of each homologous chromosome pair into four different daughter cells.
35.
36.
37.
When a germ cell has completed both rounds of meiosis, the resulting cells are a.
diploid, and each of two daughter cells has twice the number of chromosomes as the starting cell.
b.
diploid, and each of four daughter cells has half the number of chromosomes as the starting cell.
c.
haploid, and each of four daughter cells has half the number of chromosomes as the starting cell.
d.
haploid, and each of two daughter cells has twice the number of chromosomes as the starting cell.
Patricia Hunt determined that bisphenol A (BPA) was hindering the process of meiosis in the ovaries of the mice in her experiment. BPA disrupted the ability of the chromosomes to separate into four haploid cells. Which of the following statements describes possible outcome(s) of this disruption? a.
All four resulting cells will have exactly half the number of chromosomes found in the parent cell.
b.
Three of the resulting cells will have exactly half the number of chromosomes found in the parent cell. The fourth cell will have double the chromosome number found in the parent cell.
c.
Two of the resulting cells will have exactly half the number of chromosomes found in the parent cell. The other two cells will have exactly triple the chromosome number found in the parent cell.
d.
Two of the resulting cells will have exactly half the number of chromosomes found in the parent cell. A third cell will have one more than half and a fourth cell will have one fewer than half the number of chromosomes found in the parent cell.
The successful union of one male and one female gamete forms a new single cell known as a a.
chromatid.
b.
spindle.
38.
39.
40.
c.
zygote.
d.
gametocyte.
A cell taken from a newly discovered sexually reproducing animal species is found to have 19 chromosomes. This cell is most likely which type? a.
diploid somatic cell
b.
diploid gamete
c.
haploid somatic cell
d.
haploid gamete
If a diploid animal cell has a total of 18 chromosomes, how many chromosomes would be present in each of its gametes? a.
36
b.
18
c.
9
d.
6
In a sexually reproducing animal, the gametes are produced by meiosis rather than mitosis because a.
mitosis would produce too many sister cells.
b.
meiosis reduces the chromosome number so that the zygotes that are produced will have one full genome.
c.
meiosis doubles the chromosome number so that each gamete has twice the usual number of genes.
d.
meiosis ensures that the gametes are identical to the cell that produced them.
41.
42.
43.
44.
If crossing-over does not occur and homologous chromosome pairs are not independently assorted during meiosis I, resulting in all maternal chromosomes being sorted to one cell while all paternal chromosomes are sorted to another cell, what would be the genetic results in the gametes produced at the end of meiosis II? a.
Twenty-five percent of the gametes would contain only maternal DNA and 75 percent of the gametes would contain only paternal DNA.
b.
Seventy-five percent of the gametes would contain only maternal DNA and 25 percent of the gametes would contain only paternal DNA.
c.
Fifty percent of the gametes would contain only maternal DNA and 50 percent of the gametes would contain only paternal DNA.
d.
All gametes would contain equal amounts of maternal and paternal DNA.
All of the following contribute to genetic uniqueness EXCEPT a.
binary fission.
b.
independent assortment.
c.
crossing-over.
d.
random fertilization.
Which two processes combine to create genetic diversity and maintain chromosome number? a.
mitosis and meiosis
b.
meiosis and independent assortment
c.
binary fission and mitosis
d.
fertilization and meiosis
Select the steps in meiosis that generate genetic diversity. a.
prophase and metaphase of meiosis I
45.
46.
47.
b.
prophase and metaphase of meiosis II
c.
anaphase and telophase of meiosis I
d.
anaphase and telophase of meiosis II
Which of the following examples accurately describes how crossing-over results in genetic diversity? a.
Sister chromatids of maternal chromosome 1 exchange segments of genetic information with one another.
b.
Maternal chromosome 3 exchanges segments of DNA with paternal chromosome 21.
c.
Sister chromatids of paternal chromosome 1 exchange segments of genetic information with one another.
d.
Paternal chromosome 7 exchanges segments of DNA with maternal chromosome 7.
In genetic engineering, molecular biologists often combine segments of DNA from two separate organisms. This is an example of genetic recombination that occurs in a laboratory setting. Which of the following is a form of genetic recombination that occurs naturally within cells? a.
mitosis
b.
independent assortment
c.
crossing-over
d.
asexual reproduction
What is the significance of crossing-over? a.
Two copies of the same chromosome can become part of the same gamete.
b.
The resulting gametes are likely to be genetically different from each other and from the parent cell.
48.
49.
50.
c.
A pair of homologous chromosomes can exchange genetic material with other pairs of homologous chromosomes.
d.
The chromosomes are randomly distributed into the daughter cells.
Which of the following is known to result from the disruption of mitosis and meiosis in mice that are exposed to the chemical bisphenol A (BPA)? a.
Alzheimer’s disease
b.
prostate cancer
c.
autism
d.
heart disease
Select the correct statement regarding the chemical bisphenol A (BPA). a.
only disrupts the cell cycle in very large doses
b.
has been replaced with BPS, an alternative demonstrated to be safe
c.
exerts its effects on cell division by mimicking the hormone estrogen
d.
is inactivated with high heat or by microwaving
Why is it difficult to demonstrate that bisphenol A (BPA) causes disease in humans? a.
BPA is new and its chemical properties are largely unknown.
b.
BPA causes disruptions to the cell cycle that are very challenging to observe.
c.
It is difficult to administer large enough doses of BPA to see clear effects.
d.
Most people have BPA in their bodies at all times due to constant exposure.
51.
Which of the following statements is supported by the infographic?
a.
In males, the prostate is the most common site of cancer.
b.
A female is twice as likely to experience melanomas of the skin than cancer of the colon and rectum.
c.
A male is three times more likely to die from non-Hodgkin lymphoma than from having esophageal cancer.
d.
Both males and females are four times more likely to die of leukemia than from having pancreatic cancer.
52.
Diagram the major events of the eukaryotic cell cycle. Label and describe each of the distinctive cell activities that occur during each of the two major stages.
53.
Describe the G0 phase of the cell cycle. Provide an example of what type of cell would enter the G0 stage and propose why this cell would enter the G0 phase.
54.
Consider mitosis, meiosis, and binary fission. Which one of these three processes is the simplest for a cell to complete? Explain.
55.
What is the purpose of having cell cycle checkpoints? What are the consequences of not having them?
56.
A cell has completed S phase and is preparing to divide via mitosis. How is the genetic material arranged in G2 phase?
57.
Describe the two illustrated structures. When would each structure most likely be present during the cell cycle?
58.
What would happen to a cell if the cell cycle regulatory proteins pause a cell at the G1 checkpoint even in the absence of any DNA damage and with plenty of nutrients available? Could this phenomenon possibly be used to treat cancer? Explain.
59.
A diploid cell containing 56 chromosomes is undergoing meiosis. Explain how the chromosome number changes as the cells proceed through meiosis.
60.
Name the three processes that promote genetic variation in sexually reproducing organisms and explain how they operate.
61.
If cells with two pairs of homologous chromosomes can generally produce four kinds of gametes, what happens to the genetic variety of the gametes if an unspecified number of crossing-over events between homologous chromosomes occur during meiosis I?
62.
Explain which of the three cell division processes (mitosis, meiosis, and binary fission) is most complex and summarize why it is necessary to generate genetic diversity and maintain a constant chromosome number over generations in organisms.
63.
Design an experiment testing the hypothesis that increased exposure of a sexually reproducing population to BPA will result in an increase in the number of offspring that have an extra chromosome or are missing one of their chromosomes. Use the following materials and abilities: BPA, a placebo, 1,500 lab mice, and the ability to extract gametes from the mice and examine their chromosome number. Indicate in which phase of meiosis the error is most likely to occur.
64.
Compare and contrast the incidence rate per 100,000 individuals versus deaths per 100,000 individuals for breast cancer in females and for prostate cancer in males presented in the infographic. What does this suggest about the survivability of breast cancer and prostate cancer?
65.
In the eukaryotic cell cycle, cell division consists of __________, which separates the replicated DNA into two nuclei, and __________, which divides and portions the contents of the cell into two new daughter cells.
66.
Cells spend the bulk of their time in the __________ stage of the cell cycle.
67.
Binary fission is the form of asexual reproduction that occurs in __________ cells.
68.
Sister chromatids are held together at a constriction point called a
69.
Chromosomes decondense and nuclear envelopes form during the __________ portion of mitosis.
70.
In order to increase their supply of nutrients, tumors undergo __________, the formation of new blood vessels.
71.
When tumor cells gain anchorage independence and begin to invade other tissues, they transform into cancer cells, also known as __________cells.
72.
Every human somatic cell has 23 __________ pairs of chromosomes, for a total of 46 chromosomes.
73.
When everything proceeds without error, the process of __________ produces __________ daughter cells that are genetically identical to the parent cell, while the process of __________ produces __________
daughter cells that have half the genetic information present in the parent cell.
74.
The __________ assortment of homologous chromosomes during metaphase I contributes to genetic diversity among the resultant gametes.
75.
The fusion of two haploid gametes at __________ produces a genetically unique diploid organism.
76.
Crossing-over produces chromosomes with new combinations of DNA; this is followed by the independent assortment of __________ chromosomes to generate even more genetic diversity among gametes.
77.
In humans, the cancer that is most responsible for deaths is __________; it is followed by __________ in females and __________ in males.
78.
Match the stage of the eukaryotic cell cycle with the appropriate description. a.
Duplicated chromosomes separate.
b.
Cells make final preparations for cell division.
c.
Cells duplicate their genetic material.
d.
In the resting stage, cells exit the cell cycle.
e.
Cells grow and begin to prepare for division. __ 1. __ 2. __ 3. __ 4. __ 5.
79.
G0 phase G1 phase G2 phase M phase S phase
Match the event or stage of mitosis with the appropriate description. a.
prophase
b.
metaphase
c.
anaphase
d.
telophase
e.
cytokinesis __ 1. Replicated chromosomes condense and attach to the mitotic spindle. __ 2. The entire cell physically divides into two daughter cells. __ 3. The sister chromatids separate and become individual chromosomes that begin to move toward the poles of the cell. __ 4. The mitotic spindle aligns the replicated chromosomes at the center of the cell. __ 5. As new chromosomes reach the poles, the nuclear envelopes reform, and the chromatin decondenses.
80.
Match the event or stage of meiosis with the appropriate drawing. a.
prophase I
b.
metaphase I
c.
anaphase I
d.
telophase I and cytokinesis I
e.
prophase II
f.
metaphase II
g.
anaphase II
h.
telophase II and cytokinesis II
__ 1.
__ 2.
__ 3.
__ 4.
__ 5.
__ 6.
__ 7.
__ 8.
Answer Key Chapter06
1. Answer:
D
2. Answer:
B
3. Answer:
C
4. Answer:
B
5. Answer:
D
6. Answer:
D
7. Answer:
D
8. Answer:
A
9. Answer:
C
10. Answer:
A
11. Answer:
C
12. Answer:
C
13. Answer:
B
14. Answer:
C
15. Answer:
A
16. Answer:
B
17. Answer:
D
18. Answer:
C
19. Answer:
B
20. Answer:
B
21. Answer:
D
22. Answer:
C
23. Answer:
C
24. Answer:
D
25. Answer:
A
26. Answer:
B
27. Answer:
B
28. Answer:
A
29. Answer:
B
30. Answer:
C
31. Answer:
B
32. Answer:
A
33. Answer:
D
34. Answer:
B
35. Answer:
C
36. Answer:
D
37. Answer:
C
38. Answer:
D
39. Answer:
C
40. Answer:
B
41. Answer:
C
42. Answer:
A
43. Answer:
D
44. Answer:
A
45. Answer:
D
46. Answer:
C
47. Answer:
B
48. Answer:
B
49. Answer:
C
50. Answer:
D
51. Answer:
A
52. Answer:
Students should draw a circular picture similar to Figure 6.2 in the text and indicate G1, S, G2, and M at intervals around the circle. At G1, the cells grow and increase in size. During S phase, cells duplicate the genetic material. During G2 phase, the cells are growing in preparation for cell division. These cell activities occur during interphase. The other major stage is cell division, consisting of mitosis and cytokinesis. The chromosomes are separated in a characteristic manner during mitosis. In cytokinesis, the cell formally divides into two cells, each of which then enters the G1 phase of interphase.
53. Answer:
The G0 phase of the cell cycle is a nondividing state that can last for a few days or through the lifetime of the organism. An example would be most nerve cells. Nerve cells must be long enough to accommodate the size of the organism and remain stable throughout the life of the organism, so once they are formed and “fully grown” there is probably no need for them to replicate unless there is an injury. Without the necessary “go ahead” signals, a cell exits the cell cycle and enters G0.
54. Answer:
Binary fission is the most efficient process that the cells may carry out. Many prokaryotes, such as bacteria, reproduce asexually using this method of cell division. Since bacterial cells typically have only a single chromosome and they lack a nuclear envelope, binary fission is a faster and less complex process.
55. Answer:
Cell cycle checkpoints ensure that cells are ready to progress to the next stage of the cell cycle. Cell cycle regulatory proteins mediate the checkpoints. They prevent cells from progressing inappropriately or too quickly through the cell cycle phases. One consequence of uncontrolled progression through the cell cycle is cancer. Cancerous cells may self-signal in the absence of growth factors and hormones. Such signals promote unnecessary and harmful cell growth.
56. Answer:
During S phase, the uncondensed chromosomes (chromatin) duplicate, after which there are replicated chromosomes present in the nucleus. Each replicated chromosome consists of two sister chromatids that are held together at a narrowing called the centromere.
57. Answer:
The structure on the left is a single chromatin fiber (uncoiled strand of chromosome) that would most likely be present during the G1 phase of the cell cycle. The structure on the right is a duplicated, uncoiled chromosome consisting of two sister chromatids held together at the centromere; this would most likely be present during the S and G2 phases of the cell cycle.
58. Answer:
The cell would be unable to begin S (synthesis) phase. Without entering S phase, the cell would not duplicate its DNA and would not be able to complete the cell cycle; cell death would result. If you could determine a way to stimulate the cell cycle regulatory proteins in cancer cells, you might be able to use them to stop the cancer cells from reproducing.
59. Answer:
Starting with one diploid parent cell containing 56 chromosomes, meiosis produces four haploid cells, each containing a single set of 28 chromosomes. Meiosis I reduces the chromosome number to haploid (from 56 to 28 chromosomes) by separating one of each homologous chromosome pair into two different offspring cells. In meiosis II, each homologous chromosome then separates into sister chromatids that are pulled to opposite poles of the cell. After cytokinesis, four haploid cells result, each with 28 chromosomes.
60. Answer:
There are three processes that allow for genetic variation in the production of offspring. Crossing-over between nonsister chromatids during prophase I exchanges segments of DNA between maternal and paternal homologs. Independent assortment during metaphase I shuffles different combinations of maternal and paternal chromosomes into gametes. A unique egg may then be randomly fertilized with a unique sperm cell.
61. Answer:
The higher the number of crossing-over events between homologous chromosomes, the greater the genetic variation in the gametes, especially if the chromosomes in the gametes are compared to the parent cell chromosomes. The crossing-over events simply add an additional layer of genetic variation to the recombination achieved by independent assortment of homologous chromosomes.
62. Answer:
Meiosis is the most complex of the three processes. Not only is there more than one division of the genetic material, but the amount of genetic material is systematically reduced by half and four daughter cells are produced instead of two. This is important for sexually reproducing eukaryotes because it provides haploid gametes that can join with other haploid gametes to form viable diploid zygotes. Without this reduction division, the amount of genetic material would double with each generation. Additionally, crossing-over at prophase I and the independent assortment of homologous chromosomes at metaphase I produces genetic variation in the resulting haploid cells. Without this, all organisms within the population would be identical.
63. Answer:
The mice will be divided into three groups of 500 mice each. The first group will be the control group, which will not receive any treatment. The second group will be the placebo group, which will be exposed to an inert placebo. The third group will be the experimental group, which will be exposed to a specific level of BPA. All three groups will be cared for and monitored for the same length of time. Gametes extracted from all three groups of mice will be examined to determine the chromosome numbers in the gametes. Abnormalities will be recorded and compared across the groups to determine if the BPA group showed an increased rate of extra or missing chromosomes. The experiment could be repeated with a fresh set of mice and various doses of BPA to determine if the result is dose dependent. An error in meiosis I is the most likely place for the error to occur because that is when the homologous chromosomes are supposed to separate.
64. Answer:
The incidence rate per 100,000 individuals of prostate cancer is 101.6, while the death rate is 19.2; roughly 81 percent of males who get prostate cancer survive the experience. The incidence rate per 100,000 of female breast cancer is 123.7, while the death rate is 20.7; roughly 71 percent of females who get breast cancer survive the experience. The good news is that for either of these cancers, you are far more likely to survive it than you are to succumb to it!
65. Answer:
mitosis; cytokinesis
66. Answer:
interphase G1 (most time is spent in the G1 portion of interphase)
67. Answer:
bacterial archaean prokaryotic
68. Answer:
centromere
69. Answer:
telophase
70. Answer:
angiogenesis
71. Answer:
malignant
72. Answer:
homologous
73. Answer:
mitosis; two; meiosis; four
74. Answer:
independent
75. Answer:
fertilization
76. Answer:
homologous
77. Answer:
lung and bronchus cancer; breast cancer; prostate cancer
78. Answer:
1.
D
2.
E
3.
B
4.
A
5.
C
1.
A
2.
E
3.
C
4.
B
5.
D
79. Answer:
80. Answer:
1.
H
2.
A
3.
D
4.
E
5.
C
6.
F
7.
G
8.
B
Name: ___________________________ Class: _________________ Date: __________
Chapter07 1.
2.
3.
4.
Which of the following choices represents the genotype of an individual diploid organism? a.
BbCCdd
b.
BCd
c.
bcd
d.
BbCd
An allele is a.
a version of a gene.
b.
a trait that can be affected by the external environment.
c.
always codominant to its counterpart in another chromosome.
d.
the result of a change in phenotype.
Which of the following does NOT represent a phenotype? a.
a person’s susceptibility to Addison’s disease
b.
the height of a draft horse
c.
the alleles in a mouse that control hair color
d.
the extent to which an individual is shy
Which of the following statements regarding genes is NOT true? a.
Genes are located on chromosomes.
5.
6.
7.
b.
Genes consist of a sequence of DNA.
c.
Genes are the basic unit of information affecting a genetic trait.
d.
Genes are found as single copies in cells other than sperm or egg.
Which of the following statements is NOT true? a.
Two organisms with the same phenotype may have different genotypes.
b.
Two organisms with the same genotype are homozygous.
c.
A heterozygous organism may have the same phenotype as a homozygous organism.
d.
A heterozygous organism has two different alleles for a given gene.
A thoroughbred racehorse could have at most __________ alleles of the same gene for a Mendelian trait. a.
16
b.
8
c.
4
d.
2
Mutations will affect the a.
genotype without affecting the phenotype.
b.
phenotype without affecting the genotype.
c.
genotype, which may affect the phenotype.
d.
phenotype, which may affect the genotype.
8.
9.
10.
11.
When comparing a human sperm cell to a skin cell from the same individual, what differences would be expected? a.
The sperm cell would contain four alleles for a given gene; the skin cell would contain two alleles.
b.
The sperm cell would contain only one allele for a given gene; the skin cell would contain two alleles.
c.
Both sperm and skin cells may carry different alleles for an individual gene.
d.
Both sperm and skin cells would contain 46 chromosomes found as homologous pairs.
Based on Mendelian inheritance, would it be necessary to have both the genotype and phenotype for an organism when attempting to predict the inheritance pattern for a trait in offspring? a.
Yes; individuals with different genotypes often have the same phenotype.
b.
Yes; individuals with different phenotypes often have the same genotype.
c.
No; knowing the phenotype will indicate the genotype.
d.
No; knowing the genotype will indicate the phenotype.
Mendel used __________ as his research organism to study patterns of genetic inheritance. a.
garden peas
b.
snapdragons
c.
mice
d.
Siamese cats
Mendel’s laws
12.
13.
14.
a.
are less accurate than Punnett square results.
b.
determine whether an allele is dominant.
c.
explain how genes are inherited.
d.
predict inheritance of complex traits.
When Mendel proposed the law of segregation, which of the following pieces of information did he NOT have? a.
data on the outcomes of crossing two true-breeding pea plants
b.
ratios to predict the outcome of crossing two pea plants heterozygous for a single gene
c.
a prediction for how a single trait is inherited
d.
knowledge of the location of the alleles for flower color
In Mendel’s controlled mating experiments, the individuals produced by crossing two true-breeding parents are referred to as a.
the P generation.
b.
the F1 generation.
c.
the F2 generation.
d.
dihybrids.
Mendel’s manuscript discussing his pea-breeding results is considered one of the two most important scientific papers of the nineteenth century because he was the first to explain how a.
mutations produced the variety of alleles displayed by individuals of the same species.
b.
traits are passed from one generation to the next.
c.
meiosis controls the distribution of alleles to each gamete.
d.
15.
16.
17.
genes are arranged on chromosomes in the cell.
Which of the following did Gregor Mendel notice in garden peas? a.
Some plants always produced offspring with flowers that were the same color as the parent plants’ flowers.
b.
The first generation from a genetic cross of true-breeding plants always produced offspring that were intermediate in their phenotype and did not look like either parent.
c.
Garden peas always produce a variety of phenotypes in their offspring, which result from frequent mutations.
d.
Any individual pea plant carries at least three different alleles for flower color.
Why did Mendel analyze thousands of plants while conducting his research? a.
It allowed him to control the environment of his pea plants.
b.
The likelihood of seeing a clear numerical pattern is higher with a larger data set.
c.
Mendel knew that chromosomes undergo recombination during meiosis.
d.
It eliminated the probability of mutations affecting his data.
Mendel’s laws of segregation and independent assortment both have their biological basis in events that take place during a.
chromosome formation.
b.
mutation.
c.
mitosis.
d.
meiosis.
18.
19.
These images illustrate a(n)
a.
complete dominance of body size alleles.
b.
incomplete dominance of body size alleles.
c.
dihybrid cross.
d.
monohybrid cross.
Which of the following expresses Mendel’s law of segregation? a.
All dominant alleles of different genes divide into different cells from the recessive alleles.
b.
The two alleles of a gene separate during meiosis and end up in different gametes.
c.
When gametes form, the genes originally from one parent all end up in different gametes from the genes originally from the other parent.
d.
20.
21.
Gametes with recessive alleles will fuse only with each other.
The 9:3:3:1 ratio of phenotypes that occurs in the F2 generation of the cross shown below can be explained using
a.
blending inheritance.
b.
Mendel’s law of segregation only.
c.
Mendel’s law of independent assortment only.
d.
both the laws of segregation and independent assortment.
A Punnett square is used to a.
determine the source of new alleles.
b.
determine how many genes control a given trait.
c.
predict the gametes that will be produced by an organism.
d.
predict the genotypes and phenotypes of a genetic cross.
22.
23.
24.
Two organisms that are true-breeding for a certain genetic characteristic are mated and their offspring analyzed. Which of the following statements about this situation is true? a.
Both parents are heterozygotes.
b.
The offspring are either 100 percent homozygotes or 100 percent heterozygotes.
c.
The offspring represent the P generation.
d.
The gametes produced by the offspring will carry two alleles for this gene.
A pea plant that is heterozygous for the flower color gene makes gametes. What is the probability that a specific gamete contains the recessive allele for flower color? a.
0 percent
b.
25 percent
c.
50 percent
d.
75 percent
Consider a gene with two alleles. One of the alleles is dominant over the other allele. When two heterozygotes for this gene breed, they have a 25 percent chance of producing a homozygous recessive offspring. The next time these two individuals breed, what are the chances that they will once again have a homozygous recessive progeny? a.
0 percent
b.
25 percent
c.
50 percent
d.
75 percent
25.
26.
In the Punnett square shown below, the lettered circles on the top and left of the square (indicated by the arrows) represent the
a.
offspring that will be produced by the cross.
b.
genotypes of the parents involved in the cross.
c.
gametes that may be produced by each parent involved in the cross.
d.
offspring that could be produced by the cross.
Suppose D were dominant and d were recessive, and you could label the D allele in the P generation with a radioactive substance that could be inherited over several generations. You create hybrids by mating your radioactive DD individuals to dd individuals. Next, you cross two F1 individuals (with the Dd genotype). Among the 1,000 F2 offspring, how many would you predict would be radioactive? a.
250
b.
500
c.
750
d.
1,000
27.
28.
29.
30.
In a genetic cross of Gg with Gg guinea pigs, none of the four offspring were gg. This a.
disproves Mendel’s law of independent assortment.
b.
neither supports nor disproves Mendel’s law of independent assortment.
c.
supports Mendel’s law of independent assortment.
d.
supports Mendel’s law of segregation.
Which of the following did Mendel use to help him form the law of independent assortment? a.
dihybrid crosses between pea plants
b.
monohybrid crosses between pea plants
c.
traits that were codominant
d.
traits with incomplete dominance
Which of the following statements is a basic summary of one of Mendel’s laws? a.
All beneficial human genetic traits are dominant, and harmful traits are recessive.
b.
The pattern of inherited characteristics of organisms is not predictable.
c.
The separation of alleles for one gene does not affect the separation of alleles for other genes.
d.
Recessive alleles cause the death of a gamete.
Which of the following is the mechanism described by Mendel that results in a new combination of alleles in a pea plant seed? a.
mutation of multiple alleles during mitosis
b.
mutation of multiple alleles during meiosis
31.
32.
33.
c.
separation of alleles for two different genes during meiosis
d.
separation of alleles for a single gene during meiosis
What is the smallest number of traits that are needed to test Mendel’s law of independent assortment? a.
one
b.
two
c.
four
d.
eight
In a particular plant, two genes control leaf shape and fruit color. Round leaves (R) are dominant to jagged leaves (r). Yellow fruits (Y) are dominant to white fruits (y). A true-breeding round-leaved, yellow-fruited plant is mated with a true-breeding jagged-leaved, white-fruited plant. What are the genotypes of the plants involved in this cross? a.
RRYY ?0× RRYY
b.
RRYY ?0× rryy
c.
RrYy ?0× RrYy
d.
cannot determine from the information given
Which of the following represents all possible gametes that can be formed by an individual with the genetic makeup FfGgHH? a.
FGH, FgH, fGH, fgH
b.
Ff, Gg, HH
c.
FG, FH, Fg, fH, fG, fg, GH, gH
d.
FfGhHH, FFGGHH, ffgghh
34.
35.
36.
37.
The leaf color of a certain plant is controlled by one gene. For that gene, the allele G = orange and g = green. You have a plant with orange leaves but do not know whether that plant’s genotype is GG or Gg. Which of the following would help you determine the plant’s genotype? a.
cross the plant to another plant with orange leaves
b.
cross the plant to a plant with green leaves
c.
cross two true-breeding, orange-leaved plants to each other and then cross one of their offspring to the plant with the unknown genotype
d.
change the environment in which the plant grows to find the conditions that cause the leaves to produce the orange color
If two different alleles for the same trait have an equal effect on the phenotype, the alleles are a.
codominant.
b.
recessive.
c.
epistatic.
d.
incompletely dominant.
A chestnut (red-colored) horse is mated with a cremello (cream-colored) horse. Over a 10-year period, all of their offspring are palominos (goldcolored). This pattern of inheritance is best explained by a.
complete dominance.
b.
incomplete dominance.
c.
multiple gene effects.
d.
environmental effects on genes.
Feather color in a certain species of bird is controlled by a pair of alleles that exhibit incomplete dominance. If birds that are homozygous for one allele
are black and birds that are homozygous for the other allele are white, then heterozygous birds would be
38.
39.
40.
a.
black.
b.
white.
c.
gray.
d.
black with white stripes.
The observation that individuals afflicted with albinism also always have vision problems is an example of a.
codominance.
b.
incomplete dominance.
c.
pleiotropy.
d.
epistasis.
Two genes control fur color in Labrador retrievers. The first gene determines whether the pigment to be deposited in the hairs will be black or brown. The second gene determines whether the pigments are put into the dog’s hairs at all. A dog homozygous for the recessive allele of this second gene will always be yellow because no pigment is deposited in its hairs, regardless of the alleles of the first gene. This is an example of a.
epistasis.
b.
pleiotropy.
c.
codominance.
d.
incomplete dominance.
Most human genetic characters are a.
controlled by one gene.
41.
42.
b.
always inherited according to Mendel’s laws.
c.
controlled by more than one gene.
d.
not heritable.
One of the first medical tests a newborn receives determines if the child has phenylketonuria (PKU). PKU is the result of a mutation in a single gene that leads to mental retardation and a host of other phenotypes including eczema and a “musty” smell. By detecting PKU early, doctors are able to reduce the effects of this condition with a modified diet extremely low in the amino acid phenylalanine. PKU is an example of a.
epistasis.
b.
a polygenic trait.
c.
pleiotropy.
d.
codominance.
The figure shown below indicates two Labrador retrievers that are both homozygous recessive for fur color. One dog is brown and the other is yellow due to
43.
a.
pleiotropy.
b.
codominance.
c.
epistasis.
d.
incomplete dominance.
Which of the following statements is NOT true? a.
Traits that are determined by the effect of more than one gene are known as polygenic.
b.
Environmental factors can alter the effects of genes.
c.
Most traits are under the control of more than one gene.
d.
44.
45.
46.
A genotype is always expressed in the phenotype.
It would become nearly impossible to predict the phenotype of an individual with a known genotype if the a.
environment affects the phenotype.
b.
genotype of the parents is unknown.
c.
genotype of offspring is unknown.
d.
You should always be able to predict the phenotype if you know the genotype.
The pleiotropy that occurs when a single gene controls multiple skeletal traits in dogs, such as leg bone length and skull size, may be explained because a.
dogs share a common ancestor.
b.
the skeletal traits are related in the overall function of the dog.
c.
dogs have lived with humans for thousands of years.
d.
the effect of this gene depends on the environment.
A hammer is needed to pound nails into a board. Even if one has the nails, they cannot be used without first procuring a hammer. This is similar to the genetic relationship known as a.
heterozygosity.
b.
codominance.
c.
epistasis.
d.
independent assortment.
47.
48.
49.
50.
Which of the following statements explains how genetically identical plant clones can exhibit dramatic phenotypic variation? a.
Environmental conditions under which plants are grown can cause variations in phenotypes.
b.
Plants undergo mutations to adapt to temperature extremes.
c.
Adaptive mutations are immediately expressed in the current generation of plants.
d.
Genetically identical plants cannot have different phenotypes.
The coat color in a Siamese cat is determined by a temperature-sensitive allele that allows the pigment melanin to be produced in extremities of the body. What might explain this phenomenon? a.
Melanin appears darker in extremities because less light is reflected.
b.
Alleles produce proteins that function best in specific temperature ranges.
c.
Siamese cats evolved in warm climates and did not need melanin.
d.
Extremities in a cat are more prone to damage from sunlight.
Which of the following might explain how two separate genes control a single trait? a.
Both genes have the same alleles.
b.
One gene functions better at higher temperatures.
c.
The two genes control two separate steps in a pathway.
d.
Two genes cannot control a single trait.
Heart disease, cancer, stroke, diabetes, asthma, and arthritis are common in industrialized countries. These are complex traits that result from a.
malfunctions in one or more genes and are influenced by environmental factors.
51.
b.
environmental factors alone.
c.
a simple malfunction in one gene with no influence from the environment.
d.
one mutated allele with no influence from the environment.
About 600,000 people die of heart disease in the U.S. every year. Researchers have identified alleles associated with increased risk of heart disease, but it is estimated that 30 percent to 40 percent of the annual deaths due to heart disease could be eliminated by physical activity in people who are genetically predisposed to heart disease. This is an example of a a.
simple Mendelian trait.
b.
complex trait influenced by the environment.
c.
disease affected only by the environment.
d.
trait resulting solely from one specific gene.
52.
If you were a scientist studying patterns of inheritance in dogs and were given extensive information about the inheritance of multiple physical traits, such as hair color and height, would you be able to piece together the entire genome of dogs? Explain your answer.
53.
In humans there are three blood type alleles: IA, IB, and i. The blood type alleles IA and IB are fully expressed when they are present. Neither allele is considered dominant or recessive and neither is diluted when both alleles are present. The allele i is considered recessive and indicates a lack of either the IA or IB allele. How many blood type alleles are found in a given individual? What are the possible genotypes of an individual with type A blood in which only the IA allele is expressed?
54.
Explain the relationship between the genotype and the phenotype for a given trait.
55.
Gregor Mendel began his studies by crossing pea plants that bred true for flower color. One parent bred true for purple flower color and the other parent bred true for white flower color. The flower color purple is dominant and the flower color white is recessive. If Mendel had erroneously crossed purple-flowered plants that were not true-breeding with white-flowered plants, how would this have altered the first generation produced?
56.
A single gene with one dominant allele for black hair (B) and one recessive allele for brown hair (b) controls hair color in mice. A male mouse with black hair mates with a female mouse with brown hair, and they have 12 offspring. Are you able to determine the predicted ratio of hair color in their offspring using a Punnett square? Explain your answer.
57.
If an individual is a carrier for a recessive disorder (with one copy of the recessive allele), and his or her partner is also a carrier, what is the probability that they will produce a child affected by the disorder? Explain your answer.
58.
How is Mendel’s law of segregation represented in a Punnett square?
59.
Jennifer uses a dihybrid cross of fruit flies to examine inheritance patterns for eye color (black or white) and head shape (round or elongated). This cross produces 10,000 offspring, and the F2 ratio is 1 (black eyes, round head): 1 (black eyes, elongated head): 1 (white eyes, round head): 1 (white eyes, elongated head). Is this what Jennifer would have expected from a dihybrid cross? Explain why or why not.
60.
Miles is a student studying two Mendelian traits in a plant. He creates a Punnett square to predict the phenotypic ratio in the F2 generation. Interestingly, Miles finds that the phenotypic ratio does not match up with the predicted phenotypes. He soon realizes that the two genes are physically linked to each other on the same chromosome. How would close physical proximity on the same chromosome affect the law of independent assortment?
61.
What type of inheritance pattern is indicated in the body size of the dogs shown below? How does this pattern differ from Mendelian traits?
62.
If Gregor Mendel had studied a polygenic trait that did not follow the straightforward single-gene>single-phenotype pattern, do you believe he would have been able to describe how genes are passed from parents to offspring? Justify your answer.
63.
Differentiate between pleiotropy and polygenic traits.
64.
Is it possible for two organisms with the same genotype to have different phenotypes? Explain your answer.
65.
Up to 300 inherited diseases found in dogs are similar to human diseases. Based on the information shown below, why might it be easier to study the genetics of these diseases in dogs rather than in humans?
66.
Your neighbor’s dog is a Pomeranian male who is homozygous with the B allele for the IGF1 gene, which controls the activity of a growth factor. Your dog is a medium sized poodle who is heterozygous (IB) for the IGF1 gene. If your neighbor’s Pomeranian mates with your poodle, what would be the expected genotypic and phenotypic ratio in the litter of pups? What method would you use to make this prediction?
67.
You have been conducting breeding experiments with your own pea plants. After several generations, you realize that you have a plant that is true breeding for the dominant traits Round and Yellow seeds. You also have a plant that is a true breeding plant for the recessive traits of wrinkled and green seeds. You cross the homozygous dominant plant with the homozygous recessive plant to produce an F1 generation. You now cross one of the F1 generation plants with a homozygous recessive plant to
produce a generation of testcross offspring. What is the genotype and phenotype of the F1 plants? What ratio of genotypes and phenotypes would you expect to see in the testcross offspring?
68.
The observable physical characteristics of an organism are known as its __________.
69.
The genetic makeup of an organism, such as Gg, is its __________.
70.
The individual who used data from breeding garden peas to discover the patterns of inheritance that form the foundation of modern-day genetics was __________.
71.
A Punnett square shows the possible ways that gametes combine to form __________.
72.
The separation of two alleles into different cells during meiosis illustrates Mendel’s law of __________.
73.
According to Mendel’s law of __________, when gametes are formed, the separation of alleles for one gene is unrelated to the separation of alleles for other genes.
74.
In a genetic cross in which the heterozygous phenotype is intermediate between the two homozygous phenotypes, __________ dominance is expressed.
75.
Most traits in humans involve complex inheritance where the trait is governed by the action of more than one __________.
76.
When creating a Punnett square, you list the __________ of the male gametes’ genotypes across the top of the grid and the alleles of the female gametes’ genotypes down the left side of the grid.
77.
All soybeans have pods that contain seeds; this is known as a(n) __________ phenotypic trait.
78.
Physical traits, biochemical traits, and behavioral traits are all __________ that are the result of particular genes or combinations of genes and influenced by the environment.
79.
A Portuguese water dog who is BB for the coat color gene is said to have a __________ __________ genotype.
80.
Match a mode of inheritance to a statement listed below. a.
incomplete dominance
b.
epistasis
c.
polygenic
d.
pleiotropy
e.
codominance
f.
Mendelian trait __ 1. The frizzle gene in chickens affects many traits, including feather type, metabolic rate, blood flow rates, and digestion. __ 2. A parent with curly hair and a parent with straight hair produce a child with wavy hair.
__ 3. The color of wheat kernels is controlled by the interaction of two separate genes, with one gene affecting the expression of the other gene. __ 4. The appearance of a widow’s peak (pointed contour of the hairline on the forehead) is dependent on a single gene that has a dominant and a recessive allele. Individuals with one or two dominant alleles for the gene will, typically, have a widow’s peak hairline.
81.
Match the following terms with their definitions. a.
allele
b.
genotype
c.
gene
d.
phenotype
e.
chromosome
f.
mutation __ 1. __ 2. __ 3. __ 4.
82.
a physical characteristic seen in an organism a molecule of DNA and associated proteins a section of DNA that controls a genetic trait a variant of a given gene
Fur texture in a group of rabbits is determined by a Mendelian trait. Straight hair is dominant, and curly hair is recessive. Match the predicted genotypic frequencies of heterozygous offspring from the genetic crosses given. a.
0 percent
b.
25 percent
c.
50 percent
d.
75 percent
e.
100 percent
__ 1. a heterozygous straight-hair rabbit and a homozygous curly-hair rabbit __ 2. a homozygous straight-hair rabbit and a homozygous curly-hair rabbit __ 3. two heterozygous straight-hair rabbits
Answer Key Chapter07
1. Answer:
A
2. Answer:
A
3. Answer:
C
4. Answer:
D
5. Answer:
B
6. Answer:
D
7. Answer:
C
8. Answer:
B
9. Answer:
D
10. Answer:
A
11. Answer:
C
12. Answer:
D
13. Answer:
B
14. Answer:
B
15. Answer:
A
16. Answer:
B
17. Answer:
D
18. Answer:
B
19. Answer:
B
20. Answer:
D
21. Answer:
D
22. Answer:
B
23. Answer:
C
24. Answer:
B
25. Answer:
C
26. Answer:
C
27. Answer:
B
28. Answer:
A
29. Answer:
C
30. Answer:
C
31. Answer:
B
32. Answer:
B
33. Answer:
A
34. Answer:
B
35. Answer:
A
36. Answer:
B
37. Answer:
C
38. Answer:
C
39. Answer:
A
40. Answer:
C
41. Answer:
C
42. Answer:
C
43. Answer:
D
44. Answer:
A
45. Answer:
B
46. Answer:
C
47. Answer:
A
48. Answer:
B
49. Answer:
C
50. Answer:
A
51. Answer:
B
52. Answer:
No. The genome would encompass all of the genes in dogs. Multiple physical traits represent phenotypes and would allow you to gather information about some, but not all, genes.
53. Answer:
For any given gene, including blood type, an individual has two alleles. An individual with type A blood, expressing only the IA allele, could have two IA alleles (IAIA) or could have one IA allele and one i allele (IAi).
54. Answer:
The genotype for a given trait is the pair of alleles, or versions of a gene, that an individual has within his or her cells. These alleles are passed from parent to offspring. Genes code for a protein that helps produce the phenotype, or physical characteristics, of an organism; these characteristics are typically modified by environmental conditions.
55. Answer:
If Mendel had crossed plants with purple flowers that were heterozygotes rather than homozygotes, the first generation would have contained a 1:1 mix of purple flowers and white flowers. Half of the offspring would have been heterozygous for the flower color gene. The other half would have been homozygous for the recessive allele. When Mendel crossed plants that were true-breeding for flower color, all of the first generation plants were heterozygotes with purple flowers.
56. Answer:
Because the male mouse exhibits the dominant phenotype, you would need to know his genotype. Without knowing whether the male mouse is homozygous dominant (BB) or heterozygous (Bb), it is impossible to predict the outcome using a Punnett square.
57. Answer:
Both parents are heterozygous. For each parent, half of the gametes produced will contain the recessive allele. The probability of the recessive alleles from both parents joining to produce a child with two copies of the recessive allele is 1:4.
58. Answer:
Mendel’s law of segregation states that two alleles of a given gene separate during meiosis and end up in different gametes. A Punnett square shows the possible ways that alleles of a gene separate to form individual gametes and the possible combinations of those alleles through fertilization.
59. Answer:
No. The pattern predicted by the law of independent assortment for a dihybrid cross is 9:3:3:1. Mendel’s law states that two alleles should segregate independently of other pairs of alleles. The example given illustrates a ratio produced when two alleles do not segregate independently.
60. Answer:
The law of independent assortment states that during meiosis a pair of alleles for a given gene will segregate independently of another pair of alleles for another gene. If two genes are physically linked on the same chromosome, the alleles will not be able to separate during meiosis.
61. Answer:
Body size in dogs follows a pattern of incomplete dominance. With incomplete dominance, heterozygotes display an intermediate phenotype. If a trait is Mendelian, heterozygotes will display the dominant phenotype.
62. Answer:
No. Studying traits with dominant and recessive alleles was important in allowing Mendel to determine that each parent carried a pair of alleles for each trait (although the language he used to describe “alleles” was different from our modern terminology). This information contributed to our understanding of basic genetic inheritance. Polygenic traits are controlled by the actions of two or more genes, and their inheritance patterns are much more complex.
63. Answer:
Pleiotropy involves a single gene controlling multiple traits (for example, a single gene controls multiple skeletal traits in dogs). Polygenic traits are single traits controlled by multiple genes (for example, human body size is controlled by multiple genes).
64. Answer:
Yes. The expression of the genotype in an individual can be affected by the environment. Phenotype may be controlled by environmental factors. One example is hair color in Siamese cats.
65. Answer:
The size of the dog genome is smaller than the size of the human genome. Having a smaller genome makes it easier to map the genome.
66. Answer:
I would expect to see about 50 percent of the litter born to be medium-sized dogs with the genotype IB, while the other 50 percent would be small-sized dogs with the genotype BB. This prediction can be made using a Punnett square to simulate a cross between the two dogs.
67. Answer:
The F1 generation would have the heterozygous genotype, RrYy, and the phenotype would be dominant round and yellow seeds. The testcross offspring resulting from a cross between an F1 and a homozygous recessive plant would be expected to produce a 1:1:1:1 ratio of the genotypes RrYy, Rryy, rrYy, and rryy. This would yield an expected phenotypic ratio of 1:1:1:1 of round and yellow seeds, round and green seeds, wrinkled and yellow seeds, and wrinkled and green seeds.
68. Answer:
phenotype
69. Answer:
genotype
70. Answer:
Gregor Mendel Mendel
71. Answer:
offspring
72. Answer:
segregation
73. Answer:
independent assortment
74. Answer:
incomplete
75. Answer:
gene
76. Answer:
alleles
77. Answer:
invariant
78. Answer:
phenotypes
79. Answer:
homozygous dominant
80. Answer:
1.
D
2.
A
3.
B
4.
F
1.
D
2.
E
3.
C
4.
A
1.
C
2.
E
3.
C
81. Answer:
82. Answer:
Name: ___________________________ Class: _________________ Date: __________
Chapter08 1.
2.
3.
4.
The presence of two copies of the same gene on a single chromosome would indicate that a(n) __________ had occurred. a.
deletion
b.
duplication
c.
inversion
d.
translocation
Which of the following would explain two chromosomes in an individual cell that contain some, but not all, of the same genes at the same loci? a.
Both of the chromosomes are paternal.
b.
Both of the chromosomes are maternal.
c.
The chromosomes are from a common ancestor.
d.
A chromosomal alteration has occurred.
A __________ is a chart that shows genetic relationships within a family over several generations. a.
karyotype
b.
pedigree
c.
Punnett square
d.
single-gene disorder map
Humans have __________ pairs of homologous chromosomes.
5.
6.
7.
a.
46
b.
23
c.
22
d.
44
A karyotype shows a chromosomal abnormality that does not change the length of any of the chromosomes. Which abnormality does this most likely indicate? a.
inversion
b.
deletion
c.
translocation
d.
duplication
In a diploid cell, there are __________ alleles for a given gene found on __________ chromosomes. a.
two; homologous
b.
four; maternal
c.
four; paternal
d.
two; Y
Chromosomes that are NOT involved in determining gender are known as a.
autosomes.
b.
sex chromosomes.
c.
homologues.
d.
linked.
8.
9.
10.
11.
Which of the following statements about homologous chromosomes is true? a.
There are 46 pairs in humans.
b.
They contain the same genes in the same locations.
c.
They contain identical alleles in the same locations.
d.
They are also known as sex chromosomes.
A chromosomal abnormality that is usually fatal is a.
a mutation in a gene.
b.
an exchange of material between homologous chromosomes.
c.
extra copies of sex chromosomes.
d.
the addition of an extra autosomal chromosome.
Which of the following must be true for a woman who is heterozygous for a given gene? a.
She must be heterozygous for all genes.
b.
All of her eggs will contain both of the alleles for that gene.
c.
Each of her eggs will contain one allele or the other but not both alleles.
d.
She carries a rare mutation.
During cell division, a piece of a chromosome breaks off and reattaches to the same chromosome, but the piece is now in reverse order. How would this abnormality affect the chromosome? a.
An extra copy of the chromosome will be made to ensure normal function.
b.
The inverted section will be deleted to prevent problems.
12.
13.
c.
The chromosome will take on a circular configuration.
d.
Genes in the section that was inverted may lose normal function.
The individual indicated by the arrow in the pedigree represents a(n)
a.
healthy male.
b.
healthy female.
c.
affected male.
d.
affected female.
In gene therapy, a viral vector is mixed with bone marrow cells taken from the patient. The bone marrow cells are an example of which cell type? a.
stem cells
b.
sex cells
c.
haploid cells
d.
14.
15.
gametes
The karyotype in this image is from a(n)
a.
male.
b.
female.
c.
individual of undetermined sex.
d.
individual with an abnormal number of chromosomes.
What information cannot be determined by a karyotype? a.
the individual’s sex
b.
the number of autosomes
16.
17.
18.
c.
allele versions
d.
chromosomal deletions
In a karyotype of a male, which of the following would indicate an abnormality? a.
one X chromosome and one Y chromosome
b.
three copies of chromosome 22
c.
22 pairs of autosomes
d.
a total of 46 chromosomes
Ezra has XYY sex chromosomes, a disorder known as Jacob’s syndrome. Despite this condition, his only symptom is being slightly taller than average. Select the correct description of his sex chromosome abnormality. a.
His mother contributed an egg with two Y chromosomes.
b.
His mother contributed an egg with both an X and a Y chromosome.
c.
His father contributed a sperm with both an X and a Y chromosome.
d.
His father contributed a sperm with two Y chromosomes.
A karyotype from an adult male indicates a chromosomal abnormality that does not affect his health. Which of the following abnormalities is most likely to be seen? a.
three copies of the X chromosome
b.
no copies of chromosome 2
c.
a translocation between chromosome 14 and chromosome 15
d.
three copies of chromosome 22
19.
20.
21.
22.
In humans, X-linked genetic diseases a.
are associated with autosomes.
b.
tend to be expressed more in females than males.
c.
only affect males.
d.
tend to be expressed more in males than in females.
The sex of a human child is determined by the a.
loci.
b.
egg.
c.
presence or absence of specific autosomes.
d.
presence or absence of the Y chromosome.
In humans, the “master sex switch” that determines whether an embryo will become a male is the a.
X chromosome.
b.
locus.
c.
SRY gene.
d.
androgen allele.
Which of the following genotypes represents a human male? a.
XY
b.
YY
c.
XX
d.
XO
23.
24.
25.
26.
The gene for a certain sex-linked trait is found only on the Y chromosome. If the male parent has this gene, the trait will be expressed in a.
100 percent of the female offspring.
b.
50 percent of the female offspring.
c.
100 percent of the male offspring.
d.
50 percent of the male offspring.
The X chromosome in humans is a.
typically found as a pair in females.
b.
the only human sex chromosome.
c.
present only in females.
d.
always found in single copy.
Because an individual with an XX genotype is a female, is an individual with an XO (O = no second sex chromosome) a male? a.
No, because the X always overrides the Y and makes that embryo female.
b.
No, because the Y chromosome contains the gene that makes an embryo male.
c.
Yes, because if there is only one X, the embryo cannot become female.
d.
Yes, because all embryos start off as males.
A person is genetically XX and develops as a male. How could this be explained? a.
In humans, males are XX.
b.
An error in karyotyping this individual must have occurred, because XX individuals cannot develop into males.
27.
28.
29.
c.
A segment of a Y chromosome has become attached to one of the X chromosomes.
d.
The SRY gene was deleted in this individual.
Most inherited single-gene human genetic disorders are inherited as __________ alleles. a.
dominant
b.
recessive
c.
homologous
d.
sex-linked
A boy affected with an X-linked recessive condition will have inherited the disorder allele from his a.
noncarrier mother.
b.
noncarrier father.
c.
carrier father.
d.
carrier mother.
Both members of a couple are carriers for an autosomal recessive disease allele. If the couple has four children, which of the following statements must be true? a.
One of the children has the disease.
b.
Two of the children have the disease.
c.
All of the male children have the disease.
d.
Fifty percent of the children could be carriers of the disease.
30.
31.
32.
33.
Autosomal dominant diseases are exhibited by anyone who carries at least one dominant allele for that gene. How is it that dominant lethal genes, such as the one that causes Huntington disease, can persist in a population? a.
The disease-causing allele can “hide” in the heterozygous condition.
b.
The disease develops only under the influence of other genes.
c.
These diseases usually take effect later in life, after people have had children.
d.
The environment plays a large role in determining whether the gene is expressed.
Which of the following statements describes a pedigree that shows the inheritance pattern of a recessive X-linked disease? a.
Most affected individuals are females.
b.
Most affected individuals are males.
c.
Males and females are affected equally.
d.
The disease is seen in every generation.
In which of the following situations would looking at a pedigree be most useful? a.
An adopted boy is admitted to the hospital with recurrent vomiting.
b.
A young girl is born with diminished hearing and a cleft palate.
c.
Six unrelated individuals with similar symptoms are admitted to the hospital in a one-week period.
d.
Three young boys who are first cousins show symptoms of a neurological disorder.
The pedigree shows the inheritance pattern for an X-linked disorder. The individual indicated by the arrow is __________ for the disease allele.
34.
35.
a.
heterozygous
b.
homozygous dominant
c.
homozygous recessive
d.
There is not enough information to determine the answer.
An individual has the genotype XAXa for a sex-linked recessive condition. Select the best description of this individual. a.
affected female
b.
female carrier
c.
affected male
d.
male carrier
Why are X-linked recessive genetic disorders more commonly seen in males? a.
For an X-linked disorder to occur, an individual must receive one allele found only on the X chromosome and a second allele found only on the Y chromosome, which females do not have.
b.
Females must receive two copies of the recessive allele to exhibit the disorder, but males need only one copy.
36.
37.
c.
The alleles of sex-linked genes are carried only on the Y chromosome, which females do not have.
d.
Females only have X chromosomes and genes on the X chromosome are not expressed.
If a man is affected by an X-linked recessive condition and his wife is a carrier, what is the probability of their children being affected? a.
All sons will be affected.
b.
Half of their sons will be affected.
c.
All daughters will be affected.
d.
Half of their sons will be carriers.
Which of the following is true of the genetic cross shown in the figure?
a.
All of their daughters will be carriers.
38.
39.
40.
b.
Their sons have a 50 percent chance of being carriers.
c.
Their sons have a 50 percent chance of having the disorder.
d.
Their daughters have a 50 percent chance of having the disorder.
A female who is a carrier of the sex-linked gene A has the genotype a.
Aa.
b.
AA.
c.
aa.
d.
XAXa.
A female carrier of the X-linked recessive gene for red-green color blindness will display a phenotype of a.
normal color vision.
b.
XCXc.
c.
red-green color blindness.
d.
XCXC.
The genotype of a female carrier for the X-linked recessive condition Duchene muscular dystrophy, is represented as a.
XDY.
b.
XDXd.
c.
Xd Y.
d.
XDXD.
41.
42.
43.
If a female carrier for the X-linked recessive condition hemophilia, mates with a male who does not have hemophilia, what is the chance that their daughter will be a carrier of the gene? a.
0 percent
b.
25 percent
c.
50 percent
d.
75 percent
Use this pedigree to determine the pattern of inheritance.
a.
recessive and X-linked
b.
recessive and autosomal
c.
dominant and X-linked
d.
dominant and autosomal
Most inherited human disorders are the result of a.
recessive mutations of genes located on autosomes.
b.
dominant mutations of genes located on the X chromosome.
c.
recessive mutations of genes located on the Y chromosome.
d.
44.
45.
46.
simultaneous mutations of the same gene on homologous chromosomes.
If a recessive allele causes a fatal disease that kills the affected individual before he or she can reproduce, why doesn’t that allele quickly become extinct in the population? a.
Alleles are never lost from a population.
b.
The homozygous dominant individuals protect the recessive allele in their genomes.
c.
The recessive allele is carried in the genome of heterozygotes, who do not suffer from the disease.
d.
The homozygous recessive individuals give their alleles to other individuals before they die from the disease.
Which of the following information is available in a Punnett square showing the inheritance pattern for an autosomal recessive disorder? a.
the percentage of males likely to be affected by the disorder
b.
the percentage of females likely to be affected by the disorder
c.
the percentage of all children likely to be affected by the disorder
d.
the number of children born to the two parents
Among children with parents who are both carriers of Tay-Sachs, an autosomal recessive disorder, chances are that a.
75 percent will be carriers.
b.
50 percent will die in a few years.
c.
75 percent will not carry the recessive Tay-Sachs allele.
d.
50 percent will be carriers.
47.
48.
49.
Sickle-cell disease is an inherited chronic blood disease caused by an autosomal recessive allele. Suppose a man with sickle-cell disease fathers a child by a woman who is a carrier for sickle-cell disease. What are the chances this child will exhibit the disease? a.
0 percent
b.
25 percent
c.
50 percent
d.
75 percent
The parents in the following figure are carriers of a genetic disorder. (The child illustrated with dark shading has the disorder.) Based on the Punnett square, the allele that causes the disorder must be
a.
autosomal.
b.
sex-linked.
c.
dominant.
d.
incompletely dominant.
If two parents are heterozygous for an autosomal recessive disease,
50.
51.
a.
they are both considered genetic carriers for the disease.
b.
their children have no chance of inheriting the disease.
c.
their children have a 50 percent chance of inheriting the disease.
d.
all of their children will also be heterozygous.
If the male in generation II of the pedigree was affected but all other individuals in the pedigree remained as shown, what would the pattern of inheritance most likely be?
a.
X-linked recessive
b.
X-linked dominant
c.
autosomal recessive
d.
autosomal dominant
What information in a pedigree would indicate that a condition is likely dominant? a.
Twenty-five percent of the individuals in the pedigree have the condition.
52.
53.
b.
Two-thirds of the affected individuals are females.
c.
None of the affected individuals have unaffected parents.
d.
Most of the affected individuals are males.
If a genetic disorder is caused by a dominant allele, individuals with which of the following genotypes would be affected by the disorder? a.
AA and aa
b.
aa and Aa
c.
AA and Aa
d.
AA, Aa, and aa
Which of the following best estimates the occurrence of the X-linked recessive disorder Duchenne muscular dystrophy in all births per year as shown in the following infographic?
54.
a.
0.03 percent
b.
0.15 percent
c.
0.015 percent
d.
0.5 percent
The source of the gene needed for gene therapy treatment of sex-linked adrenoleukodystrophy (ALD) would be a(n) __________ chromosome with a __________ copy of the ALD gene. a.
X; functional
b.
Y; functional
55.
c.
X; nonfunctional
d.
Y; nonfunctional
Phenylketonuria (PKU) is a metabolic disorder that can result in intellectual disability if untreated. This recessive disorder is caused by a defective gene located on chromosome 12. The most reliable source for the functional gene needed for gene therapy would be a(n) a.
female that is heterozygous for the functional gene.
b.
male that is heterozygous for the functional gene.
c.
individual that is homozygous dominant for the functional gene.
d.
individual that does not have PKU.
56.
Y’zmin and Trey each carry a single recessive allele for cystic fibrosis, an autosomal recessive disease. What is the probability that a child born to this couple will inherit the disease?
57.
Karen and Jared produce three healthy children. The first child is a boy (Daniel) and the next two are girls (Leslie and Alice). Daniel grows up, marries Dana, and has two children with her. Their first child is a healthy baby boy and the second is a little girl who is diagnosed with phenylketonuria (PKU). Draw this family’s pedigree.
58.
A karyotype of a human female reveals a total of 45 chromosomes: 44 autosomes and one sex chromosome. Is this karyotype typical of human females? Explain your reasoning.
59.
A man with a translocation in a chromosome that does not affect gene function may not realize he has a translocation until he attempts to have a
child. Explain how a translocation that does not affect the individual may become problematic during reproduction.
60.
The chromosome on the left of the figure shown is chromosome number 5 from the father of a newborn child with cri du chat syndrome. The chromosome on the right is paternal chromosome number 5 in the child. What type of chromosomal abnormality has caused this syndrome in the child? Explain your answer.
61.
Would a karyotype for a human male be considered normal if it shows 45 autosomes and a single pair of sex chromosomes? Explain your reasoning.
62.
Explain how two brothers might have different X chromosomes but must share identical Y chromosomes.
63.
Explain why a human who has both an X and a Y sex chromosome could develop embryologically as a female instead of a male.
64.
Can a typical human male be a carrier of an X-linked trait? Explain your answer.
65.
Wiskott-Aldrich syndrome (WAS) is an X-linked recessive condition. Describe the possible genotypes and phenotypes of offspring and the probability of each category for each gender from a cross between a female carrier and a normal male.
66.
What characteristics of inheritance would allow you to distinguish whether a disorder is recessive autosomal, dominant autosomal, or X-linked?
67.
DNA testing reveals that Tina carries a single copy of a disorder allele on chromosome 4. She does not exhibit symptoms of the disease. Is it possible that she will develop the disease later in life? Explain.
68.
Does the following pedigree most likely represent inheritance of a condition that is autosomal recessive, dominant, or sex-linked? Explain your reasoning.
69.
Why are dominant genetic disorders more rare than recessive disorders?
70.
During routine genetic testing before the 2014 NBA Draft, former Baylor Bears basketball center Isaiah Austin was diagnosed with Marfan syndrome. This genetic condition results in connective tissue problems for the individual. One of the more life-threatening features of this condition is aortic enlargement, which can leave the aorta susceptible to rupture. In 75
percent of the cases, the allele is inherited from one parent; in the other 25 percent of the cases, a new mutation has occurred. Explain whether this condition is likely an autosomal disorder (recessive or dominant) or an Xlinked disorder; support your answer with information from the following infographic.
71.
Wiskott-Aldrich syndrome (WAS) is a sex-linked recessive blood disorder that results when an individual does not have any functional WAS allele. Explain where a functional WAS gene can be isolated and how genetic engineering could be used to treat a patient who has WAS.
72.
Ross is a genetic counselor working with a family that has lost a child to an unidentified illness. The family tells him there have been other children in the family history who have died after having the same symptoms. As Ross examines several generations of the family’s pedigree, he notices that females are affected as frequently as males and that parents never exhibit the symptoms. This information leads him to think this disorder has a(n) __________ mode of inheritance.
73.
If an individual has two alleles at a given locus that are different, the individual is said to be __________ for the gene.
74.
Every gene in a human occupies a specific position or __________ on a chromosome.
75.
Except for the sex chromosomes, all the chromosomes shown in a karyotype are numbered and are called
76.
Human males have one chromosome that females do not. That chromosome is the __________ chromosome.
77.
While examining the pedigree of a human female, you discover that she has 44 autosomes and two sex chromosomes, an X and a Y. This may lead you to suspect that there is a mutation within this individual’s __________ gene.
78.
A female who is heterozygous for a sex-linked recessive condition is referred to as a genetic
79.
Night blindness is a sex-linked recessive disorder. An individual who has the genotype XNXn for night blindness is considered a __________ for this condition.
80.
X-linked disorders more commonly affect males than females, because males have only one __________ chromosome.
81.
An allele that is not expressed in a genetic carrier is called a(n) __________ allele.
82.
A parent who is a carrier for the recessive autosomal disorder B has the genotype
83.
Zoe’s parents are both heterozygous for cystic fibrosis, an autosomal recessive disorder. Zoe has cystic fibrosis. The chance that any of Zoe’s future siblings will have cystic fibrosis is
84.
A horizontal line directly between a square and a circle in a pedigree indicates that those two individuals are a(n) __________ pair.
85.
As shown in the following infographic, the number of males born each year with hemophilia __________ the number of males born with Fragile X syndrome each year.
86.
A disease caused by a defective gene or genes is a __________ disorder.
87.
Researchers hope to develop treatments for sex-linked genetic disorders such as Wiskott-Aldrich syndrome (WAS), by using a virus to insert a functioning gene into the patient’s blood cells. This technique for correcting defective genes is called __________, which is one form of genetic engineering.
88.
Match each statement to the correct set of the following alleles. a.
Bb
b.
XaY
c.
XAXa
d.
bb
e.
XAXA
f.
BB
g.
XAY __ 1. homozygous recessive for an autosomal gene __ 2. heterozygous for an autosomal gene __ 3. homozygous dominant for an autosomal gene
__ 4. male affected by a X-linked recessive condition __ 5. female carrier of a X-linked gene
Answer Key Chapter08
1. Answer:
B
2. Answer:
D
3. Answer:
B
4. Answer:
B
5. Answer:
A
6. Answer:
A
7. Answer:
A
8. Answer:
B
9. Answer:
D
10. Answer:
C
11. Answer:
D
12. Answer:
B
13. Answer:
A
14. Answer:
A
15. Answer:
C
16. Answer:
B
17. Answer:
D
18. Answer:
C
19. Answer:
D
20. Answer:
D
21. Answer:
C
22. Answer:
A
23. Answer:
C
24. Answer:
A
25. Answer:
B
26. Answer:
C
27. Answer:
B
28. Answer:
D
29. Answer:
D
30. Answer:
C
31. Answer:
B
32. Answer:
D
33. Answer:
A
34. Answer:
B
35. Answer:
B
36. Answer:
B
37. Answer:
C
38. Answer:
D
39. Answer:
A
40. Answer:
B
41. Answer:
C
42. Answer:
B
43. Answer:
A
44. Answer:
C
45. Answer:
C
46. Answer:
D
47. Answer:
C
48. Answer:
A
49. Answer:
A
50. Answer:
D
51. Answer:
C
52. Answer:
C
53. Answer:
C
54. Answer:
A
55. Answer:
C
56. Answer:
Y’zmin and Trey have a one in four, or 25 percent, chance of producing a child with the homozygous recessive (ff) genotype that leads to the cystic fibrosis phenotype. Offspring with at least one dominant allele (FF and Ff) will not have cystic fibrosis.
57. Answer:
58. Answer:
This karyotype is not typical of human females. Human females usually have 44 autosomes and 2 sex chromosomes (XX). This female is missing one of her X chromosomes. She has Turner syndrome; she will likely live a long, healthy life but may have mild to moderate reproductive problems.
59. Answer:
A chromosome with a translocation contains segments from two nonhomologous chromosomes. During meiosis it is difficult for these chromosomes to align properly and segregate into separate cells because they are not completely homologous.
60. Answer:
The cri du chat syndrome in the child is caused by the deletion of some genetic material on chromosome number 5 from the father. This is represented by the absence of the lighter-toned segment that is present in the father’s chromosome number 5.
61. Answer:
A karyotype with 45 autosomes indicates that an extra chromosome (trisomy) is present. A normal male would have 44 autosomes (22 pairs) and one pair of sex chromosomes, XY.
62. Answer:
Males inherit one of their mother’s two X chromosomes, and thus brothers may inherit different X chromosomes. Their Y chromosome is inherited from their father, who only has one copy of the Y chromosome. Thus, the brothers must share an identical Y chromosome.
63. Answer:
Embryos that have both X and Y sex chromosomes typically develop as males because the SRY gene that is present on the Y chromosome acts as the “master switch” that directs the development of the embryo to display male characteristics instead of female characteristics. If the SRY gene on the sole Y chromosome that was inherited from the father is nonfunctional, then the embryo will develop as a female instead of a male.
64. Answer:
No, a typical human male cannot be considered a carrier of an X-linked trait. If the allele for the trait is present on the male’s only X chromosome, it will be expressed. There is no matching allele on his other sex chromosome, the Y chromosome, to conceal the phenotypic expression of the allele on his X chromosome. To be a carrier of a trait, one must have the allele but not express it. Rarely, a male has a genetic translocation that allows him to be XX and male.
65. Answer:
The female offspring from this cross would all have the normal phenotype (no WAS); they would have a 50 percent chance of being homozygous dominant genotype (XHXH ) and a 50 percent chance of being a heterozygous carrier of the allele (XHXh). Male offspring from this cross would have a 50 percent chance of having the allele for WAS (XhY ) and therefore a 50 percent chance of having WAS.
66. Answer:
Both recessive autosomal and sex-linked disorders appear to skip generations. X-linked disorders are indicated when more males than females are affected. Recessive autosomal disorders affect males and females equally. Dominant autosomal disorders affect males and females equally but are unable to “hide” in carriers because an individual with at least one allele will be affected; such disorders do not skip generations.
67. Answer:
Yes, it is possible. If the disease is recessive and Tina is a carrier, she will not develop the disease later. However, if the disease is autosomal dominant, she could show symptoms of the disease later in life. Huntington’s disease is an example of one such dominant genetic disorder in which symptoms only arise in a person’s 40s.
68. Answer:
The pedigree shows a disorder that is most likely autosomal recessive. The disease shown appears to be recessive because it skips generations, which indicates some individuals are unaffected carriers. Dominant disorders would appear in each generation. The disorder cannot be Y-linked because it appears in females. The disorder cannot be X-linked because individual II: 1 is unaffected.
69. Answer:
Dominant genetic disorders tend to cause serious health problems earlier in life than recessive disorders, and affected individuals may not live long enough to pass the affected allele on to children. Recessive alleles can remain in populations when they are “hidden” in heterozygous carriers. Dominant alleles cannot “hide” in the same way recessive alleles can and are always expressed in individuals who have at least one copy.
70. Answer:
This condition appears to be an autosomal disorder because it occurs with about the same frequency in both males and females. It is probably caused by a dominant allele because it can be inherited from one parent. Dominant disorders are also more likely to be produced by a new, spontaneous mutation in a generation.
71. Answer:
A functional WAS allele can be isolated from the X chromosome of a healthy male or a healthy female who is not a carrier of the defective WAS gene. The functional WAS gene can be inserted into a harmless virus. This genetically engineered virus is now used to insert the functional WAS gene into the genome of some of the patient’s own blood stem cells. These genetically engineered cells are reinjected into the patient where they reproduce and begin to produce the missing protein. This method of correcting a defective gene responsible for a disease is gene therapy.
72. Answer:
autosomal recessive
73. Answer:
heterozygous
74. Answer:
locus
75. Answer:
autosomes.
76. Answer:
Y
77. Answer:
SRY
78. Answer:
carrier.
79. Answer:
genetic carrier carrier
80. Answer:
X
81. Answer:
recessive
82. Answer:
Bb.
83. Answer:
25 percent 1 in 4 one-fourth
84. Answer:
mating
85. Answer:
is equal to equals is the same as
86. Answer:
genetic
87. Answer:
gene therapy
88. Answer:
1.
D
2.
A
3.
F
4.
B
5.
C
Name: ___________________________ Class: _________________ Date: __________
Chapter09 1.
2.
3.
4.
The two strands of a DNA molecule are held together by __________ bonds between their base pairs. a.
hydrogen
b.
amino acid
c.
phosphate
d.
protein
Along one side of a DNA molecule, the nucleotides are connected to each other by __________ bonds between __________. a.
covalent; phosphate groups and sugar molecules
b.
hydrogen; adenine and guanine
c.
covalent; bases and sugar molecules
d.
hydrogen; adjacent sugar molecules
Which of the following is NOT a base found in DNA? a.
thymine
b.
adenine
c.
guanine
d.
uracil
What part of a nucleotide accounts for the genetic variation between individuals?
5.
6.
7.
a.
sugar
b.
phosphate
c.
nitrogenous base
d.
polymerase
In a single strand of DNA, the total number of phosphate groups present is equal to the total number of __________ bases. a.
adenine
b.
adenine and thymine
c.
guanine and cytosine
d.
adenine, thymine, guanine, and cytosine
If a segment of double-stranded DNA has 20 percent adenine (A), how much of it is cytosine (C)? a.
20 percent
b.
30 percent
c.
40 percent
d.
60 percent
When bases of DNA correctly bind to the complementary strand, a.
A always pairs with T.
b.
A sometimes pairs with T.
c.
A always pairs with C.
d.
A sometimes pairs with C.
8.
9.
10.
11.
In a strand of double-stranded DNA, cytosine (C) will always be bound with a.
A.
b.
T.
c.
C.
d.
G.
If one strand of DNA has the sequence CGATT, the sequence of the other strand of the same molecule will be a.
CGATT.
b.
GCTUU.
c.
TACGG.
d.
GCTAA.
When looking at a single-stranded piece of DNA, a.
G will always be next to C.
b.
G will always be next to G.
c.
G will sometimes be next to T.
d.
G will never be next to A.
When examining the two complementary strands of nucleotides in one DNA molecule, it would be expected that the sum of __________ in one strand would be __________ the sum of the __________ in the other strand. a.
Gs and Cs; equal to; Gs and Cs
b.
Ts and As; equal to; Cs and Gs
c.
Ts and As; greater than; Ts and As
d.
As and Cs; less than; Ts and Gs
12.
13.
14.
15.
The sequence of DNA differs among individuals within a species. This is the reason for a.
mutation.
b.
protein structure.
c.
base-pairing.
d.
variations in phenotypes.
The hereditary genetic material present in all living cells is a.
carbohydrate.
b.
protein.
c.
DNA.
d.
RNA.
The order of the base pairs in a DNA molecule a.
differs from species to species.
b.
is identical in all organisms.
c.
is identical in organisms of the same species.
d.
differs from cell to cell in a given organism.
The CRISPR-Cas9 system is made up of two guide __________ molecules and two Cas9 __________ molecules. a.
RNA; protein
b.
protein; RNA
c.
DNA; protein
d.
16.
17.
18.
protein; DNA
Once attached to the proper DNA sequence, Cas9 proteins found in the CRISPR-Cas9 system __________ both strands of DNA. a.
polymerize
b.
cleave
c.
wind
d.
unwind
Targeting the pol gene in pig DNA works to remove the 62 porcine endogenous retrovirus (PERV) genes because the pol gene is typically __________ in all 62 copies of PERV genes and __________ in other pig genes. a.
lacking; present
b.
present; present
c.
present; lacking
d.
lacking; lacking
The CRISPR-Cas9 complex cuts through both strands of DNA in two neighboring sites. The chromosome does not break apart because during normal repair processes, the DNA sequences between the cut sites are a.
replaced with normal pig DNA.
b.
looped outward and remain attached to the chromosome.
c.
removed and the remaining DNA is relinked.
d.
reattached to the DNA but switched to the opposite direction.
19.
20.
21.
Before using the CRISPR-Cas9 system to edit the pig genome, it is necessary to sequence the pig DNA to identify any copies of porcine endogenous retrovirus (PERV) DNA. Knowing the PERV DNA sequences will help researchers determine which __________ sequences to use as guides for the CRISPR-Cas9 complex. a.
DNA
b.
RNA
c.
protein
d.
amino acid
Researchers used the CRISPR system to make 455 different cuts in the porcine endogenous retrovirus (PERV) pol genes in the pig genome. All of the PERV genes were inactivated in the pig embryos even though only 20 percent of the resulting mutations were larger than nine base pairs. The resulting mutations were successful at knocking out the PERV genes because a.
even single point mutations can be enough to make a gene product useless or inactivate a gene.
b.
large mutations are not useful in knocking out genes.
c.
inactivating 20 percent of the PERV genes is just as good as inactivating 100 percent of the PERV genes.
d.
only 20 percent of the PERV genes need to be inactivated to result in all of them being inactive.
It could help meet transplant needs to use a patient’s own stem cells to grow a human liver in a pig embryo modified by CRISPR. As an additional and essential step in the process to ensure the liver is safe for the patient, CRISPR should be used to a.
knock out all of the pig brain genes to prevent the pig brain cells from infecting the patient.
b.
insert human immune cell DNA into the pig embryo to make it more similar to the patient.
22.
23.
24.
25.
c.
insert human hemoglobin DNA into the pig embryo to make it possible for the growing pig to support the human liver.
d.
knock out all of the porcine endogenous retrovirus (PERV) genes to prevent infection of the human patient with porcine endogenous retroviruses.
The significance of specific base-pairing in DNA is that a.
it stabilizes the sugar molecule.
b.
it provides a method for making exact copies of DNA.
c.
it prevents errors in DNA replication.
d.
protein copies can be made directly from the DNA.
Once replication in a DNA molecule is complete, each new DNA molecule contains a.
one old strand and one new strand.
b.
the paired old strands and the paired new strands.
c.
new DNA polymerase.
d.
a new sequence of nucleotides.
When a cell divides, it a.
breaks down its DNA.
b.
deletes old genetic information.
c.
copies information from neighboring cells.
d.
copies its own genetic information.
DNA replication
26.
27.
a.
involves the copying of only the parts of a chromosome that encode protein.
b.
occurs before mitosis in the cell cycle.
c.
occurs immediately after mitosis.
d.
converts the double helix to two single helices.
The following figure shows a short sequence of DNA. During DNA replication, the piece of DNA depicted in this figure will produce
a.
one single-stranded molecule with the sequence CAGT.
b.
two single-stranded molecules with the sequence GTCA.
c.
one single-stranded molecule with the sequence CAGT and a separate single-stranded molecule with the sequence GTCA.
d.
two double-stranded molecules that look just like the figure.
Replication of DNA cannot begin until __________ bonds between __________ are broken. a.
phosphate; nucleotides
b.
hydrogen; complementary bases
c.
covalent; sugar molecules
d.
28.
29.
30.
hydrogen; nucleotides in one strand
A rapidly dividing cell is exposed to a chemical that converts the bond that forms between adenine and thymine to a stronger covalent bond. Which of the following is most likely to occur? a.
DNA replication would produce two molecules of DNA with mutations at every base that once held an A-T base pair.
b.
DNA replication would not occur because the two nucleotide strands that make up the DNA molecule would not be able to separate.
c.
DNA replication would occur more slowly because DNA repair proteins would have to fix the covalent bonds before replication could begin.
d.
DNA replication would be faster because covalent bonds require less energy to break than hydrogen bonds.
The adenine bases in a DNA molecule are radioactively labeled. The DNA is then placed in a solution containing unlabeled nucleotides and the enzymes needed for DNA replication. The DNA molecule is allowed to replicate twice, forming four new DNA molecules. The radioactively labeled adenine would be found in a.
each of the eight strands.
b.
two of the eight strands.
c.
all but one strand.
d.
six of the eight strands.
The polymerase chain reaction (PCR) is used to a.
produce many copies of a selected DNA sequence.
b.
insert DNA from one organism into a new host.
c.
screen for a particular gene.
d.
deliver DNA products into a human patient.
31.
32.
The following figure shows the first cycle in polymerase chain reaction (PCR). The structure marked “P” in this figure
a.
represents the heat-tolerant DNA polymerase used in PCR to copy the gene of interest.
b.
represents a sequence of DNA complementary to parts of the gene being amplified that allows DNA polymerase to attach to the gene.
c.
indicates where on the DNA that DNA polymerase should terminate replication.
d.
indicates the location of the promoter for the gene being amplified.
The DNA primers used in polymerase chain reaction (PCR) are a.
identical to the entire base sequence of one strand of the DNA.
b.
produced when a gene of interest is read by restriction enzymes.
c.
attached to the gene of interest by polymerase.
d.
complementary to DNA sequences at both ends of the DNA sequence of interest.
33.
34.
35.
36.
DNA polymerase is used by the cell to a.
perform gel electrophoresis procedures.
b.
cure patients of certain genetic diseases.
c.
make copies of a DNA sequence.
d.
attach DNA fragments to each other.
A detective finds a miniscule spot of blood on a murder suspect’s shirt. What method would the police lab be expected to use to get enough DNA from the blood droplet to perform DNA fingerprinting? a.
inserting the blood’s DNA into viral DNA
b.
polymerase chain reaction (PCR)
c.
inserting the sample’s DNA into a plasmid
d.
DNA sequencing
A segment of DNA in a test tube replicates and produces many copies of itself. What was probably in the test tube that enhanced this process? a.
repair enzymes
b.
DNA polymerase
c.
plasmids
d.
a mutagen
The polymerase chain reaction (PCR) technique could be developed only after the discovery of bacterial enzymes that were able to withstand high temperatures. Why was it necessary to use such enzymes? a.
Only bacterial DNA can be copied using the PCR method, so bacterial enzymes were necessary.
b.
Bacterial enzymes can bind to DNA outside of a cell.
37.
38.
c.
DNA can be cut into fragments only at high temperatures.
d.
The temperature required to separate DNA strands during PCR degrades other enzymes.
Viral DNA that has entered the pig genome and remains active is passed from generation to generation through a.
mutations.
b.
histone proteins.
c.
DNA replication.
d.
CRISPR-Cas9.
According to the following infographic, the number of references to CRISPR in the PubMed database __________ between 2016 and 2019.
39.
a.
quadrupled
b.
more than tripled
c.
more than doubled
d.
more than quadrupled
The first human trial using CRISPR and approved by the National Institutes of Health (NIH) used the system to edit a.
a mutated gene in human embryos and cure a genetic blood disorder.
b.
targeted genes in both human and mouse cells.
c.
bacterial genomes.
d.
a cancer patient’s own immune system cells.
40.
41.
42.
43.
Damaged DNA may be repaired by a special class of a.
nucleotides.
b.
proteins.
c.
deoxyribose molecules.
d.
phosphate bonds.
If DNA polymerase did not have the ability to proofread, then DNA replication would a.
not proceed at all.
b.
proceed more slowly.
c.
result in more mutations.
d.
result in additional copies of DNA.
Mismatch errors are a.
almost always corrected by mutagens.
b.
not considered mutations.
c.
almost always corrected by specialized proteins.
d.
usually caused by mutated proteins.
The following figure illustrates DNA undergoing replication. The region indicated by the arrow represents a
44.
45.
a.
single base pair.
b.
mismatch error.
c.
deletion.
d.
transformation.
Which of the following must occur for a mismatch error to be repaired? a.
DNA repair proteins identify damaged DNA.
b.
The sequence of nucleotides in the damaged DNA sequence guides the synthesis of the correct DNA sequence.
c.
DNA-eating enzymes within the nucleus destroy entire strands of damaged DNA.
d.
The damaged DNA undergoes DNA replication one more time.
Which of the following will NOT generally cause mutations? a.
chemicals
b.
radiation
c.
viruses
d.
DNA replication
46.
47.
48.
49.
A permanent change in the DNA base sequence due to an uncorrected mismatch error is called a(n) a.
point mutation.
b.
replication.
c.
repair protein.
d.
insertion.
The difference between the alleles of a single gene is a.
their DNA base sequences.
b.
the way they are copied when the cell divides.
c.
the type of lipid of which they are composed.
d.
that they are not heritable.
A scientist uses polymerase chain reaction (PCR) to compare the sequence of a disease gene and a healthy gene. The scientist finds that these two genes are identical except for one G in place of a T at position 256 in the gene. This type of mutation is a(n) a.
deletion.
b.
insertion.
c.
silent mutation.
d.
substitution mutation.
A species that lacks DNA repair mechanisms is likely to have __________ variations between individuals than a species that possesses repair mechanisms because __________. a.
fewer; there are fewer ways to change the DNA
b.
fewer; the repair mechanisms introduce more variation into the DNA sequence
50.
51.
52.
c.
more; more spontaneous mutations will go uncorrected
d.
more; without a repair mechanism, the cell’s DNA replication genes are inactivated
DNA fingerprinting is based on regions of DNA that vary between individuals. Many of these differences between individuals produce no change in phenotype. This type of mutation is a(n) a.
deletion.
b.
insertion.
c.
silent mutation.
d.
substitution mutation.
A pig’s pancreas is still not ready for transplant into a human even after inactivating all of the 62 porcine endogenous retrovirus (PERV) genes in a pig embryo. The pig’s __________ system genes would need to be manipulated to help prevent organ rejection by the human. a.
nervous
b.
immune
c.
digestive
d.
endocrine
If the human transplant patient in the following figure needs a new kidney because of a genetic mutation that has made her own kidneys nonfunctional, what additional step would need to occur to produce a functional kidney for this patient?
53.
a.
The mutation that resulted in her nonfunctional kidneys should be edited or corrected before her stem cells are inserted into the pig embryo.
b.
Mutated kidney genes can be easily corrected after the pig embryo begins to grow.
c.
Nothing else needs to be done. The kidney genes in the patient’s stem cells will have autocorrected themselves already.
d.
The mutated kidney genes should be corrected after the human kidney is harvested from the pig and before it is implanted in the human.
When one nucleotide in a single base pair is swapped out with another during DNA replication, the resulting change in the DNA is called a a.
deletion.
b.
chromosomal abnormality.
c.
point mutation.
d.
insertion.
54.
A chemical that disrupts hydrogen bonds is added to a test tube containing DNA. What would be the result of this reaction?
55.
When studying genomes of organisms, scientists often will only list the sequence of a single strand. Explain why the sequence of the second strand would be unnecessary information.
56.
Describe the building blocks of DNA and how they are bonded together to form the DNA double helix.
57.
What would you expect to find if you examined the DNA base pair sequence of the allele for a mutated cystic fibrosis transmembrane regulator gene
(CFTR) and compared it to the DNA base pair sequence of the allele for a fully functional CFTR gene?
58.
Using the following figure, describe how the two guide RNA molecules in the CRISPR-Cas9 system find the target DNA sequence.
59.
A scientist used CRISPR-Cas9 to inactivate the pol gene for DNA polymerase in the porcine endogenous retrovirus (PERV) sequences of a pig embryo. The resulting pig embryo cells were then placed in proximity of human cells, but there was no infection of the human cells by the PERVs. Why were the PERVs no longer able to infect the human cells?
60.
A chemical is found that binds to a replicating strand of DNA but does not allow the next nucleotide to bind to the growing chain. Explain how this chemical would affect cell division.
61.
A scientist adds a single polymerase and primer to a polymerase chain reaction (PCR) but does not add nucleotides. How many strands would be present after three replications if a single original strand was present? Explain your answer.
62.
You are working for a pharmaceutical company that hopes to produce genetically engineered human pancreatic amylase from rapidly reproducing E. coli cells. Your colleague has worked for months to isolate a minute amount of DNA that she suspects contains the gene for human pancreatic amylase. You need more of this DNA for testing and evaluation. Describe how you can easily produce millions of exact copies of this DNA.
63.
The cells in tissue that produces mammalian sperm cells are rapidly reproducing to provide a continuous supply of sperm cells. Considering the effect of heat on double-stranded DNA, what is likely to happen to the production of mutation-free sperm cells if this tissue is kept at a significantly warmer temperature than usual?
64.
Nitrous acid is a chemical that can react with DNA and change cytosine to uracil. If a cell is exposed to nitrous acid and some of the cytosine nucleotides in a gene are converted to uracil nucleotides, what should happen when that cell replicates?
65.
Being in the sun for short stretches of time is not as likely to cause mutations as is being in the sun for long stretches of time. Explain why longer exposure to ultraviolet (UV) is more likely to cause mutations.
66.
Are mutations always harmful? Justify your answer using an example.
67.
What would be the base sequence on the parallel strand of DNA complementing the sequence ATTGCGGGCTTA?
68.
A protein binds to the outside of a DNA strand. This protein will NOT likely bind to the __________ of the DNA nucleotides.
69.
A strand of DNA has the sequence GCAATTCG. The sequence of the complementary strand is
70.
Short lengths of DNA are wound around bundles of __________ to create a structure consisting of many nucleosomes strung together by strings of DNA.
71.
The CRISPR-Cas9 system is a combination of guide __________ and __________ proteins.
72.
The CRISPR-Cas9 system is used to generate a __________ mutation when most of the pol gene is “knocked out” and any remnants of the pol gene are nonfunctional.
73.
After the CRISPR-Cas9 system cuts a segment of DNA, the cell’s DNA repair process actually removes the DNA sequences between the cut sites. This repair process is most likely facilitated by both
74.
The enzyme that copies DNA is called
75.
In the first step of the polymerase chain reaction (PCR), the two strands of the DNA being amplified must be separated by exposing the DNA to high
76.
A new copy of a double helix that is composed of a template strand and a newly replicated strand of DNA is created using __________ replication.
77.
Cooling cycles during PCR amplification of DNA enable enzymes to build two new strands of __________ through __________ base-pairing.
78.
Exposure to ultraviolet (UV) light can alter DNA sequences in a cell. Uncorrected, these changes can lead to skin cancer. Individuals who have a mutation in a gene that produces DNA __________ protein may be at an increased risk for skin cancer.
79.
A mutation is due to the addition of two bases in a strand of DNA. This is called a(n)
80.
Compare the segment of DNA for normal hemoglobin DNA with the segment for sickle-cell hemoglobin DNA below. Sickle-cell disease is caused by a __________ mutation.
81.
Match the following terms to designate the smallest to largest. a.
gene
b.
base
c.
nucleotide
d.
genome
e.
base pair __ 1. smallest __ 2. second smallest __ 3. middle
__ 4. second largest __ 5. largest
82.
Match the following terms with the most correct definitions. a.
substitution point mutation
b.
deletion point mutation
c.
Insertion point mutation
d.
Chromosomal abnormality __ 1. One or more whole chromosomes is deleted or added to the genome. __ 2. One nucleotide is replaced with another in the DNA sequence of a gene. __ 3. One nucleotide is added into the DNA sequence of a gene. __ 4. One nucleotide is removed from the DNA sequence of a gene.
Answer Key Chapter09
1. Answer:
A
2. Answer:
A
3. Answer:
D
4. Answer:
C
5. Answer:
D
6. Answer:
B
7. Answer:
A
8. Answer:
D
9. Answer:
D
10. Answer:
C
11. Answer:
A
12. Answer:
D
13. Answer:
C
14. Answer:
A
15. Answer:
A
16. Answer:
B
17. Answer:
C
18. Answer:
C
19. Answer:
B
20. Answer:
A
21. Answer:
D
22. Answer:
B
23. Answer:
A
24. Answer:
D
25. Answer:
B
26. Answer:
D
27. Answer:
B
28. Answer:
B
29. Answer:
B
30. Answer:
A
31. Answer:
B
32. Answer:
D
33. Answer:
C
34. Answer:
B
35. Answer:
B
36. Answer:
D
37. Answer:
C
38. Answer:
C
39. Answer:
D
40. Answer:
B
41. Answer:
C
42. Answer:
C
43. Answer:
B
44. Answer:
A
45. Answer:
D
46. Answer:
A
47. Answer:
A
48. Answer:
D
49. Answer:
C
50. Answer:
C
51. Answer:
B
52. Answer:
A
53. Answer:
C
54. Answer:
The individual strands of DNA would separate and the tube would contain single-stranded pieces of DNA.
55. Answer:
The sequence of the second strand is complementary to the first strand and would not provide any additional information. It is a simple thing to determine the sequence based on base-pairing rules.
56. Answer:
The basic building blocks of DNA are nucleotides that are composed of deoxyribose, a phosphate group, and one of four nucleic acid bases. A sequence of nucleotides is linked together by covalent bonds between the phosphate of one nucleotide and the deoxyribose of the next one to form one strand; this forms one side of the ladder. The nucleic acid bases of one strand form complementary pairs with the bases of another strand. The base adenine will pair with thymine using two hydrogen bonds. The base cytosine will pair with guanine using three hydrogen bonds. These pairs connected by hydrogen bonds form the rungs of the DNA ladder. Once formed, the ladder twists into a double helix.
57. Answer:
The DNA base pair sequence for these two alleles should be similar, but there should also be one or more differences in these sequences because they code for different proteins.
58. Answer:
The two guide RNA molecules find the segments of the DNA with their complementary base sequence and link with it. These DNA segments of bases are “clustered regularly interspaced short palindromic repeats” (CRISPR).
59. Answer:
The pol gene that was originally present in the PERVs would have been essential for the virus DNA to replicate and form viral particles. The pol gene was mutated by removing (deleting) a portion of it, making this gene nonfunctional. If the viruses cannot replicate, they cannot infect other cells.
60. Answer:
This chemical would inhibit DNA replication because it would not be possible to add the appropriate nucleotide bases and complete the sequence. If DNA replication is not complete, then chromosome replication is not complete, nor are the chromosomes properly configured to enter into mitosis. This would prevent cells from dividing and might even cause cell death unless the damaged DNA is repaired.
61. Answer:
Without nucleotides, PCR cannot proceed. Therefore, only the single original strand would be present after three rounds.
62. Answer:
Polymerase chain reaction (PCR) is used to produce millions of exact copies of the DNA. The DNA is heated to separate the double strands into two single strands. These single strands are mixed with a solution of primer (short segments to start replication of DNA), DNA polymerase to form new DNA, and free-floating nucleotides. This mixture is placed in the PCR machine that will conduct a series of heating (unwinding DNA) and cooling (primers and nucleotides pair with the template DNA while the polymerase strings them all together) cycles to produce millions of copies of the desired DNA.
63. Answer:
If the sperm-producing cells are kept at too warm a temperature, the temperature might cause the hydrogen bonds between the base pairs to turn loose, leaving separated strands of DNA. If the DNA cannot form new hydrogen bonds, the cells will not be able to form new double-stranded DNA or chromosomes. There would likely be an increase in mutations.
64. Answer:
The gene with the uracil nucleotides would be mutated. During DNA replication, repair proteins would tag the damaged DNA segment for repair enzymes to cut and remove. Once the damaged segment has been removed, repair DNA polymerase would fill in the missing segment of DNA with the correct bases.
65. Answer:
Being in the sun for too long can overwhelm the repair enzymes. These enzymes may not be able to keep up with the number of errors, and mutations may remain.
66. Answer:
Mutations are not always harmful. A mutation is a change in an organism’s DNA sequence. This can either be harmful, helpful, or neutral depending on the change. For example, E. coli mutated to produce stronger toxin, which was beneficial to the E. coli cell.
67. Answer:
TAACGCCCGAAT
68. Answer:
nitrogenous bases
69. Answer:
CGTTAAGC.
70. Answer:
histone proteins
71. Answer:
RNA molecules; Cas9
72. Answer:
deletion
73. Answer:
repair proteins and enzymes repair proteins and DNA polymerase
74. Answer:
DNA polymerase
75. Answer:
heat temperatures
76. Answer:
semiconservative
77. Answer:
DNA; complementary
78. Answer:
repair
79. Answer:
insertion
80. Answer:
substitution point
81. Answer:
1.
B
2.
C
3.
E
4.
A
5.
D
1.
D
2.
A
3.
C
4.
B
82. Answer:
Name: ___________________________ Class: _________________ Date: __________
Chapter 10 1.
2.
3.
Prokaryotes lack membrane-enclosed organelles and thus do not have nuclei. Therefore, prokaryotic a.
cells are unable to undergo transcription and translation.
b.
cells do not need to undergo translation.
c.
cells do not need to undergo transcription.
d.
transcription and translation both take place in the cytoplasm.
A human gene put into a plant cell will a.
not produce a protein.
b.
produce a plant protein.
c.
produce the same protein produced in a human cell.
d.
produce a hybrid protein consisting of both human and plant components.
DNA technology can be used with all organisms because they all a.
contain antibodies.
b.
can contract the same diseases.
c.
share the same chemical DNA structure.
d.
contain the same genes.
4.
5.
6.
7.
Bacteria and humans use the same DNA components, and both kinds of cells also perform transcription and translation. Which of the following choices is a potentially significant outcome of this shared mechanism? a.
Bacteria are able to transcribe and translate human DNA, and thus they potentially could produce human proteins.
b.
Bacteria are able to transcribe and translate human DNA; thus, they could evolve into humans.
c.
Bacterial and human proteins are identical in amino acid sequence because the mechanism for producing them is the same.
d.
Bacterial and human DNA are identical in sequence because the method for producing them is the same.
Protein-coding genes specify the production of __________ as their immediate product. a.
rRNA
b.
tRNA
c.
DNA
d.
mRNA
The function of genes is to control the production of a.
enzymes.
b.
structural proteins.
c.
all proteins.
d.
amino acids.
Which of the following does NOT take place in the nucleus? a.
transcription
b.
intron removal
8.
9.
10.
c.
DNA replication
d.
translation
The order of the bases in DNA determines the order of the a.
amino acids in DNA.
b.
bases in a protein.
c.
amino acids in mRNA.
d.
bases in mRNA.
Some viruses produce an enzyme called reverse transcriptase, which causes the reverse process of transcription. Based on your understanding of gene expression, this enzyme should produce __________ from a(n) __________ template. a.
RNA; DNA
b.
DNA; RNA
c.
proteins; RNA
d.
RNA; protein
In bacteria, the antibiotic erythromycin prevents ribosomes from functioning. The most likely reason that bacteria die from treatment with erythromycin is because the antibiotic a.
inhibits transcription.
b.
inhibits translation.
c.
causes the wrong bases to be added to the growing mRNA strand.
d.
causes the wrong amino acids to be bound to the tRNA strands.
11.
12.
13.
14.
The key enzyme used during transcription is a.
RNA polymerase.
b.
DNA polymerase.
c.
rRNA.
d.
terminase.
As transcription begins, RNA polymerase binds to a segment of a gene called a(n) a.
promoter.
b.
intron.
c.
start codon.
d.
anticodon.
Which of the following is true of transcription? a.
It destroys the DNA template.
b.
The DNA molecule must unwind.
c.
Base pairing is unimportant.
d.
The end result is a protein.
If a strand of DNA has the sequence CGTAA, the RNA made from this molecule will have the sequence a.
CGTAA.
b.
GCUTT.
c.
TAGCC.
d.
GCAUU.
15.
16.
17.
18.
During transcription, a.
the DNA strands replicate, producing four mRNA molecules.
b.
each strand in the DNA molecule directs the production of an mRNA molecule.
c.
a template strand of DNA directs the production of an mRNA molecule.
d.
a template strand of DNA directs the production of a tRNA molecule.
Following transcription, the a.
strands of DNA bond back to each other.
b.
mRNA is digested.
c.
DNA molecule is broken down.
d.
ribosome is released from the tRNA molecule.
The information in a gene is encoded by the a.
introns of eukaryotic cells.
b.
amino acids that make up the genes.
c.
base sequences of the gene’s DNA.
d.
rRNA that transfers amino acids to ribosomes.
A mutation occurs in the promoter of a protein-encoding gene. How might this mutation affect the production of the protein encoded by the gene? a.
The mRNA made from this gene would exhibit the same mutation and therefore would not fold or function properly.
b.
The protein made from the promoter would have a different amino acid sequence and therefore would not function properly.
19.
20.
21.
c.
The promoter might not be recognized by RNA polymerase, so the enzyme would be unable to attach to the promoter and start transcription.
d.
The start codon would be missing from the mRNA made from this gene, so the mRNA could not be translated.
The bases present in an RNA molecule are a.
C, T, A, and G.
b.
U, A, C, and G.
c.
G, C, U, and T.
d.
U, C, T, and A.
In bacteria, the antibiotic chloramphenicol prevents amino acids from bonding. The most likely reason that bacteria die from treatment with chloramphenicol is because the antibiotic a.
inhibits transcription.
b.
inhibits translation.
c.
causes the wrong bases to be added to the growing mRNA strand.
d.
causes the wrong amino acids to be bound to the tRNA strands.
Which molecules are involved in translation? a.
DNA and RNA
b.
mDNA, tDNA, and rDNA
c.
mRNA, tRNA, and rRNA
d.
proteins, amino acids, and DNA
22.
23.
24.
25.
Which RNA molecule brings new amino acids to the growing protein chain in translation? a.
mRNA
b.
tRNA
c.
rRNA
d.
dRNA
The importance of tRNA is that it a.
carries a specific amino acid to the mRNA.
b.
reads the DNA molecule.
c.
contains codons that specify amino acids.
d.
is important in the construction of ribosomes.
Which of the following is true of rRNA? a.
It is made up of base pairs.
b.
It carries amino acids.
c.
It is not translated.
d.
It helps transcribe DNA.
Which of the lettered arrows in the diagram of translation below indicates a codon?
26.
27.
a.
A
b.
B
c.
C
d.
D
During translation, a.
many mRNA molecules work with one tRNA molecule and one rRNA molecule to produce a protein.
b.
one tRNA molecule works with paired mRNA molecules and many rRNA molecules to produce a protein.
c.
strings of bonded tRNA molecules work with one mRNA molecule and one rRNA molecule to produce a protein.
d.
one mRNA molecule works with several rRNA molecules and many tRNA molecules to produce a protein.
Consider a build-at-home bookshelf that comes with instructions and various pieces of wood as an analogy for translation. In this analogy, what would best match the job of the ribosome? a.
the instructions
b.
the person building the bookshelf
28.
29.
30.
31.
c.
the pieces of wood
d.
the bookshelf
In bacteria, the antibiotic tetracycline blocks the site where tRNA molecules enter the ribosome. The most likely reason that bacteria die from treatment with tetracycline is because the antibiotic a.
inhibits the cell from producing the mRNA.
b.
causes the tRNA molecules to randomly arrange into proteins that do not function.
c.
causes tRNA rather than mRNA to be made into proteins.
d.
prevents the bacteria from assembling essential proteins.
An mRNA molecule that is 99 bases long will create a protein composed of a.
33 amino acids.
b.
99 amino acids.
c.
33 tRNA molecules.
d.
99 tRNA molecules.
A smartphone app converts spoken English into Spanish. This is similar to the process by which __________ are converted into __________. a.
nitrogenous bases in DNA; nitrogenous bases in mRNA
b.
nitrogenous bases in mRNA; a sequence of amino acids
c.
amino acids in a protein; nitrogenous bases in tRNA
d.
nitrogenous bases in tRNA; nitrogenous bases in mRNA
Each set of three bases in an mRNA molecule codes for one of 20 specific
32.
33.
a.
rRNA molecules.
b.
nucleotides.
c.
amino acids.
d.
proteins.
The codon GAU codes for which amino acid?
a.
CUA
b.
CTA
c.
aspartate
d.
leucine
Which of the following codons codes for proline?
34.
a.
UCC
b.
CCU
c.
UUU
d.
CUU
Which of the following codons does NOT code for an amino acid?
35.
a.
UGA
b.
AUG
c.
GAU
d.
UAC
Use the following chart to determine the chain of amino acids that would be produced by the entire mRNA sequence UGUACGAUAGGCUAG.
36.
a.
ACAUGCUAUAUCCCG
b.
ACATGCTATATCCCG
c.
cysteine-threonine-isoleucine-glycine
d.
threonine-cysteine-tyrosine-isoleucine-proline
Which of the following codons codes for the same amino acid as the codon AGU?
37.
a.
AGA
b.
CGU
c.
UCA
d.
GCU
What is the sequence of the codon to which the transfer RNA shown in the following figure would bind during translation?
a.
UCG
b.
AGC
38.
39.
c.
TCC
d.
Serine
Using the following chart, what chain of amino acids would be produced by the sequence of this very short, complete gene: UAUUAUGCCUGAGUGAAUUGCUA?
a.
tyrosine-tyrosine-alanine
b.
tyrosine-tyrosine-alanine-stop-valine-asparagine-cysteine
c.
methionine-proline-glutamate
d.
methionine-proline-glutamate-isoleucine-alanine
In the genetic code, a codon is __________ bases long for __________. a.
two; all cell types
b.
three; all cell types
c.
three; bacterial cells and two bases long for plant cells
d.
40.
41.
42.
43.
three; plant cells and three bases long for bacterial cells
Which of the following is a codon? a.
U
b.
UU
c.
UUU
d.
UUUU
Which of the following is NOT a feature of the genetic code? a.
Every individual has a different genetic code.
b.
Each codon in the genetic code specifies only one amino acid.
c.
The genetic code is redundant.
d.
The same genetic code can be applied to virtually every organism on Earth.
In humans the tRNA with the anticodon AAU carries the amino acid leucine. In plants, this tRNA would a.
not have an anticodon.
b.
not carry an amino acid.
c.
carry the same amino acid.
d.
carry a different amino acid.
The expression of most genes is regulated by a.
internal signals only.
b.
external signals only.
44.
45.
46.
c.
both internal and external signals.
d.
neither internal nor external signals.
Gene expression is a.
nonvariable for cells; it is the same for all cells of the same type.
b.
highly variable; it changes for many different reasons throughout the life of a cell.
c.
set by internal factors early in the life cycle of a cell and remains the same from that point forward.
d.
set by external factors early in the life cycle of a cell and remains the same from that point forward.
Gene regulation is the ability to a.
cut out a certain region of DNA to save energy.
b.
increase or decrease protein synthesis from a given gene.
c.
change the sequence of a gene to produce a new protein.
d.
share genetic information between different organisms.
Liver cells are different from heart cells of the same organism because these cell types a.
have different genes.
b.
express different genes.
c.
have a different DNA sequence.
d.
mutated from a stem cell to produce new cell types.
47.
48.
49.
50.
A gene in a region of DNA that is wound more tightly around proteins in the nucleus will be a.
transcribed more often than other genes.
b.
transcribed less often than other genes.
c.
transcribed equally as often as any other gene.
d.
digested and recycled to produce new DNA.
In humans, the herbicide atrazine helps RNA polymerase bind to the promoter of the gene for the enzyme aromatase. As a result, a.
more mRNA for aromatase is produced.
b.
less mRNA for aromatase is produced.
c.
the production of aromatase is inhibited.
d.
aromatase is degraded by other enzymes in the cell.
In bacteria, a particular gene codes for a protein that helps the bacteria break down and use lactose as a food source. If no lactose is present, the a.
gene will be broken down, so no enzyme is made.
b.
gene will mutate to produce another, more useful, enzyme.
c.
promoter for this gene will be blocked, so RNA polymerase can’t bind.
d.
promoter for this gene will be enhanced, so RNA polymerase binds more readily.
Since 1918, at least __________ people worldwide have died as a result of an H1N1 influenza infection.
51.
a.
50,000,000
b.
50,285,000
c.
650,000
d.
52,535,000
The genes for limb-bud formation in vertebrates are active early in embryological development to produce the proteins needed to form the
developing arms and legs of the embryo; these genes become inactive once the limb-buds are formed. These genes are __________ regulated. a.
developmentally
b.
externally
c.
redundantly
d.
universally
52.
Explain how different cells in a human body, such as liver cells and skin cells, house the same genetic material but have different functions.
53.
A mutation in the promoter region of a specific gene prevents RNA polymerase from binding. How would this mutation affect the function of this gene?
54.
DNA viruses cause disease when the host cell uses the viral DNA to produce more viruses. The host cell uses the viral DNA to make viral proteins as well as more viral DNA; these are then used to produce more viruses and cause disease. In a eukaryotic cell, the viral DNA is often inserted into the host genome. Explain why viral DNA that stays in the cytoplasm would not cause disease.
55.
Transforming plants with a human gene produces a protein that is identical to the original human protein. Explain how this evidence demonstrates that the genetic code is universal, and list another experiment that could be used to further support this theory.
56.
Bacteria do not have a nucleus, and therefore do not use RNA splicing after translation. The initial mRNA that is produced is translated directly. An experiment transforms a bacterial cell and a eukaryotic cell with an identical
gene (of identical length). Explain how the proteins from each cell would differ.
57.
A mutation that changes the anticodon of a tRNA is generally much more detrimental to a cell than a mutation that changes the codon of an mRNA. Explain why this might be the case.
58.
Translate the following DNA sequence into a sequence of amino acids: TACTAAGGA.
59.
Which of the following mutations would be more detrimental to an organism: 1) a mutation that changes the codon GGU to GGA, or 2) a mutation that changes the codon AAU to AAA? Defend your choice.
60.
A short segment of a protein contains the following sequence of amino acids: tryptophan-valine-glycine. Can you determine the sequences of the mRNA and DNA used to produce this sequence? If so, what are the sequences of mRNA and DNA? If not, why not?
61.
Explain what is meant by “redundancy” in the genetic code.
62.
A silent mutation occurs where a DNA nucleotide has changed, but the resulting protein is identical to the protein produced before the mutation. Explain why such a mutation is possible.
63.
Organisms can regulate both transcription and translation to control gene expression. What is one advantage and one disadvantage of regulating transcription rather than translation?
64.
One concern with biopharming is that genes used to produce desired proteins could “escape” a laboratory setting and spread to food crops. What does it mean for a gene to “escape?” How would food crops be affected?
65.
Aromatase is a naturally occurring enzyme that can act to produce the hormone estradiol from fatty tissues in a woman’s body. Some forms of breast cancer (hormone receptor positive or HR+) are stimulated to grow by certain hormones such as estradiol. How could the production of aromatase be down-regulated in a woman at risk of or recovering from HR+ breast cancer?
66.
Why do humans not catch the flu from the flu vaccine?
67.
The genetic code is __________, which means that all cells use the same code.
68.
If a molecule of mRNA is a sentence, its bases are the letters, and the codons are the __________.
69.
The process of using an RNA template to make proteins is called __________.
70.
A researcher finds a molecule that is made of nucleotides and has a single amino acid bound to one end. This molecule is most likely a __________ molecule.
71.
A tRNA with the anticodon GGG would have the amino acid __________ bound to it.
72.
A protein that binds to the __________ of DNA down-regulates protein production by inhibiting the binding of RNA polymerase.
73.
DNA that is lightly packed will be __________ likely to be transcribed. Thus gene expression in that region is __________ or sped up.
74.
In order to produce a vaccine to promote immunity to COVID-19, researcher must first determine which __________ on the virus’s surface will cause the human body to mount a defense against it by producing antibodies, then they must isolate the gene.
75.
Identify if the following situations represent an increase or decrease in transcription or translation. a.
Transcription is up-regulated.
b.
Transcription is down-regulated.
c.
Translation is up-regulated.
d.
Translation is down-regulated. __ 1. __ 2. __ 3. __ 4. __ 5.
76.
RNA polymerase binds to the promoter more easily. Fewer RNA polymerase enzymes are produced. The mRNA molecules are broken down quickly in the cytoplasm. More ribosomes are produced. Fewer tRNA molecules are produced.
Determine whether each molecule plays a role in transcription, translation, or both. a.
transcription
b.
translation
c.
both transcription and translation __ 1. __ 2. __ 3. __ 4. __ 5. __ 6.
mRNA tRNA rRNA DNA amino acids RNA polymerase
77.
Match the descriptions to the molecules of transcription and translation. a.
mRNA
b.
tRNA
c.
RNA polymerase
d.
rRNA
e.
amino acids
f.
DNA __ 1. contains groups of nucleotides called codons __ 2. double-stranded molecule that ultimately provides a template for protein synthesis __ 3. important part of ribosomes __ 4. molecule that carries amino acids to ribosomes
78.
Match the steps of transcription and translation to the location where they take place within a eukaryotic cell. a.
nucleus
b.
cytoplasm __ 1. __ 2. __ 3. __ 4. __ 5.
79.
RNA splicing pairing of codons and anticodons recognition of a promoter gene construction of an mRNA molecule formation of a covalent bond between amino acids
Put the following steps in the process of transcription in chronological order. a.
first
b.
second
c.
third
d.
fourth
__ 1. __ 2. __ 3. __ 4.
80.
RNA splicing RNA polymerase exposes the DNA template strand RNA polymerase binds to the promoter region RNA bases are paired with DNA bases
Put the following steps in the process of translation in chronological order. a.
first
b.
second
c.
third
d.
fourth
e.
fifth __ 1. __ 2. __ 3. __ 4. __ 5.
A stop codon is reached. Recognition occurs between a codon and an anticodon. Amino acids are covalently bonded. mRNA binds to a ribosome. An amino acid chain is released.
Answer Key Chapter 10
1. Answer:
D
2. Answer:
C
3. Answer:
C
4. Answer:
A
5. Answer:
D
6. Answer:
C
7. Answer:
D
8. Answer:
D
9. Answer:
B
10. Answer:
B
11. Answer:
A
12. Answer:
A
13. Answer:
B
14. Answer:
D
15. Answer:
C
16. Answer:
A
17. Answer:
C
18. Answer:
C
19. Answer:
B
20. Answer:
B
21. Answer:
C
22. Answer:
B
23. Answer:
A
24. Answer:
C
25. Answer:
D
26. Answer:
D
27. Answer:
B
28. Answer:
D
29. Answer:
A
30. Answer:
B
31. Answer:
C
32. Answer:
C
33. Answer:
B
34. Answer:
A
35. Answer:
C
36. Answer:
C
37. Answer:
B
38. Answer:
C
39. Answer:
B
40. Answer:
C
41. Answer:
A
42. Answer:
C
43. Answer:
C
44. Answer:
B
45. Answer:
B
46. Answer:
B
47. Answer:
B
48. Answer:
A
49. Answer:
C
50. Answer:
B
51. Answer:
A
52. Answer:
Although all cells in an individual contain the same genetic material, they are able to control which genes are expressed. Controlling gene expression allows cells to control the proteins produced from different genes.
53. Answer:
If RNA polymerase is unable to bind to the promoter, transcription will not occur. Without an mRNA transcript, translation will also not occur. The affected gene will not direct the production of a protein.
54. Answer:
In a eukaryotic cell, the enzymes needed for transcription are in the nucleus. If the viral DNA remains in the cytoplasm, it will not get transcribed. This means that no viral proteins will be made.
55. Answer:
If the genetic code was not universal, this process would not produce an identical protein. The production of an identical protein requires that transcription, translation, and the genetic code are the same for plants and animals. Transforming the same gene into bacteria (or fungi, or any other living organism) would help support this theory if the same protein was again produced.
56. Answer:
RNA splicing removes introns from the mRNA, which produces a shorter final mRNA strand. Therefore, the eukaryotic cell would be translating a shorter mRNA strand and would produce a shorter protein.
57. Answer:
A mutation in an mRNA could result in the production of a nonfunctional protein. The effect on the cell depends on how important that particular protein is. A mutation in a tRNA could result in the wrong amino acid being added to many different proteins. This would potentially be more harmful to the cell because more proteins could be nonfunctional.
58. Answer:
The mRNA sequence produced from this DNA sequence is AUGAUUCCU, and the amino acid sequence is methionineisoleucine-proline.
59. Answer:
A mutation that changes the codon GGU to GGA would not change the amino acid inserted; in both cases the amino acid is glycine. This first mutation would be considered a silent mutation. A mutation that changes the codon AAU to AAA changes the amino acid from asparagine to lysine. Changing the amino acid may affect the structure and function of the protein, which would be more detrimental to the organism.
60. Answer:
There is only one codon that codes for the amino acid tryptophan. The mRNA used to insert this amino acid in a protein is UGG, and the corresponding DNA sequence is ACC. Valine and glycine are amino acids that are associated with redundancy in the genetic code; there are four codons that could produce each of them. More information would be required to determine the mRNA and DNA sequences for valine and glycine.
61. Answer:
There are 64 codons, and 61 that specify an amino acid. Only 20 amino acids are linked together to build proteins. Although each codon corresponds to a single amino acid, often multiple codons exist for each of the 20 amino acids.
62. Answer:
The genetic code is redundant. This means that more than one codon codes for each amino acid. A silent mutation results when the mRNA sequence before and after the mutation produces a different codon that coded for the same amino acid.
63. Answer:
Producing mRNA requires energy. If gene expression is regulated at the level of transcription, this energy does not have to be used. Producing mRNA takes time. If gene expression is regulated at the level of translation, proteins can be produced faster when up-regulating protein production.
64. Answer:
Food crops could incorporate a gene inserted into a plant species in a laboratory and begin producing the protein coded for by that gene because the genetic code is universal. Although the protein is desired in a laboratory setting, the effect of food crops producing the protein could be problematic.
65. Answer:
There are several points at which the expression of the gene for aromatase might be regulated. If there is a compound/drug that prevents RNA polymerase from binding to the promoter region of the gene for aromatase, less mRNA for aromatase would be transcribed, and therefore less aromatase would be produced. Additionally, it might be possible to use a drug to speed up the breakdown of mRNA once it enters the cytoplasm of the cell; this would also down-regulate the production of aromatase. Alternatively, a drug might be able to interfere with the posttranslational configuring of aromatase or increase the breakdown of aromatase once it is produced.
66. Answer:
Because the vaccine contains only either inactivated virus that cannot start an infection or protein molecules (phenotype) from the exterior of the virus. Without fully intact viral DNA (the virus’s genotype), the vaccine cannot produce a viral infection in the recipient.
67. Answer:
universal
68. Answer:
words
69. Answer:
translation
70. Answer:
tRNA transfer RNA
71. Answer:
Proline Pro
72. Answer:
promoter
73. Answer: more up-regulated 74. Answer:
protein
75. Answer:
1.
A
2.
B
3.
D
4.
C
5.
D
1.
C
2.
B
3.
B
4.
A
5.
B
6.
A
1.
A
2.
F
3.
D
4.
B
76. Answer:
77. Answer:
78. Answer:
79. Answer:
80. Answer:
1.
A
2.
B
3.
A
4.
A
5.
B
1.
D
2.
B
3.
A
4.
C
1.
D
2.
B
3.
C
4.
A
5.
E
Name: ___________________________ Class: _________________ Date: __________
Chapter 11 1.
2.
3.
Evolution is a.
not supported by scientific evidence.
b.
strongly supported by scientific evidence.
c.
not supported by the fossil record.
d.
too obscure to study.
Which of the following statements about evolution is true? a.
Evolution only results in the addition of traits to existing organisms.
b.
Evolution only results in the loss of traits from existing organisms.
c.
Evolution can result in the addition or loss of traits in existing organisms.
d.
Evolution has nothing to do with the addition or loss of traits.
Which of the following statements regarding the evolutionary history of an organism is FALSE? a.
Predictions of evolutionary relatedness based on fossil records often agree with predictions based on continental drift.
b.
Predictions of evolutionary relatedness based on fossil evidence often agree with those based on protein sequences.
c.
Predictions of evolutionary relatedness based on DNA usually contradict those based on anatomical evidence.
d.
Predictions based on DNA sequences provide the strongest evidence that two organisms are related.
4.
5.
6.
Breeding programs for farm-raised chickens result in a variety of unusual colors and feathers. Is this an example of evolution? a.
No; domesticated animals do not undergo evolution.
b.
No; evolution occurs over long periods of time and cannot be observed.
c.
Yes; chickens that are better adapted to the environment will survive and breed.
d.
Yes; the change in chicken coloration is a genetic change in the population over time.
Cultivation of corn over thousands of years has resulted in a modern corncob that looks very different from the tiny ancestral cob. Does this support the concept of evolution? a.
No; the change in corn was accidental and does not demonstrate the process of evolution.
b.
Yes; the change in corn is an example of natural selection and demonstrates the process of evolution.
c.
No; artificial selection is driven by humans rather than natural selection and does not demonstrate what occurs in the wild.
d.
Yes; artificial selection demonstrates that evolution can occur, even though the driving force was humans rather than natural selection.
Humans simulate the process of natural selection when they use ____________ to develop new varieties of crop plants that better meet the needs of farmers. a.
artificial selection
b.
gene flow
c.
habitat changes
d.
continental drift
7.
8.
9.
10.
Natural selection a.
is the principle cause of extinctions.
b.
is the principle cause of evolutionary change.
c.
occurs only in gametes.
d.
cannot occur without genetic drift.
The result of ____________ over evolutionary time spans is that alleles that allow organisms to survive and reproduce at a higher rate than other individuals become more common in the population. a.
natural selection
b.
artificial selection
c.
homology
d.
gene flow
Natural selection tends to a.
increase the commonality of characteristics that enhance survival and reproduction.
b.
decrease the number of individuals in any given population.
c.
lead to an increase in genetic drift.
d.
decrease the likelihood of adaptation.
Peppered moths are generally light in color and blend into the trunks of the trees on which they live. Populations of peppered moths found in areas where soot has blackened the tree trunks are dark in color. This example demonstrates a.
artificial selection.
b.
natural selection.
11.
12.
c.
genetic drift.
d.
vestigial coloration.
A group of scientists proposed that mammals with fur that contrasts with their background are hunted more by predators than mammals with fur that blends in with their background. After running several experiments, the scientists found that dark mice were attacked 25 percent of the time in a dark habitat and 75 percent of the time in a light habitat. The light-colored mice were attacked 25 percent of the time in a light habitat and 75 percent of the time in a dark habitat. These data a.
support the hypothesis because dark-colored mice are attacked more often in both light and dark environments.
b.
support the hypothesis because dark-colored mice were attacked more in light environments and light-colored mice were attacked more in dark environments.
c.
do not support the hypothesis because although dark-colored mice are captured more often in light environments, they are also captured more often in dark environments.
d.
do not support the hypothesis because light-colored mice are attacked more often in both light and dark environments.
One of the reasons scientists have had so much difficulty finding a cure for HIV/AIDS is that the HIV virus is quick to evolve resistance to the drugs used to treat it. What is the most likely mechanism for this type of evolution? a.
Certain versions of the virus persist longer in the presence of a drug than others. Those viruses may survive drug treatment and pass their genes to their offspring.
b.
Every time an HIV drug is taken, it randomly kills off most but not all virus particles. Those that survive repopulate the body of their host.
c.
Although all copies of a particular strain of the HIV virus are identical, some are better at “hiding” in regions of the body that drugs cannot reach, and those viruses “teach” their offspring where to hide.
d.
Some versions of the HIV virus produce chemicals that break down the drugs before they can harm the virus.
13.
14.
15.
16.
What is biological evolution? a.
the process of direct observation of the fossil record
b.
adaptations to common descent over time
c.
the unchanging nature of life on Earth
d.
change in the inherited characteristics of a group of organisms over generations
Fossils found in deeper layers are __________ than fossils found in more shallow layers. a.
older
b.
younger
c.
more informative
d.
less informative
Two fossils are found in a hillside. Fossil A was found in an upper layer, and fossil B was found in a lower layer. Which of the following statements is true? a.
A likely evolved from B.
b.
B likely evolved from A.
c.
A is likely the oldest of these fossils.
d.
B is likely the oldest of these fossils.
The fossil record a.
proves that all known species of organisms appeared at the same time.
17.
18.
19.
b.
contains strong evidence that major new groups of organisms arose from previously existing organisms.
c.
indicates that humans date back as far as the first indications of life.
d.
has often been artificially created by evolutionary biologists.
Equus (horses) have a single toe on their hoof, while Hyracotherium (the ancestor to horses) had four toes. Which of the following evidence would support this conclusion? a.
a transition fossil that has one toe
b.
an Equus fossil that has four toes
c.
a transition fossil that has three toes
d.
a Hyracotherium fossil that has one toe
Bears have thinner bones than whales. Hippopotami have intermediate bone thickness. What hypothesis does this support? a.
Hippopotami live in dense, murky waterways.
b.
Whales and bears both evolved from hippopotami.
c.
Hippopotami spend part of their time living in water and part living on land.
d.
Hippopotami are an intermediate species in the evolutionary lineage between whales and bears.
Neanderthal fossils a.
are likely to be found in layers above human fossils.
b.
are likely to be found in layers below human fossils.
c.
provide evidence of artificial selection during ancient times.
d.
20.
21.
22.
23.
disprove evolutionary theory because they are not ancestors of humans.
The fossils of Pakicetus, Ambulocetus, Rodhocetus, and Dorudon are examples of __________, demonstrating the fifteen million years of evolution between Indohyus and Balaena (modern baleen whale). a.
adaptive traits
b.
transitional fossils
c.
homologous traits
d.
analogous traits
Both humans and whales evolved from a common ancestor. Although our forelimbs are quite different, they are made of the same bones. This is an example of a(n) a.
artificial selection.
b.
homologous structure.
c.
transition fossil.
d.
vestigial structure.
Two different species may have similar features because of a.
continental drift.
b.
the fossil record.
c.
artificial selection.
d.
descent from a common ancestor.
A species of cave beetle that lives in total darkness is blind but has remnants of what looks like eyes. These “eyes” are
24.
25.
26.
a.
vestigial.
b.
homologous.
c.
analogous.
d.
convergent.
Whales have tiny thighbones embedded in the skin next to their pelvis. This is an example of a.
fossilization.
b.
genetic drift.
c.
a vestigial structure.
d.
an analogous structure.
The fact that small, nonfunctioning hind legs are found in the skeletons of many snakes suggests that snakes a.
are in the process of evolving legs.
b.
evolved from organisms with legs.
c.
are really populations of lizards with severe mutation in limb development.
d.
evolved from eels (snakelike fish).
The diagram below shows the bone structure of a whale flipper and a bat wing. Which of the following suggests that these two structures are homologous rather than analogous?
27.
a.
Both the flipper and the wing contain five fingerlike bone projections.
b.
The flipper is formed from the entire front appendage of the whale, but the wing is only formed from the hand part of the front appendage of the bat.
c.
The bones that form the five fingerlike projections in the flipper have much thicker bones than the bones that form these projections in the bat.
d.
The flipper of the whale contains more bones than the wing of the bat.
The hands of a human and the hands of a chimpanzee are similar in structure because humans a.
and chimpanzees share a recent common ancestor.
b.
evolved from chimpanzees.
28.
29.
30.
c.
and chimpanzees evolved from different organisms that lived in similar environments.
d.
artificially selected for chimpanzees with hands during domestication.
Although snakes and dogs are different species, they both have a bony vertebral column surrounding and protecting the nerve cord running down the center of their back. This column of bone is an example of a __________ trait and evidence of snakes and dogs sharing a common __________. a.
analogous; descent
b.
vestigial; ancestor
c.
homologous; ancestor
d.
vestigial; descent
The proteins and DNA of organisms that share a recent common ancestor are __________ the proteins and DNA of organisms that do not share a recent common ancestor. a.
more similar than
b.
less similar than
c.
identical to
d.
homologous to
Whale DNA is more similar to hippopotami DNA than to the DNA of any other mammal. This indicates that a.
whales descended from hippos.
b.
hippos descended from whales.
c.
hippos are whales’ closest living relatives.
d.
whales and hippos may be the same species.
31.
32.
The following image shows genetic comparisons of human, chicken, mouse, and chimpanzee. The shaded regions show nucleotide differences. This data supports that __________ are more closely related to __________ than to __________.
a.
humans; mice; chickens
b.
humans; mice; chimpanzees
c.
chickens; mice; chimpanzees
d.
chickens; chimpanzees; mice
Examine the figure below. According to this figure, which two breeds have the LEAST similar DNA?
33.
a.
Gun dog and Borzoi
b.
Gun dog and Spaniels
c.
Gun dogs and Scent hounds
d.
Sight hounds and Scent hounds
When comparing certain amino acid sequences in the protein hemoglobin of humans to those of other animals, scientists found that baboons had seven amino acids that were different than the human protein, dogs had 10 amino acids that were different than the human protein, gorillas had one amino acid that was different than the human protein, and lemurs had eight amino acids that were different than the human protein. Which of these animals is most closely related to humans? a.
baboon
b.
dog
c.
lemur
d.
gorilla
34.
35.
36.
37.
Whales and Indohyus share a more recent common ancestor than whales and fish. Which of the following is true? a.
Whales, fish, and Indohyus will all have the same amount of genetic similarities.
b.
Whales and Indohyus will have more similarities in their DNA than whales and fish.
c.
Whales and fish will have more similarities in their DNA than whales and Indohyus.
d.
Fish and Indohyus will have more similarities in their DNA than fish and whales.
How closely related two DNA molecules, and the organisms from which they came, are is measured through a.
vestigial traits.
b.
DNA sequence similarity.
c.
homologous traits.
d.
amino acids.
Pangaea is a.
the process of continental drift.
b.
the combined fossil record of ancient species.
c.
an ancient, giant continent.
d.
the result of natural selection.
Fossils of organisms that lived on Pangaea are likely found a.
mainly in Africa.
b.
mainly in Eurasia.
38.
39.
40.
c.
mainly in South America.
d.
widely dispersed throughout the world.
Two fossils of the same species are found in both Africa and South America. What does this indicate? a.
This organism evolved after the separation of Pangaea.
b.
This organism evolved before the separation of Pangaea.
c.
The fossil from South America evolved from the organism from Africa.
d.
The fossil from Africa evolved from the organism from South America.
Kangaroos are found only in Australia; these organisms a.
have few adaptive qualities.
b.
have a narrow biogeography.
c.
evolved few vestigial structures.
d.
evolved before the separation of Pangaea.
In the figure below, the region at the lower right indicated by the arrow is the only modern-day location of the freshwater lungfish. Fossils of the ancestors of the lungfish, however, have been found all over the world (dots throughout the map). What does the distribution of these fossils indicate?
41.
a.
When Pangaea separated to form smaller continents, the living ancestors of the lungfish were separated. When they died, some of them formed fossils in their new lands.
b.
The same species of lungfish evolved on all of Earth’s major landmasses after continental drift had stopped.
c.
The ancestors of the lungfish existed on Pangaea. After they died, some were fossilized. Their fossils were separated by continental drift.
d.
Lungfish were much more successful in the climates of North America than they were in the climates of South America.
The fossils of organisms that existed when the continents were connected are distributed across __________ continents than the fossils of organisms that evolved after the continents separated. a.
more
b.
fewer
c.
older
d.
younger
42.
43.
The genus Lycopodium includes plants that evolved before the breakup of Pangaea. The genus Sequoiadendron (Sequoia trees) evolved after Pangaea split into separate landmasses. Which genus would you expect to have the widest distribution of living representatives across the modern continents? a.
Lycopodium
b.
Sequoiadendron
c.
Both should be equally distributed.
d.
Both should be extinct.
By 200 million years ago, parts of the supercontinent of Pangaea had begun to drift away from each other. Laurasia (North America and Eurasia) separated from Gondwanaland (South America, Africa, Antarctica, Australia, and India). Which of the following would you expect to find?
a.
Plants and animals (and fossils) in North America and Europe and Asia would be dramatically similar.
b.
There would be little resemblance between the fossils of plants and animals found in South America and Africa.
44.
45.
46.
c.
There would be greater similarity between the plants and animals of Asia and Antarctica than between those of Asia and Europe.
d.
There would be less similarity between the plants and animals of North America and Europe than between those between North America and India.
Which of the following embryos will look similar to human embryos for the longest? a.
bird
b.
cat
c.
fish
d.
reptile
Why do human embryos develop gill slits? a.
The gill slits become the lungs.
b.
The ancestor of humans had gills.
c.
This helps the embryo breathe in the womb.
d.
This is an unexplained mutation in humans that does not exist in other animals.
Some whales have teeth as embryos but do not as adults. What is the most likely explanation of this phenomenon? a.
Whales are in the process of evolving teeth.
b.
Whale teeth appear as the result of a frequently occurring mutation.
c.
Whales evolved from organisms that have teeth.
d.
The allele for teeth is unusually common in some whale populations.
47.
48.
49.
50.
Tails are found a.
in all embryos.
b.
only in adults and begin forming late in development.
c.
only in embryos of organisms that will have a tail as adults.
d.
in embryos of a wide variety of organisms, some of which have a tail as adults and some of which do not.
Dolphin embryos develop hind limb buds, but these buds disappear after a short time. What is one mechanism to explain how this change occurs in the embryo? a.
The hind limbs are not used and atrophy.
b.
The dolphin does not have the gene for the production of hind limbs.
c.
The hind limbs are not adaptive, and dolphins with hind limbs do not survive as well.
d.
Genes that control the development of the embryo turn off the development of the hind limb.
Human and fish embryos share a number of features. Why is this? a.
Humans and fish share a common ancestor.
b.
Embryos of all organisms, plant and animal, look alike.
c.
Mutations in human and fish embryos have caused them to look alike.
d.
Humans and fish have exactly the same genes, but as they develop, different genes are turned on in fish than in humans.
The evolution of new organs usually builds on preexisting structures that are modified in form and sometimes function. The embryos of fish, amphibians, reptiles, birds, and mammals all have pharyngeal pouches or gill slits. These pouches develop into gills in adult fish, and they are used to absorb oxygen from their watery environment. These same pouches become parts of the __________ in humans.
51.
a.
lungs and heart
b.
eyes and nose
c.
ear and throat
d.
eyes and lungs
Consider the experimental design presented in the infographic below. What is the significance of growing the populations at 42.2oC? The increased growth temperature serves as a method of
a.
natural selection.
b.
common ancestry.
c.
direct mutation of DNA.
d.
artificial selection.
52.
A friend states that “evolution is just a theory because it does not have supporting evidence.” Evaluate this statement, including a list of the types of evidence used in drawing your conclusion.
53.
A population of grasshoppers, ranging in color from bright green to greenish-tan, live in a lush green grassland; their coloring helps to camouflage them in their environment and to hide from predators. Over the course of several years, a severe drought kills off the grasses, leaving mostly dry, tan-colored sand and topsoil with sparse green vegetation. Predict what the surviving population of grasshoppers will look like in the changed environment. Explain your answer and indicate which evolutionary process has occurred.
54.
Although they are protected in many countries, humans still hunt elephants for their ivory tusks. A mutation that results in tuskless elephants is increasing in frequency in some elephant populations. Is this an example of artificial or natural selection? Support your answer.
55.
Briefly propose how it could be possible that the cultivated vegetables Kohlrabi, Brussels sprouts, cabbage, cauliflower, broccoli, and kale are all the same species, Brassica oleracea (common wild mustard).
56.
Explain how an intermediate fossil can provide evidence for the lineage of current species.
57.
Oxygen in the molecules that make up teeth comes from the water and food that an animal ingests. Additionally, carbon isotopes incorporated into the
teeth and the shape of teeth can indicate what type of food an animal consumes. What “tooth evidence” would support the hypothesis that Indohyus spent a great deal of its life near or in the water and grazed on plants? Briefly explain your answer.
58.
Dogs have vestigial digits called dewclaws. Describe the most likely origin of these structures.
59.
Carpal tunnel syndrome happens when the median nerve in a person’s hand is compressed or squeezed, causing pain in the fingers. When the condition is severe enough, a surgeon can correct it by cutting through the transverse carpal ligament that is putting pressure on the nerve; this cutting of the ligament does not adversely affect the person’s ability to use his or her hand or fingers. What does this suggest about the trait of having a transverse carpal ligament? Briefly explain your answer.
60.
Placing a human gene into a plant produces the same protein as would be produced in a human. Some of the genes in plants are similar to human genes; others are very different. What does this information indicate about the relationship between humans and plants?
61.
Evaluate the DNA sequences presented below to determine which of the organisms (B, C, or D) shares the most closely related ancestor to organism A. Which organism shares the least closely related ancestor to A? Support your answer with DNA sequence similarity evidence from the figure that represents the DNA sequence for a single protein found in all four organisms.
62.
A fossil is found in Africa and South America but nowhere else in the world. What does this tell us about this organism?
63.
Dana finds a plant on the southeastern coast of North America and a very similar plant on the northwestern coast of Africa. Upon evaluating their DNA sequence similarity, she determines they had a common ancestor. How long ago should Dana predict that the common ancestor existed, and where should she expect to find fossil evidence of it or transitional forms? Support this prediction.
64.
Dolphin embryos have both forelimbs, which will become the flippers, and hind limbs, which will not develop. Explain how this supports the conclusion that dolphins are related to humans.
65.
Fish typically have eyes on the sides of their heads. The embryos of amphibians, birds, and mammals begin with their eyes on the sides of their heads, but the eyes move toward the center of the head during
development. What does this suggest about the common ancestor of these diverse animals? Provide additional supporting evidence from your reading.
66.
How can a researcher determine if the mutations to the RNA polymerase complex or the mutations in the rho gene were caused by the growth in increased temperatures or if they were merely selected for by growing the ancestral E. coli in the warmer temperatures?
67.
The increase in antibiotic resistance in E. coli as a result of treating healthy animals with antibiotics is an example of __________ driving evolution.
68.
The evolutionary process by which a population becomes better suited to its environment over time because advantageous traits are passed from one generation to the next is called __________.
69.
Humans bred cows specialized for milk production by allowing female cows that produce large quantities of milk to mate only with male cows with mothers that also produced large quantities of milk. This is an example of __________ selection.
70.
Grasshopper mice prey on venomous scorpions. Though the mice have some level of resistance to the scorpion venom, scorpions with more potent venom are better able to fend off attack by a grasshopper mouse. Over time, the population of scorpions all produce more potent venom. This is an example of __________ selection.
71.
The preserved remains of formerly living organisms are called __________.
72.
Indohyus’s thick bones made it easier for this animal to wade and dive in water to evade predators and find plants to eat on the river bottom. This is an example of a(n) __________, a feature that gives an individual improved function in a competitive environment.
73.
The human appendix is an example of a(n) __________ structure.
74.
An organism from which more than one species has evolved is referred to as a(n) __________. The group of organisms arising from it have a common descent.
75.
The __________ would have DNA most similar to the Borzoi.
76.
DNA is the genetic (hereditary) material found in all living things on planet Earth. The genetic code is the same for everything from bacteria to plants and humans; this is evidence that the great diversity of life evolved from a __________.
77.
Continental drift is the __________ of Earth’s landmasses through geologic time.
78.
The geographic locations where an organism (or its fossils) can be found are described as the species’ __________.
79.
The study of organisms prior to birth or hatching is called __________.
80.
Human embryos have webbing between their fingers and toes, but genes turn on during development that cause this webbing to dissolve before birth. Tiktaalik and other early amphibians had lobed fins or limbs. This evidence supports the hypothesis that humans and amphibians had a __________.
81.
The E. coli populations that survived the selective pressure of growing at warmer temperatures did so because of __________ present in their DNA.
82.
Match each example to the type of evidence supporting evolution. a.
comparative embryology
b.
fossil evidence
c.
comparative anatomy
d.
comparative DNA
e.
biogeographic evidence __ 1. Human and chimpanzee insulin genes are 98 percent similar. __ 2. Dolphins develop hind limb buds, but these structures disappear before adulthood. __ 3. Bats have the same forelimb bones as humans, but the size of these bones differs. __ 4. The freshwater lungfish Neoceratodus fosteri is found on every continent except Antarctica. __ 5. Indohyus (an extinct ancestor to the whale) has whale-like ears and slender legs tipped with hooves.
Answer Key Chapter 11
1. Answer:
B
2. Answer:
C
3. Answer:
C
4. Answer:
D
5. Answer:
D
6. Answer:
A
7. Answer:
B
8. Answer:
A
9. Answer:
A
10. Answer:
B
11. Answer:
B
12. Answer:
A
13. Answer:
D
14. Answer:
A
15. Answer:
D
16. Answer:
B
17. Answer:
C
18. Answer:
C
19. Answer:
B
20. Answer:
B
21. Answer:
B
22. Answer:
D
23. Answer:
A
24. Answer:
C
25. Answer:
B
26. Answer:
A
27. Answer:
A
28. Answer:
C
29. Answer:
A
30. Answer:
C
31. Answer:
A
32. Answer:
A
33. Answer:
D
34. Answer:
B
35. Answer:
B
36. Answer:
C
37. Answer:
D
38. Answer:
B
39. Answer:
B
40. Answer:
C
41. Answer:
A
42. Answer:
A
43. Answer:
A
44. Answer:
B
45. Answer:
B
46. Answer:
C
47. Answer:
D
48. Answer:
D
49. Answer:
A
50. Answer:
C
51. Answer:
D
52. Answer:
The word "theory" is commonly used to describe an untested hunch or guess without supporting evidence. However, scientifically, a theory is a well-substantiated explanation of an aspect of the natural world that can incorporate laws, hypotheses, and facts. Scientific theories require substantial evidence. Evidence for evolution includes direct observation, fossil evidence, shared characteristics among living organisms, comparative DNA, comparative embryology, and biogeographic evidence.
53. Answer:
The surviving population of grasshoppers will most likely be a greenish-tan color. The bright green grasshoppers will be more easily seen and eaten by their predators as the environment becomes less green. Once they are eaten, they will be unable to pass on their genes to the next generation of grasshoppers. As more of the greenish-tan grasshoppers survive to pass their genes to the next generation, there will be fewer bright green grasshoppers in the population. This is an example of adaptation, an evolutionary process by which a population becomes better suited to survive in its environment. It is driven by natural selection of the individuals who survive and reproduce at a higher rate; in this case, that would be the bettercamouflaged greenish-tan grasshoppers.
54. Answer:
This is an example of natural selection because humans are not directly selecting which animals breed. Humans are acting more as a predator in this example because they are killing individuals that have something the human desires. The elephants that are not appealing to the predator are able to survive and reproduce.
55. Answer:
The process of artificial selection makes this possible. Desired traits from the wild mustard were chosen and selectively bred for by humans to exaggerate those traits. By breeding only the plants that exhibited the selected traits, the traits became more established in the population with each generation.
56. Answer:
Intermediate fossils show some characteristics that are similar to their ancestral group and some characteristics that are similar to their modern-day organism. They also show transition characteristics in between the two organisms. This evidence is used to support lineages because it can show how the evolutionary process progressed.
57. Answer:
Examination and testing of the oxygen and carbon molecules present in the fossilized teeth of Indohyus showing results similar to (or matching) those found in modern water-going mammals who eat plants would support the hypothesis that Indohyus lived near or in water and grazed on plants. Additional support of the hypothesis would be if Indohyus’s teeth are shaped like those of modern plant-eating, water-going mammals. Comparing the fossils of extinct organisms to organisms alive today can provide evidence about the appearance and structure of extinct organisms and their lives.
58. Answer:
The ancestor of dogs had more digits than modern dogs. These structures were not harmful and were not selected against, and so remained.
59. Answer:
This would suggest that the transverse carpal ligament is a vestigial trait humans no longer need. Though it does not typically cause a problem for most people, it can become bothersome over time for others. Since cutting it does not adversely affect the person’s use of his or her hand or fingers, it would appear that it no longer actually serves any detectable function. It probably served some function in the evolutionary past of humans, or it would not be present today.
60. Answer:
The similarity of some genes indicates that humans and plants had a common ancestor at some point. However, the differences in other genes indicate that this common ancestor existed a very long time ago.
61. Answer:
It is clear that organisms A and D are most closely related with respect to this DNA sequence. There is only one base pair difference between A and D, while there are five base pair differences between A and C. A and B are most distantly related because there are sixteen base pair differences between their sequences. The fewer number of base pair differences indicates closer DNA sequence similarity and a closer shared ancestor. The greater number of base pair differences indicates a greater disparity in the DNA sequence similarity and a more distant shared ancestor.
62. Answer:
The organism lived prior to the breakup of Pangaea but had a very narrow habitat.
63. Answer:
The common ancestor of these plants would probably have existed before the supercontinent of Pangaea began to drift apart about 200 million years ago. The best places to look for fossil evidence of the common ancestor and any transitional forms would probably be in the same areas where the modern species is found (southeastern coast of North America and northwestern coast of Africa), in layers of earth that date back more than 200 million years ago.
64. Answer:
Dolphin embryos have four limbs because dolphins evolved from the same four-limbed ancestor as did humans.
65. Answer:
This suggests that these diverse groups of animals had a common ancestor in the fishes. Additionally, the embryos of fishes, amphibians, reptiles, birds, and mammals all develop pharyngeal gill slits (pouches). These pouches become the gills of adult fish, but in mammalian embryos they typically become parts of the ear and throat. These common patterns of development reflect the patterns of descent from a common ancestor, in this case, a fish.
66. Answer:
The researcher can sequence DNA samples from the original 115 ancestral E. coli populations in step one to determine if the mutations are already present in the population before it is subjected to the higher temperatures. If the mutations are already present in some of those 115 ancestral populations, then the high growth temperatures simply artificially select for those individuals who have the mutations. If the mutations are not present in the original populations, then the high growth temperatures may be contributing to the mutation of the E. coli DNA.
67. Answer:
natural selection
68. Answer:
adaptation
69. Answer:
artificial
70. Answer:
natural
71. Answer:
fossils
72. Answer:
adaptive trait
73. Answer:
vestigial
74. Answer:
common ancestor
75. Answer:
Afghan hound
76. Answer:
common ancestor
77. Answer:
movement
78. Answer:
biogeography
79. Answer:
embryology
80. Answer:
common ancestor
81. Answer:
mutations
82. Answer:
1.
D
2.
A
3.
C
4.
E
5.
B
Name: ___________________________ Class: _________________ Date: __________
Chapter 12 1.
2.
3.
Evolution can be described as a.
predesigned change in the genetic characteristics of a population of organisms over time.
b.
sudden shifts in the genetic characteristics of an individual in a population.
c.
a change in the genetic characteristics of a population of organisms over time.
d.
isolation of populations due to geologic forces.
Evolutionary changes occur when __________ acts upon populations containing individuals with genetic differences. a.
continental drift
b.
natural selection
c.
weather
d.
mutation
An example of evolution that has been readily observed is a.
a chameleon changing colors as it moves from a leaf of one color to a leaf of another color.
b.
increased resistance of bacteria to an antibiotic that is used to kill them.
c.
chimpanzees learning sign language.
d.
humans teaching dogs to obey certain commands.
4.
5.
6.
7.
What is the total number of alleles present for any given gene in a population of 100 individuals? a.
50
b.
100
c.
200
d.
400
A gene has two alleles, D and d. The frequency of the D allele in the population is 0.2. What is the frequency of the d allele in the population? a.
0.2
b.
0.4
c.
0.64
d.
0.8
If a given population has 30 RR individuals, 10 Rr individuals, and 10 rr individuals, what is the allele frequency of R? a.
0.1
b.
0.3
c.
0.5
d.
0.7
Jean-Baptiste Lamark proposed that populations evolve when traits acquired during the lifetime of a parent are passed down to offspring. What is wrong with this proposal? a.
Only changes in the DNA sequence of an organism can be inherited. Traits acquired throughout life generally do not directly involve DNA.
b.
The environment chooses which traits are necessary for survival rather than the individual.
8.
9.
10.
c.
Changes in a species occur at the individual level rather than at the population level.
d.
The inheritance of acquired traits would not lead to speciation because it would cause all of the individuals in a population to become more similar.
New alleles emerge in a species via a.
nonrandom mating.
b.
allele frequency.
c.
genetic drift.
d.
mutation.
Which of the following is true with regard to mutations? a.
Mutations occur in response to environmental pressures.
b.
Mutations are more common in slowly growing organisms.
c.
Mutations appear without regard to environmental pressures.
d.
Several mutations must occur at one time for a new phenotype to appear.
Insecticides are used to kill insects. However, insecticide-resistant insects are being found. What is the mechanism for this new insect trait? a.
An insect with a random mutation is not killed by the insecticide and reproduces.
b.
Exposing insects to insecticides leads to mutations, which make the insects resistant.
c.
Human interference with natural processes leads to genetic drift, which results in resistant insects.
d.
Insecticides kill all the insects in a population, and a different species of resistant insects colonizes the available resources.
11.
12.
The color of a certain species of beetle is determined by a single gene. Two beetles homozygous for green coloration (meaning they have two copies of the green allele) produce a single offspring with brown coloration. Brown color appeared in this offspring as a result of a.
bottleneck.
b.
gene flow.
c.
genetic drift.
d.
mutation.
Alex is a student with Strep throat (caused by a strain of bacterium) who is given a prescription for an antibiotic and is told to take the drug for two weeks. After a week, he feels better and stops taking the drug. Two months later, Alex again shows symptoms of Strep throat and decides to finish the leftover antibiotic rather than going to the doctor again. Two months after that, he develops Strep throat for a third time and returns to the doctor. This time, the antibiotic does not work. The doctor runs a test and discovers that the bacterial strain Alex is carrying is antibiotic resistant. What most likely happened? a.
Because the use of antibiotics lowers the effectiveness of the immune system, the student continually reinfected himself with the bacteria. The third time, the student happened to be reinfected with a resistant strain.
b.
When the student stopped taking the drug, a small number of bacteria—those that were more drug resistant—still survived in his body. Those bacteria repopulated his throat and, over time, drugresistant alleles became more common.
c.
The student must have eaten produce that had been genetically engineered with antibiotic-resistant genes. When he consumed them, the bacteria in the student’s throat picked up these genes through horizontal gene transfer.
d.
The antibiotic caused mutations in the bacterium. The more exposure to the antibiotic, the more mutations.
13.
14.
15.
16.
Which of the following is NOT a mode of natural selection? a.
directional selection
b.
disruptive selection
c.
dormant selection
d.
stabilizing selection
Disruptive selection operates whenever a.
natural selection is disrupted by genetic drift.
b.
there is a balanced gene pool.
c.
only the smallest individuals survive.
d.
both extremes of the phenotype are more successful.
When robins lay a clutch of more than four eggs, their chicks are often malnourished because they have so many to feed. If the robins lay fewer than four eggs, they may not have any viable offspring. As a result, robins typically lay a clutch of four eggs. This is an example of a.
disruptive selection.
b.
directional selection.
c.
stabilizing selection.
d.
convergent evolution.
The population of a cactus species in a particular area has two to seven spines with an average of four spines per square centimeter of surface area. Cacti with fewer than four spines per square centimeter are more easily eaten by the wild boars thriving in the area. Over time, the population of this cactus species in this area have an average of six spines per square centimeter of surface area. This is an example of a.
disruptive selection.
17.
18.
19.
b.
directional selection.
c.
stabilizing selection.
d.
genetic drift.
When individuals with intermediate values of an inherited phenotypic trait, like head circumference at birth, have an advantage over other individuals in the population, __________ is the apparent pattern of natural selection. a.
genetic drift
b.
disruptive selection
c.
directional selection
d.
stabilizing selection
In a shallow bay, a population of oysters is the food source for the local crabs. The lightest colored oysters blend with the color of the rocks, and the darkest colored oysters are concealed in the shadows cast by the rocks. Oysters with an intermediate coloring are easily detected by the crabs and become a tasty meal for them. Over time, fewer and fewer oysters display the intermediate coloring, while more oysters are either the lightest coloring or the darkest coloring. This is an example of a.
stabilizing selection.
b.
directional selection.
c.
disruptive selection.
d.
genetic drift.
Natural selection acts directly on __________ that increase survival and reproductive success. a.
genotypes
b.
allele frequencies
20.
21.
22.
c.
bottlenecks
d.
phenotypes
Several related bird species live in a desert. One species is much smaller than the other species. This small species nests in holes in cacti. Because the bird is so small, it can easily squeeze between the spines of the cactus and create a well-protected nest. This is an example of a.
genetic drift.
b.
mutation.
c.
natural selection.
d.
gene flow.
Two different species may have similar features because of a.
genetic drift.
b.
the founder effect.
c.
a bottleneck.
d.
descent from a common ancestor.
Convergent evolution occurs when natural selection causes distantly related organisms to a.
evolve into the same species despite the fact that they are members of separate populations.
b.
merge into one continuous population because of reversals in continental drift.
c.
evolve both analogous and homologous characteristics.
d.
evolve similar structures in response to similar environmental challenges.
23.
24.
25.
26.
Two unrelated species evolving to look more similar due to environmental pressures is called a.
gene flow.
b.
genetic drift.
c.
convergent evolution.
d.
divergent evolution.
Convergent evolution produces a.
genetic drift.
b.
lines of common descent.
c.
homologous traits.
d.
analogous traits.
Both insects and humans evolved jointed legs to allow locomotion on land. These structures are considered analogous because insects and humans a.
stopped evolving at different times in Earth’s history.
b.
evolved from different ancestors.
c.
cannot breed.
d.
faced different environmental challenges during evolutionary time.
Some finches on the Galápagos Islands eat insects, an unusual food for finches to eat. These finches a.
evolved from a lineage of birds other than finches that ate insects.
b.
learned their habits from local birds.
c.
switched to insects because they tasted better than their usual food.
d.
27.
28.
29.
30.
fill roles that birds other than finches would fill in other places.
The common ancestor of birds and bats had forelimbs but not wings. The wings on the forelimbs of birds and bats are quite different structurally. The bird wing is covered by feathers, and the bat wing consists of a thin layer of stretched skin. Select the correct statement regarding bird and bat wings. a.
Bird and bat wings are analogous traits due to shared ancestry.
b.
Bird and bat wings are homologous traits due to convergent evolution.
c.
Bird and bat wings are analogous traits due to convergent evolution.
d.
Bird and bat wings are homologous traits due to shared ancestry.
Mammals and octopuses independently evolved similar complex camerastyle eyes. This is an example of a.
convergent evolution.
b.
divergent evolution.
c.
disruptive selection.
d.
directional selection.
The central driver of evolution is a.
gene flow.
b.
genetic drift.
c.
natural selection.
d.
disruptive selection.
Which of the following is an example of gene flow? a.
mutation
31.
32.
33.
b.
genetic drift
c.
horizontal gene transfer
d.
sexual selection
For a population to evolve, there must be genetic differences between organisms in that population. These differences arise by a.
mutation.
b.
a change in an organism’s behavior.
c.
natural selection.
d.
common descent.
Genetic variation is based on a.
the inheritance of alleles accumulated during the lifetime of an individual.
b.
differences in genotypes between the individuals in a population.
c.
the accumulation of mutations in somatic cells (as opposed to gametes).
d.
the formation of new combinations of alleles during asexual reproduction.
Ultraviolet (UV) light causes mutations within skin cells. Is UV light a major driving force in the evolution of animals? a.
Yes; UV light is always present outside and can produce both favorable and harmful mutations in skin cells. Only the favorable mutations will be passed on to the next generation.
b.
Yes; a mutation in the skin cell will result in an organism that is better protected from the sun. This individual will be more likely to survive and pass on this mutation to the next generation.
34.
35.
36.
c.
No; only mutations in gametes will be passed on to the next generation. Only mutations that are passed on to offspring contribute to evolution.
d.
No; only mutations that have a favorable adaptive quality will be passed on to the next generation. UV light produces only harmful mutations.
A mutation in a gene produces the identical protein to the original gene and, therefore, an identical trait. Will evolution act upon this mutation? a.
No, because evolution acts upon phenotypes.
b.
Yes, because evolution acts upon phenotypes.
c.
Yes, because mutations contribute to evolution.
d.
No, because mutations do not contribute to evolution.
Gene flow occurs a.
as a result of genetic drift.
b.
when an individual migrates between two otherwise isolated populations of a species.
c.
as a result of mutations in one population but not in another.
d.
when individuals within a population interbreed.
During gene flow, a.
chance events alter the gene pool of a population.
b.
alleles exchange between populations.
c.
gametes circulate within a population.
d.
crossing-over creates new combinations of alleles during gamete formation.
37.
38.
39.
40.
While on a camping trip, Brian collects a white tadpole from a pond and takes it home. The tadpole develops into a white bullfrog. When the frog gets too big, he releases it into a local pond. The next year, several white bullfrogs are observed in the pond. This is an example of a.
conjugation.
b.
natural selection.
c.
gene flow.
d.
sexual selection.
Gene flow between two populations a.
makes the genetic composition of the two populations more similar.
b.
eliminates harmful alleles.
c.
magnifies the effects of genetic drift.
d.
creates genetic differences between the populations.
Which of the following is NOT a step in the evolutionary process? a.
Mutation results in the formation of new alleles, and sexual reproduction results in new combinations of alleles.
b.
New genes are introduced into a population when members of that population mate with members of other species and produce offspring.
c.
Genetic variation is inherited by the next generation of a population.
d.
Genetic drift, gene flow, and natural selection cause allele frequencies to change over time.
The illustration shows an example of
41.
42.
a.
gene transfer.
b.
genetic drift.
c.
natural selection.
d.
mutation.
An example of gene flow would be if pollen from a population __________ plant lands on __________. a.
1; the same plant (mating with itself)
b.
1; another population 1 plant
c.
1; a population 2 plant
d.
2; two other population 2 plants
In the illustration, the flying bird from a distant population moves permanently into the population shown on land. As a result, the allele frequency of A in the population on land changes from
43.
a.
1 to 0.75.
b.
0 to 0.25.
c.
0 to 0.75.
d.
1 to 0.25.
Select the correct statement regarding natural selection and sexual selection. a.
Sexual selection is a form of natural selection that acts on phenotypes that give individuals advantages in mating opportunities.
b.
Sexual selection specifically targets individuals of the opposite sex, whereas natural selection is a random process.
c.
Sexual selection transfers alleles between populations, whereas natural selection acts on individuals within a population.
d.
Sexual selection is a permutation of genetic drift that influences which individuals in a population actually reproduce each generation.
44.
45.
46.
47.
Sexual selection can result in an increased frequency of alleles, which a.
may be harmful to the individual’s survival but is always beneficial to its reproductive rate.
b.
are always beneficial to the individual’s survival but may be harmful to its reproductive rate.
c.
are always beneficial to both the individual’s survival and reproductive rates.
d.
may be harmful to both the individual’s survival and reproductive rates.
What is genetic drift? a.
gene mutation within, or between, populations
b.
chance evolutionary change occurring in small populations
c.
natural selection acting on large populations
d.
shifts in allelic frequencies due to mutation
A population of 8,250 mice occupies the sand dunes in a coastal area. A severe hurricane washes out several miles of sand dunes. As a result, only 50 mice remain. The population has experienced a.
horizontal gene transfer.
b.
gene flow.
c.
a founder effect.
d.
a genetic bottleneck.
Which of the following statements concerning evolution is FALSE? a.
Natural selection requires variation in the population.
48.
49.
50.
b.
An individual that is better adapted than others in a population will always be more reproductively successful.
c.
Genetic drift causes little evolutionary change in large populations.
d.
Evolution involves a change of frequency of alleles in the gene pool.
Compared to a large mainland population, genetic drift in a small island population is__________ important because__________. a.
less; there is less variation with which to work
b.
less; only a few individuals do all the breeding
c.
more; of a smaller gene pool.
d.
more; of the absence of competition.
A used car is shipped from Australia to the United States. Stowed away in the trunk of the car is a piece of wood infected with Australian termites. Once in the United States, the buyer of the car finds the rotting wood and dumps it on the side of the road. The termites survive and establish a colony on the side of the road but do not mate with local termite populations. This is an example of a.
genetic drift.
b.
mutation.
c.
natural selection.
d.
gene flow.
A fisherman catches and removes one trout from each of two ponds. Pond A contains 100 trout and pond B contains 1,000 trout. Which population is more affected by the fisherman? a.
Pond A; the fisherman has a greater likelihood of completely removing alleles from the gene pool by taking a fish from the smaller population.
51.
b.
Pond A; fewer fish are able to move into a small pond and find mates.
c.
Pond B; the fisherman is more likely to catch a fish that is undergoing evolution in a bigger population.
d.
Pond B; the process of evolution occurs more slowly in large populations and removing a fish speeds up the process.
Although millions of prairie chickens once occupied Illinois, in 1993 only 50 remained. Starting in 1992, scientists moved almost 300 prairie chickens from large populations in other states to Illinois to __________ Illinois prairie chicken populations. a.
prevent the development of nonheritable mutations in
b.
introduce genetic variation back into
c.
induce stabilizing selection in
d.
cause genetic drift in
52.
In an original population of 30 mice, the frequency of dark-fur-pigment alleles is 57 percent and the frequency of white-fur-pigment alleles is 43 percent. Ten generations later, the population of 30 mice now has 28 darkfur-pigment alleles and 32 white-fur-pigment alleles. What are the new allele frequencies? Is there evidence of ongoing evolution? Explain.
53.
Evaluate the accuracy of this statement: Introduction of a predator species can cause a population of prey to evolve by natural selection. Explain how you reached your conclusion.
54.
A friend states, “Exposing bacteria to antibiotics causes the cells to mutate to become antibiotic resistant.” Explain to your friend why they are incorrect and provide the correct explanation.
55.
Evaluate the accuracy of the following statement: “Individuals evolve by becoming more adapted to their environment.” Explain how you reached your conclusion.
56.
Propose an explanation for why the circumference of newborn babies’ heads would act as a stabilizing selective force in a population of humans that does not have access to modern medical care.
57.
Bees and hummingbirds are very good accidental pollinators. When they visit flowers to extract nectar, they pick up pollen from a flower and carry it to the next flower that they visit; this helps to distribute the pollen and the genes carried in the pollen to a different plant. Explain how bright red wildflowers that easily attract bees and hummingbirds might become more prevalent in a wildflower population of both red and white flowers through natural selection.
58.
New-world vultures are related to raptors, while old-world vultures are more closely related to storks. However, both of these birds eat carrion (decaying animals) and have a similar beak structure. Explain how this similarity in beak structures arose.
59.
Provide an example of analogous traits in two organisms and explain how/why those traits evolved in such distantly related organisms.
60.
a) According to the timeline, did it take longer for bacteria to become resistant to methicillin or vancomycin? b) Considering all of the antibiotics shown, it appears that bacterial resistance is expected at some point after introduction of each new antibiotic. What then, can be done to help prevent antibiotic resistance in our society?
61.
Explain why a mutation in an individual’s skin cells does not directly contribute to evolution.
62.
In the figure, the migrating bird is successful at introducing the recessive allele a into population 2 and producing offspring with the Aa genotype. Over time, these offspring mate with each other to produce offspring. Birds of various genotypes from both populations fly back and forth between the populations sharing alleles. Predict the outcome of genotype or allele frequency changes in these two populations after many generations.
63.
Two populations of mice exist: one lives in an area with light rocks, and the other lives in an area of dark rocks. A mouse with dark-colored fur from the population living on dark rocks migrates to the area of light rocks and breeds with mice there. Will this alter the allele frequency in the population? Discuss changes that may or may not be seen in the next generation and in following generations.
64.
Compare and contrast bottleneck and founder effect.
65.
Around 12,000 years ago, a massive extinction event decimated about 75 percent of the world’s large mammal populations. A small number of cheetahs survived this event and began to reproduce. Discuss the implications of this event on the genetic diversity of today’s cheetah population.
66.
Although the process of mutation is random, ___________, the primary mechanism of evolution, is nonrandom.
67.
Evolution occurs when there are changes in the frequencies of alleles and genotypes in a(n) __________ over time.
68.
A scientist is studying beak length in a species of hummingbird. The scientist establishes a population of birds with beaks ranging from very small to very long and allows the population to breed for 10 years. At the end of the experiment, she finds that the majority of birds in the population have very long beaks. This is an example of the __________ selection pattern of natural selection.
69.
When individuals with intermediate phenotypes have an advantage over all others in the population, such as the case with human birth weight in the 1930s–1940s, __________ selection is the likely mechanism of evolution responsible.
70.
Natural selection acts on __________, whereas populations evolve.
71.
When similar environmental pressures, such as permafrost in low-altitude tundra and permafrost in high-altitude alpine tundra, cause genetically distantly related organisms to evolve similar structures for survival and reproduction under similar conditions, __________ has occurred.
72.
Convergent evolution results in __________ traits, such as wings in insects and birds.
73.
A new allele may arise in a species via random ___________ of DNA in an individual.
74.
Natural selection and other mechanisms of evolution act upon the __________ that result from the novel genotypes produced by mutations.
75.
Bacteria often store genes on small, circular pieces of DNA called plasmids. The process of transmitting these plasmids and the genes they contain to other bacteria is called ____________ gene transfer and is an example of gene flow.
76.
Two populations of geese live near each other. As time passes, the populations are becoming more genetically alike. This is probably due to __________.
77.
The random changes in allele frequencies in a small population due to which individuals happen to reproduce each generation is referred to as __________.
78.
If the size of a population drops for at least one generation and causes a loss of genetic variation, a __________ occurs.
79.
Between 1980 and 1999, the Food and Drug Administration (FDA) approved 52 new antibacterial drugs. Only 24 new antibacterial drugs gained approval between 2000 and 2019. As doctors continue to prescribe the available antibiotics, populations of microbes will develop ___________ to these antibiotics.
80.
Match each example to one of the processes below. a.
genetic drift
b.
genetic bottleneck
c.
founder effect
d.
gene flow
e.
natural selection __ 1. An area consists of dark and light rocks. Mouse populations that live on the dark rocks tend to be darkly colored; mouse populations that live on the light rocks tend to be lightly colored. __ 2. By chance, certain individuals in a pack of six wolves mate during one breeding season, while other wolves in the pack do not mate. __ 3. Several bison are rotated from a herd in Montana to a herd on a wildlife preservation in Iowa. __ 4. Overfishing results in an endangered fish population with a very small population size. __ 5. Algae attach to a boat motor and are transported to a new lake, where they establish a new colony.
Answer Key Chapter 12
1. Answer:
C
2. Answer:
B
3. Answer:
B
4. Answer:
C
5. Answer:
D
6. Answer:
D
7. Answer:
A
8. Answer:
D
9. Answer:
C
10. Answer:
A
11. Answer:
D
12. Answer:
B
13. Answer:
C
14. Answer:
D
15. Answer:
C
16. Answer:
B
17. Answer:
D
18. Answer:
C
19. Answer:
D
20. Answer:
C
21. Answer:
D
22. Answer:
D
23. Answer:
C
24. Answer:
D
25. Answer:
B
26. Answer:
D
27. Answer:
C
28. Answer:
A
29. Answer:
C
30. Answer:
C
31. Answer:
A
32. Answer:
B
33. Answer:
C
34. Answer:
A
35. Answer:
B
36. Answer:
B
37. Answer:
C
38. Answer:
A
39. Answer:
B
40. Answer:
A
41. Answer:
C
42. Answer:
A
43. Answer:
A
44. Answer:
A
45. Answer:
B
46. Answer:
D
47. Answer:
B
48. Answer:
C
49. Answer:
A
50. Answer:
A
51. Answer:
B
52. Answer:
In the original population, the dark-fur-pigment allele frequency is 57 percent while the white-fur-pigment frequency is 43 percent. In the resulting population, the dark-fur-pigment allele frequency is now 47 percent (28/60 = 0.47 or 47 percent) and the white-furpigment allele frequency is 53 percent (32/60 = 0.53 or 53 percent). There has been a marked change in the allele frequencies for fur pigment in this population. Evolution corresponds to changes in a population’s allele frequency over time.
53. Answer:
This statement is true. A new predator may alter which traits are most favorable for survival. For instance, alleles for camouflage to blend in with the background could help prey escape detection. The prey population will need to adapt to the new predator if it is to survive. Some individuals in the prey population may have particular inherited characteristics that allow them to survive and reproduce at higher rates than the others in the population. These individuals will pass on those alleles to their offspring and over time, the genetic makeup of the prey population changes.
54. Answer:
This statement is false. Mutations occur randomly; some bacteria had already mutated to be antibiotic resistant prior to exposure to the antibiotics. These resistant bacteria survive when antibiotics are present, while the rest of the population is killed. The resistant bacteria then reproduce to form a population of resistant cells.
55. Answer:
This statement is false because individuals do not evolve; populations do. Individuals with particular inherited characteristics will be more likely to survive and reproduce and will pass on those successful phenotypes to the next generation. This change over time in the population is the process of evolution.
56. Answer:
As with the baby’s overall size, babies with very large circumference heads would have a more difficult time making it through the birth canal without assistance; this could easily lead to the demise of both the mother and the baby. On the other hand, babies with exceptionally small circumference heads may have an easier time making it through the birth canal, but they may also have smaller brains and other developmental problems, making it less likely they will survive to pass on their genes to the next generation. Babies with intermediate-sized heads would be more likely to survive birth and be less likely to succumb to other developmental problems before having the chance to pass on their genes to the next generation.
57. Answer:
If the bright red wildflowers attract more bees and hummingbirds than the white flowers, the allele for the red flowers will spread more easily throughout the population as the bees and hummingbirds move from one flower to the next distributing the pollen to other flowers. The seeds produced by these flowers will have the allele for red flower color and will continue to produce more red flowers and pollen as they grow. In this case, natural selection is favoring red flower color.
58. Answer:
This is an example of convergent evolution. Despite vastly dissimilar genetics, both vultures have similar environmental pressures—the need to tear into flesh—and evolved a similar strategy.
59. Answer:
Possible answers may include: Both sharks and dolphins have streamlined bodies that are well adapted for maneuverability and speed in the water. However, sharks are fish and dolphins are mammals; they do not share a recent common ancestor. Both of these animals are predators in an aquatic environment; both animals must be able to swoop in on their prey if they want to survive and reproduce in this environment. This is an example of environmental pressures giving rise to convergent evolution and producing analogous traits. Or: Plants in the deserts of North America, Africa, and Asia often resemble each other even though they have vastly different genetics. The desert environments have provided the selective pressures that encouraged survival of plants that naturally conserve water and managed to thrive in hot dry environments. The tiny spines and thick skin of these plants are analogous traits produced through convergent evolution.
60. Answer:
a) According to the timeline, resistance to methicillin happened much faster than resistance to vancomycin. Scientists hypothesize that the staph bacteria does not handle the resistance allele for vancomycin very well, and this impedes the development of widespread resistance. b) Without new antibiotics to treat resistant infections, the best course of action is to follow the Centers for Disease Control and Prevention (CDC) guidelines. (1) Always complete the prescribed course of antibiotic treatment even if you’re feeling better. (2) Only take antibiotics when they are prescribed for you by a doctor. (3) Do not seek antibiotics when your doctor says you don’t need them, for instance for viral diseases such as cold or influenza. (4) Prevent infections by practicing good hygiene.
61. Answer:
If an individual cannot pass a mutation on to its offspring, the mutation cannot directly contribute to evolution. The mutation will not cause a change in allele or genotype frequencies in the population. Only mutations in the germ line cells (eggs and sperm) can contribute to evolution in sexually reproducing organisms.
62. Answer:
The two-way gene flow between these two populations will result in them having very similar genotype or allele frequencies over time. The greater amount of gene flow back and forth will result in both populations actually looking very similar to the original population 1.
63. Answer:
The mouse with dark-colored fur will add dark alleles to the population and will produce dark-colored offspring. This may alter the allele frequency in the next few generations. However, the dark-colored mice are more likely to be killed by predators because they stand out against the light rocks. Therefore, over time, the allele frequency will likely return back to what it was before the gene flow event occurred.
64. Answer:
Both of these processes are examples of genetic drift and result in populations with a smaller gene pool. A genetic bottleneck occurs when the size of a population drops drastically due to deaths of many individuals, and by chance some alleles are lost from the population. The founder effect is due to a small group leaving the original population to found a new population. By chance, they will carry certain alleles that can have a higher frequency relative to the original population.
65. Answer:
This mass extinction followed by a few cheetahs reproducing to establish a new population is an example of a genetic bottleneck. Because there were few cheetahs to begin reproducing, there would be lots of inbreeding and a limited variety in their gene pool. Without a great deal of heritable mutations (mutations that can be passed from one generation to the next), today’s cheetah population would be very similar to those few survivors and very similar to each other. The lack of genetic diversity caused by a genetic bottleneck can result in a concentration of unfortunate genetic disorders in the population.
66. Answer:
natural selection
67. Answer:
population
68. Answer:
directional
69. Answer:
stabilizing
70. Answer:
individuals
71. Answer:
convergent evolution
72. Answer:
analogous
73. Answer:
mutation
74. Answer:
phenotypes
75. Answer:
horizontal
76. Answer:
gene flow
77. Answer:
genetic drift
78. Answer:
genetic bottleneck
79. Answer:
resistance
80. Answer:
1.
E
2.
A
3.
D
4.
B
5.
C
Name: ___________________________ Class: _________________ Date: __________
Chapter 13 1.
2.
3.
Evolution by natural selection allows species to a.
reduce mutation rate.
b.
decrease genetic variation.
c.
adjust to environmental changes.
d.
hybridize.
Which of the following statements is true about adaptation? a.
It is large-scale movement of a single species over a new geographic area.
b.
It occurs when a more adapted species causes the extinction of a less adapted one.
c.
It is the process by which natural selection improves the match between an organism and its environment over time.
d.
It is an increase in the adaptiveness of many species that have already evolved.
When a brightly colored guppy population is placed in an area containing many predators, the population changes in only a few generations to one containing only guppies with drab, dull colors that blend into their environment. This is an example of how natural selection can a.
force new color mutations to occur.
b.
convert a dominant allele into a recessive allele.
c.
improve the match between guppies and their environment.
d.
change the color preferences of female guppies.
4.
5.
6.
A lizard is attacked by a bird. The lizard escapes and survives without his hind legs. Fortunately for this lizard, the loss of his hind limbs allows him to live within a smaller crevice than other lizards of the same species, so he experiences less competition. Which of the following is true for this lizard? a.
The loss of his legs provided an overall advantage within his environment.
b.
The loss of his hind legs would be considered an adaptive trait.
c.
A lack of hind limbs should become more common in this population.
d.
This lizard will be unable to reproduce.
The faster a cheetah can run, the more likely it is to capture its prey. Cheetahs with longer legs are able to run faster than those with shorter legs. Although the existing cheetah population shows a variety of leg lengths, cheetah legs are not continuing to increase in length from one generation to the next. Which of the following is a possible explanation? a.
The genes that are involved in cheetah leg length do not undergo mutation.
b.
Cheetahs with long legs are reproductively isolated from cheetahs with short legs.
c.
Natural selection does not act on traits involved in predation.
d.
Longer cheetah leg bones are more likely to break.
Every year, environmental signals in Africa cause flycatchers to return to the Netherlands to breed. When they arrive, they depend on freshly hatched caterpillars for food. Global climate change has caused the caterpillars to hatch earlier in the Netherlands, but the environmental cues in Africa remain the same. Now, when the flycatchers return to the Netherlands, the caterpillars are no longer available as a food source. Which of the following is most likely to happen to this species of flycatcher? a.
Flycatchers may learn that caterpillars are hatching earlier and will begin flying to the Netherlands earlier.
7.
8.
9.
b.
Flycatchers will adapt to environmental change if genetic traits that aid flycatchers in utilizing food sources other than caterpillars are present.
c.
Flycatchers will not adapt to environmental change because bird species are unable to utilize new food sources.
d.
Flycatchers will remain in the Netherlands instead of returning to Africa.
Which of the following examples does NOT illustrate a difference in fitness that would lead to evolution by natural selection? a.
Male peacocks with larger, more colorful tails are more frequently chosen as mates.
b.
Moths with coloration that allows them to blend in with the bark of spruce trees are more difficult for predators to find.
c.
Wolves who are more successful hunting in packs find mates more frequently.
d.
A female panda living in a zoo in China is impregnated more frequently than a female panda living in a zoo in the United States.
Some species of orchids attract wasps to assist them in reproduction by producing flowers that look like female wasps. The flowers fool male wasps into attempting to mate with them. As a result, the wasp is covered with pollen that it takes with it to the next flower with which it attempts to mate. This example shows adaptation by a.
the orchids.
b.
the wasps.
c.
all flowering plants.
d.
ancestral wasps.
Bacteria reproduce asexually, so scientists classify them based on a.
DNA sequence similarity and morphology.
10.
11.
12.
b.
reproductive isolation.
c.
the biological species concept.
d.
the idea that they are all strains of the same species.
Using the biological species concept as a method of defining a species is NOT useful for a.
species whose ranges overlap.
b.
species that cannot produce hybrids.
c.
organisms known only from fossils.
d.
organisms that reproduce sexually.
The fossils of two adult birds are found in a nest containing several fossilized eggs. Physically, the bird fossils look very different. Scientists are most likely to classify these species using a.
the biological species concept.
b.
DNA from the fossils.
c.
morphology of the fossils.
d.
evidence of reproduction.
The red-breasted nuthatch and the white-breasted nuthatch are similar in appearance and, in many regions of the United States, their ranges overlap. The two organisms do not interbreed. Based on this information, redbreasted and white-breasted nuthatches are a.
different species.
b.
different populations of the same species.
c.
hybrids.
d.
polyploids.
13.
14.
15.
16.
Individuals of the same species generally a.
experience prezygotic barriers to reproduction.
b.
do not interbreed extensively.
c.
share many common physical and behavioral characteristics.
d.
vary only slightly in appearance.
According to the biological species concept, a species is defined when individuals of the same species a.
differ widely in their DNA sequences.
b.
always have the same physical traits.
c.
are capable of interbreeding and producing fertile offspring.
d.
must reproduce asexually.
Which of the following organisms would best be identified as a species using the biological species concept? a.
a population of mice living on a mountaintop where the nearest population of mice is 50 miles away
b.
a bacteria found living in the human gut with thousands of other bacteria
c.
dinosaurs identified by morphologically similar fossil remains located in a single valley in South America
d.
a rare plant living in a remote location in Peru that reproduces asexually
Two populations of lizards live in the same area. Which of the following evidence would convince you that they are two distinct species?
17.
18.
19.
a.
Individuals in one population display a different color pattern than individuals in the second population.
b.
Individuals in one population are noticeably larger than individuals in the second population.
c.
The two populations are not capable of interbreeding and producing fertile offspring.
d.
The two populations are capable of interbreeding and producing fertile hybrid offspring.
Populations of a single species are connected by a.
gene flow.
b.
speciation.
c.
continental drift.
d.
genetic drift.
Speciation a.
can result from geographic isolation.
b.
occurs in the absence of genetic divergence.
c.
occurs only in species living on remote islands.
d.
reduces variation.
The formation of a new species a.
can occur any time genetic divergence occurs.
b.
can occur only when two populations are geographically isolated.
c.
can occur only when two populations are sympatric.
d.
is a process that stopped occurring thousands of years ago.
20.
21.
22.
23.
Which of the following must occur for one species to split into two or more species? a.
The species must move into a new habitat.
b.
DNA sequences of genes must accumulate differences.
c.
Morphological changes must be obvious within the population.
d.
One species must undergo geographic isolation.
Some freshwater snail eggs are accidentally introduced into a new habitat that is geographically isolated from the original population. Which of the following must occur before these snails are described as two separate species? a.
gene flow
b.
sympatric speciation
c.
adaptation
d.
genetic divergence
For two populations to accumulate enough genetic differences to cause speciation, the factors that promote these differences a.
must operate in populations that are not physically separated.
b.
must have a greater effect than does the amount of ongoing gene flow.
c.
need to be combined with the forces of genetic drift.
d.
should include polyploidy.
Geographic isolation limits the __________ between separated populations of a species. a.
genetic differences
24.
25.
26.
b.
adaptation
c.
directional selection
d.
gene flow
A large population of animals is split in two by a physical barrier. Over time, the genetic makeup of the two resulting populations becomes more and more different until each population becomes a separate species. This is an example of a.
sympatric speciation.
b.
allopatric speciation.
c.
genetic drift.
d.
natural selection.
For which of the following would a mountain range most likely represent a geographic barrier that would block gene flow? a.
birds
b.
deer
c.
mice
d.
butterflies
Which of the following would NOT be expected after a population undergoes geographic isolation? a.
a decrease in gene flow
b.
an increase in gene flow
c.
allopatric speciation
d.
formation of adaptive traits
27.
28.
Two populations that live __________ do NOT provide an example of geographic isolation. a.
in two valleys on opposite sides of a steep mountain range
b.
on different mountains with a steep valley between them
c.
on opposite sides of a large river
d.
in different parts of a small lake
The two squirrel species shown in the figure below arose from the same ancestor. The Kaibab squirrel lives on the north rim of the Grand Canyon, and the Abert’s squirrel lives on the south rim. Which is the most likely explanation for their speciation?
a.
The population of ancestral squirrel occupied only one of the rims of the Grand Canyon. As the population grew, some members of the population crossed the Grand Canyon to form a new population.
b.
The population of the ancestral squirrel was split by the formation of the Grand Canyon. Since the habitats were different on each rim, the populations evolved differently and became reproductively isolated.
c.
When the Grand Canyon formed, competition for food and shelter became fierce. The two species arose through sympatric speciation as some individuals gathered food on the north rim rather than on the south rim.
d.
29.
30.
31.
The ancestral squirrel was actually a hybrid of two squirrel species. When the populations were separated and could no longer mate, the characteristics of the two species became more obvious.
How does geographic isolation lead to speciation? a.
Geographic isolation allows mechanisms of evolution to cause genetic divergence.
b.
Populations that are geographically isolated develop reproductive barriers.
c.
The habitats for geographically isolated species are always different, and this leads to morphological differences.
d.
Geographic isolation does not lead to speciation.
In general, geographical isolation occurs when a.
populations migrate to new environments.
b.
gene flow is reduced by more than 75 percent due to climate change.
c.
mutations overcome genetic drift across physical barriers.
d.
populations are separated by a distance or land formation that is great enough to limit gene flow.
Two populations of __________ are NOT an example of speciation. a.
sea urchins in the same territory that are physically unable to mate
b.
small rodents that look similar but have genetic differences
c.
morphologically distinct lizards that lack differences in DNA sequences
d.
butterflies that live in the same area but breed in different seasons
32.
33.
34.
35.
Genetic adaptations in two closely related species living within the same territory indicate that a.
gene flow is extensive between the two species.
b.
geographic isolation is required for evolution.
c.
allopatric speciation has occurred.
d.
sympatric speciation has occurred.
Two species live in the same area but breed in different parts of their habitat. These species are a.
geographically isolated.
b.
ecologically isolated.
c.
artificially isolated.
d.
likely to produce hybrids.
Which of the following is an example of a postzygotic barrier? a.
The gametes cannot join.
b.
The zygote fails to develop.
c.
The breeding seasons are different.
d.
The courtship behaviors are different.
Sympatric speciation a.
occurs only in plants.
b.
is impossible, because the populations of a species must be isolated from one another for speciation to occur.
c.
is always a result of polyploidy.
d.
36.
37.
38.
occurs when a new species emerges from a population in the absence of a geographical barrier.
Although populations of North American apple maggot flies are not geographically isolated, they appear to be in the process of diverging into two new species. Which of the following could be causing speciation between two populations in the absence of geographic isolation? a.
feeding on two different types of food
b.
producing fertile hybrids
c.
laying their eggs in the same location
d.
increased gene flow between them
Two birds that are similar in morphology and live in the same forest exhibit different courtship behaviors. Which of the following describes the relationship of these birds? a.
These birds are the same species because they share morphology.
b.
Mating would be prevented because these birds would not respond to each other’s behaviors.
c.
Allopatric speciation is occurring between these birds.
d.
Coevolution is causing these birds to have similar morphology.
Before the cultivation of the apple tree, apple maggot flies laid their eggs exclusively on the fruit of Hawthorne trees. As apple orchards became more prominent, apple maggot flies began to lay their eggs on both the fruit of the Hawthorne tree and the fruit of cultivated apple trees. Now, apple maggot flies that live on apple trees mate and lay their eggs at different times of the year than apple maggot flies that live on Hawthorne trees. Is this an example of reproductive isolation? a.
Yes; these two fly populations exhibit a postzygotic barrier that prevents hybrid individuals from developing properly.
39.
40.
b.
No; although these two fly populations do not mate in nature, they can be forced to mate in a laboratory because their DNA sequences are still the same.
c.
No; this is an example of speciation rather than reproductive isolation.
d.
Yes; these two fly populations exhibit a behavioral prezygotic barrier that prevents their gametes from encountering each other.
Which of the following is an example of a prezygotic barrier that can isolate two species living in the same geographic area? a.
The members of two populations of birds living in neighboring forests freely interbreed.
b.
One species of cichlid has the same mating behavior as another cichlid species in the same lake.
c.
The gametes of one species of orchid in a rainforest are unable to fuse with the gametes of another species of orchid in the same rain forest.
d.
Two species of wildflowers mate and produce a hybrid that is capable of successfully breeding with either species.
A rain forest is a highly complex habitat with organisms living at various levels in the trees, on the ground, and underground. Is it possible to consider two populations of insects living in the same tree to be geographically isolated? a.
No, because if they are in the same tree, they are in the same geographic area.
b.
No, because if they are in the same square acre, they cannot be considered geographically isolated.
c.
Yes, because insects only undergo allopatric speciation, and there are many species of insects.
d.
Yes, because there are so many habitats in one tree that the populations may never interact.
41.
42.
43.
44.
In many predator-prey relationships, evolutionary change in the prey will result in evolutionary change in the predator, a phenomenon known as a.
polyploidy.
b.
allopatrism.
c.
coevolution.
d.
sympatric speciation.
Close ecological interactions between two different species may lead to a.
allopatric speciation.
b.
sympatric speciation.
c.
coevolution.
d.
geographic isolation.
The rough-skinned newt produces one of the most potent toxins on the planet. Scientists in Oregon have found that as newts evolve to produce a more deadly toxin, their primary predator, the garter snake, evolves ways to resist the toxin. This is an example of a.
ecological trade-offs in the evolution of the newt.
b.
an adaptation of the newt to living in aquatic environments.
c.
reproductive isolation in a population of garter snakes.
d.
coevolution of predator and prey.
Which of the following statements gives an example of coevolution? a.
Two unrelated species form at the same time after ancestral species populate a newly formed volcanic island.
b.
Two closely related mice species on different mountaintops in the southwest United States both adapt the same trait because food sources are similar.
45.
46.
47.
c.
An ant species and a plant species both develop adaptations in response to changes in the other species.
d.
A wild cat species and a wild dog species both have similar bacteria living in their guts, which allow them to produce vitamin K.
The best explanation of the role of coevolution in speciation is that coevolution a.
leads to two species that are perfectly adapted to exist together.
b.
may lead to benefits for both of the species involved.
c.
only occurs in species like corals and sea urchins that live in marine environments.
d.
always benefits one species and harms another species.
How does coevolution lead to speciation? a.
Coevolution is the mechanism that allows allopatric speciation to occur.
b.
Coevolution causes the extinction of species that have limited genetic diversity.
c.
The adaptations that occur during coevolution are passed on to other species.
d.
An adaptation in one organism drives adaptation in a second organism.
Convergent evolution involves unrelated or distantly related organisms developing similar traits. Coevolution is similar to convergent evolution in that coevolution also a.
involves changes in unrelated, or genetically distant, organisms.
b.
often occurs in geographic isolation.
c.
is a process that occurs when food sources change.
d.
48.
49.
50.
leads to similar traits developing in two species.
Which of the following is most likely an example of coevolution? a.
The color of a rodent’s hair changes to better match a new environment.
b.
A parasitic worm develops a new mechanism to attach to the gut lining of an organism that has a special adaptation designed to shed parasitic worms.
c.
Two different species of plants produce flowers that are the same color, which attracts honeybees.
d.
Two unrelated rodent species on different continents develop flaps of skin between their front legs and bodies that allow them to glide between trees.
Which of the following is one of the three important characteristics of an adaptation? a.
An adaptation must be a physical change.
b.
Adaptations are typically simple behavioral changes.
c.
An adaptation improves an organism’s survival in its environment.
d.
An adaptation must result in a perfect match between an organism and its environment.
Which of the following is an example of a postzygotic barrier? a.
Two species produce zygotes that fail to develop normally and die prior to birth.
b.
Two species have reproductive organs that are physically incompatible.
c.
Breeding occurs at different times of the day for two species in the same area.
d.
Different courtship displays prevent two species from interbreeding.
51.
The female medium ground finch in the figure mates with the newly arrived male large cactus finch. The offspring is known as “Big Bird.” Male Big Bird’s mating song does not match the mating song of medium ground finches. Therefore, the only females on the island willing to mate with male Big Birds were female Big Birds. The ability of male Big Birds to mate only with female Big Birds because of their mating song is an example of a
a.
mechanical isolation, prezygotic reproductive barrier.
b.
ecological isolation, prezygotic reproductive barrier.
c.
hybrid sterility, post-zygotic reproductive barrier.
d.
behavioral isolation, pre-zygotic reproductive barrier.
52.
A few penguins from a particular population migrated to a newly formed island chain of Snares Islands, and they remained there without traveling back to their original island. No new penguins migrated to the Snares Islands. Over time, this colony of penguins became morphologically different from and unable to breed with penguins from their original island. This is an example of a.
gene flow overcoming genetic divergence.
b.
genetic divergence leading to speciation.
c.
ecological isolation leading to speciation.
d.
behavioral isolation leading to speciation.
53.
There is color variation in a population of insects living within an area. Some individuals are solid black, and other individuals are gray with green spots. Individuals who are solid black do not blend into the environment, and they tend to be eaten by predators. Explain how differences in survival rates will lead to more individuals in the population being gray with green spots.
54.
Within a population of mice there is an allele for a gene that leads to the production of larger front teeth. In areas where seeds have thicker coatings, larger teeth allow these mice to chew through thicker seed coatings and survive at a higher rate than mice with smaller teeth. Would you expect an increase in the percentage of mice with larger teeth in a population of mice living in an area with seeds that have thicker coatings? Explain your reasoning.
55.
A lizard learns to avoid predatory birds after being attacked and losing part of its tail to a bird. What is required for this avoidance behavior to be considered an adaptive trait?
56.
Two biologists discover two populations of toads living in the same area. Morphologically, these two populations are different. The toads in one population have much wider heads and darker coloration than the second
population. One of the biologists suggests names for the two new species. The second biologist questions whether the two populations are separate species. Why is the second biologist hesitant to declare these populations are two species?
57.
Two birds with distinct differences in their plumage successfully mate and produce viable, fertile offspring. Using the biological species concept, explain whether these two birds would be defined as a single species. Also address whether you would require more information to make this determination.
58.
A microbiologist discovers a Streptococcus bacterium living on a human scalp. She wants to know whether the bacterium she found is the same species as a Streptococcus bacterium she isolated from the throat of the same human. Explain how she could determine whether these bacteria are the same species.
59.
If two populations of beetles living in isolated areas are physically different but genetically similar, would they be considered one species or two? Explain your answer.
60.
Gene flow is completely blocked between two populations of a flowering plant for 300 years. One population develops light green leaves, tall spindly stems, and purple flowers. The other population develops dark green leaves, short stems, and white flowers. At the end of the 300 years, people begin planting these flowering plants together in decorative gardens. People quickly realize that these two flowering plants are capable of interbreeding. Did speciation occur during the 300-year separation? Explain your reasoning.
61.
This figure shows two squirrels that represent two separate species. Explain how the geographic barrier between these two populations led to the formation of two distinct species.
62.
Speciation may be described as either allopatric or sympatric. What is the primary difference between the two types of speciation?
63.
Choose two different reproductive barriers that lead to sympatric speciation and explain how they work.
64.
Explain how a change in the depth, either a lengthening or shortening, of flowers that contain nectar eaten by a particular species of hummingbird would potentially lead to a change in the hummingbird.
65.
Summarize how genetic divergence between two populations leads to reproductive barriers that isolate species living in the same area. Give specific examples of the barriers produced.
66.
Explain how a new polyploid number in a plant might arise and how it can lead to the development of a new plant species.
67.
Explain how and/or why sexually reproducing organisms might be more able to adapt to new environments and possibly give rise to new species.
68.
Individual organisms with inherited characteristics that enable them to survive and reproduce are said to have greater __________ fitness than individuals who fail to survive and reproduce.
69.
Based on the __________ species concept, organisms that interbreed and produce fertile offspring are most likely classified as a species.
70.
The great diversity of life on Earth is caused by the formation of new species in a process known as __________.
71.
When populations of a species are separated by a physical barrier, thereby becoming geographically isolated and subsequently reproductively isolated from one another, __________ speciation can occur.
72.
Two species live near each other but do not respond to each other’s courtship displays. This is an example of __________ isolation, a type of prezygotic barrier.
73.
Two species evolving together in response to interactions between the two species is referred to as __________.
74.
There are approximately 8.74 million eukaryotic species on Earth. Of the groups shown in the infographic below, __________ make up approximately 11 percent of the known species.
75.
Over time, two populations of a penguin species become increasingly genetically dissimilar from each other. This accumulation of changes in the DNA sequences is recognized first as __________.
76.
Match each numbered statement to one of the terms listed. a.
coevolution
b.
biological species concept
c.
morphological species concept
d.
speciation
e.
morphology
f.
adaptation __ 1. __ 2. __ 3. __ 4.
77.
an organism’s physical characteristics process by which one species splits to form two species or more process of evolution through natural selection evolution in one species that leads to reciprocal adaptation in another species
Determine the type of reproductive barrier described in each statement. a.
hybrid sterility
b.
behavioral isolation
c.
ecological isolation
d.
zygote death
e.
gametic isolation __ 1. Two toad species in the same habitat breed at different times of the year. __ 2. A horse and a donkey successfully mate; their offspring is sterile. __ 3. The gametes of sea urchins living on a reef together are incapable of fusing.
__ 4. Female fruit flies recognize only the mating rituals of male fruit flies that are the same species.
78.
Identify whether a type of reproductive barrier is prezygotic or postzygotic. a.
prezygotic
b.
postzygotic __ 1. __ 2. __ 3. __ 4. __ 5.
hybrid sterility gametic isolation zygote death mechanical isolation ecological isolation
Answer Key Chapter 13
1. Answer:
C
2. Answer:
C
3. Answer:
C
4. Answer:
A
5. Answer:
D
6. Answer:
B
7. Answer:
D
8. Answer:
A
9. Answer:
A
10. Answer:
C
11. Answer:
C
12. Answer:
A
13. Answer:
C
14. Answer:
C
15. Answer:
A
16. Answer:
C
17. Answer:
A
18. Answer:
A
19. Answer:
A
20. Answer:
B
21. Answer:
D
22. Answer:
B
23. Answer:
D
24. Answer:
B
25. Answer:
C
26. Answer:
B
27. Answer:
D
28. Answer:
B
29. Answer:
A
30. Answer:
D
31. Answer:
C
32. Answer:
D
33. Answer:
B
34. Answer:
B
35. Answer:
D
36. Answer:
A
37. Answer:
B
38. Answer:
D
39. Answer:
C
40. Answer:
D
41. Answer:
C
42. Answer:
C
43. Answer:
D
44. Answer:
C
45. Answer:
B
46. Answer:
D
47. Answer:
A
48. Answer:
B
49. Answer:
C
50. Answer:
A
51. Answer:
D
52. Answer:
B
53. Answer:
Individuals with adaptive coloration will tend to survive and reproduce at higher rates. The adaptive coloration will be passed on to their offspring, and that trait will become more common in the population. This is an example of evolution by natural selection.
54. Answer:
In an area with seeds that have a thicker coating, mice with larger teeth will survive and reproduce at a higher rate than mice with smaller teeth. Therefore, the percentage of mice with larger teeth will be expected to increase in frequency. The larger teeth are considered an adaptive trait.
55. Answer:
This trait would need to be an inherited trait, not just a learned behavior. This trait would also need to increase survival and successful reproduction.
56. Answer:
The second biologist would probably like more information about whether the two groups can interbreed and produce fertile offspring.
57. Answer:
The biological species concept is based on the ability of individuals to interbreed and produce fertile offspring. Although these two birds look different from each other, they fit the definition of a species because they are capable of interbreeding and producing viable, fertile offspring. No further information is required in this case.
58. Answer:
The biological species definition will not help in this case because bacteria reproduce asexually. The researcher would need to use other information, such as DNA sequence similarity and morphology, to determine whether these are the same species.
59. Answer:
Although the physical differences may lead to these two populations being considered two species, the lack of genetic divergence would most likely still allow these two populations to interbreed if they came into contact with each other. At this point in time the two populations should be considered one species because of the potential for interbreeding.
60. Answer:
Although these two populations diverged morphologically, they did not undergo speciation because they were still capable of interbreeding. The amount of genetic divergence was not enough to prevent them from reproducing. For speciation to occur, genetic divergence must lead to reproductive isolation.
61. Answer:
Geographic barriers prevent gene flow between populations of a species. Given enough time, a lack of gene flow between two populations leads to genetic divergence as mechanisms of evolution, such as mutation, genetic drift, and natural selection, occur. This is an example of allopatric speciation.
62. Answer:
Allopatric speciation occurs when two populations become separate species after they are separated by a geographical barrier. Sympatric speciation occurs when two populations become reproductively isolated in the absence of a geographical barrier.
63. Answer:
Sympatric speciation occurs when new species form in the same geographic location. Ecological, behavioral, and mechanical isolation all prevent mating from occurring. Gametic isolation prevents fertilization after mating has occurred. There are also two postzygotic barriers—zygote death and hybrid performance—that act as barriers after fertilization has occurred.
64. Answer:
If the nectar contained in these flowers was the primary food utilized by the hummingbird, it would be reasonable to assume that the birds with longer bills would best be able to access the nectar and thus would survive and reproduce. The greater reproductive fitness of these birds would lead to evolution by natural selection. The change in one species due to an adaptation in another species is coevolution.
65. Answer:
Genetic divergence leads to populations with different inherited traits. Inherited traits control prezygotic traits such as the time that mating occurs (ecological isolation), mating behaviors (behavioral isolation), the shape of reproductive organs (mechanical isolation), and the gametes formed (gametic isolation). Another possibility is that postzygotic barriers may be introduced as genetic divergence occurs.
66. Answer:
When two plant species hybridize, they may produce viable offspring that have a chromosome number that differs from either of the parent species if there was a mistake separating the chromosomes during meiosis in the parent plants. The change in the number of chromosome sets in the gametes of the new polyploid offspring will mean it will differ from both of the parental plants’ chromosome numbers and will be unable to breed with them. The new polyploid may be able to pollinate only its own eggs or other similar polyploids with the same chromosome number. This prezygotic barrier will isolate the new polyploid from the parental plant species. As the new plant is isolated, it may form a successful species.
67. Answer:
The process of sexual reproduction in a species provides that species with a way of shuffling genes through meiosis and then recombining them with other genes through fertilization. Sexual reproduction produces a wide array of genetic diversity in each generation of offspring. This genetic diversity provides valuable possibilities for adaptations to new or changing environments. These genetic variations may accumulate to the point of genetic divergence that reproductively isolates a population of new individuals from previous generations or populations. When this happens, speciation is occurring.
68. Answer:
biological
69. Answer:
biological
70. Answer:
speciation
71. Answer:
allopatric
72. Answer:
behavioral
73. Answer:
coevolution
74. Answer:
insects
75. Answer:
genetic divergence
76. Answer:
1.
E
2.
D
3.
F
4.
A
1.
C
2.
A
3.
E
4.
B
1.
B
2.
A
3.
B
4.
A
5.
A
77. Answer:
78. Answer:
Name: ___________________________ Class: _________________ Date: __________
Chapter 14 1.
2.
3.
4.
Which kind of organism makes up the oldest fossil found on Earth? a.
protist
b.
animal
c.
bacteria
d.
plant
The first eukaryotes evolved approximately __________ years ago. a.
200,000
b.
200 million
c.
2 billion
d.
2 trillion
The appearance of eukaryotes may have been delayed until more __________ accumulated in Earth’s atmosphere. a.
oxygen
b.
nitrogen
c.
carbon
d.
sulfur
Of all the estimated species on earth, approximately what percentage have been named and placed into an evolutionary tree? a.
100 percent
5.
6.
7.
b.
10 percent
c.
1 percent
d.
Less than 1 percent
Which of the following is not included in the Domain classification? a.
archaea
b.
bacteria
c.
protists
d.
eukarya
In a fictional movie set in a land dominated by flowering plants, advancing and retreating glaciers, and a cast that includes a human, a wooly mammoth, a saber-toothed cat, and dinosaurs, the __________ would be most out of place in the setting according to the geological timeline of life on Earth. a.
saber-toothed cat and the human
b.
wooly mammoth and the human
c.
saber-toothed cat and the dinosaurs
d.
dinosaurs
At the base of the evolutionary tree of all life is the __________ ancestor. a.
universal
b.
convergent
c.
derived
d.
descended
8.
9.
Evolutionary tree diagrams representing the relationships between various organisms can be drawn only when those organisms share a a.
common cellular metabolism.
b.
distinct lineage.
c.
common cellular organization.
d.
common ancestor.
In the evolutionary trees below, which of the nodes corresponds to the MOST recent common ancestor of troodontids, dromaeosaurids, and Archaeopteryx?
10.
a.
A
b.
B
c.
C
d.
D
Evolutionary trees are based on
11.
12.
13.
a.
the principle of convergent evolution.
b.
a set of shared characteristics believed to have arisen in a common ancestor.
c.
similarities in the function of a characteristic or trait.
d.
consensus among biologists regarding the usefulness of particular traits.
Any two groups of organisms will have __________ most recent common ancestor(s). a.
two
b.
no more than four
c.
only one
d.
as many as 16
The __________ trait occurs between each branch on an evolutionary tree. a.
evolution of a new derived
b.
loss of a derived
c.
evolution of a shared ancestral
d.
evolution of a convergent
Based on the evolutionary tree below, which of the following species would be most closely related to theropods? a.
Archaeopteryx
b.
Ancestors of modern birds
c.
Troodontids
d.
14.
Xiatingia
Based on the tree of life shown below, which two kingdoms most recently diverged from a common ancestor? a.
Plantae and Fungi
b.
Animalia and Plantae
c.
Protists and Fungi
d.
Animalia and Fungi
15.
16.
17.
18.
Which of the following categories of classification would most likely contain the greatest number of species? a.
phylum
b.
genus
c.
family
d.
class
The Cambrian explosion a.
caused a lack of air in Earth’s atmosphere.
b.
was caused by an increase in volcanic activity.
c.
was volcanic in nature.
d.
increased the diversity of animal life on Earth.
The Cambrian explosion occurred primarily in the oceans. The first challenges that had to be overcome during the mass colonization of dry land in the Ordovician period were a.
support of body structure without buoyancy in water, movement, and reproduction.
b.
photosynthesis, cellular respiration, and reproduction.
c.
DNA replication, photosynthesis, and cellular respiration.
d.
DNA replication, phagocytosis, and cellular respiration.
During the Devonian period, plants evolved which of the following key innovations to overcome the harsh, dry conditions of life on land and flourish?
19.
20.
a.
waterproof cuticle, vascular systems, structural support tissues, leaves, roots, seeds, and specialized reproductive structures
b.
amniotic eggs with a hard shell, photosynthesis, flowers with protected seeds
c.
flowers with protected seeds, photosynthesis, hard-shelled amniotic eggs
d.
photosynthesis, flowers with protected seeds, waterproof cuticle
The Cambrian explosion resulted in the evolution of more than 17,000 species of an animal known as the trilobite. The sheer number of trilobite fossils found in modern times suggests that trilobites were abundant, perhaps the rulers of the seas. Today, no living descendants of this group exist. What happened? a.
Trilobites evolved before the first mass extinction, so it is possible that any of the five mass extinctions could have wiped out the entire group.
b.
In order to disappear from the planet entirely, trilobites must have undergone the process of adaptive radiation.
c.
It is unlikely that trilobites could have survived the increase in atmospheric oxygen once the process of photosynthesis had evolved.
d.
Being so plentiful, trilobites must have been the major food source for terrestrial dinosaurs. The extinction of the trilobite may have caused the mass extinction of dinosaurs.
According to the tree below, which of the following combinations of organisms are MOST closely related?
21.
22.
a.
amoebas and plants
b.
animals and brown algae
c.
plants and green algae
d.
fungi and amoebas
The current classification system used by biologists is a.
complex and unchanging.
b.
universally accepted by all biologists.
c.
based on four generalized types of living organisms: Bacteria, Archaea, Eukarya, and Protista.
d.
updated and revised whenever new information becomes available.
In order to best determine relationships among different organisms, scientists examine a.
DNA and behavior.
b.
DNA and body structures.
c.
body structures and behavior.
d.
DNA, body structures, and behavior.
23.
24.
25.
The emergence of each new branch on the evolutionary tree represents a.
the addition of a new Linnaean taxon within that lineage.
b.
the completion of a generation for that particular organism.
c.
the introduction of the most important features of a group.
d.
a common ancestor and the introduction of a new shared derived feature.
Branches on the evolutionary tree are sometimes rearranged by scientists because a.
new, related fossils or new information about existing fossils changes the understanding of the relationships.
b.
new, unrelated fossils are intentionally put on the tree with existing fossils.
c.
scientists are trying to prove a nonexistent relationship between species.
d.
scientists have proven a relationship between two or more species.
The evolutionary history of the protists remains unresolved, but it is being refined with the addition of DNA evidence. This is an example of how scientific a.
data may change our interpretation of an evolutionary tree without challenging our understanding of evolution.
b.
data proves that a hypothesis regarding an evolutionary tree is true.
c.
evidence proves that the theory of evolution is wrong.
d.
evidence proves that the Protista did not share the same universal ancestor as the rest of the living organisms on Earth.
26.
27.
28.
Evolutionary trees are continually revised by scientists as new information becomes available from various sources such as a.
better understanding of the details of physiological processes.
b.
additional, similar fossils found in relation to the geological time period.
c.
the continued evolution of current Earth species.
d.
the identification of alien species that have reached Earth via meteorites and comets.
Which of the following statements about bird evolution is NOT correct? a.
Scientific studies have revealed so many errors in the traditional dinosaur-bird evolutionary tree that none of it is considered useful to understanding the evolution of birds and flight.
b.
Scientific studies of the Xiaotingia fossil caused scientists to adjust the traditional dinosaur-bird evolutionary tree.
c.
Scientific comparisons of Archaeopteryx and Xiaotingia fossils caused scientists to adjust the traditional dinosaur-bird evolutionary tree.
d.
It is important to understand the dinosaur-bird evolutionary tree in order to have a better understanding of how flight evolved.
Scientists use existing fossils to predict what the transitional forms between organisms might look like. Why might it be so hard for scientists to find fossils of these transitional forms? a.
Scientists have no way to determine how deep in a rock to look for a transitional fossil, so they just have to dig and dig until they find the right fossil.
b.
Because of continental drift, the exact location of where a transitional fossil should be found cannot be determined. Looking for a particular fossil that could be anywhere on the planet is like looking for a needle in a haystack.
c.
Fossils of transitional species may have never formed due to environmental conditions, or if they did form, natural processes like erosion may have destroyed them.
d.
29.
30.
The transitional form of any organism is only hypothetical in nature; it never truly existed on the planet and, therefore, could never become a fossil.
Which of the kingdoms below share the ability to perform photosynthesis?
a.
Plantae and Fungi
b.
Plantae and Protista
c.
Fungi and Protista
d.
Animalia and Fungi
A marine biologist has isolated a microorganism from the Gulf of Mexico. This organism is unicellular, photosynthetic, uses a flagellum to swim, and has been observed ingesting smaller microorganisms in its vicinity. To what kingdom does this organism most likely belong? a.
Fungi
b.
Animalia
c.
Plantae
d.
Protista
31.
32.
33.
34.
What criteria best characterize membership in the kingdom Protista? a.
a continuous lineage of descent from a common ancestor
b.
a large assortment of unique shared derived traits
c.
a common evolutionary heritage
d.
the inability to meet the characteristics that define each of the remaining eukaryotic kingdoms
Resolving the relationship between the various kingdoms has been challenging because species often resemble one another. For example, the kingdom __________ contains some organisms that are animal-like and others that are plant-like. a.
Bacteria
b.
Fungi
c.
Archaea
d.
Protista
Gymnosperms and angiosperms are believed to be more closely related to one another than the other major plant groups because a.
they alone possess vascular systems.
b.
both groups produce separate male and female gametes.
c.
they provide their embryos with stored food in seeds.
d.
they alone possess a waxy cuticle.
Although it is costly to produce fruit, the large number of fruit-producing plant species attests to its success as an evolutionary adaptation. In what way is fruit production helpful to plants? a.
Fruits attract pollinators like insects and birds to move pollen between different plants.
35.
36.
37.
b.
Fruit toxins can discourage potential consumers from eating the plant.
c.
Plants can store energy in fruits during summer and then later recover the energy during winter, when the fruit decomposes.
d.
Consumers eating fruits also eat seeds that, when not digested, can be deposited far from the parent plant and increase the range of that plant species.
Neighboring plant or fungi cells share a common cell wall, making multicellularity relatively simple. How do animal cells remain connected to one another? a.
Animal cells share a common plasma membrane rather than a common cell wall.
b.
Long interconnecting fibers extend from the nucleus of one cell to the nucleus of an adjacent cell.
c.
Most animals produce a felt-like extracellular matrix to which their cells can attach.
d.
Animal cells are connected to each other by the cytoskeleton.
Upon examining specimens recovered from the small intestine of a murder victim during the autopsy, clusters of cells are found that are attached to each other by shared cell walls. The outer layers of these cells are covered with a waxy cuticle, and there is evidence of many green organelles inside the more intact cells in the clusters. What type of cells might these be? a.
plant cells
b.
fungal cells
c.
bacteria
d.
protozoan cells
The most ancient lineage in kingdom Animalia is the __________, followed closely by the __________.
38.
39.
40.
a.
sponges; cnidarians
b.
echinoderms; chordates
c.
chordates; deuterostomes
d.
arthropods; protostomes
Imagine the discovery of an undescribed nonphotosynthetic, multicellular organism. To determine whether it is a(n) __________, it would need to be examined microscopically to determine if its cells __________. a.
animal or fungi; have cell walls
b.
animal or plant; have nuclei
c.
plant or fungi; have cell walls
d.
animal or fungi; contain DNA
When making sourdough bread, bakers use a combination of microorganisms to produce the sour flavor and to leaven the dough before baking. The organisms typically used to produce the lactic acid that give sourdough its distinctive flavor are very small rod-shaped prokaryotic organisms known generally as Lactobacilli. These microorganisms are from the kingdom __________. The other organisms that produce the leavening effect are nonphotosynthetic eukaryotes, have cell walls, absorb their nutrients from their environment, and (in this case) are very tolerant of acidic environments. These microorganisms are from the kingdom __________. a.
Bacteria; Fungi
b.
Plantae; Fungi
c.
Animalia; Bacteria
d.
Plantae; Bacteria
For the species Homo sapiens the first part of the name, Homo, denotes the
41.
42.
a.
class.
b.
family.
c.
order.
d.
genus.
The most recent previous mass extinction, which occurred during the Cretaceous period, may have been caused by a.
extra heat from the sun.
b.
the pull of the moon on Earth.
c.
the dinosaurs.
d.
an asteroid hitting Earth.
The figure below shows the number of living taxonomic families that existed on Earth during the last 540 million years. The sudden decreases in family numbers at 445, 360, 250, 200, and 65 million years ago represent Earth’s five mass extinction events. Based on this data, which mass extinction had the biggest impact on the overall diversity of life on Earth?
43.
44.
a.
200 million years ago
b.
250 million years ago
c.
360 million years ago
d.
445 million years ago
Why might many new species form in the aftermath of a mass extinction? a.
Gene flow among the remaining species would be increased, giving rise to many new genetic recombinations.
b.
Changed environments and reduced competition would provide opportunities for new adaptations.
c.
New environments would increase mutation rates.
d.
Populations of remaining species would expand rapidly and reduce geographic isolation.
The mass extinction at the end of the Cretaceous period about 65 million years ago (mya) is believed to have been caused by a massive comet or asteroid smashing into what is now known as the Yucatan Peninsula in the Gulf of Mexico. The debris arising from this impact would have blocked the sun’s rays from reaching Earth. How would this cause a mass extinction? a.
With no sunlight, the plants would not be able to photosynthesize, and they would die. Any animals that fed on those plants would also die, and this chain reaction would continue up the food chain.
b.
A giant fireball would have spontaneously incinerated every living thing, and the evolution of life on Earth would have started completely fresh.
c.
A massive wave spread out from the epicenter of the impact and drowned all of the terrestrial life on Earth. Evolution of all life on land started over after that event.
d.
All of the terrestrial plants and animals choked to death on the debris cloud.
45.
46.
47.
The mass extinction at the end of the Permian period (about 250 million years ago) is thought to have killed off as many as 60 percent of the animal families. What group of animals dominated life on land at that time? a.
trilobites
b.
mammals
c.
reptiles
d.
amphibians
Mass extinctions cause the loss of many species, no matter how well adapted those species were before the extinction. Why might previous adaptations NOT help a species survive a mass extinction? a.
The rapid environmental changes that cause mass extinctions do not leave the organisms time to adapt.
b.
Ongoing continental drift allows more species to interbreed, which lowers the genetic variability available for adaptation.
c.
Adaptive radiations are stronger than adaptations.
d.
Well-adapted organisms will not be affected by mass extinction; these are the groups that will survive.
What is a likely reason the Cretaceous extinction about 65 mya is the best studied mass extinction? a.
It is the most recent previous mass extinction. Therefore, the fossils are typically closer to the surface and more easily reached for study.
b.
It was by far the most far-reaching extinction and most interesting extinction event because it killed everything in the oceans.
c.
It was the mass extinction farthest back in time, and it gave rise to the Cambrian explosion.
d.
It was the mass extinction event that killed off all of the animals and plants that arose during the Cambrian explosion.
48.
49.
50.
51.
The mass extinction at the end of the Ordovician period killed a.
50 percent of marine animal families, including many trilobites.
b.
50 percent of terrestrial and marine animal families, including many trilobites.
c.
90 percent of terrestrial and marine animal families, and 100 percent of terrestrial plants.
d.
100 percent of trilobites and 90 percent of terrestrial and marine animal families.
Roughly 360 mya at the end of the __________ period, a mass extinction wiped out 30 percent of animal families, including many fishes and trilobites. The terrestrial animals at this time would have included __________. a.
Devonian; many insects, other invertebrates, and amphibians
b.
Cambrian; dinosaurs and mammals
c.
Silurian; mammals and humans
d.
Carboniferous; reptiles and humans
The fourth mass extinction occurred about 200 mya at the end of the __________ period. This extinction eliminated 35 percent of the existing animal species, including __________. a.
Triassic; reptiles, early dinosaurs, and the first mammals
b.
Jurassic; dinosaurs, the first birds, and many flowering plants
c.
Silurian; insects, birds, and mammals
d.
Carboniferous; insects, birds, and mammals
When did photosynthesis evolve, and how did it influence the evolution of life on Earth?
52.
The following is a list of several geologic periods, listed in alphabetical order: Cretaceous, Jurassic, Paleogene/Neogene, Quaternary, and Triassic. Re-order the names of the periods beginning with the most recent. Then, choose one of these geologic time periods and describe the major events during that period.
53.
List the three domains of life. Then, identify which two domains are most closely related to one another. Finally, indicate which domains are classified as prokaryotes and which are classified as eukaryotes.
54.
Early birds had small, thick skulls and two toes on each foot. Archaeopteryx had a long, almost pointy skull and three toes on each foot. Early birds and Archaeopteryx shared the traits of feathers, clawed hands, and a long, bony tail. Examine the two trees presented in the figure below. Assuming that Xiaotingia shared traits with Archaeopteryx that neither of them shared with birds, and looking only at the traits presented here, which of the trees shows the most likely relationship between these three animals? Support your answer by indicating which tree branch is initiated by which characteristic.
55.
According to the figure of Xu’s dinosaur-bird tree shown below, was Archaeopteryx the ancestor of modern birds? Explain your answer.
56.
Identify key characteristics for kingdom Fungi, and provide three examples of members of this kingdom.
57.
The following Linnaean classifications are listed alphabetically: class, family, genus, kingdom, order, phylum, and species. Re-order these classification names beginning with the category that includes the largest number of organisms and ending with the category with the least number.
58.
List the four kingdoms within the domain Eukarya, and list one characteristic for each of the four kingdoms.
59.
List at least three basic functions of life that are handled differently on land than they are in water.
60.
Briefly explain how new scientific findings may change the arrangement of an evolutionary tree while enhancing our understanding of evolution.
61.
Explain two ways that mass extinctions can have a profound impact on evolved biodiversity in the ecosystem.
62.
If Earth’s current mass extinction were to end tomorrow, what would be expected to occur with adaptive radiations?
63.
How is the current mass extinction, shown in the figure below, similar to past mass extinctions? What is the cause of the current mass extinction?
64.
Information about the decline in animal groups during the first five mass extinctions was expressed as a percentage of animal families that went extinct. Can the graph shown below be used to determine the percentage of animal families lost during the current mass extinction? If so, what is the percentage of animal families that have gone extinct since 1500? If not, why not?
65.
In an evolutionary tree, a given ancestor and all its descendants make up a __________, or branch.
66.
About 540 mya, there was an astonishing burst of evolutionary activity that correlated to the first appearance in the fossil record of most of the major living animal groups. Popularly known as the __________, this geologic time changed the face of life on Earth.
67.
The domain __________ encompasses the traditional four kingdoms of Protista, Plantae, Fungi, and Animalia.
68.
The evolution of sperm-cell-containing structures called __________ freed gymnosperms from requiring water for fertilization.
69.
Canis lupus is the scientific name for wolves. Canis refers to the __________ name.
70.
According to the classification chart shown below, humans are in the order __________.
71.
According to the classification chart shown below, humans are in the phylum __________.
72.
Because there is always new information to discover and interpret, scientists must be prepared to revise their __________ when there is evidence to suggest it is not correct.
73.
The fossil record indicates that species have become extinct throughout the history of life. There have been five __________, during which greater than 50 percent of Earth’s species became extinct.
74.
Correctly match the definition with the correct geologic time period. a.
Quaternary
b.
Jurassic
c.
Carboniferous
d.
Ordovician
e.
Precambrian
f.
Paleogene/Neogene
g.
Triassic
h.
Devonian
i.
Cambrian
j.
Cretaceous
k.
Permian
l.
Silurian __ 1. large and relatively sudden increase in the diversity of animal life; increase in diversity of algae; first vertebrates; 490–540 mya __ 2. increase in diversity of fishes; first hints of colonization of land by insects and other invertebrates; 415–445 mya __ 3. increase in diversity of land plants; first amphibians colonize land; mass extinction late in period; 360–415 mya __ 4. continents come together to form Pangaea; reptiles dominate life on land by 265 mya; mass extinction at end of period; 250–300 mya __ 5. continents begin to separate; diverse dinosaurs; first birds; first flowering plants; 145–200 mya __ 6. continents near present positions; increased diversity of flowering plants, birds, mammals, and pollinating insects; 2.6–65 mya __ 7. repeated advance and retreat of glaciers; evolution of humans; extinction of large mammals and birds; 0–2.6 mya __ 8. flowering plants begin to dominate life on land; mass extinction at end of period, including extinction of the last dinosaurs; 65–145 mya
__ 9. origin of life; photosynthesis causes oxygen content of Earth’s atmosphere to increase; first eukaryotes; first multicellular organisms; 540 mya–3.8 bya __ 10. early dinosaurs; first mammals; mass extinction at end of period; 200–250 mya __ 11. further increases in diversity of marine invertebrates and vertebrates; plants and fungi begin to colonize land; mass extinction at end of period; 445–490 mya __ 12. extensive forests; amphibians dominate life on land; increase in diversity of insects; first reptiles; 300–360 mya
75.
Use the figure shown below to match the Linnaean classifications with category names for humans.
a.
genus
b.
order
c.
family
d.
kingdom
e.
species
f.
class
g.
phylum
__ 1. __ 2. __ 3. __ 4. __ 5. __ 6. __ 7.
76.
Animalia Hominidae Homo Mammalia Homo sapiens Primates Chordata
Match each adaptation with the most specific group in which that adaptation arose. (Not all groups will be used.) a.
gymnosperms
b.
angiosperms
c.
plants
d.
animals
e.
chordates
f.
fungi __ 1. __ 2. __ 3. __ 4. __ 5.
development of true tissues production of chitin to strengthen and protect the body development of a waxy cuticle to retain moisture first plants to produce pollen flowering plants with a fleshy ovary wall to protect seeds
Answer Key Chapter 14
1. Answer:
C
2. Answer:
C
3. Answer:
A
4. Answer:
D
5. Answer:
C
6. Answer:
D
7. Answer:
A
8. Answer:
D
9. Answer:
D
10. Answer:
B
11. Answer:
C
12. Answer:
A
13. Answer:
B
14. Answer:
D
15. Answer:
A
16. Answer:
D
17. Answer:
A
18. Answer:
A
19. Answer:
A
20. Answer:
C
21. Answer:
D
22. Answer:
D
23. Answer:
D
24. Answer:
A
25. Answer:
A
26. Answer:
B
27. Answer:
A
28. Answer:
C
29. Answer:
B
30. Answer:
D
31. Answer:
D
32. Answer:
D
33. Answer:
C
34. Answer:
D
35. Answer:
C
36. Answer:
A
37. Answer:
A
38. Answer:
A
39. Answer:
A
40. Answer:
D
41. Answer:
D
42. Answer:
B
43. Answer:
B
44. Answer:
A
45. Answer:
C
46. Answer:
A
47. Answer:
A
48. Answer:
A
49. Answer:
A
50. Answer:
A
51. Answer:
Roughly 2.8 billion years ago (bya), during the Precambrian period, a group of bacteria evolved a type of photosynthesis that released oxygen as a by-product. This increased the atmospheric oxygen concentration over time. The first singlecelled eukaryotes evolved about 2.1 bya. By roughly 650 mya the atmospheric oxygen concentrations had reached a level that supported the evolution of more complex multicellular organisms (aerobic organisms were capable of more efficient cellular respiration and therefore had more energy to fuel a more complex living system).
52. Answer:
Quaternary, Paleogene/Neogene, Cretaceous, Jurassic, and Triassic The Quaternary period includes the evolution of humans, advancement and retreat of glaciers, and extinction of large birds and mammals. The Paleogene/Neogene period was the age when mammals began to dominate, flowering plants and pollinating insects increased, and continents were near their present positions. During the Cretaceous period, flowering plants dominated, and the last of the non-avian dinosaurs went extinct at the end, along with many other organisms. During the Jurassic period dinosaurs diversified, and the first birds and flowering plants appeared. The Triassic period was the period when early dinosaurs and the first mammals appeared.
53. Answer:
The three domains of life are Bacteria, Archaea, and Eukarya. The most closely related are Archaea and Eukarya. The domains Bacteria and Archaea include prokaryotes. The domain Eukarya includes eukaryotes.
54. Answer:
Xu’s dinosaur-bird tree is the more probable tree. Feathers, clawed hands, and a long, bony tail would be part of the therapod branch, according to this tree. Small, thick skulls and two toes on each foot would initiate the “birds” branch of the tree. A long, almost pointy skull and three toes on each foot would likely initiate the deinonychosaurs branch of this tree. However, it is important to keep in mind that there are many other traits that have been presented in this evaluation.
55. Answer:
Xu’s tree indicates that Archaeopteryx is not the ancestor of modern birds. Archaeopteryx is categorized in the clade arising from deinonychosaurs, commonly called raptors, and separate from modern birds and their ancestors.
56. Answer:
Fungi are eukaryotes. Some fungi are single-celled, such as yeasts and some molds, while others are multicellular, like mushrooms. These organisms digest organic material outside the body and absorb the molecules released as breakdown products. Their manner of obtaining nutrients makes them especially helpful as decomposers in ecosystems. Fungi produce protective cell walls around the plasma membrane. Like animals, fungi can store surplus food energy in the form of glycogen.
57. Answer:
kingdom, phylum, class, order, family, genus, species
58. Answer:
Kingdom Protista includes organisms that do not fit into the other three kingdoms. Most protists are single-celled; some are animal-like, some are plant-like, and others are fungus-like. The kingdom Plantae includes multicellular autotrophs that form the basis for most land-based food webs. The kingdom Fungi includes mushrooms, molds, and yeasts. The fungi are heterotrophs and their cells contain cell walls. The kingdom Animalia includes heterotrophic organisms that lack a cell wall; animals contain true tissues.
59. Answer:
The support structure required, movement, reproduction, regulation of temperature, and the control of water loss are some basic functions that are handled differently on land than they are in water.
60. Answer:
Upon finding and evaluating fossils, it is possible that formerly unknown species may be identified. As the relationship of any newly discovered species to previously known species is determined, it may change the way we understand the relationships of known species. This does not undermine our understanding of evolution; it only enhances it by adding to our knowledge and understanding. The more that is learned about the relationships between related species, the better we will understand the evolutionary progression.
61. Answer:
One way that a mass extinction impacts biodiversity is that entire groups of organisms quickly die out, and they (or anything like them) may never be seen again in the history of life on Earth. A second way that mass extinction impacts biodiversity is that it eliminates one or more dominant species (or groups of species), and whatever caused the mass extinction may have also altered the environment. Both of these occurrences would leave voids in the ecosystem and open up new niches/opportunities for other species to fill. Species could evolve along similar paths to fill the newly vacant niches, or very different innovations could evolve from the surviving species to fill the voids. This all leads to a dramatically altered evolutionary history and biodiversity.
62. Answer:
After mass extinctions occur there are typically great adaptive radiations as remaining organisms expand to fill gaps left by organisms that became extinct. New species form as organisms fill new roles and expand into new habitats.
63. Answer:
In all mass extinctions a high number of species, including plants and animals, go extinct. Scientists agree that the cause of the current mass extinction is human activity.
64. Answer:
To determine the percentage of animal families lost you need to know the total number of animal families. The information shown indicates the number of species lost within each group, but does not give a total number of animal species. You need more information to calculate the percentage of animal families that have gone extinct since 1500.
65. Answer:
clade
66. Answer:
Cambrian explosion
67. Answer:
Eukarya
68. Answer:
pollen
69. Answer:
genus
70. Answer:
primates
71. Answer:
Chordata
72. Answer:
hypothesis
73. Answer:
mass extinctions
74. Answer:
1.
I
2.
L
3.
H
4.
K
5.
B
6.
F
7.
A
8.
J
9.
E
10.
G
11.
D
12.
C
75. Answer:
76. Answer:
1.
D
2.
C
3.
A
4.
F
5.
E
6.
B
7.
G
1.
D
2.
F
3.
C
4.
A
5.
B
Name: ___________________________ Class: _________________ Date: __________
Chapter 15 1.
2.
3.
4.
Bacteria and archaea are both classified as a.
eukaryotes.
b.
protists.
c.
fungi.
d.
prokaryotes.
Which of these comparisons is correct? a.
Eukaryotes are more abundant than prokaryotes.
b.
Prokaryotes reproduce at a slower rate than eukaryotes.
c.
Archaeans and eukaryotes have membrane-enclosed organelles, but bacteria do not.
d.
Prokaryotic cells are both simpler and generally smaller than eukaryotic cells.
Which of the following pairs of domains are most closely related? a.
Bacteria and Archaea
b.
Bacteria and Eukarya
c.
Archaea and Eukarya
d.
Domains Bacteria, Archaea, and Eukarya are equally related.
Which of the following groups of characteristics defines prokaryotes? a.
single-celled, membrane-enclosed organelles, nucleus
5.
6.
7.
b.
single-celled or multicellular, no nucleus, single circular chromosome
c.
single-celled, single circular chromosome, no membrane-enclosed organelles
d.
single-celled or multicellular, no nucleus, single linear chromosome
A single-celled organism has linear DNA enclosed within a nucleus. This organism must be a(n) a.
eukaryote because it has a nucleus.
b.
bacterium because it is single-celled.
c.
archaean because it has linear DNA.
d.
prokaryote because it has a nucleus.
How are Bacteria and Archaea related? a.
Bacteria and Archaea both belong to the domain Prokarya.
b.
Archaea split off from the shared ancestor of the Bacteria and Eukarya.
c.
Bacteria evolved directly from Archaea.
d.
Archaea and Bacteria are two distinct domains of life.
Why do prokaryotes reproduce more rapidly than single-celled eukaryotes? a.
Prokaryotic cells each have a single linear chromosome.
b.
Prokaryotic cells have a simpler structure than eukaryotic cells.
c.
Prokaryotes live in more diverse environments than eukaryotes.
d.
Prokaryotes adhere to each other to form multicellular organisms.
8.
9.
Prokaryotes are capable of reproducing more rapidly than eukaryotes because prokaryotes a.
have spherical shapes.
b.
have complex machinery for cell division.
c.
have a single circular chromosome.
d.
have more flexible plasma membranes.
Approximately how many generations does it take for the population of prokaryotes shown in the figure to double?
a.
one generation
b.
two generations
c.
three generations
d.
10.
11.
12.
four generations
An experiment is performed to see if an antiseptic will change the skin microbiome. Skin swabs are used before an antiseptic is applied, after the antiseptic is applied, and on the same area 48 hours later. It is observed that the antiseptic drastically reduced the numbers of Staphyloccocus and other bacteria. After 48 hours Staphylococcus reappears as the most common species. What can be inferred from these results? a.
Antiseptics are only effective against one type of bacteria.
b.
Staphylococcus has a short generation time.
c.
Staphylococcus tolerates oxygen better than other bacteria.
d.
Staphylococcus uses sporulation to survive antiseptic treatment.
A prokaryotic cell and a eukaryotic cell are placed in an environment ideal for growth of both cells. After 24 hours it is observed that the prokaryote cell population is significantly greater than the eukaryote cell population. This has occurred because prokaryotes a.
use quorum sensing to inhibit growth of eukaryotes.
b.
have a simpler structure, which allows more rapid reproduction.
c.
use RNA instead of DNA as the genetic material.
d.
are typically larger than most eukaryotic cells.
The bacterial population shown in the figure has a generation time of 10 minutes. Starting with a single bacterium at generation zero, approximately how much time will have passed when the population reaches 100 cells?
13.
14.
a.
20 minutes
b.
50 minutes
c.
70 minutes
d.
100 minutes
Many bacteria have a shorter generation time at warmer temperatures. Why do food safety guidelines recommend rapidly cooling leftover foods and maintaining them at refrigerator temperatures? a.
Prokaryotes are incapable of reproducing at refrigerator temperatures.
b.
Many bacteria reach disease-causing levels rapidly when food is warm.
c.
Refrigerator temperatures reduce the amount of oxygen available for aerobic bacteria.
d.
Prokaryotes require light for reproduction, and the inside of a refrigerator is dark.
Escherichia coli, a bacterium that normally lives in the gut of humans, will have the shortest generation time when it is found
15.
16.
17.
a.
on foods in a refrigerator set to a low temperature.
b.
on the inside of a toilet at room temperature.
c.
in an incubator set close to human body temperature.
d.
on foods left out at room temperature.
The generation time for a certain prokaryote is 30 minutes. If one cell from this species is added to growth medium in a petri dish and incubated at an ideal temperature, how many cells will be present after three hours? a.
16
b.
32
c.
64
d.
86
Citizens use an app to document the location of ash trees in their community. These citizen scientists are participating a.
in data analysis.
b.
in experimental design.
c.
in data collection.
d.
as experimental subjects.
Professional scientists benefit from citizen science because citizens a.
review their experimental designs.
b.
increase their ability to collect samples.
c.
help report results from studies to other citizens.
d.
eliminate the need for peer-review prior to publication.
18.
19.
20.
21.
Citizen science projects contribute to scientific research by the public a.
collectively forming hypotheses for experiments.
b.
designing and carrying out experiments.
c.
participating in the collection of data.
d.
peer-reviewing professional research.
Individuals who participate in research as experimental subjects are a.
data collectors.
b.
citizen scientists.
c.
professional scientists.
d.
data analyzers.
If a professional scientist is trying to build an extensive database of bacterial swabs from humans in all parts of the world, what is the most cost-effective way to increase the number of samples collected in a one-year time period? a.
Train citizens of many countries to collect samples from people in their local area.
b.
Hire more researchers to travel around the world to obtain samples.
c.
Send a single professional scientist to collect samples in locations throughout the world.
d.
Pay for citizens around the world to travel to a central laboratory where samples will be collected.
Archaeans are often referred to as “extremophiles” because they are a.
capable of living in extreme environments where other organisms cannot function.
22.
23.
24.
b.
the only living organisms to reproduce using binary fission, an extreme form of asexual reproduction.
c.
examples of the earliest life-forms on Earth and have existed for an extremely long time.
d.
single-celled organisms that have extreme mechanisms for causing diseases in humans.
Which prokaryotic cell structure is correctly paired with its shape? a.
bacillus; rod
b.
coccus; spiral
c.
bacillus; sphere
d.
spirillum; rod
Cells that lack membrane-enclosed organelles and have a single circular chromosome may be a.
bacteria only.
b.
archaea only.
c.
eukaryotes only.
d.
either bacteria or archaea.
Compared to the domain Bacteria, members of the domain Archaea tend to live a.
in environments with more oxygen.
b.
more frequently on human skin.
c.
in more mild environments.
d.
in more extreme environments.
25.
26.
27.
28.
Archaea are able to live in extreme environments because they have a.
simpler cells than eukaryotes.
b.
evolutionary adaptations that most other organisms lack.
c.
a thick capsule.
d.
flagella that other organisms lack.
Archaeans known as halophiles would most likely be found living in a(n) a.
salt lake.
b.
mineral hot spring.
c.
deep-sea hydrothermal vent.
d.
abandoned copper mine.
A water sample is taken from a mineral hot spring. The water is found to be highly acidic. Which of the following organisms is most likely to be living in this sample? a.
a eukaryotic rotifer
b.
a bacterium typically found living in belly buttons
c.
an archaean
d.
a multicellular eukaryote
Which of the following are most well known for their ability to thrive in extreme environments that feature extremely high temperatures, high salt concentrations, or very acidic conditions? a.
archaeans
b.
bacteria
c.
prokaryotes
d.
29.
30.
31.
32.
eukaryotes
In which of the following environments would you expect to find thermophiles? a.
a hot spring
b.
a salty lake
c.
a copper mine
d.
a landfill
Prokaryotes that are observed attaching onto nonliving surfaces most likely possess a.
pili.
b.
a capsule.
c.
a flagellum.
d.
a nucleus.
Prokaryotes that are observed “swimming” through a liquid environment most likely possess a.
pili.
b.
a capsule.
c.
a flagellum.
d.
a nucleus.
Prokaryotes may pick up pieces of DNA from the environment or other bacteria and incorporate these pieces into their own genome through a.
vertical gene transfer.
33.
34.
35.
b.
horizontal gene transfer.
c.
sexual reproduction.
d.
binary fission.
Small loops of extrachromosomal DNA in the cytoplasm of prokaryotes are called a.
spores.
b.
plasmids.
c.
ribosomes.
d.
pili.
Structures produced by bacteria, but not archaeans, that are extremely resistant to boiling and freezing temperatures are a.
spores.
b.
plasmids.
c.
ribosomes.
d.
pili.
A disease-causing bacterium may be protected from the immune system by a slippery a.
pilus.
b.
flagellum.
c.
capsule.
d.
cell wall.
36.
37.
38.
39.
Disease-causing bacteria in a human begin to multiply rapidly when they sense that their numbers are high enough to overpower an immune response. This is possible because of a.
quorum sensing.
b.
plasmids.
c.
horizontal gene transfer.
d.
sporulation.
Bacterial conjugation is the process in which a bacterium a.
splits in two.
b.
exchanges DNA directly with another bacterium.
c.
adheres to a surface to form a biofilm.
d.
takes in DNA from its environment.
Which of the following prokaryotes would be most likely to survive a full year in a freezing arctic tundra? a.
an anaerobic bacterium
b.
an aerobic bacterium
c.
a bacterium capable of sporulation
d.
a nitrogen-fixing bacterium
If one forgets to brush his or her teeth, bacteria may use __________ to attach onto the surface of the teeth. a.
flagella
b.
pili
c.
DNA loops
d.
40.
41.
42.
plasma membranes
Archaeans found in deep-sea hydrothermal vents would be expected to a.
use carbon dioxide in photosynthesis.
b.
obtain energy from inorganic chemicals.
c.
produce oxygen gas as a by-product.
d.
obtain energy from sunlight.
Anaerobic archaeans living in hydrogen-rich environments may feed on hydrogen and release __________ gas as a by-product. a.
oxygen
b.
carbon dioxide
c.
methane
d.
nitrogen
A prokaryote living in a deep-sea environment that has limited gases and a deep layer of dead organic matter most likely fits in the category represented by the letter __________ in the figure below.
43.
a.
A
b.
B
c.
C
d.
D
A photosynthetic, heterotrophic prokaryote fits in the category represented by the letter __________ in the figure below.
44.
45.
a.
A
b.
B
c.
C
d.
D
A photosynthetic, autotrophic prokaryote fits in the category represented by the letter __________ in the figure below.
a.
A
b.
B
c.
C
d.
D
Heterotrophic bacteria and archaeans that are decomposers are important in a.
water cycling.
b.
nutrient cycling.
46.
47.
48.
c.
capturing sunlight energy.
d.
carbon fixation.
Prokaryotes can be found in most habitats because they a.
are smaller than eukaryotes.
b.
can survive in both oxygen-rich and oxygen-free environments.
c.
have a single circular chromosome.
d.
can obtain energy from sunlight.
One of the earliest prokaryotes on Earth, the cyanobacteria, played an important role in the evolution of multicellular eukaryotes. These early prokaryotes changed Earth’s chemistry when they began a.
recycling nutrients locked in organic matter.
b.
producing oxygen as a by-product of photosynthesis.
c.
capturing energy from inorganic iron ore.
d.
existing in oxygen-free environments.
An individual with a deep, closed belly button is more likely to have more __________ bacteria living in his or her belly button compared to an individual with a shallow, open belly button. a.
anaerobic
b.
aerobic
c.
nitrogen-fixing
d.
photoheterotrophic
49.
50.
51.
Prokaryotes described as chemoautotrophs are represented by the category labeled __________ in the figure below.
a.
A
b.
B
c.
C
d.
D
Which of the following organisms found in the human microbiome is NOT known to be a pathogen? a.
archaeans
b.
gut bacteria
c.
fungi
d.
skin bacteria
The belly button project has used citizen scientists to collect information about the prevalence of different belly button species. Using the graphic shown below, determine species abundance from most abundant to least abundant.
a.
Staphylococcaceae, Porphyromonos, Corynebacterium, Anaerococcus
b.
Porphyromonos, Anaerococcus, Staphylococcaceae, Corynebacterium
c.
Corynebacterium, Staphylococcaceae, Anaerococcus, Porphyromonos
d.
Anaerococcus, Porphyromonos, Corynebacterium, Staphylococcaceae
52.
List three characteristics shared between bacteria and archaea.
53.
What characteristics allow prokaryotes to reproduce at a much faster rate than eukaryotes?
54.
Beginning with a single bacterium for generation 0, calculate the number of cells present at generation 4.
55.
Explain why the growth curve shown in the figure changes from a relatively flat line to a steeper upward line as the generation number increases.
56.
If the generation time for the bacterium shown in the figure below is 30 minutes, how much time will have gone by when the population has reached 1,000?
57.
A bacterium that normally resides on human skin and does not cause disease has a very short generation time compared to disease-causing bacteria. How might this shorter generation time be beneficial to the human?
58.
Ben drinks directly out of a new milk container and then leaves the milk out of the refrigerator for at least an hour before remembering to put it away. The next morning, his roommate complains that the milk he just bought has already turned sour. Why did the milk turn sour more quickly than usual?
59.
In some cases, science is advanced when the public participates in collecting, and sometimes analyzing, data. Name one way in which citizen scientists benefit from this type of collaborative effort.
60.
After boiling water for a short period of time, the water is checked for the presence of actively dividing cells. When it is determined that no active, dividing cells are present, the water is used to make agar, a solid medium used for bacterial growth. Within 48 hours there are numerous colonies of cells growing on the agar. What type of prokaryote is growing? Why was cell division not detected originally in the boiled water?
61.
Explain how bacteria can incorporate a gene for antibiotic resistance from another bacterial cell.
62.
What role do pili serve in the formation of biofilms, such as dental plaques?
63.
Describe one way in which prokaryotes directly help plants.
64.
An experiment investigates whether plants called legumes can grow in a sterile environment free of bacteria. The soil, growing containers, and all materials are sterilized, and seeds are planted. The seeds sprout, but all of the seedlings die very quickly from nitrogen deficiency. Why?
65.
The bacterium Clostridium difficile (C. diff) can cause infection in the human intestine that leads to diarrhea and abdominal cramping. One way to treat this infection is with a fecal transplant from a healthy donor to the patient’s intestine using a colonoscopy. Explain how this treatment helps the patient.
66.
If prokaryotes were unable to convert nitrogen gas into ammonia or nitrate, how would life on Earth be different than it is today?
67.
What is the phenomenon referred to as dysbiosis? What problems may occur as a result of dysbiosis?
68.
Bacteria and archaea are together referred to as __________.
69.
A citizen scientist documenting dates when migratory birds arrive in an area are participating in data ____________.
70.
A prokaryote living in a hot hydrothermal vent deep in the ocean is most likely a(n) __________.
71.
The prokaryotic structures used to link bacteria together or to adhere to surfaces are called __________.
72.
Prokaryotes typically reproduce by splitting in two through a process called __________.
73.
Dental plaque that forms on the surface of teeth is an example of a(n) __________.
74.
A prokaryote that uses carbon dioxide for photosynthesis and sunlight for energy is called a(n) __________.
75.
Match each prokaryotic cell structure with its description. a.
capsule
b.
pilus
c.
flagellum
d.
cell wall
e.
plasmid __ 1. loop of non-chromosomal DNA __ 2. helps protect disease-causing bacteria from destruction by the immune system __ 3. spins like a propeller to allow movement through a liquid environment __ 4. links bacteria together or attaches them to a surface in their environment __ 5. surrounds the cell, just outside of the plasma membrane
76.
Match each bacterium with its shape. a.
rod-shaped
b.
spiral
c.
spherical __ 1. Micrococcus __ 2. Streptobacillus __ 3. Spirochete
77.
Match each term describing prokaryotes with ways of obtaining energy and carbon. a.
photoheterotroph
b.
chemoautotroph
c.
photoautotroph
d.
chemoheterotroph __ 1. a prokaryote that consumes organic matter to obtain energy and carbon __ 2. a prokaryote that obtains energy from inorganic iron ore and carbon from carbon dioxide __ 3. a prokaryote that uses sunlight to obtain energy and consumes organic matter to obtain carbon
__ 4. a prokaryote that uses sunlight to obtain energy and takes in carbon dioxide to conduct photosynthesis
Answer Key Chapter 15
1. Answer:
D
2. Answer:
D
3. Answer:
C
4. Answer:
C
5. Answer:
A
6. Answer:
D
7. Answer:
B
8. Answer:
C
9. Answer:
A
10. Answer:
B
11. Answer:
B
12. Answer:
C
13. Answer:
B
14. Answer:
C
15. Answer:
C
16. Answer:
C
17. Answer:
B
18. Answer:
C
19. Answer:
B
20. Answer:
A
21. Answer:
A
22. Answer:
A
23. Answer:
D
24. Answer:
D
25. Answer:
B
26. Answer:
A
27. Answer:
C
28. Answer:
A
29. Answer:
A
30. Answer:
A
31. Answer:
C
32. Answer:
B
33. Answer:
B
34. Answer:
A
35. Answer:
C
36. Answer:
A
37. Answer:
B
38. Answer:
C
39. Answer:
B
40. Answer:
B
41. Answer:
C
42. Answer:
D
43. Answer:
C
44. Answer:
A
45. Answer:
B
46. Answer:
B
47. Answer:
B
48. Answer:
A
49. Answer:
B
50. Answer:
A
51. Answer:
C
52. Answer:
Both are single-celled organisms, have a single circular chromosome located in the cytoplasm, and lack a nucleus and membrane-enclosed organelles. Both reproduce quickly using a process called binary fission. Both groups are widespread, extremely abundant, and show a wide diversity in metabolism.
53. Answer:
Prokaryotic cells are smaller and simpler in structure compared to eukaryotic cells. Prokaryotic cells lack membrane-enclosed organelles and a nucleus. Prokaryotes also have a single circular loop of DNA rather than the multiple linear chromosomes found in eukaryotes.
54. Answer:
The number of cells present at generation 4 is 16. Each cell will divide into two cells during a generation. The single starting cell becomes two cells (generation 1). Those two divide into four cells (generation 2). Four cells divide into eight cells (generation 3), and those eight divide into 16 cells (generation 4).
55. Answer:
The growth curve indicates exponential growth as each individual cell divides into two cells each generation. In this way, the population doubles each generation. During the early generations, the difference between the number of parent cells and the number of daughter cells is much less than the difference between those numbers in later generations. For instance, in generation 2 the population doubles from 2 to 4 cells, whereas in generation 9 the population doubles from 256 to 512 cells.
56. Answer:
Five hours will have passed. The growth curve shows a population around 1,000 at generation 10. Ten times 0.5 hours (30 minutes) equals 5 hours to reach that population size.
57. Answer:
The bacterium with the shorter generation time will be able to divide more rapidly than the disease-causing bacteria. Through competition, the larger number of cells produced will use up resources in the environment that could otherwise be used by disease-causing bacteria.
58. Answer:
As the milk was sitting out of the refrigerator, it had time to warm up, and bacteria within the milk were able to divide more rapidly. The sour taste was from by-products of bacterial metabolism. Drinking directly out of the container added even more bacteria to those that were already present.
59. Answer:
Citizen scientists may learn new things, have fun, and/or feel a sense of purpose when they engage in this type of work.
60. Answer:
The organism is a bacterium that produces spores; archaea do not undergo sporulation. Spores are thick-walled, dormant structures that are capable of surviving boiling conditions. When conditions improve, these cells resume normal activities and undergo cell division.
61. Answer:
Bacteria can transfer a gene for antibiotic resistance to other bacterial cells using plasmids, which are loops of nonchromosomal DNA. This process is called horizontal gene transfer. One form of horizontal gene transfer called bacterial conjugation involves a bacterium directly trading DNA with another bacterium. In addition, a bacterium can take up DNA from a dying bacterium that bursts open and releases DNA.
62. Answer:
Pili are structures that allow bacteria to adhere to each other and to a surface. Attaching to a surface is the first step in the formation of a biofilm.
63. Answer:
In a process called nitrogen fixation, some bacteria convert nitrogen gas in the air into ammonia, a form that plants can use.
64. Answer:
Although the air we breathe contains abundant nitrogen gas, plants are unable to utilize this form of nitrogen. Some plants called legumes form symbiotic relationships with nitrogen-fixing bacteria. These bacteria convert nitrogen gas into ammonia or nitrate, which can then be used by the plant.
65. Answer:
The fecal transplant contains a healthy balance of microorganisms that can compete with the C. diff for limited resources available within the intestine. This competition counters the dysbiosis, or imbalance of the human microbiome, that caused the infection. This treatment has a very high cure rate and is an alternative to the standard antibiotic treatment.
66. Answer:
Plants called legumes form a symbiotic relationship with prokaryotic cells called nitrogen-fixing bacteria. These bacteria convert nitrogen gas in the air into a form that plants can take up and use. If prokaryotes were unable to perform this role, the plants would not be able to survive. In addition, other organisms that rely on these plants would also not exist.
67. Answer:
Dysbiosis is a term used when the healthy balance in the human microbiome shifts out of balance. Dysbiosis may result in human illness because microbial biodiversity helps to keep pathogens from overwhelming human defenses.
68. Answer:
prokaryotes
69. Answer:
collection
70. Answer:
archaean
71. Answer:
pili pilus
72. Answer:
binary fission
73. Answer:
biofilm
74. Answer:
photoautotroph
75. Answer:
1.
E
2.
A
3.
C
4.
B
5.
D
1.
C
2.
A
3.
B
1.
D
2.
B
3.
A
4.
C
76. Answer:
77. Answer:
Name: ___________________________ Class: _________________ Date: __________
Chapter 16 1.
2.
3.
Eukaryotic DNA is enclosed in two concentric layers of cell membranes that form the __________ in the eukaryotic cell. a.
nuclear envelope
b.
nucleoid
c.
Golgi apparatus
d.
rough endoplasmic reticulum
Eukaryotic cells can complete tasks such as digesting and storing food and ridding the cell of waste products because they contain an elaborate system of internal membranes and compartments. This degree of complex compartmentalization is lacking in a.
protists.
b.
fungi.
c.
prokaryotes.
d.
plants.
Chromosomal DNA is found in the cytoplasm of __________ cells. a.
eukaryotic
b.
prokaryotic
c.
protozoan
d.
fungal
4.
5.
6.
7.
The volume of a prokaryotic cell is, on average, __________ than that of a eukaryotic cell. a.
10 times greater
b.
10 times less
c.
1,000 times greater
d.
1,000 times less
Select the true statement. a.
Plants and animals both produce zygotes when sperm and egg cells fuse together.
b.
Multicellularity evolved one time in a single lineage of eukaryotes.
c.
Asexual reproduction allows eukaryotes to combine genetic information from two parents.
d.
Protists and prokaryotes can reproduce sexually in a process called binary fission.
An organism that produces sperm cells must be __________. a.
single-celled
b.
a plant
c.
multicellular
d.
an animal
Which plants are dependent on a watery environment for fertilization? a.
bryophytes, ferns, and gymnosperms
b.
bryophytes and ferns
c.
bryophytes only
d.
ferns only
8.
9.
10.
Which term best describes free-living, single-celled protists that are nonphotosynthetic and motile? a.
kelps
b.
slime molds
c.
algae
d.
protozoans
The bacterium that causes strep throat would be a __________ that belongs to the __________. a.
prokaryote; domain Bacteria
b.
eukaryote; group protists
c.
prokaryote; domain Archaea
d.
eukaryote; domain Bacteria
The organism Entamoeba histolytica is one of the causes of amoebic dysentery. Infection occurs when cysts of this organism are swallowed and enter the patient’s digestive tract. These cysts each have four nuclei, and once in the digestive tract the cysts divide into four cells, each with its own nucleus. Each new cell can invade the mucosal lining of the digestive tract by pushing its pseudopodia into the lining. This organism is a __________ that belongs to the __________. a.
prokaryote; domain Bacteria
b.
eukaryote; group protists
c.
prokaryote; group protists
d.
eukaryote; domain Bacteria
11.
12.
13.
14.
Protists and other organisms that use energy and carbon from a variety of sources to fuel their growth and reproduction are most appropriately referred to as a.
autotrophs.
b.
auxotrophs.
c.
heterotrophs.
d.
mixotrophs.
A drop of pond water is examined with a microscope, revealing small, green, motile, unicellular organisms that seem to be moving by whipping a small flagellum around. These organisms most likely belong to a.
kingdom Fungi.
b.
kingdom Plantae.
c.
protists.
d.
kingdom Animalia.
Some protists break down waste material by consuming dead organisms and releasing nutrients into the environment to be reused by producers and cycled back into the food chain. These protists are a.
decomposers.
b.
producers.
c.
autotrophs.
d.
auxotrophs.
As Charlotte snorkels near the shoreline, she notices large masses of something green swaying with the surf. She suspects this to be a large plant in the ocean. She collects a sample. Upon closer examination, she discovers that there are no vascular structures to absorb and transport
water and nutrients throughout the organism, but there are chloroplasts present in the cells. This organism most likely belongs to
15.
16.
a.
kingdom Fungi.
b.
kingdom Plantae.
c.
kingdom Animalia.
d.
protists.
Within the group protists, __________ are photosynthetic and may or may not be motile. a.
protozoans
b.
algae
c.
fungi
d.
plantae
According to the phylogenetic tree, which of the following combinations are most closely related?
17.
a.
Red algae and Forams
b.
Green algae and Amoebas
c.
Diplomonads and Euglenoids
d.
Ciliates and Amoebas
The organism that causes malaria is transmitted to humans by mosquito bites. Once in the human bloodstream, this unicellular organism takes up residency inside the red blood cells. It has a nucleus and other cellular structures that are visible upon microscopic examination of the blood. This pathogenic organism is in the group a.
protist, Plasmodium.
b.
Archaea, Protozoan.
18.
19.
20.
c.
protist, slime mold.
d.
Archaea, Amoeba.
It is particularly important for pregnant women to carefully wash their hands and take other precautions if they have a pet cat and are changing the litter box. An organism occasionally carried by cats, pigs, and sheep can infect humans and pass from mother to child in utero, resulting in severe symptoms in the growing child. Microscopic examination of this single-celled organism shows a nucleus and other visible cellular organelles. This pathogenic organism is the a.
bacterium Plasmodium vivax.
b.
protist Plasmodium vivax.
c.
bacterium Toxoplasma gondii.
d.
protist Toxoplama gondii.
The __________ lack a vascular system and tend to grow in low mats. Examples include liverworts and mosses. a.
gymnosperms
b.
bryophytes
c.
angiosperms
d.
aquatic algae
On a hike, Cheryl notices some flat green plants clinging to the side of a damp rock. She brings a few of these flat but leaf-shaped plants back to the lab to examine under the microscope and determines that these plants are only a few cells thick and have no vascular tissues. They appear to be absorbing water directly through their surfaces. These little plants are probably a.
angiosperms.
21.
22.
23.
b.
aquatic algae.
c.
bryophytes.
d.
gymnosperms.
An autotrophic organism that grows on land, has vascular tissues, but does not produce seeds could be a a.
bryophyte.
b.
liverwort.
c.
gymnosperm.
d.
fern.
Fiddlehead greens are the curled, young fronds of a fern. Harvested very early and trimmed close to the ground, they provide a tasty addition to salads. These multicellular, photosynthetic, vascularized organisms that do not produce seeds belong to a.
the domain Archaea.
b.
the kingdom Plantae.
c.
the kingdom Fungi.
d.
protists.
Gingko biloba is the sole surviving species of what was once many species. Popular as ornamentals in the United States and Europe, Ginkgos are trees that can reach heights of 90 feet or more. They have wedged-shape leaves that show a branching network of vascular tissues. Pollen is produced on male trees, and the seeds are produced on female trees but are not enclosed in a fruit structure. The Gingko biloba is an example of a(n) a.
gymnosperm.
b.
angiosperm.
24.
25.
26.
c.
aquatic alga.
d.
bryophyte.
Which of the following is NOT an evolutionary advantage of seed-bearing plants? The plant embryo a.
has a supply of stored food to use until it is ready to begin photosynthesis.
b.
and food supply are encased in a protective covering.
c.
is protected from drying out and predation.
d.
will be able to immediately start photosynthesis.
Which of the following describes the primary evolutionary advantage of producing flowers on a plant? a.
Water and minerals are absorbed by the whole plant through the flower.
b.
Photosynthesis occurs, and CO2 is absorbed throughout the entire plant.
c.
It enhances sexual reproduction by attracting animal pollinators through scent, shape, and color.
d.
Materials such as cotton and pharmaceuticals are produced for human use.
In the late spring, Miles moves into a new house with a small tree growing in the yard. The flowers on this tree have five white petals tinged with pink. Later in the summer, he notices a small fruit where each of the flowers had bloomed. Miles does not take long to realize this is an apple tree, Malus pumila. This apple tree is a(n) __________ from kingdom Plantae. a.
gymnosperm
b.
angiosperm
27.
28.
29.
c.
bryophyte
d.
cycad
Pignoli are pine nuts that have lent themselves to culinary uses as far back as the Roman Empire. Pignoli are “naked seeds” harvested from the scales of the cones produced by the Italian Stone Pine tree. The Italian Stone Pine and other pine nut–producing trees are __________ from kingdom Plantae. a.
gymnosperms
b.
angiosperms
c.
bryophytes
d.
cycads
Basil will produce tiny flowers if it is not kept trimmed back. After these tiny flowers are pollinated, they produce tiny seeds encased in a papery covering. Basil is an example of a(n) a.
bryophyte.
b.
fungus.
c.
angiosperm.
d.
gymnosperm.
Based upon the evolutionary traits visible in blooming rose bushes in a garden, a reasonable deduction would be that the a.
lack of an extensive vascular system means they are bryophytes.
b.
presence of seeds means they are gymnosperms.
c.
lack of visible fruit means they are ferns.
d.
presence of flowers means they are angiosperms.
30.
31.
32.
Pinus sylvestris, Scotch Pine, is native to Europe and Asia. Many Americans refer to them as “Christmas trees.” This species of tree grows from the “naked seeds” produced on cones and released about 22–24 months after pollination. This tree is an example of a(n) __________ from kingdom __________. a.
gymnosperm; Fungi
b.
gymnosperm; Plantae
c.
angiosperm; Fungi
d.
angiosperm; Plantae
Cycas revoluta and Zamia furfuracea are species of cycads commonly used as ornamental plants in landscaping. Both species can grow fairly large and produce “naked seeds” on very large and unusual-looking cones made of specialized leaves. Neither of these species produces flowers. These species are examples of a.
gymnosperms.
b.
bryophytes.
c.
angiosperms.
d.
ferns.
In angiosperms the modified leaf evolved into the ovary wall, layers of tissue that enclose and protect the ovules. Once fertilized, these ovules develop into __________, and the ovary wall becomes the fruit wall. The fruits of many plants provide food for heterotrophs. a.
stomata
b.
seeds
c.
cellulose
d.
pollen
33.
34.
35.
When you take a bite out of an apple, what specifically are you eating? a.
plant embryo
b.
“naked seed”
c.
ovule
d.
ovary
There are three major groups of fungi: zygomycetes, ascomycetes, and basidiomycetes. These groups are named for their a.
modes of obtaining food energy.
b.
differing abilities to produce mycelia.
c.
unique reproductive structures.
d.
ability to photosynthesize carbon compounds.
According to the phylogenetic tree shown,
a.
ascomycetes are more closely related to zygomycetes than they are to basidiomycetes.
36.
37.
38.
b.
basidomycetes are more closely related to zygomycetes than they are to ascomycetes.
c.
zygomycetes are more closely related to basidiomycetes than they are to ascomycetes.
d.
zygomycetes have an equally close relationship to basidiomycetes and ascomycetes.
Like plant cells, all fungal cells have a.
a protective cell wall that surrounds the plasma membrane and encases the cell.
b.
the ability to photosynthesize carbon compounds for energy.
c.
the ability to store extra food energy in the form of glycogen.
d.
only a plasma membrane surrounding the cell for protection.
Truffles are the subterranean fruiting body of a mychorrhizal fungus and usually found in close association with tree roots. The mycelial mat of the truffle a.
provides energy-packed sugars to the trees while the tree roots absorb water and minerals from the soil and share them with the truffles.
b.
absorbs water and minerals from the soil and shares them with the tree while the tree provides energy-packed sugars to the truffles.
c.
absorbs energy-packed sugars, water, and nutrients from the soil and shares them with the tree roots.
d.
photosynthesizes sugars and absorbs water and minerals from the soil before sharing these products with the tree.
Fungi often form mutualistic relationships with plants. These mutualistic relationships are typically characterized by benefits to a.
only the plant.
39.
40.
41.
b.
only the fungus.
c.
both the plant and the fungus.
d.
a third species nearby, but neither the plant nor the fungus benefits.
A lichen is a mutualistic association between a fungus and a photosynthetic prokaryote such as a.
red algae.
b.
brown algae.
c.
diplomonads.
d.
cyanobacteria.
Jim is mowing the lawn and accidently runs over a large round object that seems to explode in a cloud of dust. Upon closer examination, he determines that the object was actually the club-shaped reproductive structure of an organism that has cells with cell walls but no chloroplasts, and the dust particles were actually spores. This organism is probably a __________ that belongs to kingdom __________. a.
basidiomycete; Fungi
b.
ascomycete; Plantae
c.
zygomycete; Fungi
d.
basidiomycete; Plantae
Grapes harvested and crushed into juice will often produce a fermented beverage containing alcohol. Grains (such as wheat, barley, rye, or corn) will also produce an alcoholic beverage if they are soaked and allowed to ferment. Which of the following organisms, naturally present in the environment, is the likely cause of the fermentation? a.
angiosperms
42.
43.
44.
b.
yeasts
c.
basidiomycetes
d.
ciliates
Lignin is a chemical in cell walls that increases the rigidity of a plant. Which plant group was the first to feature lignin in its cell walls? a.
bryophytes
b.
gymnosperms
c.
ferns
d.
angiosperms
Eva returns from her month-long holiday and discovers that she left a loaf of bread sitting on the countertop. The bread is now covered in a fuzzy black, gray, and white coating. Because she’s curious, she decides to take the bread with her to a biology lab and examine a bit of the fluff under the microscope. She sees branching, colorless hair-like threads running throughout the bread and small round black spores over the surface of the bread. This is likely an example of a __________. a.
green alga
b.
basidiomycete
c.
diplomonad
d.
zygomycete
In the photo, the plant on the __________ is most likely to be host to mycorrhizal fungi because the __________.
45.
46.
a.
left; fungi are obviously stunting its growth
b.
right; mycelial mat of the fungus is enhancing the supply of water and essential minerals to the plant
c.
right; mycelial mat of the fungus is photosynthesizing sugars to provide the plant with energy
d.
left; mycelial mat of the fungus is photosynthesizing toxic sugars and pulling in minerals that are harming the plant
Because ginseng has bright-red seed heads that develop from its flowers after pollination, ginseng is a(n) __________. a.
angiosperm
b.
gymnosperm
c.
bryophyte
d.
heterotroph
What does pollen contain? a.
plant embryos
b.
cells that develop into sperm
c.
seeds
d.
47.
48.
49.
spores
Paramecium caudatum is a unicellular species that uses cilia for locomotion. Each organism of this species contains two nuclei and ingests bacteria and other microorganisms in the environment. This species is a(n) a.
alga, a type of protist.
b.
bryophyte, a type of plant.
c.
zygomycete, a type of fungus.
d.
protozoan, a type of protist.
Which is the most dominant and diverse plant group on Earth? a.
gymnosperms
b.
ferns
c.
angiosperms
d.
bryophytes
Many of the 7,000 crops cultivated or collected by humans for food contain seeds encased in a fruit, like the one seen in the image. These types of crops are __________.
a.
angiosperms
b.
gymnosperms
c.
liverworts
d.
bryophytes
50. Five cereal crops provide 60 percent of the food energy taken in by the world’s human population. As shown in the image, these cereals (grains) are rice, maize, wheat, millet, and sorghum. The portion of these crops consumed by humans is actually the seed with its protective coverings from the fruit. These crops are __________. a.
gymnosperms
b.
bryophytes
c.
angiosperms
d.
ferns
51.
Explain how the compartmentalization of eukaryotic cells enables them to have a much greater cell volume than prokaryotes and still efficiently carry out cell functions and move materials in and out of the cell.
52.
Compare and contrast prokaryotes and eukaryotes.
53.
List several characteristics of protists. How does the definition of a protist differ from how the plant, animal, and fungi kingdoms are defined?
54.
Examine the phylogenetic tree and explain whether or not the red, green, and brown algae are equally related to each other and why.
55.
Explain the advantage afforded to plants with the evolution of roots containing vascular tissues.
56.
Plants evolved within the group of green algae. Despite all of the differences between land plants and aquatic algae, describe two characteristics that plant cells and green algal cells have in common.
57.
Propose an explanation for how the evolution of lignin in cell walls led to the evolution and growth of the gymnosperms known as giant redwood trees.
58.
Propose an explanation for how the evolution of flowers contributed to the global distribution and variety of angiosperms.
59.
When you eat a mushroom, what part of the fungus are you consuming? In terms of reproduction, why is it important that this part of the fungus be above ground?
60.
Explain why or how fungal body forms often make fungi good decomposers.
61.
How does the key evolutionary innovation of angiosperms contribute to the successful domestication of plants for crops to feed the world’s human population?
62.
How does the environment benefit when plant and fungi species are protected from extinction?
63.
The diameter of a eukaryotic cell is typically __________ than that of a prokaryotic cell.
64.
The reproductive structure of a fungus that can survive for long periods of time in a dormant state is called a __________.
65.
Prokaryotes reproduce through a type of __________ reproduction known as binary fission. This occurs when a cell splits into two genetically identical cells.
66.
There are two broad categories of protists. The __________ are heterotrophic and motile. The algae are photosynthetic and may or may not be motile.
67.
Some protozoans move on a solid surface and obtain food using cellular projections called __________.
68.
The amoeba shown in the picture uses its food vacuoles to __________ food.
69.
The first land plant with a vascular system was the ancestor of present-day __________.
70.
The first plants to evolve the seed were __________.
71.
The key evolutionary innovation in __________ is the flower.
72.
Fungi digest organic material outside the body and absorb the breakdown products. Thus, fungi are absorptive __________.
73.
Single-celled species of fungi are collectively referred to as __________.
74.
Fungi are similar to animals in that they store surplus food energy in the form of __________.
75.
The International Union for Conservation of Nature announced that 31 percent of cactus species, renowned for their unique forms and beautiful __________, are in danger of extinction.
76.
According to the infographic shown, 95 percent of the food energy taken in by the world’s human population is provided by __________ crops in kingdom __________.
77. a.
A
b.
B
c.
C
d.
D __ 1. flowers evolve
__ 2. adaptation to terrestrial life __ 3. seeds evolve __ 4. vascular tissue evolves
78.
Match these organisms to their correct taxonomic grouping(s). a.
brown algae
b.
liverworts and mosses
c.
Streptococcus thermophilus (prokaryote used in making yogurt)
d.
zygomycetes (molds) __ 1. __ 2. __ 3. __ 4.
domain Bacteria domain Eukarya, protists domain Eukarya, kingdom Plantae domain Eukarya, kingdom Fungi
Answer Key Chapter 16
1. Answer:
A
2. Answer:
C
3. Answer:
B
4. Answer:
D
5. Answer:
A
6. Answer:
C
7. Answer:
B
8. Answer:
D
9. Answer:
A
10. Answer:
B
11. Answer:
D
12. Answer:
C
13. Answer:
A
14. Answer:
D
15. Answer:
B
16. Answer:
C
17. Answer:
A
18. Answer:
D
19. Answer:
B
20. Answer:
C
21. Answer:
D
22. Answer:
B
23. Answer:
A
24. Answer:
D
25. Answer:
C
26. Answer:
B
27. Answer:
A
28. Answer:
C
29. Answer:
D
30. Answer:
B
31. Answer:
A
32. Answer:
B
33. Answer:
D
34. Answer:
C
35. Answer:
D
36. Answer:
A
37. Answer:
B
38. Answer:
C
39. Answer:
D
40. Answer:
A
41. Answer:
B
42. Answer:
C
43. Answer:
D
44. Answer:
B
45. Answer:
A
46. Answer:
B
47. Answer:
D
48. Answer:
C
49. Answer:
A
50. Answer:
C
51. Answer:
The compartmentalization of eukaryotic cells by organelles helps these large cells to efficiently carry out cellular processes such as respiration, photosynthesis, digestion, and the elimination of cellular waste. The compartments, or organelles, keep the chemicals needed for cellular processes isolated from each other and from the cell’s cytosol. The organelles facilitate communication and the movement of materials throughout the large cell. The large cell size makes it possible for some eukaryotic cells to engulf their food source, package it into a vesicle for digestion, and then package the waste into a vesicle that will carry it to the cell membrane to be disposed.
52. Answer:
Prokaryotes are simpler and usually smaller than eukaryotes. The chromosomal DNA in prokaryotic cells is found in the cytoplasm, whereas eukaryotic cells house their chromosomal DNA within a membrane-bound nucleus. In addition, prokaryotes lack the membrane-enclosed organelles that allow eukaryotes to more efficiently carry out specialized tasks, such as sending messages, converting energy to useable form, or cleaning up. Prokaryotes include all organisms within the domains Bacteria and Archaea. The domain Eukarya includes the protists as well as all organisms within the kingdoms Plantae, Fungi, and Animalia.
53. Answer:
All protists are eukaryotic. Most protists are unicellular and microscopic, but some are multicellular and large. Protists can have different sizes, different shapes, and obtain their nutrients in a variety of ways. They are grouped together because they do not cleanly fit into any other kingdom in the domain Eukarya. This is unusual because organisms are assigned to the other eukaryotic kingdoms (Plantae, Fungi, Animalia) based upon characteristics that make them similar to each other. Plants are multicellular autotrophs that perform photosynthesis and have unique adaptations that allow them to survive on land. Fungi are absorptive heterotrophs that digest organic matter externally and absorb the nutrient building blocks. Animals are multicellular heterotrophs that ingest food.
54. Answer:
This tree indicates that the red and green algae are more closely related to each other than either is related to the brown algae. According to this tree, the red and green algae share a more recent common ancestor. The ancestor common to all three organisms is two nodes back from the red and green algae and three levels back from the brown algae. So, they are not all equally related.
55. Answer:
The evolution of roots containing vascular tissues made it possible for plants to grow larger on land. The plants no longer needed to absorb water and minerals through all of their surfaces or die from dehydration. The roots could now absorb water and minerals from the soil while providing support and a solid point of attachment to the land.
56. Answer:
Plant cells and green algal cells both use chloroplasts in order to perform photosynthesis. In plants, photosynthesis occurs primarily in the leaves, whereas in green algae photosynthesis occurs throughout the organism. The cells of plants and green algae also both have strong but flexible cell walls composed of cellulose. Cellulose provides structural strength to the cells.
57. Answer:
The cell walls of land plants were originally made of cellulose, like those of green algae from which plants evolved. Beginning with ferns, plants gained the ability to produce and incorporate lignin in their cell walls, resulting in plants that could grow taller with a solid, rigid network of connected cell walls. Taller plants might have had an advantage getting sunlight. As some of these taller plants subsequently evolved the production of pollen, they would have had a reproductive advantage of being able to spread their genes farther in the wind. Gymnosperms, such as the redwood trees, were the first to evolve pollen.
58. Answer:
The flowers characteristic of angiosperms facilitate sexual reproduction by providing a meeting place for male and female gametes. A nearly endless variety of floral shapes, colors, and scents attract pollinators to carry the pollen to other plants; this promotes increased genetic diversity in the population. The greater the genetic diversity in the population, the more likely a portion of the population will be able to thrive and reproduce in new conditions. Additionally, the flowers develop into fruit with seeds. Some types of fruit are consumed by animals who then deposit the seeds in distant locations. All of this contributes to the global distribution and variety of angiosperms.
59. Answer:
Commonly called a mushroom, the fruiting body of a fungus produces spores for reproduction. Spores released from a fruiting body that extends up in the air are more likely to catch a wind current or attract an animal that can carry them longer distances.
60. Answer:
The branching hair-like threads of hyphae increase the surface area of the fungus; they are also capable of growing or penetrating into the structures of dead organisms. As the hyphae grow through the dead material, they excrete chemicals that digest the dead material. The fungal hyphae then absorb some of the nutrients for energy. The rest of the nutrients remain in the soil or environment to be absorbed by other organisms.
61. Answer:
The key evolutionary innovation of angiosperms is the flower. Flowers provide an environment for sexual reproduction by bringing together male gametes (sperm cells) and female gametes (egg cells). This ability to exchange genetic information between different individuals of the same species provides farmers the opportunity to select, breed, and reproduce crops based on their desirable traits. Farmers have domesticated crops by fertilizing desired plants with pollen from plants that are hearty and easier to grow or produce better-tasting, more nutritious food. These plants are eaten, and their seeds are used to grow the next generation of plants to feed the world’s population.
62. Answer:
Plants and fungi are integral components of a healthy ecosystem. Plants make up the producers in terrestrial food webs. Plants prevent runoff and soil erosion by taking up water and holding the soil in place. Plants are an important sink of atmospheric carbon dioxide, and they produce oxygen that is required by many organisms. Fungi are decomposers that help break down dead organisms and return their nutrients to the soil. Fungi are also an important food source for animals.
63. Answer:
greater larger
64. Answer:
spore
65. Answer:
asexual
66. Answer:
protozoans
67. Answer:
pseudopodia
68. Answer:
digest
69. Answer:
ferns
70. Answer:
gymnosperms
71. Answer:
angiosperms
72. Answer:
heterotrophs
73. Answer:
yeasts
74. Answer:
glycogen
75. Answer:
flowers
76. Answer:
thirty; Plantae 30; Plantae
77. Answer:
1.
D
2.
A
3.
C
4.
B
1.
C
2.
A
3.
B
4.
D
78. Answer:
Name: ___________________________ Class: _________________ Date: __________
Chapter 17 1.
2.
3.
The correct two-word Latin scientific name for modern humans is a.
Homo sapiens.
b.
Homo neanderthalensis.
c.
homo sapiens.
d.
homo neanderthalensis.
Which of the following terms could NOT be used to describe humans? a.
eutherian
b.
mammal
c.
primate
d.
marsupial
The first vertebrates to evolve lacked jaws and had skeletons made from a strong, flexible tissue called cartilage. As shown in the following figure, __________ are a modern example of this ancient group of vertebrates known as jawless fishes.
4.
a.
amphibians
b.
reptiles
c.
ray-finned fishes
d.
lampreys
The phylum Chordata includes several subgroups of organisms. To which subgroup do humans belong? a.
vertebrates
5.
b.
cephalochordates
c.
urochordates
d.
monotremes
Rafael is relaxing on the veranda of his beachfront home on the Gulf of Mexico when he notices a small (about 5 inches long), green, four-footed animal clinging to the ceiling. As it begins to run down the wall, he catches it and notices that it is covered with dry scales, has a long tail, and has specialized toe pads that allow it to stick to surfaces. According to the following figure, this animal most likely belongs to which class?
6.
a.
Mammalia
b.
Amphibia
c.
Reptilia
d.
Osteichthyes
Which of the groupings of animals shown in the following figures are most closely related to each other?
a.
lampreys, lancelets, rays
b.
amphibians, sharks, birds
7.
8.
c.
lemurs, reptiles, amphibians
d.
lemurs, chimps, humans
According to the following phylogenetic tree, which of these groups of animals would display radial symmetry?
a.
flatworms
b.
nematodes
c.
cnidarians
d.
arthropods
Which of the following organisms displays bilateral symmetry?
9.
10.
11.
a.
sponges
b.
jellyfish
c.
bees
d.
amoebas
Which of the following organisms displays radial symmetry? a.
flatworm
b.
sea anemone
c.
spider
d.
human
Which of the following is an example of the last segment of an arthropod’s body having evolved into a beneficial trait? a.
human thorax with an arm
b.
bird thorax with a wing
c.
lizard abdomen with a leg
d.
wasp abdomen with a stinger
Based on the following image, which of the choices identify the body segments of lobster?
12.
13.
a.
head, thorax, abdomen
b.
vertebrae, notochord, cartilage
c.
claws, walking legs, swimming legs
d.
tail segments, antennae, eyes
Damien is camping in the south-central United States when he happens across an animal with several “armored” plates covering its back and shoulders. The plates are bony and separated by thin bands of flexible skin. The belly of this short-legged, four-footed animal is covered with skin and soft fur. Damien also notices four young ones scurrying along behind the adult. This animal is most likely a(n) a.
eutherian mammal.
b.
marsupial amphibian.
c.
marsupial mammal.
d.
eutherian reptile.
Echidnas are spiny animals named after a character in Greek mythology that was half woman and half snake and perceived to have characteristics
of both. Echidnas are covered in coarse hair or spines. They lay eggs, and after they hatch, the poorly developed young quickly attach to the mother’s mammary glands. Echidnas are
14.
15.
16.
a.
marsupials.
b.
monotremes.
c.
hominins.
d.
eutherians.
Baleen whales are large, ocean-dwelling animals that were once hunted for their modified hair, called baleen. The young are fully developed at birth and nurse on their mother’s mammary glands. Baleen whales are a.
monotremes.
b.
hominins.
c.
eutherians.
d.
marsupials.
Possums are found throughout much of Central and North America. Although their bodies are covered in hair, their tails and ears are hairless. They have many teeth and opposable, clawless “thumbs” on their rear appendages. They produce poorly developed young that live in the mother’s pouch for about two and a half months before climbing onto her back. Possums are a.
eutherians.
b.
primates.
c.
monotremes.
d.
marsupials.
The development of upright posture in hominins is likely an adaptation for
17.
18.
19.
a.
living on the ground instead of in the trees.
b.
living on land instead of in the water.
c.
no longer needing to carry tools.
d.
having no functional knees.
Which of the following is an advantage of bipedalism in hominins? a.
Standing on two feet makes it easier to climb trees.
b.
Standing on four feet elevates the head, making it easier to see over obstacles and to see farther to allow earlier detection of predators.
c.
Walking on two feet requires more muscle groups and more energy than walking on all fours.
d.
The hands are free to carry food, tools, and weapons.
All primates have opposable thumbs. This means that the thumbs can be touched a.
together.
b.
to each of the other fingers on the opposite hand.
c.
to each of the other fingers on the same hand.
d.
to each of the toes on both feet.
According to the following evolutionary tree, when did hominins branch away from the other apes?
20.
a.
35 mya
b.
12–16 mya
c.
7–8 mya
d.
5–7 mya
Which of the following is a feature of hominins that helps to distinguish them from other apes? a.
quadrupedal walking
b.
upright posture
c.
opposable big toe
d.
21.
22.
23.
face pulled forward
Which of the following traits was likely deleterious for early hominins? a.
a large brain compared to body size
b.
bipedal walking
c.
a pronounced arch and pronounced heel in the foot
d.
an opposable big toe on the foot
Which of the following anatomical changes was an especially important contributor to the development of full bipedalism in hominins? a.
the face pulled forward with the spinal cord entering the rear of the skull
b.
the gain of opposable big toes
c.
restructuring of the pelvis accompanied by a change in the angle of the knee joints that support body weight
d.
having no arch in the foot
Fossilized foot bones show that some hominids living between 3 and 3.5 mya walked upright but had partially opposable big toes. This suggests that a.
the shift to bipedalism was not sudden and complete, and the earliest bipedal hominins may have also spent some time in the trees for shelter or to find food.
b.
the shift from quadrupedalism (walking on four limbs) to bipedalism happened abruptly about 2.5 mya when hominins could no longer find any food in the trees.
c.
hominins actually shifted from bipedalism to quadrupedalism, as it proved to be an advantage when acquiring food.
d.
having a partially opposable big toe helped bipedal hominins run faster when trying to avoid their predators.
24.
25.
The positioning of the toe indicated by the arrow in the following figure suggests that the animal with this fossil hominid foot
a.
most likely always traveled on four feet.
b.
most likely spent all its time swinging in the trees.
c.
traveled mostly on four feet but also spent a great deal of time swinging in the trees.
d.
probably walked upright on two feet and may have spent time in the trees.
An archaeological dig in Africa discovers a collection of stone tools in a cave along with several skeletons. These bipedal skeletons date to about 3.5 mya and show no evidence of a partially opposable toe. Measurements indicate that the brains would have been a little less than a third of the volume of the modern human brain. The teeth found on these skeletons look more like those of an ape than those of a human. This skeletal discovery is most likely which of the following? a.
Sahelanthropus tchadensis
b.
Ardipithecus ramidus
26.
27.
c.
Australopithecus afarensis
d.
Homo erectus
Examine the skulls shown in the following figure. What can be said regarding trends in braincase size and teeth over time?
a.
Older hominin fossils have larger braincases and generally smaller, more humanlike teeth.
b.
More recent hominin fossils have larger braincases and generally smaller, more humanlike teeth.
c.
More recent hominin fossils have smaller braincases and generally larger, more apelike teeth.
d.
There is no apparent change in braincase size or size and structure of the teeth in hominins.
How is mitochondrial DNA inherited in humans? a.
All mitochondrial DNA is inherited from the mother.
28.
29.
30.
b.
Fifty percent of mitochondrial DNA is inherited from the mother and 50 percent from the father.
c.
All mitochondrial DNA is inherited from the father.
d.
Only 75 percent of mitochondrial DNA is inherited from the father; the other 25 percent is inherited from the mother.
How is nuclear DNA inherited? a.
All nuclear DNA is inherited from the father’s ancestral line.
b.
Seventy-five percent of nuclear DNA is inherited from the mother’s ancestral line and 25 percent from the father’s ancestral line.
c.
All nuclear DNA is inherited from the mother’s ancestral line.
d.
Fifty percent of nuclear DNA is inherited from the mother’s ancestral line and 50 percent from the father’s ancestral line.
Which of the following best describes the source of a human’s mitochondrial DNA? a.
It is all inherited from the mother.
b.
It is all inherited from the father.
c.
Half is inherited from the mother and half from the father.
d.
Seventy-five percent is inherited from the mother and 25 percent from the father.
Which of the following best describes the source of a human’s DNA? a.
It is all inherited from the mother.
b.
It is all inherited from the father.
c.
Half is inherited from the mother and half from the father.
d.
Seventy-five percent is inherited from the mother and 25 percent from the father.
31.
32.
33.
34.
Eggs provide __________ to the zygote. a.
both nuclear and mitochondrial DNA
b.
only nuclear DNA
c.
only mitochondrial DNA
d.
no DNA
Sperm provide __________ to the zygote. a.
both nuclear and mitochondrial DNA
b.
only nuclear DNA
c.
only mitochondrial DNA
d.
no DNA
The hypothesis that Neanderthals evolved sometime after hominins migrated out of Africa would be supported by the presence of Neanderthal DNA in the a.
mitochondria of modern African humans.
b.
genomes of modern African humans.
c.
genomes of modern humans in all ethnic groups except for those of Africans.
d.
genomes of Australopithecus africanus.
If a female’s mitochondrial DNA were sequenced and compared to the sequence of mitochondrial DNA isolated from her mother’s paternal grandmother (the mom of her mom’s dad), she likely __________be a significant match because __________.
35.
36.
a.
would not; a person’s mitochondrial DNA is inherited from her mom who inherited it from her mom
b.
would not; a person’s mitochondrial DNA is inherited from her dad who inherited it from his mom
c.
would; a person inherits her mitochondrial DNA from her dad who inherited it from his mom
d.
would; a person inherits her mitochondrial DNA from her mom who inherited from her dad
DNA from a fossil is found, and it is hypothesized that the mother was a Neanderthal and the father was a human. Which of the following would support this hypothesis? a.
finding discernible amounts of nuclear Neanderthal and human DNA but no mitochondrial Neanderthal DNA
b.
finding discernible amounts of mitochondrial and nuclear Neanderthal DNA along with nuclear human DNA
c.
finding significant amounts of human mitochondrial and nuclear DNA along with some nuclear Neanderthal DNA
d.
finding all the nuclear DNA to be Neanderthal and all the mitochondrial DNA to be human
The infamous American outlaw Jesse Woodson James died April 3, 1882. His body was originally interred on the James’s farm but was later moved to Mt. Olivet Cemetery in Kearney, Nebraska. Some people have hypothesized that his death was staged. Researchers have exhumed the body and analyzed mitochondrial DNA found in the teeth with that of mitochondrial DNA from hair samples from the burial site on the James farm—and they matched. These samples were then compared to the mitochondrial DNA of Jesse’s sister Susan’s great-grandson and her greatgreat-grandson. The hypothesis that the body buried in Mt. Olivet Cemetery is not Jesse James would be supported if the mitochondrial DNA from the grave a.
matches the mitochondrial DNA obtained from Susan’s great-grandson and great-great-grandson.
37.
38.
39.
b.
does not match the mitochondrial DNA obtained from Susan’s greatgrandson and great-great-grandson.
c.
matches Susan’s mitochondrial DNA.
d.
matches not only the mitochondrial DNA obtained from Susan’s greatgrandson and her great-great-grandson but also the mitochondrial DNA from Susan’s daughter.
In 2010, Dr. Svante Pääbo published research indicating that all modern ethnic groups other than Africans carry traces of Neanderthal DNA in their nuclear genomes. His earlier work indicated no overlap between Neanderthal mitochondrial DNA and that of Homo sapiens. Which of the following is NOT a likely possible hypothesis that could be supported by this information? a.
The shared nuclear DNA could be a remnant of DNA from a common ancestor shared by Neanderthals and Homo sapiens.
b.
The shared nuclear DNA could be the result of interbreeding between male Neanderthals and female Homo sapiens.
c.
The shared nuclear DNA could be a remnant of DNA from Homo erectus, one of the most recent species since Australopithecus.
d.
The shared nuclear DNA is definitely the result of interbreeding between female Neanderthals and male humans.
Fossil evidence indicates that the first members of the genus Homo arose in Africa approximately __________ years ago. a.
2 to 3 million
b.
200,000
c.
500,000
d.
1 million
Examine the following hominin evolutionary tree. Which species are most closely related?
40.
41.
a.
Homo habilis and Homo sapiens
b.
Homo erectus and Homo sapiens
c.
Australopithecus africanus and Homo habilis
d.
Australopithecus afarensis and Homo habilis
Evidence indicates that archaic Homo sapiens gave rise to which of the following? a.
Homo habilis and Homo neanderthalensis
b.
modern humans and Homo habilis
c.
modern humans and Homo neanderthalensis
d.
Homo rudolfensis and Homo neanderthalensis
Is it possible for Homo sapiens and Neanderthals to be related even if humans are not the direct descendants of Neanderthals?
42.
43.
a.
No, because this would mean there is no connection at all between humans and Neanderthals.
b.
No, because the evolution of humans is clearly linear.
c.
Yes, but only because humans and Neanderthals commonly interbred.
d.
Yes, because humans and Neanderthals share a common ancestor.
Fossilized hominin bones have been found in Germany along with some tools and evidence of charred and fossilized bones from large animals dating to about 350,000 years ago. The hominin bones bear resemblance to both Homo erectus and Homo sapiens. Which of the following is the most likely possible identity of these fossils? a.
Australopithecus anamensis
b.
Homo habilis
c.
Paranthropus boisei
d.
archaic Homo sapiens
Fossils from different species of the genus Homo dating from 1.7–1.9 mya have been found in ecologically diverse areas across central Asia, China, and Indonesia. These species appear to be closely related to Homo erectus. Which of the following is a likely explanation of these findings? a.
Homo erectus migrated across the Asian continent and expanded into a new ecological role. These groups became increasingly reproductively isolated from other Homo erectus groups and eventually formed new species in the genus Homo.
b.
Homo sapiens migrated across the Asian continent and expanded into a new ecological role. These groups became increasingly reproductively isolated from other Homo sapiens groups and eventually formed new species in the genus Homo that were more like Homo erectus and less like Homo sapiens.
44.
45.
46.
c.
Homo floresiensis migrated across the Asian continent and expanded into a new ecological role. These groups became increasingly reproductively isolated from other Homo floresiensis groups and eventually formed new species in the genus Homo that were more like Homo erectus and less like Homo floresiensis.
d.
Homo neanderthalensis migrated across the Asian continent and expanded into a new ecological role. These groups became increasingly reproductively isolated from other Homo neanderthalensis groups and eventually formed new species in the genus Homo that were more like Homo erectus and less like Homo neanderthalensis.
It is possible that modern humans may have comingled with which of these other ancestors? a.
Paranthropus aetheopicus
b.
Homo neanderthalensis
c.
Australopithecus africanus
d.
Australopithecus afarensis
When researchers determined that the jawbone of an Italian Neanderthal dating to around 43,000–45,000 years ago showed the presence of an intermediate chin and mitochondrial Neanderthal DNA, they hypothesized that the jawbone belonged to an individual who was the product of a mating between a modern human and a Neanderthal. This hypothesis would be further supported if the fossil had a.
Neanderthal and Homo sapiens genomic DNA.
b.
only Neanderthal mitochondrial and genomic DNA.
c.
only Neanderthal genomic DNA.
d.
both Neanderthal and Homo habilis genomic DNA.
When researchers found a fossilized jawbone from a late (about 43,000– 45,000 years ago) Italian Neanderthal, they noted that the shape of the
jawbone suggested that the individual had an intermediate chin instead of no chin like most Neanderthals. This would provide evidence supporting which of the following hypotheses?
47.
48.
a.
Homo habilis and Homo neanderthalensis successfully bred with each other while they were present in central Africa.
b.
Homo habilis and Homo neanderthalensis successfully bred with each other while they were present on the Italian peninsula of Europe.
c.
Modern Homo sapiens and Homo neanderthalensis successfully bred with each other while they were present on the Italian peninsula of Europe.
d.
Modern Homo sapiens and Homo neanderthalensis successfully bred with each other while they were present in central Africa.
Consider that fossils of Homo erectus dating between 1.66 and 1.85 mya have been found scattered across Eastern Europe through China and Southeast Asia and dating back to 2.4 mya in Africa. The earliest known specimens of anatomically modern Homo sapiens in Africa date back to roughly 200,000 years ago and 40,000 to 60,000 years ago across Europe and Asia, with some at 115,000 years ago in India. Additionally, Homo neanderthalensis was present across Europe by 150,000 years ago and then spread into western Asia. If there were no evidence indicating the presence of any other early Homo species in Europe, which of the following hypotheses might be supported by this information? a.
Homo neanderthalensis is a possible common ancestor to Homo erectus and Homo sapiens.
b.
Homo erectus is a possible common ancestor to Homo neanderthalensis and Homo sapiens.
c.
Homo sapiens is a possible common ancestor to Homo erectus and Homo neanderthalensis.
d.
Homo floresiensis is the most likely common ancestor to Homo erectus, Homo neanderthalensis, and Homo sapiens.
You are a researcher excavating a site in a cave in Israel. There are many layers of sediment and primitive artifacts (flint tools for cutting and scraping) from ancestral Homo species within the cave. As you work your way deeper
and deeper through the layers, you notice that artifacts in the deeper layers (laid down before 350,000 years ago) do not show any signs of having been exposed to fire. Artifacts in layers more recent than 350,000 years ago show rapidly increasing evidence of exposure to fire. Your colleagues working in nearby caves and caves scattered around the eastern Mediterranean Sea have found similar evidence dating in the same time frames. The evidence is also consistent with that of European sites. What does this suggest about the use of fire by ancestral humans?
49.
a.
Ancestral humans could not have migrated into climates cooler than those found in Africa until about 150,000 years ago because they had not yet figured out how to use fire before that time.
b.
Ancestral humans (about 200,000 years ago) were simply using fire that they obtained from lightning-sparked wildfires; they did not make or maintain their own fires.
c.
Ancestral humans who had migrated to areas around the eastern Mediterranean Sea and Europe very likely learned to control and use fire around the same time (about 300,000 to 350,000 years ago), and they became increasingly good at it.
d.
The hominins occupying the caves and making and using fire must have been modern Homo sapiens because no other human ancestors were still surviving 300,000–350,000 years ago and no other human ancestors were ever able to use fire.
Which of the following is the strongest evidence suggesting that Homo sapiens may have intermingled with other species such as H. heidelbergensis and H. neanderthalensis? a.
Evidence of DNA shared between the species suggests that they may have intermingled with each other.
b.
Fossils from all or some of these Homo species dating to the same time period and found in overlapping geographic areas suggests that they may have intermingled with each other.
c.
Fossils from all or some of these Homo species found in overlapping geographic areas, as well as evidence of DNA shared between the species suggests that they may have intermingled with each other.
d.
50.
51.
Fossils from all or some of these Homo species dating to the same time period and found in overlapping geographic areas that showed phenotypes intermediate to at least two of the other species as well as evidence of DNA shared between the species suggests that they may have intermingled with each other.
In light of the out-of-Africa hypothesis, which of the following is a probable reason why species such as Homo neanderthalensis, Homo floresinensis, and Homo erectus do not exist today? a.
Modern Homo sapiens outcompeted and replaced other hominin species as they migrated around the world.
b.
Extensive gene flow between human populations led to a blending of traits that resulted in the evolution of Homo sapiens.
c.
As modern Homo sapiens developed new and more accurate hunting skills, they were able to hunt other hominin species to extinction.
d.
Climate change in Africa caused the extinction of all hominin populations except the ones that gave rise to modern Homo sapiens.
Consider that fossils of Homo erectus dating between 1.66 and 1.85 mya have been found scattered across Eastern Europe and through China and Southeast Asia and dating back to 2.4 mya in Africa. The earliest known specimens of anatomically modern Homo sapiens in Africa date back to roughly 200,000 years ago and 40,000 to 60,000 years ago across Europe and Asia, with some dated to 115,000 years ago in India. Additionally, Homo neanderthalensis was present across Europe by 150,000 years ago and then spread into western Asia. Concerning the out-of-Africa hypothesis, this suggests that a.
hominins migrated north from Africa, spreading out across Europe and Asia three times.
b.
hominins migrated north from Africa, spreading out across Europe and Asia at least twice.
c.
there was only one major migration of hominins out of Africa.
d.
there must have been at least seven major migrations of hominins out of Africa.
52.
Which of these currently existing organisms are eutherian mammals and are most closely related to humans? a.
chimpanzees
b.
mice
c.
zebra fish
d.
platypuses
53.
Between annelids, chordates, cnidarians, echinoderms, and nematodes, which two groups of organisms are most closely related? Support your answer with information from the following phylogenetic tree.
54.
Compare and contrast amphibians with reptiles and birds using the following phylogenetic tree.
55.
How might being bilaterally symmetrical be an evolutionary advantage for a fish?
56.
Explain segmentation and its significance for an animal such as a lobster.
57.
Compare and contrast the three types of mammals.
58.
The kangaroo is a marsupial. Briefly discuss the developmental state of a young kangaroo at birth and how it would be nourished until it is ready to survive on its own.
59.
Briefly explain the difference between hominids and hominins.
60.
Which of the primates shown in the following figure could act as an outgroup (a group that is closely related to the rest of the organisms on the tree but clearly stands apart) to be compared to the other primates when constructing an evolutionary tree? Support your answer.
61.
The fossil of a male hominin is discovered, and it appears to share traits with both humans and Neanderthals. What could mitochondrial-DNA sequencing and whole-genome DNA sequencing convey about the fossil’s parents?
62.
In 2012, researchers determined that the Neanderthal DNA had been introduced into the human genome between 90,000 and 40,000 years ago. Does this support the hypothesis that Neanderthal DNA present in the human genome is a remnant from a common hominin ancestor? Support your answer by indicating roughly when DNA from Neanderthals would have been introduced to the human genome if that Neanderthal DNA were a remnant from a common hominin ancestor.
63.
Consider that fossils of Homo erectus dating between 1.66 and 1.85 mya have been found scattered across Eastern Europe through China and Southeast Asia and dating back to 2.4 mya in Africa. The earliest known specimens of anatomically modern Homo sapiens in Africa date back to roughly 200,000 years ago and 40,000 to 60,000 years ago across Europe and Asia, with some dating back 115,000 years ago in India. Additionally, Homo neanderthalensis was present across Europe by 150,000 years ago and then spread into western Asia. If there were no evidence indicating the presence of any other early Homo species in Europe, propose a hypothesis that would be supported by this information.
64.
You are a researcher excavating a site in a cave in Israel. There are many layers of sediment and primitive artifacts (flint tools for cutting and scraping) from ancestral Homo species within the cave. As you work your way deeper and deeper through the layers, you notice that artifacts in the deeper layers (laid down before 350,000 years ago) do not show any signs of having been exposed to fire. Artifacts in layers less than 350,000 years ago show rapidly increasing evidence of exposure to fire. Your colleagues working in nearby caves and caves scattered around the eastern Mediterranean Sea have found similar evidence dating in the same time frames. The evidence is also consistent with that of European sites. What does this suggest about the use of fire by ancestral humans?
65.
What evidence would support the hypothesis that a male Homo sapiens mated with a female Homo neanderthalensis and produced offspring?
66.
You and your brother share the same father but have different mothers. Compare and contrast your brother’s mitochondrial and nuclear DNA profiles and yours.
67.
All chordates have a dorsal __________, which is a flexible rod along the center of the body that is critical for development.
68.
In vertebrates, the dorsal notochord has evolved to become the cushioning discs between __________, which are the strong, hollow sections of the backbone.
69.
An animal that can be divided by just one vertical plane into two halves that mirror each other displays __________ symmetry.
70.
If an animal’s body can be sliced symmetrically along any number of vertical planes passing through the center of the animal, this displays __________ symmetry.
71.
Egg-laying mammals that lack a placenta are
72.
Humans and polar bears are examples of __________, mammals that nourish their developing offspring through a well-developed placenta prior to birth.
73.
Members of the “human” branch of the ape family, including modern humans as well as our extinct relatives, are properly referred to as
74.
Humans did not evolve from chimpanzees. Humans and chimpanzees share a
75.
All your mitochondrial DNA was inherited from your
76.
The fossil record indicates that the first Homo sapiens originated between 400,000 and 300,000 years ago. Homo erectus, who had a brain larger than Homo habilis and a skull more similar to H. sapiens, probably migrated from Africa about 2 mya. The fact that these species often existed in the same locations at the same time and their fossils share certain characteristics while displaying some intermediate characteristics suggests that these prehistoric __________ species may have reproduced with each other.
77.
Fossil evidence from around the world indicates that anatomically modern humans first evolved in Africa about 195,000–200,000 years ago from a population of archaic Homo sapiens and then successfully migrated to and inhabited almost all continents by 13,000 years ago. During tens of thousands of years, modern humans lived alongside other __________ genera, eventually replacing them.
78.
The DNA compared across species in this infographic is __________ DNA.
79. a.
A
b.
B
c.
C
d.
D
e.
E
f.
F
g.
G
h.
H
i.
I
j.
J __ 1. __ 2. __ 3. __ 4. __ 5. __ 6. __ 7. __ 8. __ 9. __ 10.
amniotic egg backbone bony skeleton four limbs fur, mammary glands jaws lobed fins notochord scales skull
Answer Key Chapter 17
1. Answer:
A
2. Answer:
D
3. Answer:
D
4. Answer:
A
5. Answer:
C
6. Answer:
D
7. Answer:
C
8. Answer:
C
9. Answer:
B
10. Answer:
D
11. Answer:
A
12. Answer:
A
13. Answer:
B
14. Answer:
C
15. Answer:
D
16. Answer:
A
17. Answer:
D
18. Answer:
C
19. Answer:
D
20. Answer:
B
21. Answer:
D
22. Answer:
C
23. Answer:
A
24. Answer:
D
25. Answer:
C
26. Answer:
B
27. Answer:
A
28. Answer:
D
29. Answer:
A
30. Answer:
C
31. Answer:
A
32. Answer:
B
33. Answer:
C
34. Answer:
A
35. Answer:
B
36. Answer:
B
37. Answer:
D
38. Answer:
A
39. Answer:
B
40. Answer:
C
41. Answer:
D
42. Answer:
D
43. Answer:
A
44. Answer:
B
45. Answer:
A
46. Answer:
C
47. Answer:
B
48. Answer:
C
49. Answer:
D
50. Answer:
A
51. Answer:
B
52. Answer:
A
53. Answer:
Echinoderms and chordates are the two that are most closely related. These two groups share a recent common ancestor that had a notochord. Nematodes are at least two common ancestors away from echinoderms and chordates and do not have a notochord. While annelids share the trait of bilateral symmetry with nematodes, echinoderms, and chordates, the annelids are at least five common ancestors away from all these groups. Cnidarians are at least four common ancestors away from the other four groups.
54. Answer:
Amphibians, reptiles, and birds all have four limbs. The fact that reptiles and birds not only have an amniotic egg (making it possible for them to complete their life cycles on land) but also have scales sets them apart from amphibians.
55. Answer:
Most bilaterally symmetrical animals like fish have nearly identical body parts on each side of their bodies. This facilitates movement in these animals. Fish typically have paired fins on either side of their bodies; this arrangement of fins helps them swim faster and maneuver efficiently. This makes them better at chasing down their food and evading their predators. Therefore, they have the evolutionary advantage of being more likely to survive to pass their genes along to the next generation.
56. Answer:
Segmentation in animals occurs when their body plans include repeated segments or units. Specialized appendages with diverse functions often originate in pairs from specific segments of an animal’s body. An example of this would be the claws, walking legs, swimming legs, and tail segments of the lobster. The different types of legs and tail segment give the lobster the ability to move efficiently in its environment, while the claws provide defense and eating abilities; all these features help the lobster survive.
57. Answer:
Almost all mammals have body hair and sweat glands and almost all produce milk in their mammary glands. Mammals are typically sorted into three different general groups based on how their offspring develop prior to birth. Eutherians nourish their offspring inside the mother’s body through the placenta until the fairly well-developed young are born. Marsupials have a simpler placenta that does not nourish the developing young for as long a time. The marsupial’s young are poorly developed at birth and spend the first period of their lives inside their mother’s pouch to complete their development. Finally, there are monotremes. The monotremes, like the platypus, are mammals that actually lay eggs. These mammals do not produce a placenta.
58. Answer:
The young kangaroo would not be fully developed to survive when it is born because marsupials do not produce a welldeveloped placenta to nourish the young in utero. Because marsupials are also mammals, we should expect the young to nurse on the mother’s mammary glands inside the protective, external pouch until the young kangaroo is developed enough to leave the pouch.
59. Answer:
All members of the ape family belong to the grouping known as hominids. The hominins are a special grouping of bipedal apes that includes humans.
60. Answer:
The lemurs could serve as an outgroup. They branched off about 65 mya and are least like the rest of the primates. Characteristics of the other primates could be compared to those of the lemurs to determine their relationships. The rest of the primates are all more closely related to each other than they are to the lemurs because they share more recent common ancestors.
61. Answer:
Finding a significant amount of human mitochondrial DNA when the whole-genome DNA is about half human and half Neanderthal would indicate that the mother was human and the father was Neanderthal. Finding no human mitochondrial DNA but finding that about half of whole-genome DNA was human and half was Neanderthal would indicate that the father was human.
62. Answer:
If the Neanderthal DNA present in the human (Homo sapiens) genome were a remnant from a common hominin ancestor, it would have been introduced into the human genome at least 900,000 to 1 million years ago. This is at least 10 times older than the Neanderthal DNA that is present in modern Homo sapiens. Therefore, the 2012 results do not support the hypothesis that Neanderthal DNA that is present in the human genome is a remnant from a common hominin ancestor.
63. Answer:
Homo erectus is a possible common ancestor to Homo neanderthalensis and Homo sapiens.
64. Answer:
Ancestral humans who had migrated to areas around the eastern Mediterranean Sea and Europe very likely learned to control and use fire around the same time (about 300,000 to 350,000 years ago), and they became increasingly good at it.
65. Answer:
Analyzing DNA from fossilized bones that showed traits intermediate to both Homo sapiens and Homo neanderthalensis and finding that it contains genomic DNA from both species along with mitochondrial DNA only from Homo neanderthalensis would support the hypothesis that a male H. sapiens successfully mated with a female H. neanderthalensis.
66. Answer:
My brother and I would share about 50 percent of our nuclear DNA because we each inherited 50 percent of our nuclear DNA from our father. We would not share a very similar mitochondrial DNA profile because we had different mothers. We would have each inherited all our mitochondrial DNA from our different mothers.
67. Answer:
notochord
68. Answer:
vertebrae
69. Answer:
bilateral
70. Answer:
radial
71. Answer:
monotremes
72. Answer:
eutherians
73. Answer:
hominins
74. Answer:
common ancestor
75. Answer:
mother
76. Answer:
hominin
77. Answer:
Homo
78. Answer:
nuclear
79. Answer:
1.
H
2.
C
3.
E
4.
G
5.
J
6.
D
7.
F
8.
A
9.
I
10.
B
Name: ___________________________ Class: _________________ Date: __________
Chapter 18 1.
2.
3.
4.
Which of the following terms describes all organisms on Earth plus their environments? a.
biosphere
b.
ecosystem
c.
habitat
d.
species
The Pacific ocean a.
is an example of a biosphere.
b.
is part of the biosphere.
c.
contains one biosphere.
d.
contains multiple biospheres.
An example of a study focused on the biosphere is one that measures how a.
introducing wolves into an area affects the deer population.
b.
building a dam affects plant and animal populations in an area.
c.
human habitation has changed the population size of caribou in a decade.
d.
acidification of the oceans affects aquatic and terrestrial organisms.
Ecologists study __________ factors. a.
only biotic
5.
6.
7.
8.
b.
only abiotic
c.
both biotic and abiotic
d.
neither biotic nor abiotic
Humans are __________ factors __________ the biosphere. a.
biotic; within
b.
biotic; outside
c.
abiotic; within
d.
abiotic; outside
The term “biotic” includes a.
all living organisms.
b.
all nonliving components of the biosphere.
c.
both living and nonliving components of the biosphere.
d.
only those living and nonliving factors that interact with each other.
Cutting down trees in a forest can affect the flow of a river. This is an example of a(n) __________ factor affecting a(n) __________ factor. a.
biotic; biotic
b.
abiotic; biotic
c.
biotic; abiotic
d.
abiotic; abiotic
Biology is the study of life. Would biologists study abiotic components in an ecosystem?
9.
10.
11.
a.
Yes; biologists study all living organisms regardless of size.
b.
No; biologists study only those living organisms that have a significant effect on the ecosystem.
c.
Yes; understanding living organisms includes understanding the nonliving factors on which they depend.
d.
No; biologists only study living components of the ecosystem; the nonliving components would be studied by chemists or geologists.
Which of the following would best be considered an aspect of climate? a.
a large thunderstorm
b.
average rainfall
c.
a shifting hurricane
d.
a widespread blizzard
Although the terms “climate” and “weather” are often used interchangeably, they are not the same. Climate differs from weather in that a.
weather includes amount of rainfall per year and climate does not.
b.
climate is based on biomes, whereas weather is not.
c.
climate describes long-term patterns, whereas weather describes short-term fluctuations.
d.
climates are described in terms of long-term average temperature, and weather is described by other factors, such as prevailing winds.
Which of the following is NOT a major factor in shaping the climate of a local region? a.
the intensity of solar radiation
b.
global patterns of atmospheric circulation
c.
the dominant herbivorous organisms of a region
d.
12.
13.
14.
global patterns of oceanic circulation
Over one particular week in August, the average air temperature in the midwestern United States is 36 degrees Celsius. This is a reference to a.
climate.
b.
weather.
c.
climate change.
d.
global warming.
Atmospheric scientists anticipate a 3.5°C temperature rise in the next century. What impacts would such a change bring? a.
Many locations around the world would experience more frequent extreme weather events.
b.
There would be a positive impact on the world’s agricultural systems as ocean evaporation and terrestrial rainfall would increase.
c.
Sea levels could fall, improving the ease of navigability and shipping.
d.
The polar ice caps would increase in size.
Why are scientists so focused on the climate change occurring in Greenland? a.
Changes at the Earth’s poles show the potential dangers from climate change.
b.
Greenland is experiencing a catastrophic drought linked to global warming.
c.
A rising sea level rise is the only measure of global warming that can currently be studied.
d.
Greenland is the only country that has experienced rising temperatures over the last 20 years.
15.
16.
17.
18.
Which of the following is NOT a consequence of climate change? a.
increased droughts
b.
decreased flooding
c.
decreased biodiversity
d.
an increase in ocean temperature
What will happen in the future if humans continue to impact natural systems at the same rates as today? a.
The environment is much too big and the human population much too small in comparison to have any serious consequences.
b.
Human societies may experience severe disruptions in essential ecosystem services.
c.
Some short-term changes may be experienced, but their magnitude will likely be no greater than that of changes that have occurred naturally.
d.
Some beneficial and necessary reductions in population growth will occur.
Species that will most likely prosper as projected climate change occurs will a.
have narrow tolerances and be able to live in specialized environments.
b.
have broad tolerances and be able to live in a variety of habitats.
c.
live in very stable environments.
d.
live only if they form mutualistic relationships with other organisms.
An individual’s home is part of their __________ footprint. a.
carbon
19.
20.
21.
b.
food
c.
built-up land
d.
goods-and-services
Cooking __________ would decrease one’s food footprint the most. a.
chicken instead of steak
b.
steak instead of chicken
c.
steak instead of vegetables
d.
vegetables instead of steak
Increased carbon dioxide levels in the atmosphere have contributed to acidification of the oceans. This change of the water’s pH due to a change in CO2 concentrations is an example of the effects of __________ on a(n) __________ factor in the biosphere. a.
global warming; biotic
b.
global warming; abiotic
c.
human activities; biotic
d.
human activities; abiotic
The levels of carbon dioxide in the atmosphere a.
peaked around 1950 and have begun slowly decreasing since then.
b.
are high but not higher than the highest estimated levels in the last 420,000 years.
c.
are estimated to be higher than at any time in the past 420,000 years.
d.
began decreasing when the burning of fossil fuels increased.
22.
23.
The following graph indicates that global temperatures have a.
varied randomly over the last 160 years.
b.
shown no real trend over the last 160 years.
c.
tended to increase, especially in the last 100 years.
d.
tended to decrease over the last 160 years.
The following figure shows atmospheric carbon dioxide levels. This graph was developed by measurements obtained in which of the following two ways?
24.
25.
a.
direct measurements on Mauna Loa, Hawaii, and air bubbles trapped in ice
b.
studies of plant structures in response to differing CO2 levels and measurements of carbon dioxide within rock layers
c.
carbon isotope levels in seafloor sediments and air bubbles trapped in ice
d.
measurements from undisturbed bat droppings in caves on a South Pacific island and carbon isotope levels in seafloor sediments
Greenhouse gases warm the planet by a.
absorbing and dispersing solar radiation.
b.
magnifying the energy of solar radiation.
c.
producing and emitting infrared radiation.
d.
absorbing and reemitting infrared radiation.
Decreasing __________ would have the greatest effect in decreasing greenhouse gases.
26.
27.
28.
a.
logging
b.
burning of forests
c.
construction in cities
d.
fossil fuel consumption
One of the major effects of an increase in atmospheric carbon dioxide is a.
an increase in average global temperatures.
b.
cooler average temperatures as carbon dioxide reflects sunlight back into space.
c.
an acceleration of ozone depletion.
d.
a decrease in the acidity of oceans and lakes.
One unusual aspect of the recent rise in CO2 levels is that a.
there is no known mechanism for its occurrence.
b.
CO2 reacts so quickly with other compounds that the rise should not be occurring.
c.
it has occurred relatively slowly in the last 100 years.
d.
it has occurred relatively rapidly in the last 100 years.
Not all gases are greenhouse gases. A greenhouse gas is a gas that a.
participates in biogeochemical cycling in the biosphere.
b.
absorbs heat that radiates away from Earth’s surface.
c.
does not participate in biogeochemical cycling in the biosphere.
d.
does not absorb heat that radiates away from Earth’s surface.
29.
30.
31.
32.
How much has Earth’s mean surface temperature increased since the early twentieth century? a.
32°F (0°C)
b.
1.4°F (0.8°C)
c.
2°F (1.1°C)
d.
11.5°F (1.8°C)
An increase in average temperatures worldwide is called a.
climate change.
b.
global warming.
c.
the greenhouse effect.
d.
a weather pattern shift.
Increasing carbon sinks will __________ global warming and __________ climate change. a.
increase; decrease
b.
increase; increase
c.
decrease; increase
d.
decrease; decrease
Global warming occurs a.
mainly at the equator.
b.
mainly at the North Pole.
c.
mainly at the South Pole.
d.
equally at both the equator and the poles.
33.
34.
35.
36.
Which term encompasses all the others? a.
climate change
b.
global warming
c.
greenhouse effect
d.
weather patterns
Which of the following does NOT represent evidence for global warming? a.
The 10 hottest years on record have occurred since 1990.
b.
In Europe, bird and butterfly species have shifted their ranges northward.
c.
The hole in the ozone layer over Antarctica has been growing.
d.
Plants in northern latitudes have increased the length of their growing seasons.
Climate change will affect a.
animals but not plants.
b.
all organisms in the biosphere.
c.
natural organisms but not humans.
d.
weak organisms but not strong organisms.
In comparison to past estimates, extinction rates are currently high. Which of the following is the most plausible explanation? a.
Natural fluctuations in climate causes extinctions.
b.
Continental drift is causing rapid changes in climate, which, in turn, causes extinctions.
37.
38.
39.
c.
Previous extinctions make the survival of contemporary species more difficult.
d.
Humans are affecting many aspects of the global environment.
Which of the following choices is a major difference between human-caused global climate change and change that occurs naturally? a.
Human-caused global climate change occurs more quickly, leaving organisms less time to adapt.
b.
Human-caused global climate changes are of a smaller scale than naturally caused changes.
c.
Naturally caused global climate change occurs only at one place on Earth at a time.
d.
Naturally caused global climate changes are limited to the terrestrial habitats where humans live.
The hydrologic cycle includes __________ factors. a.
only biotic
b.
only abiotic
c.
both biotic and abiotic
d.
neither biotic nor abiotic
The movement of warm air at the equator occurs because warm air is __________ than cool air. a.
less dense
b.
denser
c.
able to hold less water
d.
able to hold more water
40.
41.
42.
43.
There are many deserts at 30?0? latitude because at this altitude, dry air a.
rises.
b.
sinks.
c.
cools.
d.
warms.
One of the primary forces that causes atmospheric circulation is convection, which occurs when a.
the rotation of Earth exerts friction on the atmosphere.
b.
warm air at the surface rises and displaces the cooler air above it.
c.
winds blowing north or south are deflected to the left or right by Earth’s rotation.
d.
the tilt of Earth’s axis of rotation causes the atmosphere to slide toward the equator.
Carbon dioxide makes up approximately __________ percent of Earth’s atmosphere. a.
94
b.
44
c.
14
d.
0.04
Carbon dioxide levels are increasing because a.
human agriculture has greatly increased the amount of carbon dioxide given off by plants during respiration.
b.
humans release carbon that was formerly sequestered in fossil fuels into the atmosphere.
44.
45.
c.
holes in the ozone layer have reduced the total amount of photosynthesis occurring in the biosphere.
d.
the huge growth in the human population and in numbers of domestic livestock has increased the amount of carbon dioxide being released through respiration.
What best describes the relationship between cutting down forests and changes in atmospheric carbon dioxide levels? a.
Herbivore populations decline in the absence of forests, and without their respiration, less carbon dioxide is recycled into the atmosphere.
b.
The carbon dioxide used by the plants for cellular respiration would all be released into the atmosphere at once.
c.
Trees naturally die and decompose, but when turned into lumber, their carbon is prevented from recycling back to the atmosphere.
d.
In the absence of forest plants, there would be less carbon dioxide removed from the atmosphere for use during photosynthesis.
Biodiesel fuel is produced from oils synthesized by and harvested from living plants. How does the use of biodiesel fuel compare to the use of fossil fuels with respect to the amount of carbon dioxide released into the atmosphere? a.
There is no difference; the combustion of the fuel produces carbon dioxide regardless of its source.
b.
It is better; converting plant material to biodiesel permanently traps carbon dioxide and prevents its entry into the atmosphere.
c.
It is worse; because biodiesel produces lower mileage, more must be burned, causing a proportional increase in the release of carbon dioxide.
d.
It is better; because living plants are the source of the biodiesel fuel, burning it simply represents nutrient recycling.
46.
47.
48.
49.
The single most significant human-caused contribution (about 75 percent) to the worldwide increase in atmospheric carbon dioxide is a.
acid rain and the subsequent chemical reactions that release carbon dioxide from the soil.
b.
nitrogen supplements that accelerate decompositional activity and recycle carbon before it can become sequestered in the soil.
c.
the burning of fossil fuels and the subsequent emission of carbon dioxide.
d.
deforestation and the subsequent decline in photosynthesis.
Burning forests will __________ carbon levels in the atmosphere, which will __________ climate change. a.
increase; increase
b.
increase; decrease
c.
decrease; increase
d.
decrease; decrease
Climate change increases fires in the rainforest. This will a.
decrease climate change as carbon sinks are formed.
b.
decrease climate change as carbon reservoirs are released.
c.
further increase climate change as carbon sinks are formed.
d.
further increase climate change as carbon reservoirs are released.
Based on the following portion of a figure showing ecological footprints, which country would you predict would emit more greenhouse gases in a given year? a.
China
50.
51.
b.
Brazil
c.
India
d.
United Kingdom (U.K.)
Based on the understanding of your ecological footprint, which of the following actions would decrease your overall footprint? a.
buy a larger home
b.
eat less vegetables and more meat
c.
reduce the amount you travel
d.
purchase an additional vehicle
Scientists have started to record what happens to areas in the Amazon rainforest that have been burned. They are recording which plants grow back and how water and carbon cycles are affected by the new growth. They are also performing experiments to look for ways to encourage the return of the rainforest. This work is significant because if the burned rainforests do not recover, a.
water and carbon cycles will be disrupted.
b.
they will absorb more carbon than they release.
c.
they will become carbon sinks.
d.
a primary source of food for most of the world’s population will be lost.
52.
During a debate on sustainability, a presenter states that humans do not need to protect the planet because our technology puts us outside the biosphere. Evaluate the validity of this statement.
53.
Describe how both biotic and abiotic factors can affect the population size of deer in a forest.
54.
How do the terms “weather” and “climate” differ?
55.
Describe how burning fossil fuels can warm the planet.
56.
Describe an analogy between greenhouse gases and an inanimate object such as a winter jacket.
57.
A friend notes that the past winter was a particularly cold one and claims this is evidence that global warming is not occurring. Evaluate the validity of this statement.
58.
How has the increase in global temperatures impacted coastal cities around the planet?
59.
In what way are greenhouse gases considered beneficial?
60.
What trend is apparent when comparing the following two graphs?
61.
The following graph indicating average global temperature only shows recorded temperatures back to 1880. If there is a correlation between carbon dioxide levels and average global temperature, what would be expected if the average global temperature graph were extended back to the year 1500?
62.
A climate change skeptic states that climate change may affect polar bears and some other organisms, but not humans. Evaluate the validity of this statement.
63.
Describe how a decrease in plant populations can affect the water cycle.
64.
How does deforestation in a tropical rainforest affect the water cycle?
65.
How do trees and other plants help prevent global warming?
66.
How can deforestation result in forests serving as a carbon source?
67.
What is an ecological footprint, and what unit is used to express one’s ecological footprint?
68.
A habitat is being studied for its impacts from climate change. There are 100 species of plants that have been identified in the habitat, along with 100 species of birds. Assuming the estimated extinctions in the infographic shown here, would you expect more plants or bird species to be present in the habitat over time?
69.
The biosphere is defined as all the living organisms on Earth along with the __________ in which they live.
70.
Nonliving factors in the biosphere are called __________ factors.
71.
The widespread, long-term pattern of weather in a region is called
72.
As a group, __________ gases allow light energy to pass through the atmosphere but absorb heat energy on its way through the atmosphere to outer space.
73.
Scientists predict that increases in atmospheric carbon dioxide concentrations will continue to cause temperatures on Earth to rise, a phenomenon known as ________.
74.
Burning of fossil fuels releases the greenhouse gas __________, which is correlated to an increase in Earth’s surface temperature.
75.
Drought, species extinction, and melting of glaciers are all consequences of
76.
The term __________ describes the process of water released to the atmosphere from plants.
77.
Match each term to the correct example. a.
biotic
b.
abiotic
c.
biosphere
d.
weather
e.
climate __ 1. a redwood tree __ 2. Earth __ 3. a single storm
__ 4. a rock formation __ 5. the average rainfall of a region
Answer Key Chapter 18
1. Answer:
A
2. Answer:
B
3. Answer:
D
4. Answer:
C
5. Answer:
A
6. Answer:
A
7. Answer:
C
8. Answer:
C
9. Answer:
B
10. Answer:
C
11. Answer:
C
12. Answer:
B
13. Answer:
A
14. Answer:
A
15. Answer:
B
16. Answer:
B
17. Answer:
B
18. Answer:
C
19. Answer:
D
20. Answer:
D
21. Answer:
C
22. Answer:
C
23. Answer:
A
24. Answer:
D
25. Answer:
D
26. Answer:
A
27. Answer:
D
28. Answer:
B
29. Answer:
B
30. Answer:
B
31. Answer:
D
32. Answer:
D
33. Answer:
A
34. Answer:
C
35. Answer:
B
36. Answer:
D
37. Answer:
A
38. Answer:
C
39. Answer:
A
40. Answer:
B
41. Answer:
B
42. Answer:
D
43. Answer:
B
44. Answer:
D
45. Answer:
D
46. Answer:
C
47. Answer:
A
48. Answer:
D
49. Answer:
D
50. Answer:
C
51. Answer:
A
52. Answer:
All things on the planet, including humans and our technology, are part of the biosphere. We, like all other organisms on the planet, depend on Earth for our needs and must protect it (if we wish to preserve ourselves).
53. Answer:
Predators and food are two biotic factors that can affect deer population size. More food increases the size of the population; more predators decrease the size of the population. Water and shelter are abiotic factors that can affect population size, as are storms and other weather events.
54. Answer:
“Weather” refers to short-term atmospheric trends in a limited geographic region. “Climate” refers to a long-term pattern of weather in a region.
55. Answer:
Burning fossil fuels releases carbon dioxide. Carbon dioxide absorbs infrared radiation and reemits the radiation back to Earth’s surface. Increasing this gas decreases the radiation that can escape the biosphere and increases global temperatures.
56. Answer:
Greenhouse gases absorb and trap heat around Earth in a similar manner to the way car windows trap heat in a car or a winter jacket holds heat near one’s body.
57. Answer:
Global warming refers to increased average surface temperatures on the planet but does not mean that all locations will always be warmer year-round. The unusually cold winter is an example of weather rather than climate.
58. Answer:
The increase in global temperatures has led to the melting of glaciers and polar ice caps. Melting glaciers have caused a rise in sea levels, which is impacting coastal cities. Coastal cities are experiencing increased flooding and some may eventually be below sea level.
59. Answer:
Greenhouse gases have existed for more than 4 billion years. These gases have been responsible for holding heat near Earth and maintaining temperatures that are compatible with life.
60. Answer:
Average global temperature and levels of atmospheric carbon dioxide are both increasing over the same time period (1880– present); global temperature and carbon dioxide are positively correlated.
61. Answer:
Carbon dioxide levels remained relatively constant between 1500 and 1880. If carbon dioxide levels and average global temperature are correlated, one would expect the average global temperature to remain relatively constant extending from 1880 back to 1500.
62. Answer:
Some organisms may be affected more dramatically if they are less able to adapt, but all organisms on the planet will be affected by climate change. Increased numbers of storms, higher food prices, and increased numbers of droughts are a few of the effects that will be felt by humans.
63. Answer:
Plants absorb water from the soil and release it into the atmosphere. Decreasing plant populations slows this portion of the water cycle and can make the air drier in a given region. The increased water in the soil increases groundwater flow and water flow through streams.
64. Answer:
Trees absorb water from soil and prevent water runoff. The water absorbed by trees is returned to the atmosphere through transpiration. When trees are removed through deforestation, water runs off into streams and is not returned to the atmosphere through transpiration. The outcome is a reduction in rainfall.
65. Answer:
Trees act as a carbon sink: they absorb more carbon dioxide from the atmosphere than they release. Carbon dioxide is a significant greenhouse gas, so as more is removed, global warming is reduced.
66. Answer:
When trees are cut down and burned, the carbon stored in their tissues is released into the atmosphere (some of the carbon stored in their tissues is released, but not all of it).
67. Answer:
An ecological footprint is a measurement of the amount of land area required to produce resources and absorb waste from an individual or a population. Ecological footprints are expressed in Earth equivalents.
68. Answer:
Based on the data from the infographic, 7.3 percent of the plants should go extinct but only 6.3 percent of birds, so over time, more bird species would be expected than plant species.
69. Answer:
physical environments physical spaces
70. Answer:
abiotic
71. Answer:
climate.
72. Answer:
greenhouse
73. Answer:
global warming
74. Answer:
carbon dioxide CO2
75. Answer:
climate change
76. Answer:
transpiration
77. Answer:
1.
A
2.
C
3.
D
4.
B
5.
E
Name: ___________________________ Class: _________________ Date: __________
Chapter 19 1.
2.
Which of the choices is a true statement based on the following map?
a.
The population density of Aedes aegypti mosquitoes is highest in the Southeast United States.
b.
The northern states are not within the range of Aedes aegypti mosquitoes.
c.
The southern states are affected by the Zika virus.
d.
The population size of Aedes aegypti mosquitoes in the United States is 1.5 million.
The term “population density” describes the a.
body size of different species.
b.
number of individuals per unit area.
3.
4.
5.
6.
c.
number of populations per unit area.
d.
number of species per unit area.
A population will remain at a constant size when emigration equals immigration and a.
food is not a limiting factor.
b.
number of births equals number of deaths.
c.
predators leave the area.
d.
available space remains the same.
The size of a population can be decreased by a.
a higher birthrate.
b.
immigration.
c.
emigration.
d.
a reduced death rate.
The definition of an area, relative to a population study, a.
is constant.
b.
is always 1 square meter.
c.
depends on the questions being asked.
d.
depends on whether the area is terrestrial or aquatic.
In a neighborhood with an area of 500 acres, there are 3,000 mosquitoes. The population density in this neighborhood a.
is 6 mosquitoes per acre.
7.
8.
9.
b.
is 3,000 mosquitoes.
c.
is 1.5 million mosquitoes per acre.
d.
cannot be determined from the information given.
Which of the following statements does NOT explain why population density is often difficult to measure? a.
Individuals may be difficult to detect within some habitats.
b.
The population size may be very large.
c.
An accurate count of the population size may not be available.
d.
Individuals may be moving between populations.
Nene, which are Hawaiian geese, live on Maui. Their population density is approximately 0.2 per square kilometer and Maui is approximately 1,800 square kilometers in size. Approximately how many nene live on Maui? a.
18
b.
130
c.
360
d.
1,800
Which of the following has the highest population density? a.
1 grasshopper living in an area of 10 square meters
b.
100 rabbits living in an area of 10,000 square meters
c.
200 sparrows living in an area of 20,000 square meters
d.
1,500 oysters living in an area of 1,500 square meters
10.
11.
12.
13.
A census found that there were 5.2 people per acre in a certain region in 2012. In 2017 a census found 1.2 people per acre there. This change represents a(n) __________ in population __________. a.
decrease; size
b.
decrease; density
c.
increase; size
d.
increase; density
There were 250 elk in a population within a park in 1900. By 2000 there were 325 elk. This change represents a(n) __________ in population __________. a.
decrease; size
b.
decrease; density
c.
increase; size
d.
increase; density
A population of 100 individuals is undergoing exponential growth with a population doubling time of 1 year. What size will this population be in 2 years? a.
100
b.
150
c.
200
d.
400
A population of 100 individuals has a doubling time of 25 years. What size will this population be in 100 years? a.
100
14.
15.
b.
400
c.
800
d.
1,600
A new species is introduced into a given area. The population size begins to grow slowly, then grows at a very rapid rate, and finally levels off at a stable number. This growth pattern is best represented by a(n) a.
oscillating cycle.
b.
J-shaped population curve.
c.
C-shaped population curve.
d.
S-shaped population curve.
According to the following figure, human populations began to experience exponential growth around
16.
a.
160,000 BCE.
b.
1800.
c.
1945.
d.
2005.
Which of the following populations would be most likely to experience a Jshaped growth pattern? a.
all the animals in the San Diego Zoo
b.
single-celled Paramecia without a constant food supply
c.
a founding colony of rats on a small island with abundant resources
d.
a beehive infected at midsummer with a deadly bacterial disease
17.
18.
19.
Which of the following pieces of information would be most useful in determining whether a population is undergoing logistic growth versus exponential growth? a.
total population size taken during a current census
b.
population doubling time
c.
the carrying capacity for the same species in a different environment
d.
the shape of the growth curve for the population over time
A population is counted at 100 individuals in 1998. In 2006, a new count found 1,600 individuals. The doubling time for the population is __________ year(s). a.
0.5
b.
1
c.
1.5
d.
2
Which of the following choices best explains why some introduced species experience an initial period of exponential growth when they first move from their native habitat into a new habitat? a.
They do not yet have any natural predators or diseases in their new habitat.
b.
Most introduced species show better survival in a new habitats than in their old one.
c.
Because most native species display exponential growth, many introduced species will do so also.
d.
Native species always leave open habitat types that a new species can inhabit.
20.
21.
22.
23.
A giant puffball mushroom can produce and release trillions of spores. With this many spores produced, why do giant puffball mushrooms undergo logistic growth when in established habitats? a.
Giant puffball mushrooms use chemicals to limit the number of spores that survive in order to ensure that adults have access to nutrients.
b.
The length of time for spore germination to occur is one factor that leads to logistic growth in all species.
c.
Limiting resources, such as food, water, and space, control the maximum population size of all species.
d.
Mushrooms are biologically unique organisms that are incapable of experiencing exponential growth even in habitats with unlimited resources.
If a population is growing with no constraints on its resources, it will a.
grow exponentially.
b.
grow logistically.
c.
remain at its carrying capacity.
d.
double every 30 days.
The maximum population size that can be supported by its habitat is known as a.
maximum increase.
b.
carrying capacity.
c.
exponential growth.
d.
population balance.
According to the following figure, human populations are projected to reach carrying capacity in approximately __________ years.
24.
25.
a.
30
b.
75
c.
85
d.
105
The top of the “S” in an S-shaped curve indicates that the population a.
is on the verge of collapse.
b.
is experiencing abnormally heavy pressure from predators.
c.
has reached its carrying capacity.
d.
is poised for further exponential growth.
The carrying capacity for Paramecia caudatum as shown in the following figure is
26.
27.
a.
12 days.
b.
200/ml of medium.
c.
100/ml of medium.
d.
24 days.
The carrying capacity of owls in an Alaskan forest is 7 per square kilometer. What will happen if 12 owls are confined to a 1-square-kilometer area? a.
The owls will survive together and develop ways to share resources.
b.
The owls may survive but the population size in the future will most likely be close to 7.
c.
The population of owl prey organisms will increase proportionately to support a larger population of owls.
d.
A short-term exponential growth of owls will occur because more mating pairs will form.
Which of the following statements about carrying capacity is true? a.
An S-shaped curve represents a population’s ability to increase its numbers above the carrying capacity of its habitat.
b.
J-shaped curves show the immediate limiting effect of carrying capacity on a newly introduced organism.
28.
29.
c.
The carrying capacity is the same for all organisms in the same area.
d.
The carrying capacity is established by the resource with the most limited availability.
Is it reasonable to expect that all habitats suitable for a given organism will have the same carrying capacity for that organism? a.
Yes; unless the carrying capacities are the same, the habitat will not be suitable.
b.
Yes; the carrying capacity is determined solely by the type of organism being considered.
c.
No; an organism may be able to live in many locations, but the resources it requires may be available in varying amounts.
d.
No; it is not possible for two habitats to have the same carrying capacity.
This graph shows the growth of a population of Paramecium caudatum. The greatest amount of daily growth occurred when the population was at approximately __________ percent of its carrying capacity.
a.
10
b.
25
c.
50
d.
30.
31.
100
When an isolated population reaches its carrying capacity, a.
the birthrate > the death rate.
b.
the birthrate = the death rate.
c.
the birthrate < the death rate.
d.
It is not possible to generalize these values.
The following figure shows that in the early 1980s, the willow tree population of a certain area leveled off at 475 trees and then remained stable. This most likely occurred because the
a.
trees occupied all of the available space that willows were able to occupy.
b.
tree seedlings were shaded by the grasses.
c.
population growth rate exceeded the death rate.
d.
32.
trees depleted all of the nutrients in the soil and the trees could no longer grow.
The following figure shows that the human population was small and relatively stable for nearly 12,000 years but has increased dramatically in the past 200 years. How might this increase in population growth be explained?
a.
Disease prevented any significant growth of the human population.
b.
For most of human history, people were too malnourished to have children.
c.
People simply chose to have fewer children in the past than they do today.
d.
Prior human populations were at existing carrying capacities, but newly developed technologies have increased the carrying capacity and permitted the recent expansion.
33.
34.
35.
36.
Which of the following populations would be most vulnerable to an outbreak of disease? a.
10 grasshoppers living in an area of 100 square meters
b.
100 rabbits living in an area of 10,000 square meters
c.
200 sparrows living in an area of 20,000 square meters
d.
250,000 people living in an area of 100,000 square meters
The decrease in the availability of food or cover that accompanies increasing population size illustrates the concept of a(n) __________ factor. a.
density-dependent
b.
density-independent
c.
exponential growth
d.
logistic growth
In 1978, a drought on the Galapagos Islands caused a reduction in the production of seeds on which one of Darwin’s finches, a kind of bird, fed. This caused a decrease from 1,400 to 200 birds. This population change factor a.
would not be considered a part of the carrying capacity for these birds.
b.
was density-dependent.
c.
was density-independent.
d.
resulted in exponential growth for the bird population.
Density-dependent factors are more likely to limit population growth when a.
there are more individuals living in the same amount of space.
b.
the population moves into a larger habitat.
c.
food is abundant.
d.
37.
38.
39.
weather conditions become milder.
Which of the following would likely occur as a population reaches carrying capacity? a.
Density-independent deaths would increase.
b.
Density-dependent deaths would increase.
c.
The use of resources, such as food and space, would decrease.
d.
Birthrates would increase in order to maintain population size.
For most populations, irregular fluctuations in size or density a.
are less commonly experienced than the smooth J-shaped growth curve.
b.
occur commonly before carrying capacity is reached.
c.
are more common than the smooth J-shaped growth curve.
d.
occur only when density-independent factors dominate.
The effects of pollution are generally considered to be density independent because a.
the contamination level of any organism is unaffected by variations in population density.
b.
when food supplies become limited, the organisms are more likely to consume contaminated foods.
c.
at high densities, the organisms are more likely to contact the pollutant.
d.
when the organisms are stressed by overcrowding, the pollutant becomes more toxic.
40.
Which of the following situations illustrates a link between the effects of density-dependent and density-independent factors? a.
A flood causes a river to overflow and drown a herd of deer.
b.
A drought occurs; a small herd of deer survives, whereas a larger herd in the same area perishes.
c.
A population of deer increases to a size at which individuals are competing with each other to get enough food.
d.
Density-dependent and density-independent factors cannot affect the same population of organisms at the same time.
Answer Key Chapter 19
1. Answer:
B
2. Answer:
B
3. Answer:
B
4. Answer:
C
5. Answer:
C
6. Answer:
A
7. Answer:
B
8. Answer:
C
9. Answer:
D
10. Answer:
B
11. Answer:
D
12. Answer:
D
13. Answer:
D
14. Answer:
D
15. Answer:
B
16. Answer:
C
17. Answer:
D
18. Answer:
D
19. Answer:
A
20. Answer:
C
21. Answer:
A
22. Answer:
B
23. Answer:
A
24. Answer:
C
25. Answer:
B
26. Answer:
B
27. Answer:
D
28. Answer:
C
29. Answer:
C
30. Answer:
B
31. Answer:
A
32. Answer:
D
33. Answer:
D
34. Answer:
A
35. Answer:
C
36. Answer:
A
37. Answer:
B
38. Answer:
C
39. Answer:
A
40. Answer:
B
Name: ___________________________ Class: _________________ Date: __________
Chapter 19.2 1.
2.
3.
Which of the following populations would be most likely to experience a Jshaped growth pattern? a.
all the animals in the San Diego Zoo
b.
single-celled Paramecia without a constant food supply
c.
a founding colony of rats on a small island with abundant resources
d.
a beehive infected at midsummer with a deadly bacterial disease
Which of the following pieces of information would be most useful in determining whether a population is undergoing logistic growth versus exponential growth? a.
total population size taken during a current census
b.
population doubling time
c.
the carrying capacity for the same species in a different environment
d.
the shape of the growth curve for the population over time
A population is counted at 100 individuals in 1998. In 2006, a new count found 1,600 individuals. The doubling time for the population is __________ year(s). a.
0.5
b.
1
c.
1.5
d.
2
4.
5.
6.
Which of the following choices best explains why some introduced species experience an initial period of exponential growth when they first move from their native habitat into a new habitat? a.
They do not yet have any natural predators or diseases in their new habitat.
b.
Most introduced species show better survival in a new habitats than in their old one.
c.
Because most native species display exponential growth, many introduced species will do so also.
d.
Native species always leave open habitat types that a new species can inhabit.
A giant puffball mushroom can produce and release trillions of spores. With this many spores produced, why do giant puffball mushrooms undergo logistic growth when in established habitats? a.
Giant puffball mushrooms use chemicals to limit the number of spores that survive in order to ensure that adults have access to nutrients.
b.
The length of time for spore germination to occur is one factor that leads to logistic growth in all species.
c.
Limiting resources, such as food, water, and space, control the maximum population size of all species.
d.
Mushrooms are biologically unique organisms that are incapable of experiencing exponential growth even in habitats with unlimited resources.
If a population is growing with no constraints on its resources, it will a.
grow exponentially.
b.
grow logistically.
c.
remain at its carrying capacity.
d.
double every 30 days.
7.
8.
The maximum population size that can be supported by its habitat is known as a.
maximum increase.
b.
carrying capacity.
c.
exponential growth.
d.
population balance.
According to the following figure, human populations are projected to reach carrying capacity in approximately __________ years.
a.
30
b.
75
c.
85
d.
105
9.
10.
11.
The top of the “S” in an S-shaped curve indicates that the population a.
is on the verge of collapse.
b.
is experiencing abnormally heavy pressure from predators.
c.
has reached its carrying capacity.
d.
is poised for further exponential growth.
The carrying capacity for Paramecia caudatum as shown in the following figure is
a.
12 days.
b.
200/ml of medium.
c.
100/ml of medium.
d.
24 days.
The carrying capacity of owls in an Alaskan forest is 7 per square kilometer. What will happen if 12 owls are confined to a 1-square-kilometer area? a.
The owls will survive together and develop ways to share resources.
b.
The owls may survive but the population size in the future will most likely be close to 7.
12.
13.
14.
c.
The population of owl prey organisms will increase proportionately to support a larger population of owls.
d.
A short-term exponential growth of owls will occur because more mating pairs will form.
Which of the following statements about carrying capacity is true? a.
An S-shaped curve represents a population’s ability to increase its numbers above the carrying capacity of its habitat.
b.
J-shaped curves show the immediate limiting effect of carrying capacity on a newly introduced organism.
c.
The carrying capacity is the same for all organisms in the same area.
d.
The carrying capacity is established by the resource with the most limited availability.
Is it reasonable to expect that all habitats suitable for a given organism will have the same carrying capacity for that organism? a.
Yes; unless the carrying capacities are the same, the habitat will not be suitable.
b.
Yes; the carrying capacity is determined solely by the type of organism being considered.
c.
No; an organism may be able to live in many locations, but the resources it requires may be available in varying amounts.
d.
No; it is not possible for two habitats to have the same carrying capacity.
This graph shows the growth of a population of Paramecium caudatum. The greatest amount of daily growth occurred when the population was at approximately __________ percent of its carrying capacity.
15.
16.
a.
10
b.
25
c.
50
d.
100
When an isolated population reaches its carrying capacity, a.
the birthrate > the death rate.
b.
the birthrate = the death rate.
c.
the birthrate < the death rate.
d.
It is not possible to generalize these values.
The following figure shows that in the early 1980s, the willow tree population of a certain area leveled off at 475 trees and then remained stable. This most likely occurred because the
17.
a.
trees occupied all of the available space that willows were able to occupy.
b.
tree seedlings were shaded by the grasses.
c.
population growth rate exceeded the death rate.
d.
trees depleted all of the nutrients in the soil and the trees could no longer grow.
The following figure shows that the human population was small and relatively stable for nearly 12,000 years but has increased dramatically in the past 200 years. How might this increase in population growth be explained?
18.
a.
Disease prevented any significant growth of the human population.
b.
For most of human history, people were too malnourished to have children.
c.
People simply chose to have fewer children in the past than they do today.
d.
Prior human populations were at existing carrying capacities, but newly developed technologies have increased the carrying capacity and permitted the recent expansion.
Which of the following populations would be most vulnerable to an outbreak of disease? a.
10 grasshoppers living in an area of 100 square meters
b.
100 rabbits living in an area of 10,000 square meters
c.
200 sparrows living in an area of 20,000 square meters
d.
19.
20.
21.
22.
250,000 people living in an area of 100,000 square meters
The decrease in the availability of food or cover that accompanies increasing population size illustrates the concept of a(n) __________ factor. a.
density-dependent
b.
density-independent
c.
exponential growth
d.
logistic growth
In 1978, a drought on the Galapagos Islands caused a reduction in the production of seeds on which one of Darwin’s finches, a kind of bird, fed. This caused a decrease from 1,400 to 200 birds. This population change factor a.
would not be considered a part of the carrying capacity for these birds.
b.
was density-dependent.
c.
was density-independent.
d.
resulted in exponential growth for the bird population.
Density-dependent factors are more likely to limit population growth when a.
there are more individuals living in the same amount of space.
b.
the population moves into a larger habitat.
c.
food is abundant.
d.
weather conditions become milder.
Which of the following would likely occur as a population reaches carrying capacity?
23.
24.
25.
a.
Density-independent deaths would increase.
b.
Density-dependent deaths would increase.
c.
The use of resources, such as food and space, would decrease.
d.
Birthrates would increase in order to maintain population size.
For most populations, irregular fluctuations in size or density a.
are less commonly experienced than the smooth J-shaped growth curve.
b.
occur commonly before carrying capacity is reached.
c.
are more common than the smooth J-shaped growth curve.
d.
occur only when density-independent factors dominate.
The effects of pollution are generally considered to be density independent because a.
the contamination level of any organism is unaffected by variations in population density.
b.
when food supplies become limited, the organisms are more likely to consume contaminated foods.
c.
at high densities, the organisms are more likely to contact the pollutant.
d.
when the organisms are stressed by overcrowding, the pollutant becomes more toxic.
Which of the following situations illustrates a link between the effects of density-dependent and density-independent factors? a.
A flood causes a river to overflow and drown a herd of deer.
b.
A drought occurs; a small herd of deer survives, whereas a larger herd in the same area perishes.
26.
27.
28.
c.
A population of deer increases to a size at which individuals are competing with each other to get enough food.
d.
Density-dependent and density-independent factors cannot affect the same population of organisms at the same time.
A J-shaped population growth pattern indicates that a population is a.
using all resources in an area and birthrates are equal to death rates.
b.
growing at its maximum rate and birthrates are higher than death rates.
c.
unaffected by diseases and birthrates are equal to death rates.
d.
closely linked to prey, which are available in unlimited supply, and birthrates are higher than death rates.
When bacteria become resistant to antibiotics and experience an unpredicted, sudden increase in population size, they are exhibiting a(n) a.
irregular fluctuation.
b.
cyclical fluctuation.
c.
S-shaped growth curve.
d.
logistic growth pattern.
A predictable pattern in which the population sizes of two species increase and decrease in response to each other’s densities is called a(n) a.
irregular fluctuation.
b.
cyclical fluctuation.
c.
density-dependent population change.
d.
density-independent population change.
29.
30.
31.
Arctic foxes eat small mammals called lemmings. If lemmings are the main food source of arctic foxes in an area, what would be expected when lemming populations decrease? a.
A density-independent decrease would occur in arctic fox populations.
b.
A density-dependent decrease would occur in arctic fox populations.
c.
Arctic foxes would remain at their carrying capacity by switching to another food source.
d.
The arctic fox population would decrease slightly before rising again.
Which of the following examples illustrates a cyclical fluctuation? a.
A new disease is introduced into a population of humans and 15 percent of the humans die.
b.
A population of snowy owls decreases when weasel populations decrease.
c.
A ban on the pesticide DDT precedes an increase in a bald eagle population.
d.
A small population of lizards is introduced on an island where resources are unlimited.
Which of the following statements describes a cyclical fluctuation? a.
There is a predictable pattern in which a mosquito population increases and decreases in size based on precipitation.
b.
There is an unpredictable change in which a mosquito population develops resistance to an insecticide.
c.
A rare natural disturbance limits the growth of mosquitoes and causes a decrease in the typically stable population size.
d.
Limited water in an area restricts the growth of a mosquito population to a level considered to be carrying capacity.
32.
33.
34.
Lynx feed on rabbits, and the growth curves for these two species fluctuate together. This relationship is an example of a(n) a.
S-shaped growth curve.
b.
J-shaped growth curve.
c.
irregular fluctuation.
d.
tightly linked cycle.
Studies of the population-size cycles seen between the snowshoe hare and the Canadian lynx showed that lynx populations __________ in size when hare populations __________ in size. a.
decrease; increase
b.
increase; decrease
c.
decrease; decrease
d.
There is no relationship between population sizes of snowshoe hare and Canadian lynx.
When comparing the peaks on both the following graphs, the lynx population reaches its maximum
35.
36.
37.
a.
slightly after the hare population reaches its maximum.
b.
slightly before the hare population reaches its maximum.
c.
at the same time that the hare population reaches its maximum.
d.
at random intervals that do not appear linked to changes in hare populations.
The success of ending the spread of Zika virus through the use of genetically modified (GM) mosquitoes is NOT dependent on a.
mosquito populations.
b.
the amount of virus circulating between humans and mosquitoes.
c.
human populations.
d.
development of a Zika vaccine.
In a tropical environment with plenty of rainfall and standing water, adult mosquitoes are able to consistently lay eggs and the resulting larvae easily grow into new breeding adults. There are few, if any, constraints on this mosquito population. What type of growth would you expect to see for this population of mosquitoes? a.
exponential growth represented by an S-shaped growth curve
b.
exponential growth represented by a J-shaped growth curve
c.
logistic growth represented by an S-shaped growth curve
d.
logistic growth represented by a J-shaped growth curve
Authorities in Brazil wanted to reduce the number of Dengue fever cases among citizens in a neighborhood of Sāo Paulo. They begin by distributing fine mesh netting to cover the barrels people use to collect rainwater. The netting prevents the carrier of Dengue fever, adult Aedes aegypti, from laying their eggs in the water barrels, thus interrupting the mosquito’s life cycle. This form of mosquito
38.
39.
40.
a.
is density dependent.
b.
promotes logistical population growth of the mosquito.
c.
promotes exponential population growth of the mosquito.
d.
is density independent.
The pesticide DDT moves through the food chain as one animal eats another. Bald eagles ingested DDT when they ate fish contaminated with the pesticide. DDT caused the eagles to produce eggs with weak shells, resulting in low birthrates for the birds. The number of bald eagle breeding pairs in the lower 48 states of the United States went from around 100,000 in 1800 to 417 in the early 1960s. In 1972, the use of DDT was banned in the United States. Current estimates put the number of breeding pairs between 14,000 and 15,000. What type of population limit was/is DDT in regard to bald eagles? a.
density dependent
b.
density independent
c.
cyclical fluctuation
d.
irregular fluctuation
Although daylilies are perennial (they grow back every year without being replanted), they often stop producing flowers when their rhizomes become crowded underground. This is an example of a.
cyclical fluctuation between two populations.
b.
irregular fluctuation between two populations.
c.
density-dependent population change.
d.
density-independent population change.
Use a specific example to explain how population density may change for people living in one country without any change in population size.
41.
You are told that the population size of mosquitoes is 50. What information would you need to determine the population density?
42.
A population of 10 yeast cells is put into a flask with growth media that contains all the nutrients required for growth. The yeast has a doubling time of 2 hours; 4 hours after addition of the yeast to the flask, the population size is 40 cells. After 3 days, the population size stabilizes at around 500 cells. Is this population exhibiting logistic or exponential growth? Explain your reasoning.
43.
How would population doubling time change as a population experiencing exponential growth approaches carrying capacity?
44.
Describe the shape of the growth pattern for a population undergoing exponential growth. When would a population experience this type of growth?
45.
Why do logistic growth curves have an S shape?
46.
Is it possible for the carrying capacity of a population to change? If so, give an example. If not, explain why not.
47.
What causes an S-shaped growth curve to flatten out at the top?
48.
How could a researcher use historical population size data for a predator and its prey to determine whether the two strongly influence each other?
49.
Is a death rate increase from influenza an example of a density-dependent population change or a density-independent population change?
50.
Two humans are infected with a new, deadly form of influenza. One of the individuals lives in a crowded city and travels frequently for work. The other individual lives in a remote, rural village with limited travel into or out of the village. Which of these situations is more likely to impact human populations? Is this situation considered density dependent or density independent?
Answer Key Chapter 19.2
1. Answer:
C
2. Answer:
D
3. Answer:
D
4. Answer:
A
5. Answer:
C
6. Answer:
A
7. Answer:
B
8. Answer:
A
9. Answer:
C
10. Answer:
B
11. Answer:
B
12. Answer:
D
13. Answer:
C
14. Answer:
C
15. Answer:
B
16. Answer:
A
17. Answer:
D
18. Answer:
D
19. Answer:
A
20. Answer:
C
21. Answer:
A
22. Answer:
B
23. Answer:
C
24. Answer:
A
25. Answer:
B
26. Answer:
B
27. Answer:
A
28. Answer:
B
29. Answer:
B
30. Answer:
B
31. Answer:
A
32. Answer:
D
33. Answer:
C
34. Answer:
A
35. Answer:
D
36. Answer:
B
37. Answer:
D
38. Answer:
B
39. Answer:
C
40. Answer:
Population density is the number of individuals per unit of area; population size is the total number of individuals in a defined area. If individuals within a country move from one area to another, such as from rural areas into urban areas, the total number of individuals within the country will remain stable, but the population density will change.
41. Answer:
Population density requires knowing the unit of area because density is the number of individuals in a given area.
42. Answer:
This population exhibits logistic growth with an S-shaped curve. The initial growth from 10 to 40 cells indicates that exponential growth was occurring at first, when resources were not limited. The stabilization around a maximum population size, in this case 500 cells, occurred when resources became limited.
43. Answer:
The population doubling time would increase as the growth rate decreases when the population approaches carrying capacity and stabilizes at its maximum population size.
44. Answer:
Exponential growth leads to a J-shaped growth pattern. This type of pattern is seen when resources are unlimited.
45. Answer:
A logistic growth curve shows a steep increase in population size during the exponential growth phase, when resources are unlimited and the population is growing maximally. As the population nears its carrying capacity, the growth rate slows and then flattens out as resources become limited. This flattening out occurs when the population reaches carrying capacity.
46. Answer:
Carrying capacity, which refers to the maximum population size that can be supported in an area, can decrease or increase depending on the availability of resources. One example includes increases in technology that have allowed an increase in the carrying capacity of human populations.
47. Answer:
The flattening at the top of an S-shaped growth curve occurs as a population reaches its carrying capacity and resources become limited.
48. Answer:
A researcher could look for a cyclical pattern in which the predator population increases and decreases slightly after corresponding increases and decreases in the prey population.
49. Answer:
Influenza is a disease and, like other diseases, it spreads more easily and increases death rates as population density increases. This is an example of density-dependent population change.
50. Answer:
Disease is an example of a density-dependent factor. When the density of a human population increases or when humans travel, it is much more likely that humans infected with a disease will encounter healthy individuals and spread the disease. The individual in a crowded city is much more likely to spread this disease to others.
Name: ___________________________ Class: _________________ Date: __________
Chapter 19.3
1.
If there are 100 people living in a 2-square-kilometer area, the population density is __________ people per square kilometer.
2.
Population size __________ when the combination of death and emigration rates is lower than the combination of birth and immigration rates.
3.
Genetic modification of mosquitoes is designed to reduce the population __________ of mosquitoes.
4.
In a neighborhood in Rio de Janeiro, the mosquito population __________ is 3.85 female mosquitoes per acre.
5.
One measure of population growth is the period in which a population increases to twice its size. This is referred to as the __________ of the population.
6.
At room temperature, a population of dangerous bacteria on a piece of raw chicken increases from 100,000 to 400,000 in 40 minutes. Its doubling time is __________ minutes.
7.
If we humans do not limit our population growth rate, we will exceed the __________ of our environment, leading to a larger population than the environment can support.
8.
Predation increases are responsible for density-__________ changes in population size.
9.
Weather is a density-__________ factor that can affect the size of a population.
10.
A population change in which the populations of two species rise and fall together in a predictable pattern is called a(n) __________.
11.
In nature, populations tend to experience unpredicted rises and falls in population size. This type of change is called a(n)
12.
West Nile virus is spread by the mosquito Culex pipiens. If the larvae of Culex pipiens must compete with other insect larvae in their watery habitat, limiting the amount of water available for the developing larvae would decrease the __________ of the environment for the mosquito and help reduce its overall population size.
13.
Match each term to its correct statement.
a.
population size
b.
population density
c.
carrying capacity
d.
logistic growth
e.
exponential growth __ 1. __ 2. __ 3. __ 4.
the maximum sustainable population size in a given environment total number of individuals in a population within a given area unlimited growth of a population with no constraint on resources number of individuals within a population per unit of area
14.
Determine which examples are density-dependent population changes and which are density-independent population changes.
a.
density-dependent population change
b.
density-independent population change __ 1. A population of hares increases when the population of lynxes in the same area decreases. __ 2. An insecticide used to reduce mosquito populations indirectly decreases bald eagle populations. __ 3. A virus spreads through a population of wild dogs and 20 percent of the dogs die. __ 4. A wildfire sweeps through a forest and kills 90 percent of the oak trees. __ 5. Yeast cells fill a broth-filled flask, resources become constrained, and growth is limited.
15.
Two humans are infected with a new, deadly form of influenza. One of the individuals lives in a crowded city and travels frequently for work. The other individual lives in a remote, rural village with limited travel into or out of the village. Which of these situations is more likely to impact human populations? Is this situation considered density dependent or density independent?
16.
Your friend is planning a trip to Africa. She mentions to you that that she is more worried about contracting sleeping sickness than she is worried about contracting mosquito-transmitted malaria after having watched a TV show highlighting sleeping sickness. Based on this image indicating the rank of the 15 deadliest animals, is her fear fact-based? Briefly explain your answer.
17.
Consider the population decline of reindeer on St. Paul Island due to habitat destruction. What would you predict will happen to the reindeer population in a few years. How is the population size of the reindeer linked to the population of grazable plant?
Answer Key Chapter 19.3
1. Answer:
50 fifty
2. Answer:
increases
3. Answer:
size
4. Answer:
density
5. Answer:
doubling time
6. Answer:
20 twenty
7. Answer:
carrying capacity
8. Answer:
dependent
9. Answer:
independent
10. Answer:
cyclical fluctuation
11. Answer:
irregular fluctuation.
12. Answer:
carrying capacity
13. Answer:
14. Answer:
1.
C
2.
A
3.
E
4.
B
1.
A
2.
B
3.
A
4.
B
5.
A
15. Answer:
Disease is an example of a density-dependent factor. When the density of a human population increases or when humans travel, it is much more likely that humans infected with a disease will encounter healthy individuals and spread the disease. The individual in a crowded city is much more likely to spread this disease to others.
16. Answer:
Mosquitoes are responsible for a much larger proportion of deaths than the tsetse fly, which transmits sleeping sickness. Your friend’s fear is not reasonable.
With fewer reindeer grazing during the winter, the food source for the reindeer will likely begin to regrow producing more available food for the surviving reindeer. This should lead to an increase in the reindeer population as resources once again become available. The reindeer population and the grazable plant population are linked in a density-dependent relationship.
17. Answer :
Name: ___________________________ Class: _________________ Date: __________
Chapter 20 1.
2.
3.
Can a human being be considered an ecological community? a.
Yes; for example, a community of microorganisms lives within the human digestive system.
b.
Yes; human beings live with other humans, own pets, and grow domesticated crops.
c.
No; a community is formed from many populations, and it takes more than one individual to make up a population.
d.
No; human populations are artificial rather than natural and are considered to fall outside ecology.
Ecological communities a.
have clearly fixed boundaries and are always defined on the same scale.
b.
can be nested within larger ecological communities.
c.
are defined as groups of four or more species within a given area.
d.
are groups of species that do not fluctuate over time.
How do ecological communities change over time? a.
Interactions between and among species may cause changes in ecological communities over time.
b.
Keystone species typically become the most common species within an ecological community.
c.
Species richness typically declines as one species outcompetes all the other species.
d.
Ecological communities are defined at a given point in time; any change leads to reclassification of the community.
4.
5.
6.
Which of the following statements about communities is true? a.
They usually have few species of organisms.
b.
There can be complex interactions between the organisms that make up a community.
c.
They are more abundant in temperate areas.
d.
They are made up of mammal species only.
Which of the following would be least likely to occur if a single species were removed from an ecological community? a.
The species richness would change.
b.
The relative species abundance would change.
c.
The diversity of the community would change.
d.
The community would cease to exist.
Which of the following best explains why a grass species might disappear when a meat-eating species is removed from a community? a.
The meat-eating species protects grass directly as a way to provide cover for itself while stalking its prey.
b.
The grass seeds are dispersed by meat eaters, which travel long distances and deposit grass seeds in their feces.
c.
The meat-eating species eats organisms that eat grass. Removing the meat eater allows an increase in the abundance of grass-eating organisms.
d.
The loss of meat eaters from a community typically causes drastic changes in the physical environment that prevent grasses from sprouting.
7.
8.
Which of the following ecological communities has the greater ecological diversity? a.
the bottom dwellers of a small pond that includes 12 species of bacteria, 10 species of protists, 3 species of fungi, 13 species of invertebrate animals, and 1 species of fish
b.
a small lawn with 2 species of pine trees, 1 species of squirrel, 1 species of grass, and 8 species of invertebrate animals
c.
a large, deep, cold lake with 2 species of aquatic plants, 6 species of phytoplankton, 4 species of protozoans, 3 species of invertebrate animals, and 4 species of fish
d.
a field with 3 species of bacteria in the soil, 5 species of grasses, 6 species of invertebrate animals, 2 species of birds, and 1 species of mammal
In comparing the following two communities, community
a.
A has a higher relative species abundance.
b.
B has a higher relative species abundance.
9.
10.
c.
A has more primary producers than community B.
d.
B has more primary producers than community A.
In comparing the following two communities, community
a.
A has a higher species richness.
b.
B has a higher species richness.
c.
A has more primary producers than community B.
d.
B has more primary producers than community A.
A measurement of how common one species is compared to another species is referred to as a.
an ecological community.
b.
species richness.
11.
12.
13.
c.
relative species abundance.
d.
keystone species.
The total number of different species living within a community is referred to as a.
an ecological community.
b.
species richness.
c.
relative species abundance.
d.
keystone species.
Which species has the highest relative abundance in a forest of trees that is 30 percent loblolly pine, 15 percent shortleaf pine, 10 percent white oak, 10 percent red oak, 20 percent sweetgum, 5 percent hickory, 5 percent dogwood, and 5 percent redbuds? a.
redbud
b.
shortleaf pine
c.
loblolly pine
d.
sweetgum
Which of the following communities would be considered to have the greatest species richness? a.
an elk gut with 240 species of microorganisms, where 95 percent of the microorganisms are bacteria
b.
a small forest in North America made up of 10 species of birds, 125 insect species, and 5 tree species
c.
a community of 150 small invertebrates classified as 15 different species living within a puddle
d.
14.
15.
16.
a large grassland community in South America with 175 species of grasses, birds, and insects
In a typical prairie food web, energy moves from grass to grasshopper to field mouse to fox. Which organism is the secondary consumer? a.
the grass
b.
the grasshopper
c.
the mouse
d.
the fox
Into which category would a human be assigned when eating pepperoni pizza? a.
producer and primary consumer
b.
primary and secondary consumer
c.
primary consumer
d.
producer
Why would a food web rather than a food chain be the preferred way to represent the movement of food through the community? a.
Food chains are oversimplified and suggest that a consumer eats only a single food item.
b.
Food webs place producers at the bottom, whereas food chains place them at the top.
c.
Food webs are based on a foundation of producers.
d.
Ecologists prefer to use food chains to describe food movements.
17.
18.
19.
Which of the following could represent the linear flow of energy within a food web? a.
wolves, lions, and cheetahs
b.
grass, bushes, and trees
c.
lettuce, rabbits, and foxes
d.
sheep, cows, and horses
Which of the following is an example of a food web? a.
Seeds are eaten by a sparrow, the sparrow is eaten by a hawk, and the hawk’s eggs are eaten by a snake.
b.
Seeds and grasses are eaten by various insects and small herbivores, the insects are eaten by a meadowlark, the small herbivores are eaten by a hawk, the meadowlark and hawk eggs are eaten by snakes, and the snakes are eaten by owls.
c.
Goats eat grass; the goats are milked and eaten by humans.
d.
Seeds are eaten by a tufted titmouse, the titmouse is eaten by a hawk, the hawk eggs are eaten by snakes, and the snakes are eaten by owls.
Why is the existence of food webs important even though food chains also exist? a.
Food webs address the activities of consumers, whereas food chains address the activities of producers.
b.
Food chains describe all aspects of interactions within a community, whereas food webs tell us what organisms eat and which are eaten by other organisms.
c.
Food webs are smaller groupings than food chains. Food chains allow us to look at the overall picture, whereas food webs provide specific directional information.
d.
Food webs tie together many more organisms than a food chain does. If one organism in a food chain disappears, a food web may allow the organisms in the chain to survive based on their interactions with other organisms.
20.
Study the following food web. What would be a reasonable outcome following the complete disappearance of wolves?
a.
Coyotes may decline because they eat wolves.
b.
Coyotes may increase because one of their primary predators is gone.
c.
Grass, willow, and berries will increase as more elk become available.
d.
Voles may decline as coyotes become less abundant.
21.
22.
23.
24.
The removal of a keystone species from a community usually results in a.
the death of all other community members.
b.
the disappearance of that community.
c.
substantial changes in the abundance of many species.
d.
minor changes, if any.
The sea star Pisaster ochraceus is a keystone species. Ten years after P. ochraceus is removed from selected intertidal communities along the Washington coast, how might those communities compare to control communities? a.
The communities might be statistically indistinguishable from one another.
b.
Sea star prey, such as mussels, might increase in abundance and crowd out other community members.
c.
Other predators might simply replace P. ochraceus and take advantage of prey that P. ochraceus consumed.
d.
Prey species, such as mussels, might decline, but most species within the community would be unaffected.
A species of bat is removed from a community by being hunted to extinction. Within two years scientists notice that seeds from several plants are no longer germinating. The bat was a a.
community-defining species.
b.
keystone species.
c.
primary consumer.
d.
producer.
If a disease quickly spreads through a desert and kills all the moths that are the sole pollinators of long-lived yucca plants, the most likely outcome would be that
25.
26.
a.
another pollinator would quickly take over and begin to pollinate the yucca plants.
b.
the yucca plants would self-pollinate.
c.
the yucca plants would die in the season after the last yucca moth died.
d.
the yucca plants would not be pollinated and could eventually go extinct.
Which of the following choices best explains, from an ecological perspective, why there are laws that require conducting a wildlife survey before certain building or other land-use projects may proceed? a.
If a keystone species is found, it can be moved to another area where it will establish a new community of organisms.
b.
If the only local habitat for a keystone species is disturbed, the entire community of populations will be affected.
c.
If the species are surveyed before the land is used, they will all be more likely to survive the building project.
d.
If the species are surveyed before the land is used, they will all be more easily distributed to other habitats.
Which of the following experiments would help to identify a keystone species? a.
Introduce more of the suspected species into the area and observe the effects on other community members.
b.
Introduce an invasive species related to the suspected species into the area and observe the effects on the suspected species.
c.
Remove the suspected species from the area and observe the effects on other community members.
d.
Introduce additional individuals of the suspected species’ food source into the area and observe the effects on community members.
27.
28.
29.
30.
Which of the following statements represents a mutualistic relationship? a.
One organism benefits while another organism is harmed by the relationship.
b.
Both organisms benefit from the relationship.
c.
One organism is neither harmed nor benefited by the relationship while the other organism is harmed by it .
d.
Both organisms are harmed by the relationship.
The relationship between house pets and people would be best described as a.
parasitic.
b.
mutualistic.
c.
predator-prey.
d.
competitive.
Every healthy human digestive system is home to countless microorganisms. In a normal digestive system, what type of relationship would this be considered? a.
parasitic
b.
pathological
c.
competitive
d.
mutualistic
Clownfish have evolved to live safely between the stinging tentacles of certain sea anemones. The fish receive protection from predators, whereas the anemones receive some food from the fish. This relationship is an example of a.
commensalism.
31.
32.
33.
b.
consumer interaction.
c.
competitive limitation.
d.
mutualism.
What statement best describes a parasitic relationship? a.
Both the parasite and the host benefit.
b.
Only the parasite benefits; the host is harmed.
c.
Both the parasite and the host are harmed.
d.
Only the host benefits; the parasite is harmed.
Predators are able to a.
have a mutualistic relationship with their prey.
b.
cause the abundance of their prey to fall.
c.
quickly alter the behavior of their prey.
d.
drive their prey to extinction.
Human cells contain mitochondria, which are responsible for processing the energy needed by the cells. The ancestors of mitochondria may once have been free-living prokaryotes. If mitochondria were still considered to be separate organisms within human cells, which of the following would best describe a human’s relationship with them? a.
parasitic
b.
competitive
c.
mutualistic
d.
pathogenic
34.
35.
36.
37.
Antibiotic therapy sometimes reduces the population of gut-inhabiting microorganisms. Bloating and diarrhea often follow until the populations reestablish themselves. This observation suggests that these microorganisms participate in a(n) __________ relationship with humans. a.
competitive
b.
exploitative
c.
mutualistic
d.
pathogenic
Pathogens are considered a special type of parasite because they a.
invariably kill their prey.
b.
affect specific portions of the host.
c.
cause disease in their hosts.
d.
live on or in the host organism.
In __________ competition, species compete indirectly for a shared resource, with each reducing the amount available to the other competitor. a.
exploitative
b.
restrictive
c.
interference
d.
advantageous
The following photograph depicts two butterfly species, the monarch (on the right) and its mimic, the viceroy (on the left). The mimicry by the viceroy allows it to
38.
39.
a.
exploit food resources that are otherwise available only to monarchs.
b.
find mates among available monarchs.
c.
avoid predation because eating the monarch will make the birds vomit.
d.
find locations for laying eggs that are only available to monarchs.
Which of the following examples best illustrates interference competition? a.
Soil levels of potassium are gradually reduced by the hemlocks and cedars in a climax forest.
b.
The growth of starling populations usually coincides with declines in songbirds because both use abandoned cavities for nesting.
c.
When larger animals become scarce, wolves often prey on mice, which reduces the availability of mice to coyotes.
d.
Rough-skinned newts contain enough toxin in their skin glands to kill almost any predator.
The activity of predators has caused their prey to evolve a variety of protective characteristics. How are prey able to acquire new features? a.
Prey selectively breed in order to increase the frequency of protective traits in their population.
b.
Prey undergo population explosions that allow them to outnumber their predators and thus develop new protective features.
c.
Prey organisms mate with other species in order to acquire new protective traits.
d.
40.
41.
42.
43.
Natural selection acts on genetic variability that is already present in the prey population.
During __________, a newly created habitat is inhabited. a.
primary succession
b.
climax community formation
c.
disturbance colonization
d.
keystone recovery
The process that establishes new communities and restores disturbed communities is termed a.
secondary growth.
b.
eutrophication.
c.
diversification.
d.
succession.
All of the following disturbances EXCEPT __________ would be considered natural. a.
fire
b.
flood
c.
windstorm
d.
mining
Undisturbed communities with species compositions that remain stable over time are referred to as a.
climax communities.
44.
45.
46.
b.
primary successors.
c.
secondary successors.
d.
keystone communities.
Secondary succession, rather than primary succession, would be most likely to occur a.
on an island that has just risen out of the ocean.
b.
on bare ground exposed by the retreat of a glacier.
c.
on the surface of recently cooled lava.
d.
in a forest that had burned to the bare ground.
In which of the following situations would succession be expected to take the longest? a.
The location is far from any other landforms.
b.
A forest fire burns 1,200 acres in Texas.
c.
Sand dunes form a new island within a half mile of a mainland.
d.
Humans log an area and then burn the remaining undergrowth.
Which of the following statements is true? a.
Primary succession occurs after disturbances, such as forest fires.
b.
Secondary succession only occurs after human intervention.
c.
Primary succession tends to take longer than secondary succession.
d.
It typically takes less than 25 years for a climax community to develop after a disturbance.
47.
48.
49.
50.
Communities change with respect to several timescales. An example of long-term change would be the a.
annual variability in population size.
b.
presence or absence of a migrant species.
c.
species composition of the community.
d.
decline in prey abundance during a harsh winter.
Once a climax community develops, is it likely to remain that way indefinitely? a.
No; over long-term timescales, climate change will probably occur, causing the community to eventually change.
b.
No; once a climax community develops, the lack of biotic variability eventually degrades the habitat.
c.
Yes; once a climax community develops, it will always remain undisturbed.
d.
Yes; climax communities become so stable that they prevent disturbances from occurring.
Which of the following can occur when the climate of an area changes? a.
Natural selection causes the community to quickly adapt and survive the change with little noticeable effect.
b.
The area becomes uninhabitable to all species and is abandoned.
c.
The community may relocate to an area with a climate similar to that of the original location.
d.
Continental drift restores communities to climates similar to those from which the communities came.
The following figure illustrates how, although pines first established themselves as the dominant tree in the Lake Michigan sand dune
community, black oaks ultimately become the dominant species. What best explains the gradual reduction of the pine?
51.
a.
Oaks trap sand, causing the dune to level out; pines can only survive in the low, protected areas between the dunes.
b.
Soil composition improves, allowing oaks to become established and preventing new pines from surviving.
c.
Pines replace the grasses, but this destabilizes the dune and increases the amount of moving sand. The loss of pines is not related to the presence of the oaks.
d.
Oak seeds were always present in the sand; they simply require more time to germinate.
The following infographic indicates that over time, as the population of wolves increased, the average height of aspen trees
a.
along the riverbanks without logs increased, while tree height on riverbanks with downed logs decreased.
b.
in uplands with downed logs increased, while tree height in uplands without logs decreased.
c.
along riverbanks increased, while tree height in uplands decreased.
d.
increased in all the areas surveyed.
52.
53.
Which of the following best describes the relationship of elk to a tree species such as aspen and cottonwood? a.
herbivory
b.
mutualism
c.
commensalism
d.
competition
A population of gray squirrels is found in a habitat that feeds on hazelnuts. A group of red squirrels moves into the habitat. The competitive exclusion principle would suggest that the red squirrels a.
will be able to also feed on hazelnuts.
b.
must find another food source if they are to remain in the habitat.
c.
will not survive in the habitat.
d.
will be able to outcompete the gray squirrels and take over the habitat.
54.
Describe an example of an ecological community. Include a brief discussion of its ecological diversity.
55.
Define the two key pieces of information used to examine diversity within a community.
56.
Describe the relative species abundance and species richness that would be expected in an ecologically diverse community.
57.
Does the following diagram represent a food web or a food chain? Identify which organism(s) in the diagram occupy the following roles: producers,
primary consumers, secondary consumers, tertiary consumers, and quaternary consumers.
58.
Identify a single food chain within the following diagram by indicating the organism at each level from producer to primary consumer, secondary consumer, and tertiary consumer.
59.
A “keystone” is defined in masonry as the stone at the top of an arch that holds the arch together. Using this definition and your knowledge of keystone species, explain how the role of a keystone species within an ecological community is analogous to the keystone within an arch.
60.
Compare and contrast mutualism and commensalism and provide an example of each.
61.
Compare and contrast exploitative and interference competition.
62.
How does primary succession differ from secondary succession?
63.
Provide an example of primary succession.
64.
The reintroduction of wolves to Yellowstone National Park has been followed by a marked increase in the number of aspen trees (and also an increase in their height) along with a decrease in the number of elk. What other evidence would support the hypothesis that the wolves are a keystone species in the Yellowstone ecological community? Explain your answer.
65.
Using the data in the following infographic, illustrate how the removal of a keystone species such as the wolves from Yellowstone can lead to secondary succession and eventually restoration of a climax community.
66.
Discuss the hypotheses regarding how the reintroduction of wolves to the Yellowstone ecosystem has facilitated regrowth of two native tree species, aspen and cottonwood.
67.
An ecological __________ is an association of populations of different species that live in the same area.
68.
The __________ of a community has two components: the number of different species that live in the community and the relative abundances of those species.
69.
One of the factors governing diversity within a community is species __________, which is defined as the total number of different species living within that community.
70.
When removed from a community, a __________ has a far greater effect on the community than its mere numbers would have suggested.
71.
__________ consumers feed on primary consumers as part or all of their diet.
72.
A(n) __________ is a single sequence of who eats whom in a community.
73.
Follicle mites live in the hair follicles of human skin. They feed on single cells but do little if any harm to the human; and the mite has a stable place to live and reproduce. This is an example of
74.
In a situation where two species reduce the amount of a resource (like food) for each other but the two do not directly interact or have contact with each other, they are said to be in __________ competition with each other.
75.
Two populations will likely compete when they occupy the same __________ or set of conditions and resources that a population needs in order to survive and reproduce in its habitat.
76.
The general process by which species in a community are replaced over time is called
77.
A community whose species are NOT replaced by other species is classified as a __________ community.
78.
A(n) __________ may begin when a new habitat is formed, such as when a retreating glacier deposits rock and soil.
79.
The information presented in the chapter and in the figure shown here suggests that the __________ is a keystone species in Yellowstone National Park.
80.
Sometimes the presence of a predator in an area can affect the behavior of its prey, causing the prey to avoid areas where they are easily seen by the predator. This behavior is called the
81.
Match each term to one of the following examples.
a.
mutualism
b.
commensalism
c.
exploitation
d.
competition __ 1. an elk eating an aspen sapling __ 2. a bird building a nest in a tree __ 3. bears and wolves both consuming carcasses within the same area __ 4. a fish that consumes parasites found on a shark
Answer Key Chapter 20
1. Answer:
A
2. Answer:
B
3. Answer:
A
4. Answer:
B
5. Answer:
D
6. Answer:
C
7. Answer:
A
8. Answer:
A
9. Answer:
B
10. Answer:
C
11. Answer:
B
12. Answer:
C
13. Answer:
A
14. Answer:
C
15. Answer:
B
16. Answer:
A
17. Answer:
C
18. Answer:
B
19. Answer:
D
20. Answer:
B
21. Answer:
C
22. Answer:
B
23. Answer:
B
24. Answer:
D
25. Answer:
B
26. Answer:
C
27. Answer:
B
28. Answer:
B
29. Answer:
D
30. Answer:
D
31. Answer:
B
32. Answer:
B
33. Answer:
C
34. Answer:
C
35. Answer:
C
36. Answer:
A
37. Answer:
C
38. Answer:
B
39. Answer:
D
40. Answer:
A
41. Answer:
D
42. Answer:
D
43. Answer:
A
44. Answer:
D
45. Answer:
A
46. Answer:
C
47. Answer:
C
48. Answer:
A
49. Answer:
C
50. Answer:
B
51. Answer:
D
52. Answer:
A
53. Answer:
B
54. Answer:
A community of organisms living in a tree hole is an example of a simple ecological community. This community could be ecologically diverse if, for example, it includes a variety of protozoans, bacteria, fungi, and small invertebrate animals living together in the tree hole. The greater the number of different species present, the greater is the species richness and diversity in the community.
55. Answer:
Both relative species abundance, a comparison of how common species are, and species richness, the total number of species within the community, characterize the diversity within a given community.
56. Answer:
An ecologically diverse community would have a high value for species richness; there would be many different species represented in the community. Even if one or more of the species has a high relative abundance value, the community is still ecologically diverse if it includes many different species.
57. Answer:
This diagram represents a food web. The producers are grass, willow, and berries. The primary consumers include elk, pronghorn, coyote, vole, and snowshoe hare. The secondary consumers include coyote, red fox, and gray wolf. The tertiary consumer is the gray wolf, and there is no quaternary consumer represented here.
58. Answer:
One single food chain in this diagram would begin with grass as the producer, snowshoe hare as the primary consumer, coyote as the secondary consumer, and gray wolf as the tertiary consumer. Another example would be grass as the producer, snowshoe hare as the primary consumer, red fox as the secondary consumer, and gray wolf as the tertiary consumer.
59. Answer:
A keystone species holds an ecological community together much as the keystone in an arch holds the arch together. If you remove a keystone species from a community, the community will undergo dramatic changes and may collapse. Also, keystone species have a large impact on their community even though they are not the community’s most abundant members. Within an arch, there is only one keystone, yet that single stone holds the arch together.
60. Answer:
Commensalism occurs when one party in a relationship benefits while the other party neither benefits nor is harmed. For example, barnacles on a whale benefit by being moved through a constant stream of nutrient-rich water from which they can feed. The whale is neither helped nor harmed by these organisms. In a mutualistic relationship, both parties benefit (typically by increased survival and/or reproduction) from the relationship. For example, a clownfish living near a sea anemone provides nutrient-rich excrement for the sea anemone along with deterring the anemone’s predators. At the same time, the clownfish is provided with a safe haven from its own predators.
61. Answer:
Exploitative and interference competition both have negative consequences for the interacting species and typically involve species with similarities in resource use, such as feeding habits. Exploitative competition involves indirect competition for shared resources; interference competition is direct competition that occurs when one species physically gets in the way of a second species.
62. Answer:
Primary succession takes place in newly created habitats, such as newly formed islands. Primary succession occurs when the first species colonizes an area. Secondary succession occurs when an area is disturbed, such as when a keystone species is removed. Secondary succession is typically more rapid than primary succession because in secondary succession there are already some species in the habitat.
63. Answer:
Primary succession occurs in a newly created habitat such as the seemingly barren soil left behind by a retreating glacier or newly appearing sand dunes. The first species to inhabit the area often makes it more hospitable for other species by providing food or making reproduction in the habitat easier. For example, after a glacier recedes, the new soil may be populated by moss spores or flowering plant seeds blown in on the wind. As these plants grow and reproduce, they become a food source for animals that may migrate into the area and become part of the community in the new habitat.
64. Answer:
Additional evidence to support the hypothesis that the wolves are a keystone species in the Yellowstone ecological community would include additional data about other species in the community. It would be helpful to know if overall species richness, as well as healthy ratios of relative species abundance, are increasing and therefore contributing to increased ecological diversity in the community.
65. Answer:
Secondary succession often occurs after a profound disturbance within an ecological community. This disturbance can be physical, such as a forest fire. The removal of a keystone species also causes significant disturbance to an ecological community. When the community’s ecological structure is drastically altered, such as when there is a loss of some species and the encroachment of invasive species in the absence of native species, the gradual restoration to its natural state is secondary succession. Because some of the native species are still in the ecosystem, secondary succession does not take as long as primary succession. The return of the wolves to Yellowstone has facilitated the return of aspen, cottonwoods, beaver, and other species. If allowed to continue, this process can lead an ecological community back to its original climax community, with species composition remaining stable over long periods of time.
66. Answer:
Before the reintroduction of wolves to Yellowstone, nearly 100 percent of young aspen plants were being eaten and cottonwoods had stopped producing new saplings. Within four years after wolves returned to Yellowstone, only 18–24 percent of young aspens were eaten and the average height of the aspens increased. Within six years, cottonwoods had experienced a population boom accompanied by rapid growth. The hypotheses proposed to explain these phenomena were: (1) the wolves were reducing the number of elk that were eating the young saplings; or (2) the elk were afraid of the wolves and stayed out of areas where they were likely to become prey, instead remaining in the open along the creeks and riverbanks where saplings grow. It is difficult to determine which hypothesis is correct, but there is support for both the predation of elk and the fear effect keeping elk away from the saplings along riverbanks as contributing to the rapid regrowth of aspens and cottonwoods.
67. Answer:
community
68. Answer:
diversity ecological diversity
69. Answer:
richness
70. Answer:
keystone species
71. Answer:
Secondary
72. Answer:
food chain
73. Answer:
commensalism.
74. Answer:
exploitative
75. Answer:
ecological niche
76. Answer:
succession
77. Answer:
climax
78. Answer:
community
79. Answer:
wolf
80. Answer:
fear effect
81. Answer:
1.
C
2.
B
3.
D
4.
A
Name: ___________________________ Class: _________________ Date: __________
Chapter 21 1.
2.
3.
4.
Which of the following groups of organisms would NOT be considered consumers? a.
herbivores
b.
predators
c.
decomposers
d.
photosynthesizers
All the living organisms present in an ecosystem comprise the __________, which is the biotic portion of the ecosystem. a.
community
b.
abiotic
c.
population
d.
biome
A community of organisms together with the physical environment in which they live is known as a(n) a.
population.
b.
community.
c.
ecosystem.
d.
biota.
Which of the following are likely biotic components of a desert ecosystem?
5.
6.
7.
a.
sand, sun, and occasional rain
b.
cacti, sage brush, scorpions, and snakes
c.
oak trees, rhododendrons, squirrels, and moss
d.
moss, large pine trees, frogs, and otters
The chemical and physical components of an ecosystem are considered to be __________, or nonliving. a.
abiotic
b.
biota
c.
biotic
d.
abalone
Which of the following would be abiotic components of an arctic, marine ecosystem? a.
salt water, ice, snow, sun, wind, rocks, and sand
b.
polar bears, seals, salmon, seaweed, and puffins
c.
buffalo, meadowlarks, eagles, grasses, and cottonwood trees
d.
deer, skinks, squirrels, oak trees, pine trees, and mosses
Which of the following are examples of primary producers in a beech-maple woodland? a.
mosses, grasses, beech trees, and maple trees
b.
phytoplankton and seaweed
c.
phytoplankton, reeds, and marsh grasses
d.
squirrels, skinks, deer, and opossums
8.
9.
10.
11.
Ecologists often define an ecosystem by describing how __________ and __________ are acquired and distributed by the biotic community. a.
energy; nutrients
b.
producers; consumers
c.
decomposers; consumers
d.
nutrients; producers
Rabbits, foxes, tapeworms, and fungi are all examples of a.
consumers.
b.
primary producers.
c.
abiotic ecosystem components.
d.
photosynthesizers.
A tallgrass prairie or beech-maple woodland are examples of ecologists distinguishing an ecosystem according to the a.
types of producers it contains; this, in turn, establishes the type of consumers that the ecosystem supports.
b.
climate in which it is located.
c.
type of consumers it contains; this, in turn, establishes the type of producers that the consumers support.
d.
daily rainfall amounts; this does not affect the types of consumers or producers present in the ecosystem.
What would happen to nutrient cycling in a forest ecosystem if all the bacteria, protozoans, fungi, and worms were eliminated? a.
Dead plant and animal matter would accumulate more quickly than it is decomposed, and the soil would become depleted of nutrients.
12.
13.
14.
b.
Dead plant and animal matter would decay more rapidly than it is decomposed, and the soil would accumulate nutrients at a faster rate.
c.
There would be no discernible change in the rate at which dead plants and animals decompose and no change in the rate of nutrient accumulation in the soil.
d.
Dead plant and animal matter would accumulate more quickly than it is decomposed, and the soil would accumulate nutrients at a faster rate.
The water in a deep crater in a bay on a tropical island is a striking pure blue color. The water in the surrounding ocean is more of a green color. Which of the following is a logical hypothesis? a.
The water in the bay has a low level of phytoplankton and primary productivity, while there is a higher concentration of phytoplankton in the surrounding ocean.
b.
The water in the bay has a high level of phytoplankton and primary productivity, while there is a lower concentration of phytoplankton in the surrounding ocean.
c.
The concentration of phytoplankton and primary productivity in the bay and the surrounding ocean is the same, and it is very high.
d.
The concentration of phytoplankton and primary productivity in the bay and the surrounding ocean is the same, and it is almost zero.
Areas of the ocean that are very cloudy due to large amounts of stirred sediment or eroded soil are likely to experience __________ productivity levels. a.
decreased primary
b.
increased primary
c.
no change in primary
d.
an increase in primary productivity levels with a decrease in secondary
Almost all life on Earth is directly or indirectly dependent on
15.
16.
17.
a.
solar energy.
b.
predation.
c.
physical productivity.
d.
human civilization.
Which of the following series best represents the energy flow in an ecosystem? a.
sun > consumer > producer > metabolic heat
b.
consumer > producer > decomposer > sun
c.
producer > consumer > decomposer > sun
d.
sun > producer > consumer > metabolic heat
The primary contribution of decomposers to an ecosystem occurs when they a.
capture solar energy.
b.
recycle nutrients sequestered in organisms back to the physical environment.
c.
regulate the number of producers.
d.
prevent consumer overpopulation.
In an ecosystem, energy differs from nutrients in that a.
energy is recycled through photosynthesis, but nutrients are recycled through the atmosphere.
b.
nutrients are recycled, but energy eventually moves out of the system and is lost.
c.
nutrients are recycled through plant roots, but energy is recycled through leaves.
d.
18.
19.
20.
21.
energy is recycled by producers, but nutrients are recycled by consumers.
Which of the following statements about cycling within an ecosystem is FALSE? a.
Energy is recycled within an ecosystem.
b.
Carbon is recycled within an ecosystem.
c.
Nutrient cycling occurs in all ecosystems.
d.
Human activities affect nutrient cycling.
Within the ecosystem, nutrients a.
move in a one-way path from producers toward consumers.
b.
regularly cycle between organisms and the nonliving environment.
c.
are consumed by their use and thus are not available for recycling.
d.
are rarely limiting because they are constantly replenished as Earth’s crust erodes.
In the absence of __________, nutrient recycling within the ecosystem would completely stop. a.
rocks
b.
secondary consumers
c.
decomposers
d.
predators
In the absence of __________, nutrients would not move from the abiotic to the biotic portion of the nutrient cycle within an ecosystem.
22.
23.
24.
a.
primary producers
b.
herbivores
c.
carnivores
d.
omnivores
Energy does not cycle through an ecosystem. This is because energy enters an ecosystem through photosynthesis as it changes to chemical energy. This is then used to fuel metabolic activities in a.
plants only, and all the excess energy is lost as metabolic heat.
b.
consumers only, and all the excess energy is lost as metabolic heat.
c.
decomposers only, and all the excess energy is lost as metabolic heat.
d.
producers, consumers, and decomposers, and all the excess energy is lost as metabolic heat.
Human activities a.
rarely affect nutrient cycles.
b.
can alter nutrient cycles on local and global scales.
c.
tend to cause only local changes in nutrient cycles.
d.
generally improve nutrient cycling in ecosystems.
In the following diagram, how do nutrient and energy flow differ?
25.
26.
a.
Energy flow is one-way, whereas nutrients are recycled.
b.
Energy is recycled, whereas nutrient flow is one-way.
c.
Only about 10 percent of energy flows from trophic level to trophic level; nutrient flow from trophic level to trophic level is 100 percent.
d.
Energy flows only to primary producers and decomposers, whereas nutrients flow only to secondary consumers and decomposers.
The ultimate destination of most energy in an ecosystem a.
is used to construct the bodies of decomposers.
b.
is trapped as fossil fuels when producers die and become fossilized.
c.
is continuously recycled back into the ecosystem.
d.
eventually returns to space in the form of heat.
A decline in phytoplankton could affect the climate of Earth through altering the __________ cycle by moving less __________ from the atmosphere into phytoplankton tissues. Since __________ is a greenhouse gas, having more of it in the atmosphere could contribute to global warming.
27.
28.
29.
a.
carbon; carbon dioxide; carbon dioxide
b.
phosphorous; phosphorous; phosphorous
c.
hydrologic; water; water
d.
oxygen; oxygen; oxygen
On average, what percentage of the energy from one trophic level of an energy pyramid is transferred to the next trophic level? a.
10 percent
b.
33 percent
c.
50 percent
d.
90 percent
When humans consume rice, they occupy which trophic level of a food chain? a.
primary consumer
b.
secondary consumer
c.
tertiary consumer
d.
primary producer
When humans consume herbivores such as cattle, they occupy which trophic level of a food chain? a.
primary consumer
b.
secondary consumer
c.
tertiary consumer
d.
primary producer
30.
31.
32.
33.
If a person needs to consume 100 kcal of energy and chooses to do so by eating chicken, how many kcal of grain would the chicken need to consume to make 100 kcal available to the human? a.
1,000
b.
10,000
c.
100,000
d.
1,000,000
If a person needs to consume 1,000 kcal of energy and chooses to do so by eating soybeans, at least how many kcal of soybeans would have to grow to provide that 1,000 kcal for the human? a.
100
b.
1,000
c.
10,000
d.
100,000
Tuna are predatory fish that consume smaller, carnivorous fish that have fed on zooplankton. The zooplankton had fed on phytoplankton. The tuna would be considered the __________ trophic level of the food chain. a.
second
b.
third
c.
fourth
d.
first
Tuna are predatory fish that consume smaller, carnivorous fish that have fed on zooplankton. The zooplankton had fed on phytoplankton. When a human eats tuna, that person is the __________ trophic level of the food chain.
34.
35.
36.
a.
second
b.
third
c.
fourth
d.
fifth
There are 5,000,000 kcal of energy stored in grain that could be fed to either beef cattle or humans. A farmer chooses to feed the grain to the cattle to fatten them up for human consumption. How many kcal would now be available as beef to feed the humans? a.
500,000
b.
50,000,000
c.
5,000
d.
500
If there are 50 kcal of energy in the tertiary consumer trophic level, how many kcal would be expected in the primary consumer level? a.
50
b.
100
c.
500
d.
5,000
Your spacecraft crash-lands on an airless, lifeless moon. All that survives, along with the crew and you, are some chickens, and several bags of grain. The air and water recyclers are functioning. To maximize the energy provided from the food supply until a rescue craft arrives, you and the crew should a.
feed the grain to the chickens and do not eat the chickens; eat only their eggs.
37.
38.
39.
b.
eat all the chickens immediately and then eat the grain.
c.
eat one chicken each week until they are gone.
d.
give the grain to the chickens and eat a chicken each day. When the chickens have all been eaten, shift to eating whatever grain is left.
If there are 20,000 kcal available in the primary producer level of an ecosystem, how many kcal would be available in the secondary consumer level? a.
200
b.
20
c.
2
d.
2,000
A grassland ecosystem has 400,000 kcal of energy stored in the primary producer level. Grasshoppers eat the grass, meadowlarks eat the grasshoppers, and a hawk eats the meadowlarks. How many kcals are now stored, and available, in the hawk? a.
40,000
b.
4,000
c.
400
d.
40
There are 5 million kcal of energy stored in grain that could be fed either to chickens or humans. A small village of starving people needs to be fed. The most efficient way to feed the majority of the villagers is to feed a.
all the grain to the villagers.
b.
all the grain to chickens and let the villagers eat the eggs.
c.
all the grain to chickens and let the villagers eat the chickens.
d.
40.
41.
42.
some of the grain to chickens and some of it to the villagers.
The primary difference between consumers and decomposers is that consumers obtain their nutrients by eating __________, while decomposers obtain their nutrients from __________. a.
other live organisms; dead consumers
b.
only dead consumers; other live consumers
c.
other live organisms; photosynthesis
d.
other live organisms; other live organisms
What best explains the following observation: consumers directly use approximately 20 percent of a forest’s net primary productivity (NPP), whereas decomposers directly use approximately 80 percent? a.
Decomposers are more efficient at obtaining energy than consumers.
b.
Forest ecosystems do not have a very high NPP, so they cannot support as many consumers as other ecosystems can.
c.
Consumers eat only certain parts of organisms, such as fruits or muscle tissue, whereas decomposers obtain energy from the entire body of the food organism.
d.
Secondary consumers eat the primary consumers more quickly than the primary consumers can eat the producers, thus leaving most of the NPP available to the decomposers.
Other than the polar tundra, the LEAST productive terrestrial biomes tend to be a.
deserts.
b.
temperate forests.
c.
tropical forests.
d.
estuaries.
43.
44.
45.
46.
Other than tropical forests, the most productive biomes tend to be a.
estuaries.
b.
deep oceans.
c.
deserts.
d.
tundra.
Which of the following is NOT an easily testable hypothesis regarding net primary productivity (NPP)? a.
An increase in temperature will likely result in an increase of NPP in terrestrial ecosystems.
b.
An increase in temperature will likely result in an increase of NPP in marine ecosystems.
c.
An increase in available sunlight will likely result in an increase of NPP in marine and terrestrial ecosystems.
d.
An increase of water in a marine ecosystem will likely result in tastier products of NPP.
An ecosystem that experiences a small increase in nutrients available to primary producers is likely to show a.
an increase in net primary productivity.
b.
a decrease in net primary productivity.
c.
no change in net primary productivity.
d.
a decrease in net primary productivity followed by an immediate return to average net primary productivity.
In marine ecosystems, net primary productivity tends to be
47.
48.
a.
greater along shorelines, where terrestrial nutrients enter the marine environment.
b.
lower where the oceans border land because terrestrial pollution suppresses marine productivity.
c.
lowest in areas where upwelling brings colder water to the surface.
d.
greater than the net primary productivity on land.
Why are deserts and tundra among the least productive terrestrial biomes? a.
Water is not easily accessible by plants in desert and tundra biomes, and both these biomes experience extreme temperature conditions. Water availability and temperature are important limiting factors in net primary productivity (NPP).
b.
There is too much water available in the tundra and not enough available in the desert. The extreme temperatures of these biomes do not affect NPP.
c.
There is not enough sunlight available in either the tundra or the desert biomes to sufficiently support NPP.
d.
There is far too much sunlight and water available in both the desert and tundra biomes. These factors cause photosynthesis to be suspended and result in dramatically decreased NPP.
The following figure shows the productivity in marine biomes around the world, with the darkest areas being the most productive. The pattern of productivity in marine ecosystems as shown suggests that
49.
a.
marine productivity is as sensitive to temperature as terrestrial productivity.
b.
without shade from overhead vegetation, marine productivity typically exceeds that found in terrestrial ecosystems.
c.
marine ecosystems are also limited by sunlight, with the highest productivity at the equator.
d.
most marine productivity results from the input of terrestrially derived nutrients.
To best use Earth’s net primary productivity to feed the most people, diets should be modified to include only __________, thus moving __________ the food chain and gathering the maximum amount of energy available from a given biomass of producers. a.
meat; higher up
b.
meat; lower down
c.
plant material; lower down
d.
50.
51.
plant material; higher up
As shown in the following figure, the productivity in terrestrial biomes around the world is greatest in areas near the equator that also receive high amounts of yearly rainfall. This pattern of productivity in terrestrial ecosystems suggests that
a.
terrestrial productivity is highly sensitive to temperature and available sunlight.
b.
without shade from overhead vegetation, marine productivity typically exceeds that found in terrestrial ecosystems.
c.
neither sunlight nor temperature limits terrestrial ecosystems.
d.
most terrestrial productivity results from the input of marine-derived nutrients.
Between late 1997 and mid-2008, satellites observed that warmer-thanaverage ocean temperatures led to below-average chlorophyll concentrations in the oceans. This finding suggests that continued warming of Earth’s oceans could lead to a(n) __________ in net primary productivity
in the oceans, and the oceans would, therefore, remove __________ carbon dioxide from the atmosphere.
52.
a.
decrease; less
b.
increase; less
c.
decrease; more
d.
increase; more
Several research teams have questioned Boyce, Worm, and Lewis’s data that indicates a loss of 500 million tons of phytoplankton a year from Earth’s oceans. Is it important for researchers to accurately determine trends in net primary productivity (NPP) in the oceans because a.
there are similarities between the NPP requirements on land and in the ocean.
b.
there are no similarities between the NPP requirements on land and in the ocean.
c.
the loss of 500 million tons of phytoplankton each year could have a negative effect on the ocean’s NPP and all the ocean life that depends on it.
d.
the loss of 500 million tons of phytoplankton each year could have a positive effect on the ocean’s NPP and all the ocean life that depends on it.
53.
Why don’t ecosystems always have sharply defined physical boundaries?
54.
Use examples to explain how an ecological community differs from an ecosystem.
55.
Describe how chemical nutrients enter and are recycled through an ecosystem.
56.
Explain how energy enters and progresses through a food chain.
57.
Explain why only roughly 10 percent of the energy available in one trophic level is available in the next higher trophic level.
58.
Using the following food chain, explain how many calories are available in the consumer trophic levels (2-4) and why.
59.
Describe what estuaries are, where they can be found, their relative productivity, and the reasons for their productivity level.
60.
Compare and contrast grassy marsh wetlands to bogs and explain why one of these freshwater biomes is more productive than the other.
61.
On what four factors does net primary productivity rely, and what terrestrial ecosystem is the most productive because of these factors?
62.
Propose an explanation for why whales swimming up and down through the water column in the ocean ecosystem can help remove tons of carbon dioxide from the atmosphere each year.
63.
How and why does the global pattern of net primary productivity (NPP) differ between the oceans and terrestrial ecosystems?
64.
Explain the difference in net primary productivity (NPP) between temperate grasslands and tropical grasslands. Include data units.
65.
Should the scientific community accept, without question, Boyce, Worm, and Lewis’s hypothesis that Earth’s oceans are losing 500 million tons of phytoplankton per year? Support your answer.
66.
A group of living communities interacting with one another and their shared physical environment is a(n)
67.
A variety of species living together and interacting with each other in a defined place form a(n)
68.
Ecologists often define an ecosystem with regard to how both __________ and __________ are acquired and distributed by the biotic community.
69.
Chemical elements required by living organisms are both __________ and __________ within and across ecosystems.
70.
At each trophic level, a portion of the energy originally captured by producers is lost as __________, being typically released as a by-product of cellular respiration.
71.
Producers capture energy from the __________ and transform it into fuel energy that passes up the food chain as one organism eats another.
72.
Each level of an energy pyramid corresponds to a step in a food chain and is called a(n) __________ level.
73.
Ecologists use a(n) __________ to represent the amount of energy available to organisms in an ecosystem.
74.
Strict vegetarians, or vegans, would be considered __________ consumers in an energy pyramid.
75.
Assessing the overall net primary productivity (NPP) of an ecosystem is important in determining how an ecosystem works, because __________ capture influences the amount of food that is available to other organisms in the ecosystem.
76.
The shallowest but most productive of the aquatic biomes are __________. These tidal ecosystems exist where rivers flow into the ocean.
77.
Regions of Earth that are defined by their unique climatic and ecological features are known as __________. The flora and fauna residing there are particularly adapted to the climate and defining ecological features.
78.
The amount of energy captured by photosynthetic organisms, minus the amount lost as heat from respiration and other life processes, is called
79.
The units used in the following infographic report total energy available from primary producers in indicated biomes in
80.
Since 1931, the phytoplankton biomass in the Northeast Atlantic Ocean has been monitored by the ____________ (CPR) survey, whereby a special instrument is pulled through the ocean by commercial fishing vessels to collect millions of samples of plankton.
81.
Match each term to its correct description. a.
tropical forest
b.
chaparral
c.
boreal forest
d.
tundra
e.
desert
f.
temperate deciduous forest
g.
grassland __ 1. Found at the poles and on mountaintops, the vegetation of this biome is dominated by low-growing flowering plants, and the rock landscape is covered in mosses and lichens. Rodents provide food for carnivores such as foxes and wolves. The few large mammals include bears and musk oxen. __ 2. Characterized by warm temperatures and roughly 12 hours of daylight every day year-round, this biome receives either seasonally heavy rains or year-round rains that leach nutrients from the soil. Much of the soil nutrients are locked up in the biomass of the heavy vegetation. It is one of the most richly biodiverse and productive ecosystems on the planet. __ 3. This biome is dominated by dense growths of drought-resistant plants that thrive in the alternating cool, rainy winters and hot, dry summers. The vegetation includes scrub oak, pine, mountain mahogany, and manzanita. It is inhabited by jackrabbits, gophers, lizards, and snakes. __ 4. Nearly one-third of Earth’s land surface is covered with this biome, which does not retain heat because it lacks moisture. The plants have small leaves, like the spines on cacti, to minimize water loss. Most of the animals are nocturnal. __ 5. This biome is commonly found in both temperate and tropical latitudes. It does not receive enough moisture to support vigorous
tree growth, so it is dominated by grasses and herbaceous plants. Burrowing rodents like voles and prairie dogs are common. __ 6. This biome is dominated by trees and shrubs adapted to relatively rich soil, snowy winters, and moist, warm summers. With oak, maple, hickory, beech, and elm, this biome displays good diversity. Squirrels, rabbits, deer, raccoons, beavers, bobcats, mountain lions, bears, and many amphibians and reptiles constitute the consumer community. __ 7. Dominated by coniferous trees that grow in northern or highaltitude regions with cold, dry winters and mild summers, this biome also has nutrient-poor soils, and therefore a relatively low plant diversity. Large herbivores such as elk and moose live alongside smaller carnivores such as weasels, wolverines, and martens. Larger carnivores include lynx and wolves.
Answer Key Chapter 21
1. Answer:
D
2. Answer:
A
3. Answer:
C
4. Answer:
B
5. Answer:
A
6. Answer:
A
7. Answer:
A
8. Answer:
A
9. Answer:
A
10. Answer:
A
11. Answer:
A
12. Answer:
A
13. Answer:
A
14. Answer:
A
15. Answer:
D
16. Answer:
B
17. Answer:
B
18. Answer:
A
19. Answer:
B
20. Answer:
C
21. Answer:
A
22. Answer:
D
23. Answer:
B
24. Answer:
A
25. Answer:
D
26. Answer:
A
27. Answer:
A
28. Answer:
A
29. Answer:
B
30. Answer:
A
31. Answer:
C
32. Answer:
C
33. Answer:
D
34. Answer:
A
35. Answer:
D
36. Answer:
B
37. Answer:
A
38. Answer:
C
39. Answer:
A
40. Answer:
A
41. Answer:
C
42. Answer:
A
43. Answer:
A
44. Answer:
D
45. Answer:
A
46. Answer:
A
47. Answer:
A
48. Answer:
D
49. Answer:
C
50. Answer:
A
51. Answer:
A
52. Answer:
C
53. Answer:
Ecosystems do not always have sharply defined boundaries because they can vary in size from the very small, such as a suburban neighborhood park, to the very large, like the entire area of the plains of the American Midwest. Smaller ecosystems are often nested inside larger ecosystems. The physical and interactive boundaries of ecosystems sometimes overlap, as is the case in estuaries found between freshwater and marine ecosystems, all of which may be surrounded by terrestrial ecosystems.
54. Answer:
An ecological community is an association of species that live in the same area. This differs from an ecosystem in that an ecosystem is actually a group of these communities not only interacting within themselves but also interacting with the other neighboring communities and abiotic factors in the environment. For instance, a small ecological community of protists interacting with each other in a tidal pool is also part of a larger coastal marine ecosystem. The coastal marine ecosystem might include other ecological communities, such as starfish and otters feeding on mollusks. The mollusks might interact with the tidal pool by feeding on the protists, and all these species are affected by the ebb and flow of the ocean tides.
55. Answer:
Chemical nutrients enter the ecosystem primarily through plants. Carbon typically enters the ecosystem through photosynthesis that transforms CO2 into sugars and (eventually) other carbohydrates. The carbohydrates are consumed by plant-eating animals, and those animals are consumed by predators. Plants and animals use the carbohydrates as fuel for energy and give off CO2, which then cycles back through photosynthesis. Other nutrients from the soil cycle through the ecosystem as they are absorbed by plants, and the plants are then consumed by animals. The nutrients in dead plants and animals are returned to the soil by decomposers.
56. Answer:
Energy enters the food chain as light energy from the sun. The light energy is captured by primary producers that convert it to chemical energy stored in the chemical bonds of sugars. These sugars are consumed and used by primary consumers (and also by the same primary producers) in cellular respiration to release energy for cellular growth and life functions. The primary consumers may be consumed by secondary consumers and so on. However, as the energy passes through each level of the food chain, about 90 percent is lost as metabolic heat energy and not transferred to the next level.
57. Answer:
Only about 10 percent of the energy available in a trophic level is available in the next trophic level (that consumed it) because nearly 90 percent of the energy was lost and not transferred to the next level. This loss can be in the form of waste when part of the biomass is not eaten—for example, when you peel off the exterior of an onion before slicing it to eat or trim the fat from your steak. The waste can also be due to part of the energy being inaccessible to the consumer. Humans cannot digest cellulose in plant cells, so we cannot access the energy stored in cellulose. A great deal of the energy loss is due to metabolic heat. When cells burn glucose for energy, this chemical reaction releases energy in the form of heat. This heat dissipates into the atmosphere and is not passed to the next trophic level.
58. Answer:
There will be only 1,000 calories available in the second trophic (primary consumer) level, followed by only 100 available calories in the third trophic (secondary consumer) level. Finally, there will be only 10 calories available in the fourth trophic (tertiary consumer) level. Ninety percent of the energy consumed by the consumers of a trophic level is used for survival and reproduction. This leaves only 10 percent of the energy to be stored and available for the next trophic level.
59. Answer:
Estuaries are shallow, aquatic biomes located where rivers flow into the ocean; therefore, they have a constant ebb and flow of fresh and salt water. Estuaries are the most productive aquatic biome because of the constant flow and stirring of nutrients brought in by the river. Additionally, they are not very deep; plenty of sunlight can penetrate the water to fuel photosynthesis in phytoplankton. The abundant presence of grasses and sedges also contributes to the overall productivity of this biome as well as providing nursery habitat for the young of many species.
60. Answer:
Grassy marsh wetlands are characterized by shallow standing water with many rooted plants emerging through the water’s surface; this provides lots of sunlight to the plants for photosynthesis, as well as sunlight that can penetrate the water’s surface to encourage photosynthetic algae in the water. The thriving plant and algae populations provide food for a complex community of species. Bogs are not nearly as productive as grassy marshes. Although bogs are also a type of wetland, the water in them is stagnant (not moving or fresh) and very oxygenpoor, so few species thrive there.
61. Answer:
Generally the most productive terrestrial ecosystems are tropical forests because they bring together an efficient combination of the four factors affecting net primary productivity: plenty of water, plenty of sunlight, moderate to warm temperatures, and a high availability of nutrients, which are sequestered within the vegetation of this ecosystem.
62. Answer:
When a whale swims up and down through the water column of the ocean, it stirs up and displaces the water in that area and brings photosynthetic plankton closer to the surface of the water. This stirring of the water also increases the volume of water exposed to the atmosphere and therefore (likely) increases the amount of carbon dioxide from the atmosphere that dissolves in the water. This is important because now the photosynthetic plankton are not only closer to the sunlight but also have more carbon dioxide readily available to them. They can now use the energy from the sunlight and the carbon dioxide from the atmosphere to photosynthesize sugars for use as energy in the ocean food chain. Therefore, the whale plays a part to decrease greenhouse gases in the atmosphere.
63. Answer:
The NPP is highest near the equator in terrestrial biomes and decreases nearer the poles. This is probably a function of sunlight (for photosynthesis) being more available closer to the equator. This same pattern is not seen in the oceans. NPP for oceans is typically higher near shorelines and relatively low in the open oceans. The most likely explanation for this difference is that the waters nearer the shorelines are richer in nutrients that have flowed into the ocean from the surrounding land, rivers, and streams. These nutrients contribute to the success of the photosynthetic plankton in this area. Deeper ocean water tends to be cooler and contain fewer nutrients.
64. Answer:
Researchers estimate the NPP of tropical grasslands to be 1,770 grams of carbon per square meter per year. The estimate for temperate grasslands is only 790 grams of carbon per square meter per year; this is a difference of 980 grams of carbon per square meter per year. Both these biomes are terrestrial biomes. The NPP of terrestrial biomes is greatly dependent upon their proximity to the equator and the increased availability of sunlight in this region. Tropical biomes are located closer to the equator than are temperate biomes. Therefore, it makes sense that with increased sunlight available to tropical grasslands, they would be more productive than temperate grasslands.
65. Answer:
No, the scientific community should not unquestioningly accept Boyce, Worm, and Lewis’s hypothesis that Earth’s oceans are losing 500 million tons of phytoplankton per year. Decisions about how the oceans’ resources are used and cared for are based on what we know about net primary productivity (NPP) in the oceans. If those decision are based on inaccurate data, then it becomes difficult to make good decisions. Multiple research teams have uncovered data that disagrees with the data shared by Boyce, Worm, and Lewis. It is important for the scientific community to critically examine all the current data to determine which set, or combinations of data, most accurately depict the NPP of Earth’s oceans. Additional research will also be needed to confirm whether this dramatic loss of phytoplankton is actually occurring.
66. Answer:
ecosystem
67. Answer:
ecological community
68. Answer:
energy; nutrients nutrients; energy
69. Answer:
recycled; reused reused; recycled
70. Answer:
metabolic heat heat
71. Answer:
sun
72. Answer:
trophic
73. Answer:
energy pyramid pyramid
74. Answer:
primary
75. Answer:
energy
76. Answer:
estuaries
77. Answer:
biomes
78. Answer:
net primary productivity NPP
79. Answer:
grams per square meter per year g/m2/yr
80. Answer:
Continuous Plankton Recorder
81. Answer:
1.
D
2.
A
3.
B
4.
E
5.
G
6.
F
7.
C
Name: ___________________________ Class: _________________ Date: __________
Chapter 22 1.
2.
3.
Which of the following statements accurately distinguishes tissues from organs? a.
Organs consist of cells, whereas tissues do not.
b.
Organs are limited to one location in the human body, whereas most tissues move throughout the body.
c.
Each organ performs multiple functions, whereas a designated tissue performs only one function.
d.
Organs consist of multiple tissue types, whereas tissues consist of one or more cell types.
Which of the following is a type of epithelial tissue? a.
skin
b.
tendons
c.
bone
d.
neurons
For homework, an instructor asks students to write a paragraph discussing how the mouth, stomach, and small intestines work together to process food and provide nutrients to the body. Which level of biological organization is the class studying? a.
tissues
b.
organ systems
c.
cells
d.
organs
4.
5.
6.
7.
Which of the following is a collection of organs? a.
bone, tendons, and fat
b.
reproductive, immune, and integumentary
c.
heart, lungs, and liver
d.
neurons, smooth muscle, and skin
Insulin is a protein hormone that helps cells use glucose found in the blood; it is produced by the pancreas and is circulated throughout the body by the circulatory system. In type 1 diabetes, insulin-producing cells in the pancreas are attacked and destroyed by the body’s immune cells. This is an example of the a.
digestive, circulatory, and excretory systems affecting one another.
b.
importance of only one system being needed to perform a function.
c.
importance of the excretory system in removing wastes and other toxins from the body.
d.
endocrine, digestive, circulatory, and immune systems affecting one another.
Epithelial, connective, muscle, and nervous are the four broad categories of animal body a.
organs.
b.
organ systems.
c.
tissues.
d.
cells.
Cardiac, smooth, and skeletal are all types of __________ tissue; they generate force to move structures within the body by contracting.
8.
9.
10.
a.
epithelial
b.
muscle
c.
nervous
d.
connective
After about an hour of basking in the sun, the body temperature of the marine iguana reaches 37° C. Then it dives into the water to feed. Once in the water, its body temperature rapidly drops and the iguana must return to the rocks to warm up. This process is an example of a.
tissue shock.
b.
negative feedback.
c.
set point control.
d.
positive feedback.
Negative feedback a.
stops a process before it reaches its set point.
b.
determines what the set point of a process should be.
c.
slows down or shuts off a process when a set point is reached.
d.
prevents positive feedback.
Some species of fish that live in the extremely cold waters of the Arctic Ocean have evolved an “antifreeze” protein that prevents water from freezing. This protein might be important to homeostasis because it would a.
be involved in transporting water into fish cells during cold weather. The more water there is in the cell, the smaller are the chance that ice crystals will form inside it.
b.
prevent ice crystals from forming inside fish cells, which would prevent damage to the plasma membrane when temperatures are low.
11.
12.
13.
c.
be involved in removing solutes from fish cells during cold weather. With fewer solutes in the cell, essential chemical reactions are more likely to occur.
d.
allow this species of fish to survive global warming by enabling the fish to carry out chemical reactions that would normally be prevented by warm temperatures.
Homeostatic pathways are a sequence of steps that reestablish the “normal state” of a living organism's internal environment. What determines the parameters of this “normal state”? a.
Living systems depend on signals from the environment to regulate these conditions.
b.
Organisms have a genetically predetermined set point that must be internally maintained.
c.
Living systems monitor positive feedback mechanisms and shut off negative feedback loops to regulate these processes.
d.
Actually, most living systems do not regulate temperature or water content, so these features typically fluctuate a great deal.
During blood clotting, a broken blood vessel triggers a cascade of factors that collectively reduce blood loss. In this example, the clotting factors are functioning as part of a.
thermoregulation.
b.
a negative feedback loop.
c.
osmoregulation.
d.
a positive feedback loop.
If you drink a large, sugary cola, your blood glucose levels will rise. Cells within your pancreas will respond by producing insulin, a hormone that allows glucose to enter the cells. As more glucose enters your cells, there will be less glucose in your bloodstream. Once the glucose level in your
blood has dropped to a healthy concentration, your pancreas will cease to produce extra insulin. This is an example of a __________ loop.
14.
15.
a.
thermoregulation
b.
positive feedback
c.
neutral feedback
d.
negative feedback
David has been eating a larger-than-usual amount of salty foods and notices that his hands and feet are swelling and he is retaining excess water in his system. After drinking several glasses of water and going for a run, he has to make several trips to the bathroom to urinate. The most likely reason why David had to make so many trips to the bathroom is that the extra salt caused him to retain extra water in his system. Drinking additional water and exercising helped to circulate blood through his body and then to his urinary system, where the extra water was filtered out of the blood. This is an example of a.
thermoregulation.
b.
osmoregulation.
c.
immunoregulation.
d.
digestive regulation.
Asexual and sexual reproduction in animals is similar in that both a.
increase genetic variation in the offspring.
b.
produce offspring that have double the amount of genetic information of the parent(s).
c.
rely on parental chromosomes to mix in new ways.
d.
generate offspring that carry parental genes.
16.
17.
18.
19.
Which of the following terms describes how the male sperm and the female egg typically fuse in animals? a.
internal fertilization
b.
hormonal contraception
c.
spermatogenesis
d.
hermaphroditism
Some organisms switch from male to female or vice versa. The most likely reason for the change is the a.
loss of reproductive ability.
b.
loss of chromosomes from one year to the next.
c.
ability to reproduce asexually versus sexually.
d.
availability of environmental resources.
Which of the following statements about sexual reproduction in humans is true? a.
Only one parent contributes genes to the offspring.
b.
Both parents contribute genes to the offspring.
c.
The offspring are identical to their parents.
d.
Only one parent is needed to produce offspring.
Gamete formation in human males is different from gamete formation in human females in that human males a.
have a shorter reproductive life span than human females.
b.
make sperm throughout their lives, beginning at puberty, whereas human females are born with all their primary oocytes poised to develop into eggs that may be fertilized.
20.
21.
22.
c.
produce gametes in the gonads, whereas human females produce eggs in the gut.
d.
make two polar bodies during spermatogenesis, whereas human females do not.
The number of chromosomes in secondary spermatocytes is fewer than in primary spermatocytes because __________ are separated during meiosis __________. a.
sister chromatids; II
b.
sister chromatids; I
c.
homologous pairs; II
d.
homologous pairs; I
Mature female eggs develop under the control of hormones within the a.
cervix.
b.
ovaries.
c.
uterus.
d.
oviduct.
A product of the first round of meiosis in males is a.
the primary oocyte.
b.
sperm.
c.
the first polar body.
d.
secondary spermatocytes.
23.
24.
25.
A human female has a diploid chromosome number of 46 (2n = 46). Based on this information, which of the following cells is NOT properly matched with its chromosome number? a.
diploid precursor cell: 46 chromosomes
b.
egg: 23 chromosomes
c.
secondary oocyte: 46 chromosomes
d.
first polar body: 23 chromosomes
Which of the following sequences places spermatogenesis in the correct order from start to finish? a.
sperm, primary spermatocyte, secondary spermatocytes, diploid precursor cell
b.
diploid precursor cell, secondary spermatocytes, primary spermatocyte, sperm
c.
primary spermatocyte, secondary spermatocytes, diploid precursor cell, sperm
d.
diploid precursor cell, primary spermatocyte, secondary spermatocytes, sperm
Which letter in the following figure identifies a primary spermatocyte?
26.
a.
A
b.
B
c.
C
d.
D
Which cell in the following figure is the first to be haploid?
27.
a.
A
b.
B
c.
C
d.
D
A product of meiosis I that will NOT reach ovum formation is the
28.
a.
secondary oocyte.
b.
second polar body.
c.
primary oocyte.
d.
first polar body.
Which cell in the following figure is a diploid cell and contains duplicated chromosomes?
29.
a.
the secondary oocyte
b.
the egg
c.
the primary oocyte
d.
the first polar body
Immediately after fertilization, a(n) __________ will be found in the oviduct. a.
embryo
b.
ovum
c.
zygote
d.
spermatocyte
30.
31.
32.
33.
If follicle-stimulating hormone (FSH) is not produced by a female’s pituitary gland, a.
estradiol will be produced by the follicle.
b.
there will not be stimulation of an ovarian follicle.
c.
progesterone will be secreted by the corpus luteum.
d.
luteinizing hormone will stimulate ovulation before the follicle develops.
Which of the following statements about human sperm and eggs is correct? a.
Sperm are visible to the eye, whereas eggs are microscopic.
b.
A woman’s supply of eggs is limitless.
c.
Eggs have twice as much genetic information as sperm.
d.
Sperm are much smaller than eggs.
When certain hormones are added to the uterus, they induce thickening in the cells lining its walls. Which of the following hormones is likely to be responsible for this change? a.
estradiol
b.
testosterone
c.
progesterone
d.
follicle-stimulating hormone
The structure in the male reproductive tract that has a function similar to that of the female fallopian tubes is the a.
vas deferens.
b.
seminiferous tubules.
c.
penis.
d.
34.
35.
36.
testes.
Sperm that are ejaculated from the body pass through the __________ last. a.
vas deferens
b.
seminiferous tubules
c.
penis
d.
testes
Which of the following sequences places the direction traveled by an egg in the correct order? a.
ovary, oviduct, uterus, vagina
b.
oviduct, uterus, ovary, vagina
c.
uterus, ovary, oviduct, vagina
d.
vagina, uterus, ovary, oviduct
Which of the locations highlighted in the following figure is the site of embryo implantation?
37.
38.
a.
A
b.
B
c.
C
d.
D
Which of the following sequences places the direction traveled by sperm in the correct order? a.
seminiferous tubules of the testes, vas deferens, penis
b.
vas deferens, testes, seminiferous tubules, penis
c.
vas deferens, seminiferous tubules of the testes, penis
d.
seminiferous tubules, vas deferens, testes, penis
During gestation, human development is divided into several stages called a.
semesters.
b.
trimesters.
c.
conceptions.
d.
39.
40.
41.
42.
gestations.
By the end of a normal first trimester, a human embryo has a.
not yet developed visible limbs.
b.
developed recognizable arms and legs.
c.
reached its birth length.
d.
gained about 50 percent of its birth weight.
Disruptions to the development of an embryo can happen at any time during pregnancy. The most vulnerable time period in the development of a zygote/embryo/fetus is the __________ week. a.
1st
b.
20th
c.
30th
d.
40th
Significant weight gain and the growth of hair on the fetus’s head are events that occur during which trimester of pregnancy? a.
first
b.
second
c.
third
d.
It varies, depending on when the mother eats the most.
The human embryo develops in a fluid-filled sac called the a.
uterus.
43.
44.
45.
b.
placenta.
c.
umbilical cord.
d.
amnion.
When is fetal development initiated? a.
at the establishment of organ systems
b.
at the beginning of the heartbeat
c.
when the baby’s sex can determined
d.
when hair begins to grow on the baby’s body
Your friend Tula, who is pregnant, learns that you are studying biology and tries to quiz you about your knowledge of pregnancy. She tells you that her baby has just starting kicking, and she asks you to guess how far along she is. Based on your understanding of life in the womb, you would answer that she is in about her __________trimester. a.
first
b.
third
c.
second
d.
fourth
Which of the following forms of contraception is hormonal? a.
a female condom
b.
birth control pills
c.
a contraceptive sponge
d.
sterilization
46.
47.
48.
49.
Which of the following hormones is partially responsible for initiating labor contractions? a.
luteinizing hormone
b.
oxytocin
c.
testosterone
d.
progesterone
In the last few weeks of pregnancy, the level of estrogen in the woman’s blood rises. This increase causes a.
the fetus to develop more rapidly.
b.
the amount of prostaglandins secreted by the placenta to decrease.
c.
the muscles of the uterus to become more sensitive to the hormone oxytocin.
d.
even more estrogen to be released from the pituitary gland.
Oxytocin is secreted by a.
only the fetus.
b.
the placenta.
c.
only the mother.
d.
the fetus and then the mother.
Males and females both produce estrogens, progestogens, and androgens. Which of the following is accurate for typical males and typical females? a.
Males have more estrogens than androgens. Females have more androgens than estrogens.
b.
Both males and females have more estrogens than androgens.
50.
c.
Males have more androgens than estrogens. Females have more estrogens than androgens.
d.
Both males and females have more androgens than estrogens.
According to the following infographic, which of the following is a temporary artificial barrier that prevents fertilization of an ovum by sperm?
a.
diaphragm and condom
b.
the pill
c.
sterilization, male or female
d.
intrauterine device
51.
52.
53.
The cell resulting from the union of one sperm cell with one egg cell is known as a(n) a.
embryo.
b.
zygote.
c.
fetus.
d.
infant.
The causes of birth defects most likely involve a.
a combination of genetic and environmental factors.
b.
viruses alone.
c.
only heavy alcohol consumption by the pregnant mother.
d.
only genetic factors.
Birth control pills and other hormone-based contraceptives suppress ovulation by mimicking the hormone levels of pregnancy. Examine the following figure and determine which hormone(s) are most likely present in hormone-based contraceptives.
54.
a.
follicle-stimulating hormone and prostaglandin
b.
luteinizing hormone and estradiol
c.
follicle-stimulating hormone and luteinizing hormone
d.
progesterones and estrogens
If follicle-stimulating hormone (FSH) and luteinizing hormone (LH) stimulate the production of sperm and the release of testosterone in males in a homeostatic negative feedback loop pathway, an increase in which of the following hormones might inhibit the production of sperm? a.
FSH
b.
LH
c.
testosterone
d.
FSH and LH
55.
During an exam review session, your classmate claims that tissues and organs are the same thing because they both contain cells. Explain why your classmate’s comment is incorrect. Compare and contrast these components of living systems.
56.
When people exercise, their muscle cells complete cellular respiration by using oxygen to help burn glucose. This process produces carbon dioxide that must be expelled from the body and requires increased amounts of oxygen to be delivered to the muscles. Describe the organs and the functional relationship between the two organ systems responsible for delivering oxygen to muscles and carrying away carbon dioxide.
57.
How would the nervous system act on the circulatory and respiratory systems to maintain a homeostasis of the blood gases carbon dioxide and oxygen during exercise or rest?
58.
Based on your knowledge of the significant role that proteins play in living systems, explain why it is critical for humans to maintain a temperature set point of around 37oC.
59.
The average pH of human blood is about 7.41 (just a little bit alkaline), and the pH of the human stomach is usually between pH 1 and 2 (very acidic). Based on your knowledge of the significant role that proteins play in living systems (digestive proteins in the stomach, many different proteins in the blood and other organs), explain why it would not be healthy for a human to attempt to increase the alkalinity of his or her body by drinking “alkaline water.”
60.
Compare and contrast the process of gamete formation in human males versus human females.
61.
In an ectopic pregnancy, a fertilized egg implants on the wall of the oviduct. In many cases, the zygote must be removed surgically and the developing zygote is lost. Explain how fertilization leading to a productive pregnancy should occur. In your answer, be sure to indicate the proper locations of ovum fertilization and of implantation and development of the zygote.
62.
Human ova are viable for fertilization for only about 24–48 hours after ovulation. Human sperm have been observed to survive as long as 7 days within the female reproductive tract. What influence might these viability times have on someone’s timing to become pregnant or when using abstinence as a method of contraception?
63.
Ramona is pregnant and she would like to find out the sex of the baby before her delivery date. Because this is her first baby, she doesn’t know when she should have an ultrasound to determine the baby’s sex. At what point in time during fetal development do a baby’s sexual organs develop? How does this point differ from when the child is genetically designated to develop into a male or a female?
64.
Explain why exposure to harmful agents such as alcohol, radiation, and the German measles (Rubella) virus during the first trimester can have profound effects on a developing human embryo.
65.
Various forms of contraception prevent pregnancy. What are the similarities between birth control pills and a diaphragm? How do the modes of action of these two contraceptive tools differ?
66.
Explain how the hormone oxytocin plays a role in the progression of labor.
67.
The end of the third trimester of pregnancy is marked by childbirth. Describe the feedback loop involving hormones and resulting in the birth of the child.
68.
The consumption of “alkaline water” is a trending practice. Proponents of drinking these high-pH waters claim that they promote health by “adjusting” the body’s pH and neutralizing acidity in the digestive tract as well as the blood stream and other areas of the body. Is this claim likely to be true? Support your answer.
69.
A collection of one or more cell types that carry out distinct and coordinated activities in the body is called
70.
Explain how birth control pills disrupt the human female menstrual cycle to prevent pregnancy.
71.
The brain, spinal cord, and nerves all function together as the __________ called the nervous system.
72.
In homeostatic regulation, cells seek to ensure relatively constant conditions by maintaining a normal state called the
73.
Homeostatic pathways depend on __________ to control processes in the body.
74.
Oogenesis occurs within the __________ of human females.
75.
In humans, sperm that is deposited within the vaginal tract eventually reaches an egg in the oviduct. This process, which is common to land animals, is called __________ fertilization.
76.
In human males, spermatogenesis occurs in the __________ of the __________.
77.
The development of internal male reproductive structures such as the sperm ducts and prostate gland are an important role of __________, the primary androgen.
78.
When estradiol levels reach a certain level in human females, they stimulate the pituitary gland to release __________, which triggers ovulation.
79.
The __________ is the site of ovum fertilization in human females.
80.
In humans, the average time period for development from zygote to childbirth is __________ weeks.
81.
By the end of __________ weeks, the face, tail, limbs, and most organs have begun to differentiate within the human embryo.
82.
Positive feedback occurs when the hormone oxytocin stimulates __________ to increase the number and intensity of contractions during labor and delivery.
83.
In human males, spermatogenesis occurs when diploid germ cells undergo meiosis inside the __________ of the testes.
84.
Match the male and female reproductive structures with the roles they perform during fertilization. a.
oviduct
b.
vagina
c.
uterus
d.
penis
e.
ovary
f.
testes __ 1. __ 2. __ 3. __ 4. __ 5. __ 6.
female reproductive tract where sperm is deposited sites of spermatogenesis in sexually mature males hollow tubule where fertilization occurs male reproductive structure that deposits sperm into the female site of oocyte production and maturation organ where the zygote implants and the embryo gestates
Answer Key Chapter 22
1. Answer:
D
2. Answer:
A
3. Answer:
B
4. Answer:
C
5. Answer:
D
6. Answer:
C
7. Answer:
B
8. Answer:
B
9. Answer:
C
10. Answer:
B
11. Answer:
B
12. Answer:
D
13. Answer:
D
14. Answer:
B
15. Answer:
D
16. Answer:
A
17. Answer:
D
18. Answer:
B
19. Answer:
B
20. Answer:
D
21. Answer:
B
22. Answer:
D
23. Answer:
C
24. Answer:
D
25. Answer:
B
26. Answer:
C
27. Answer:
D
28. Answer:
C
29. Answer:
C
30. Answer:
B
31. Answer:
D
32. Answer:
C
33. Answer:
A
34. Answer:
C
35. Answer:
A
36. Answer:
C
37. Answer:
A
38. Answer:
B
39. Answer:
B
40. Answer:
A
41. Answer:
C
42. Answer:
D
43. Answer:
A
44. Answer:
C
45. Answer:
B
46. Answer:
B
47. Answer:
C
48. Answer:
D
49. Answer:
C
50. Answer:
A
51. Answer:
B
52. Answer:
A
53. Answer:
D
54. Answer:
C
55. Answer:
Although tissues and organs both have cells as components, they are not the same thing. Tissues are on a lower level of the biological hierarchy of organization than organs. Tissues consist of one or more cell types that work together to perform a common function. Organs consist of one or more tissues that share a common function.
56. Answer:
The two organ systems responsible for carrying carbon dioxide from muscles and then supplying oxygen to the muscles are the circulatory system and the respiratory system. The circulatory system (the heart, veins, arteries, and blood) is responsible for carrying carbon dioxide–rich blood to the respiratory system (lungs, bronchii, trachea, and pharynx), where it can diffuse out of the blood and oxygen can diffuse into the blood. The heart pumps the blood through the lungs and the entire body through a closed network of vessels.
57. Answer:
The nervous system would maintain homeostasis of blood gases during exercise by sensing that carbon dioxide levels are increasing in the blood. When the brain gets this message, it would send out a message to the heart to start pumping faster and to the lungs to increase the rate of respiration; these two actions would speed up the rate at which the body would get rid of carbon dioxide and pick up oxygen. If the body were resting, muscles would not be working so hard and would burn less energy. The nervous system would sense that the body has less carbon dioxide to expel and does not need to speed up the intake of oxygen.
58. Answer:
Proteins are macromolecules that participate in nearly every chemical reaction that occurs within living systems. Proteins may act as enzymes, transporters, or even as structural molecules. With elevations in body temperature, these molecules may become denatured, losing their structure and function. This change would have severe and detrimental outcomes for the host organism because it would have a negative effect on its metabolism.
59. Answer:
Changing the normal pH of the body would upset the body’s homeostasis. Proteins that work within a living system only work at a particular pH. If the pH is not correct, the proteins lose their functional shape and cannot do their jobs. Proteins that promote digestion in the stomach must be at a very acidic pH to function properly. If the pH of the stomach becomes alkaline, the stomach will not be able to digest certain foods. Likewise, functional proteins in the blood and other organs will not be able to do their jobs if people were to actually increase their body pH past pH 7.45 or so. If the proteins that your body requires to sustain life cannot do their job, you will get sick and die.
60. Answer:
Gamete formation in males and females is similar, because both begin with a diploid precursor cell undergoing meiosis. During the two stages of meiotic cell division, the chromosome number is reduced in half so that the gametes are haploid. In addition, both processes only occur in the gonads. The processes differ, however, in the number of gametes they produce and the timing of gamete production. A woman is born with all the primary oocytes she will have, whereas a mature male produces sperm cells throughout his lifetime. Spermatogenesis generates four haploid gametes, whereas oogenesis creates only one egg. During cell division, the egg divides unequally, generating polar bodies that will not become mature egg cells.
61. Answer:
During sexual intercourse, a male ejaculates into the vagina, depositing millions of motile sperm. The sperm travel through the cervix and enter the uterus. They then enter the oviduct, where they encounter an ovum. Within the oviduct, a single sperm fertilizes a mature egg cell. The zygote then moves through the oviduct into the uterus for implantation and development.
62. Answer:
If a woman has had unprotected intercourse in the week before she ovulates, there is a reasonable chance she may become pregnant because the two viability times overlap. The sperm would have plenty of time to swim up to the oviducts to meet the newly ovulated egg. This also means that a woman who does not want to become pregnant would need to be sure to not engage in unprotected intercourse in the 7 days before she expects to ovulate. The timing of a woman's reproductive cycle can be altered by physical and environmental stresses. Therefore, as an added precaution, she should probably not have intercourse for 8 to 10 days before she expects to ovulate.
63. Answer:
The sex of a human baby is genetically determined at conception when a sperm fertilizes an egg. The female egg only carries X chromosomes, but a sperm cell may carry either an X or a Y chromosome. The combination of gametes produces either a zygote with two X chromosomes (destined to become a female) or a zygote with an X and a Y chromosome (destined to become a male). The expression of traits coded for by genes carried on these chromosomes is not observed until around the 3rd month of gestation, when the sex organs differentiate. Therefore, an ultrasound to determine sex will typically be performed after this point, which occurs between 18 and 20 weeks of pregnancy.
64. Answer:
During the first trimester, the bases for all of the embryo’s organ systems and anatomy are established. If the mother encounters a harmful agent that interrupts any of the processes involved in forming the organ systems and overall anatomy of the embryo, then everything else that needs to build on the products of those processes will be unable to properly form.
65. Answer:
Birth control pills and the diaphragm both use chemical methods to prevent fertilization of the egg. However, the methods of preventing fertilization differ. Birth control pills release hormones that mimic hormone levels of pregnancy; as a result, the ovaries fail to ovulate. Therefore, sperm that reach the oviducts during sexual intercourse do not encounter an egg. The diaphragm uses both chemical and physical means to prevent pregnancy. Diaphragms contain spermicides that kill sperm cells (chemical control). In addition, they form a protective barrier that limits the passage of sperm into the cervix.
66. Answer:
As estradiol levels spike late in pregnancy, the woman’s uterine muscles become more sensitive to oxytocin. The elevation in oxytocin levels secreted by the fetus and the woman’s pituitary gland triggers the onset of powerful uterine contractions that help push the baby through the birth canal. This interaction between multiple hormones is an example of positive feedback.
67. Answer:
At least three hormones interact in a positive feedback loop to initiate and complete labor and delivery (childbirth). Near the end of gestation, estrogen levels rise in the mother’s blood stream; this increases sensitivity of the uterine muscles to the hormone oxytocin. Oxytocin is initially secreted by the fetus and then later in the birth process by the mother’s pituitary gland. Oxytocin acts in two ways, it stimulates contractions in the uterine muscles and production of prostaglandins by the placenta. Prostaglandins, in turn, further promote uterine contractions. The contractions stimulate further production of oxytocin and so on. This positive feedback loop continues while the contractions open up the mother’s cervix and eventually push the infant out of the mother’s body. Once the infant is born, the hormone levels begin to subside. The final stage of childbirth is the expulsion of the placenta.
68. Answer:
No, this claim is not likely to be true. The human body must maintain homeostasis to function properly, and there are homeostatic feedback loops in place to help maintain constant levels such as temperature and pH. Physical conditions such as temperature and pH must remain constant for enzymes and proteins in the body to function properly. This tells us that attempting to “adjust” the body’s pH by simply drinking a highly alkaline water will be thwarted by the body’s feedback systems designed to maintain a constant pH. Additionally, highly alkaline substances can actually harm the tissues that are in contact with them.
69. Answer:
tissue.
70. Answer:
Birth control pills contain hormones such as progesterone and estrogens. By increasing the levels of these hormones in the female system, a feedback loop is closed that tells the pituitary gland not to produce follicle-stimulating hormone (FSH). Without FSH, no new ovarian follicle will develop and there will be no secondary oocyte released (no ovulation). If no secondary oocyte is released, then fertilization and pregnancy cannot occur.
71. Answer:
organ system
72. Answer:
set point.
73. Answer:
feedback loops
74. Answer:
ovaries
75. Answer:
internal
76. Answer:
seminiferous tubules; testes
77. Answer:
testosterone
78. Answer:
luteinizing hormone LH
79. Answer:
oviduct
80. Answer:
38 thirty-eight
81. Answer:
4 four
82. Answer:
prostaglandins
83. Answer:
seminiferous tubules
84. Answer:
1.
B
2.
F
3.
A
4.
D
5.
E
6.
C
Name: ___________________________ Class: _________________ Date: __________
Chapter 23 1.
2.
3.
Numerous studies of life expectancy in the United States indicate that __________ is more deadly than any other health risk factor. a.
obesity
b.
smoking
c.
poor cardiorespiratory fitness
d.
diabetes
Which of the following statements is true regarding amino acids and adult humans? a.
The body can synthesize all 20 different amino acids.
b.
Twelve essential amino acids must be obtained through diet.
c.
Amino acids are micronutrients that are required in tiny amounts.
d.
Amino acids are the building blocks for constructing proteins in the body.
The microscopic banding appearance of skeletal muscle is due to the presence of a.
nuclei.
b.
sarcomeres.
c.
interconnecting branches.
d.
spindle-shaped cells.
4.
5.
6.
7.
Which body part contains muscle composed of cells that are as long as the entire muscle? a.
stomach
b.
blood vessel
c.
heart
d.
arm
A student uses a microscope to examine a prepared tissue slide. After observing osteocytes, it becomes clear that the specimen must belong to a.
muscle.
b.
cartilage.
c.
bone.
d.
skin.
The most likely potential problem faced by a person who is following a very low-protein diet is the failure to a.
take in the carbon, hydrogen, and oxygen required for life.
b.
acquire necessary amounts of essential amino acids.
c.
absorb sufficient quantities of carbohydrates in the gut.
d.
produce vitamins and minerals required by living organisms.
What connects the femur (thigh bone) to the tibia (shin bone) at the knee? a.
tendon
b.
ligament
c.
cartilage
d.
synovial sac
8.
9.
10.
11.
What part of the skeleton cushions joints and protects the ends of bones? a.
cartilage
b.
spongy bone
c.
compact bone
d.
collagen
Babies may receive an injection of vitamin K at birth. The most likely reason for this is that vitamin K is required a.
for calcium absorption, and babies need to build strong bones.
b.
to prevent bleeding, and babies are born with low levels of this vitamin.
c.
for the formation of visual pigments in the eyes, and babies use their eyes more often than their other senses.
d.
to build cell membranes, and babies are growing rapidly.
Which of the following vitamins is NOT associated with building or maintaining bones and teeth? a.
vitamin B12
b.
vitamin C
c.
vitamin D
d.
vitamin E
The muscular tongue positions food between the teeth for chewing and pushes food to the back of the oral cavity for swallowing. The tongue contains a.
smooth muscle, which is under voluntary control.
b.
skeletal muscle, which is under voluntary control.
12.
13.
14.
15.
c.
skeletal muscle, which is under involuntary control.
d.
smooth muscle, which is under involuntary control.
The most abundant dietary mineral in the body is __________, which is a major component of bone. a.
sodium
b.
calcium
c.
iodine
d.
fluoride
The largest organ system in the human body is the __________ system. a.
integumentary
b.
skeletal
c.
muscular
d.
digestive
The layers of skin from outermost to innermost are a.
hypodermis, dermis, and epidermis.
b.
dermis, hypodermis, and epidermis.
c.
epidermis, dermis, and hypodermis.
d.
dermis, epidermis, and hypodermis.
The epidermis of the skin consists of __________ tissue. a.
connective
16.
17.
18.
b.
epithelial
c.
muscle
d.
nervous
Pancreatic cancer is an especially dangerous disease in humans because the pancreas is a.
the organ that produces and stores bile.
b.
the site of synthesis for all the essential amino acids.
c.
one of the organs through which food must pass on its way to the large intestine.
d.
an organ that manufactures many different kinds of digestive enzymes.
If a disease reduces the number of villi within the small intestine, one would expect a(n) a.
increased secretion of acid to break down proteins.
b.
decrease in the surface area for absorption.
c.
decrease in storage spaces for partially digested food.
d.
increase in the surface area for helpful bacteria.
The function of chewing food is to a.
provide mechanical digestion and increase the surface area of the food for further digestion.
b.
make food immediately ready for nutrient absorption in the stomach.
c.
increase the amount of vitamins in the food.
d.
decrease the surface area of the food in order to speed digestion.
19.
20.
21.
22.
The function of the esophagus is to a.
break down food physically.
b.
break down food chemically.
c.
carry food to the stomach.
d.
prepare undigested material and waste for disposal.
Food passing through our digestive tract would contain the fewest nutrients when it reaches the __________, which is responsible for the absorption of water and minerals. a.
small intestine
b.
stomach
c.
large intestine
d.
esophagus
The human liver produces bile, a substance that a.
aids in the absorption of vitamin C.
b.
allows fats to dissolve more easily in the watery contents of the gut.
c.
neutralizes the acids that are produced by pepsin.
d.
breaks the bonds between amino acids.
Which letter in the following figure identifies the site where most digestion and nutrient absorption take place?
23.
24.
a.
A
b.
B
c.
C
d.
D
Which organ stores and releases bile? a.
pancreas
b.
small intestine
c.
gallbladder
d.
large intestine
Which of the following describes compact bone? a.
contains bone marrow within cavities
b.
honeycombed appearance
25.
26.
27.
28.
c.
most abundant at the knobby ends of long bones
d.
forms the outer region of all bones
What attaches to the bones of the arms and legs, resulting in locomotion? a.
cartilage
b.
skeletal muscle
c.
smooth muscle
d.
ligaments
How rapidly an organism can absorb nutrients generally depends on the a.
surface area available for absorption.
b.
length of the large intestine.
c.
ratio of ingested macronutrients to micronutrients.
d.
volume of the organism that is taking up the nutrients.
The salivary glands produce saliva, which contains enzymes that break down a.
fats.
b.
proteins.
c.
starches.
d.
all macronutrients.
Several vitamins are produced by bacteria that reside in the a.
oral cavity.
29.
30.
b.
stomach.
c.
small intestine.
d.
large intestine.
Protein digestion begins in the a.
oral cavity.
b.
stomach.
c.
small intestine.
d.
large intestine.
The structure indicated by the arrow in the following illustration of a knee joint is a
a.
bone.
b.
ligament.
c.
tendon.
d.
synovial sac.
31.
32.
33.
The structure indicated by the arrow in the following illustration of a knee joint is a
a.
bone.
b.
ligament.
c.
tendon.
d.
synovial sac.
Which part of the skeleton belongs to the appendicular division? a.
spinal column
b.
pelvis
c.
rib cage
d.
skull
If you damage a ligament in your knee, you have damaged a
34.
35.
36.
a.
connection between two bones.
b.
connection between bone and muscle.
c.
mineral-based component of your skeleton.
d.
nonliving component of your skeleton.
Repeated kneeling can lead to swelling of the front of the knee that feels squishy, like a water balloon. This condition is sometimes referred to as “water on the knee.” A likely source of this fluid would be a.
tendons around the knee.
b.
ligaments around the knee.
c.
marrow within spongy bone.
d.
synovial sacs.
The knee is part of the __________ skeleton, which is the portion of the skeleton primarily involved with __________. a.
axial; protection
b.
axial; movement
c.
appendicular; protection
d.
appendicular; movement
One of the most common knee injuries is the tearing of the anterior cruciate ligament (ACL). How would an injury like this affect the function of the knee? a.
Ligaments attach muscle to bone, so tearing of the ligament would mean that the knee muscles would no longer be able to cause the joint to bend.
b.
Ligaments lubricate the cartilage in a joint, and tearing the ligament would let the lubricant leak out. This would cause bones in the knee to grind against each other, making it painful to bend the knee.
37.
38.
39.
c.
Ligaments hold the bones of the knee in the proper orientation. Tearing the ligament could disrupt the alignment of the knee, making the knee difficult to bend.
d.
Ligaments are the muscles that surround a joint. Muscle tears can be painful, but they heal quickly and they usually do not affect knee function.
The dense tissue that combines strength with flexibility and provides support in the nose and ears is a.
adipose tissue.
b.
cartilage.
c.
epidermal tissue.
d.
muscle.
Which of the following is an accessory organ of the digestive system? a.
stomach
b.
pancreas
c.
small intestine
d.
esophagus
Which tissue type is responsible for reducing friction within joints? a.
cartilage
b.
bone
c.
ligaments
d.
tendons
40.
41.
The muscle shown in the following figure
a.
is under conscious control.
b.
lacks myofibrils.
c.
lacks nuclei.
d.
is an involuntary muscle.
Which of the following statements about cardiac muscle is true? a.
Cardiac muscle is like skeletal muscle in that skeletal muscle has involuntary contractions.
b.
Cardiac muscle is like smooth muscle in that smooth muscle has a banded appearance.
c.
Cardiac muscle contains bands like skeletal muscle, but its contractions are involuntary like smooth muscle.
d.
Cardiac muscle is like smooth muscle in that it contains no bands.
42.
43.
44.
45.
If a drug attacked and destroyed involuntary muscle cells only, the movement of the __________ would be affected. a.
arms
b.
legs
c.
heart
d.
eyes
Vanessa has been lifting weights to increase the strength in her arms. The muscles she is strengthening a.
contain branched muscle fibers.
b.
lack a banded appearance.
c.
are involuntary muscles.
d.
contain myofibrils.
Voluntary muscle that has a banded appearance would be expected to be found a.
within the wall of the esophagus.
b.
in a muscle that bends the knee.
c.
in the heart.
d.
within the wall of the stomach.
The power that moves food along the esophagus comes from __________ muscle. a.
skeletal
b.
smooth
c.
cardiac
d.
46.
47.
48.
49.
voluntary
During a muscle contraction, a.
actin and myosin filaments both shorten in length.
b.
actin filaments shorten in length when myosin filaments bind to actin.
c.
myosin filaments become attached to the Z discs in a sarcomere.
d.
myosin and actin filaments overlap to a greater degree.
Skeletal muscle fibers run the length of the a.
sarcomere.
b.
entire muscle.
c.
tendon.
d.
actin and myosin filaments.
As a muscle contracts, the a.
Z discs move closer together.
b.
sarcomeres extend.
c.
muscle creates energy.
d.
myofibrils break down.
Which animal is correctly paired with its type of skeleton? a.
shark; exoskeleton
b.
hawk; exoskeleton
c.
human; endoskeleton
d.
50.
51.
52.
53.
lobster; endoskeleton
Which of the following sequences correctly describes the organization of muscle tissue from smallest to largest component? a.
myofibrils to sarcomeres to muscle fibers
b.
sarcomeres to myofibrils to muscle fibers
c.
muscle fibers to sarcomeres to myofibrils
d.
sarcomeres to muscle fibers to myofibrils
Which of the following statements about myofibrils is true? a.
They consist of a single sarcomere.
b.
They contain a single muscle fiber.
c.
They have no Z discs.
d.
They contain many sarcomeres.
Which bone belongs to the division of the skeleton that generally functions to protect vital organs? a.
collarbone
b.
hip
c.
rib
d.
femur
The longest segment of the gastrointestinal (GI) tract is the a.
small intestine.
b.
large intestine.
c.
esophagus.
d.
colon.
54.
Why is dietary fiber important in a human’s diet?
55.
Name the two divisions of the skeleton and summarize the overall function of each division. In addition, list several bones that belong to each division.
56.
Atair has been diagnosed with celiac disease, an autoimmune disorder that damages the villi lining the small intestine. What are villi and how will damaged villi affect the function of Atair’s digestive system?
57.
Trace the pathway of food through the gastrointestinal (GI) tract from mouth to anus and summarize how each GI tract organ functions along the path.
58.
Explain how the skin of the integumentary system is made up of epithelial, connective, muscle, and nervous tissue.
59.
Describe how secretions from the gallbladder and the pancreas relate to the functions of the small intestine.
60.
Doris visits a physician because she says it feels like bones in her knee are grinding against one another. What two structures within her knee joint could likely be damaged?
61.
What human body system is formed by cartilage and bone? List one role of cartilage and one role of bone in that system.
62.
List three characteristics of each type of muscle (skeletal, cardiac, and smooth). Then indicate which of those characteristics are unique to only one type of muscle.
63.
How does the contraction of a sarcomere relate to the shortening of an entire muscle?
64.
Your friend recently added dark chocolate to her diet after being diagnosed with a condition called anemia in which red blood cells are limited in their ability to carry oxygen. Based on her dietary change, what nutrient must be important in the formation of normal red blood cells? Is there an alternative food choice that could provide this nutrient? Use the infographic to help explain your answer.
65.
Based on the following figure, individuals who exercise vigorously for 3.76 hours per week have roughly the same percentage chance of living longer as individuals who exercise vigorously for 12.50 hours per week. Explain these findings.
66.
Examine the following figure and reflect on your personal exercise habits. State the amount of time spent weekly on moderate exercise and list the exercises you regularly participate in (activities include walking, hiking, bicycle riding, and other activities that do not involve sprinting or extremely heavy breathing). Then, state the amount of time spent on vigorous exercise and list the exercises you regularly in participate in (activities include running, swimming, playing basketball, and any activity that involves sprinting, such as indoor cycling). Finally, are you comfortable with your current “fitness retirement plan”? What specific changes can you make to your routine that would increase your chance of living longer?
67.
Lipids are nutrients required by the body in large quantities. Therefore, lipids are classified as
68.
__________ are small, organic nutrients that do not provide the human body with energy and are required only in small quantities; however, they help regulate metabolic processes.
69.
The layer of skin that routinely comes in contact with the external environment is the
70.
The enzymatic digestion of carbohydrates begins in the
71.
The __________ is the digestive organ that contracts to mix food particles with acid and enzymes and also holds food until it can pass farther along for continued digestion.
72.
Surgical removal of the gallbladder makes it more difficult for the patient to digest
73.
The outermost region of all bones is made up of __________ bone.
74.
Ligaments are composed of connective tissue that connects __________ to bone.
75.
The __________ skeleton is the division of the skeleton that protects the brain and spinal cord.
76.
Lacking sarcomeres, __________ muscle has no visible bands under the microscope.
77.
Muscles that move food along the digestive tract and cause the heart to pump blood without conscious thought are called __________ muscles.
78.
The contractile units within myofibrils of skeletal muscle are called
79.
Match each vitamin to one of the following functions or deficiencies. a.
vitamin C
b.
vitamin D
c.
vitamin K
d.
vitamin E
e.
vitamin A __ 1. Deficiency of this vitamin reduces calcium absorption and leads to poor formation of bones and teeth. __ 2. This vitamin is used to produce visual pigments in the eyes. __ 3. This vitamin protects lipids in cell membranes. __ 4. Deficiency of this vitamin leads to scurvy. __ 5. Deficiency of this vitamin affects the ability to control bleeding.
80.
Match each organ in the digestive system with its function. a.
stomach
b.
mouth
c.
small intestine
d.
pancreas
e.
gallbladder
f.
large intestine
g.
liver __ 1. __ 2. __ 3. __ 4. __ 5. __ 6. __ 7.
production of bile storage of bile secretion of digestive enzymes into the small intestine absorption of water and minerals beginning of starch digestion production of acid and protein-digesting enzymes secretion of digestive enzymes and absorption of most nutrients
Answer Key Chapter 23
1. Answer:
C
2. Answer:
D
3. Answer:
B
4. Answer:
D
5. Answer:
C
6. Answer:
B
7. Answer:
B
8. Answer:
A
9. Answer:
B
10. Answer:
D
11. Answer:
B
12. Answer:
B
13. Answer:
A
14. Answer:
C
15. Answer:
B
16. Answer:
D
17. Answer:
B
18. Answer:
A
19. Answer:
C
20. Answer:
C
21. Answer:
B
22. Answer:
B
23. Answer:
C
24. Answer:
D
25. Answer:
B
26. Answer:
A
27. Answer:
C
28. Answer:
D
29. Answer:
B
30. Answer:
A
31. Answer:
C
32. Answer:
B
33. Answer:
A
34. Answer:
D
35. Answer:
D
36. Answer:
C
37. Answer:
B
38. Answer:
B
39. Answer:
A
40. Answer:
A
41. Answer:
C
42. Answer:
C
43. Answer:
D
44. Answer:
B
45. Answer:
B
46. Answer:
D
47. Answer:
B
48. Answer:
A
49. Answer:
C
50. Answer:
B
51. Answer:
D
52. Answer:
C
53. Answer:
A
54. Answer:
Although dietary fiber does not contribute any energy or chemical building blocks, it is a necessary component of a healthy diet because it controls the rate at which carbohydrates are absorbed.
55. Answer:
The bones of the skeleton can be classified as belonging to either the axial skeleton or the appendicular skeleton. The axial skeleton protects vital internal organs. The skull bones protect the brain, the spinal column is composed of vertebrate that protect the spinal cord, and the rib cage protects the heart and lungs. The appendicular skeleton permits body movement. The appendicular skeleton includes the bones of the upper and lower limbs as well as their attachments to the axial skeleton. Upper limb bones and their attachment to the axial skeleton include the collarbone, shoulder blade, humerus, ulna, radius, wrist, and hand bones. Lower limb bones and their attachment to the axial skeleton include the hip bones, femur, kneecap, tibia, fibula, and foot bones.
56. Answer:
Villi are fingerlike projections of the lining of the small intestine that increase the surface area available for the absorption of nutrient building blocks. With damaged villi, Atair will not be able to adequately absorb vitamins, minerals, and other nutrients into his bloodstream.
57. Answer:
Ingestion of food occurs at the mouth, or oral cavity. The teeth mechanically break down food and enzymes in saliva chemically digest starches, or carbohydrates. Swallowing moves the food into the pharynx (throat), which conducts food into the esophagus (gullet). The esophagus leads to the stomach, where food is converted into a liquid paste and mixed with acids and enzymes that begin the breakdown of proteins. The stomach empties into the small intestine. The liver, gallbladder, and pancreas are accessory organs that deliver bile and digestive enzymes to the small intestine, which is the longest portion of the GI tract. Most digestion and absorption of the resulting nutrient building blocks occur along the length of the small intestine. What remains in the tract continues to the large intestine, where additional water and minerals are reabsorbed. Finally, the feces leave the body through the anus.
58. Answer:
The epidermis, or outermost layer of skin, consists of epithelial tissue. Under the epidermis is the dermis, a layer of skin made up of connective tissue. Also found within the dermis are tiny smooth muscles called arrector pili muscles that attach to hairs and can cause “goosebumps.” Finally, the dermis contains nerve endings that detect touch, temperature and other sensations.
59. Answer:
The small intestine is responsible for completing the digestion of carbohydrates, fats, and proteins. Bile from the gallbladder breaks fat globules into smaller droplets upon which fatdegrading enzymes act. Secretions from the pancreas contain enzymes that chemically digest carbohydrates, fats, and proteins into their nutrient building blocks. The cells lining the small intestine then absorb these nutrients and move them into the bloodstream.
60. Answer:
Cartilage provides a smooth surface where bones join together. Synovial sacs within the knee joint contain lubricating fluid between bony surfaces. One or both of these structures could be damaged.
61. Answer:
Cartilage and bone form the skeletal system in humans. Cartilage provides cushioning within joints and gives form to the nose, the ears, and part of the rib cage. Bones protect underlying organs and provide attachment points for muscles.
62. Answer:
Skeletal muscle is VOLUNTARILY CONTROLLED, ATTACHES TO BONES, has LONG MUSCLE FIBERS THAT EXTEND THE LENGTH OF THE MUSCLE, and exhibits a microscopic banding appearance due to the presence of sarcomeres. Cardiac muscle is involuntarily controlled, only FOUND IN THE WALL OF THE HEART, has BRANCHED MUSCLE FIBERS, and has sarcomeres that produce the microscopic banding appearance. Smooth muscle is involuntarily controlled, FOUND IN THE WALLS OF HOLLOW ORGANS such as blood vessels and the stomach, has SPINDLE-SHAPED CELLS, and LACKS SARCOMERES AS WELL AS THE MICROSCOPIC BANDING appearance. (Characteristics listed in capital letters are unique to that one type of muscle tissue.)
63. Answer:
Many sarcomeres align end-to-end along the length of a myofibril. When all of these sarcomeres shorten at the same time, the entire myofibril shortens. Each skeletal muscle fiber (cell) is packed with myofibrils, all running parallel to each other along the length of the muscle fiber. The muscle fiber contracts when all of the myofibrils within the muscle cell shorten at the same time. Muscle fibers bundle together in groups, and many muscle fiber bundles make up the whole muscle. The coordinated contraction of many muscle cells causes the whole muscle to shorten.
64. Answer:
Iron must be part of red blood cells. One alternative food choice is white beans.
65. Answer:
Increasing time spent exercising correlates with an increased lifespan. The figure shows that this effect is most dramatic when comparing individuals getting less than 1.25 hours/week of vigorous exercise (21 percent chance of living longer) with those who vigorously exercise between 2.51 and 3.75 hour per week (37 percent chance of living longer). Individuals who vigorously exercise between 3.76 and 6.25 hours per week only further improve their chances of living longer by a couple of percentage points. Individuals who vigorously exercise 6.26 and 12.50 hours per week do not get any additional increase in lifespan than those who vigorously exercise between 3.76 and 6.25 hours per week. Thus, it appears that the beneficial effects of vigorous exercise plateau and then become maxed out with increasing duration of vigorous exercise.
66. Answer: Student answers will vary depending on their current amount of time spent on moderate and vigorous exercise and the particular activities that they engage in. It is important that students getting less than 2.5 hours of moderate exercise per week (or 1.25 hours of vigorous exercise per week) consider spending enough additional time on specific types of exercise to raise their chance of living longer. 67. Answer:
macronutrients
68. Answer:
vitamins
69. Answer:
epidermis
70. Answer:
mouth. oral cavity.
71. Answer:
stomach
72. Answer:
fats lipids
73. Answer:
compact
74. Answer:
bone
75. Answer:
axial
76. Answer:
smooth
77. Answer:
involuntary
78. Answer:
sarcomeres
79. Answer:
80. Answer:
1.
B
2.
E
3.
D
4.
A
5.
C
1.
G
2.
E
3.
D
4.
F
5.
B
6.
A
7.
C
Name: ___________________________ Class: _________________ Date: __________
Chapter 24 1.
2.
3.
Blood leaving the right ventricle of the heart travels next to the a.
right atrium.
b.
body.
c.
lungs.
d.
left ventricle.
Another name for the “pacemaker” of the heart is the a.
atrioventricular (AV) node.
b.
sinoatrial (SA) node.
c.
atrium.
d.
ventricle.
One side of the heart pumps blood into the pulmonary circuit, and the other side of the heart pumps blood to the systemic circuit. How do these different functions affect the structure of the heart? a.
The left side of the heart has one large chamber, whereas the right side has two chambers.
b.
The right side of the heart has three chambers, whereas the left side has two chambers.
c.
The left side of the heart has a thicker muscular wall than the right side.
d.
The right side of the heart has a thicker muscular wall than the left side.
4.
5.
6.
Which of the following does NOT facilitate exchange of materials by diffusion? a.
cells lying within 0.03 millimeters of blood vessels
b.
a large surface area within alveoli
c.
the presence of the extracellular matrix within connective tissue
d.
thin, porous walls in capillaries
Shortages of iron in a person’s diet can cause iron-deficiency anemia, a condition that reduces the amount of hemoglobin in red blood cells. Irondeficiency anemia is a potentially serious condition that is characterized primarily by a a.
change in the color of blood from its normal red to various shades of blue and purple.
b.
reduction in the blood’s capacity to transport oxygen.
c.
delay in the time required for the blood to clot and a potential for extensive blood loss in the event of trauma.
d.
reduction in the concentration of white blood cells and an increased vulnerability to infection.
A newborn is diagnosed shortly after birth with a rare heart defect that prevented the valve between the left atrium and the left ventricle from fully forming. An expected outcome of this defect would be that a.
oxygen-poor and oxygen-rich blood would mix.
b.
blood would flow through the body in more than one direction.
c.
body cells would receive less oxygen-rich blood than normal.
d.
blood flow from the left ventricle to the body would increase.
7.
8.
9.
10.
The liquid portion of human blood cannot absorb enough oxygen to meet the body’s demands. However, __________ in red blood cells greatly increase(s) the oxygen-carrying capacity of human blood. a.
carbon dioxide
b.
ions
c.
water
d.
hemoglobin
Which of the following statements about hemoglobin is true? a.
Hemoglobin is an enzyme involved in the process of cellular respiration.
b.
Hemoglobin transports oxygen from cells that are undergoing cellular respiration to red blood cells.
c.
Hemoglobin binds to oxygen and releases it near cells that are performing cellular respiration.
d.
Hemoglobin makes the blood more acidic, enabling it to absorb more oxygen.
People with sickle-cell disease have deformed hemoglobin molecules and often suffer muscle pains, even at low levels of exertion. These symptoms might occur because the deformed hemoglobin a.
is unable to carry the amount of oxygen required for normal muscle activities.
b.
cannot diffuse across the cells’ membranes from the blood plasma.
c.
causes damage to the muscle cells as it enters the muscle.
d.
decreases the ratio of surface area to volume in a person’s lungs.
At high altitudes, gases are less concentrated. A person in a high altitude might gasp for air because
11.
12.
13.
a.
the surface area of the lungs will be decreased.
b.
the amount of hemoglobin in the blood will decrease.
c.
hemoglobin will not be able to bind to oxygen as well at a higher altitude.
d.
the amount of oxygen that could diffuse into the blood will be decreased.
Why do humans rely on a circulatory system to distribute oxygen? a.
Diffusion does not occur in organisms that have more than about 300 cells.
b.
Humans do not need as much oxygen as small organisms do, so we use inefficient transport systems such as the circulatory system rather than diffusion.
c.
Humans need an internal transport system in order to quickly replace oxygen that is lost because of our high surface area of skin.
d.
Diffusion is very slow over all but the shortest distances, so oxygen must be delivered to our cells to speed up the process.
Which component of whole blood would an investigator examine to determine the concentration of dissolved carbon dioxide or hormones such as testosterone? a.
plasma
b.
platelets
c.
white blood cells
d.
red blood cells
Which of the following features could be found in a vein, but NOT in an artery? a.
a one-way valve
14.
15.
16.
b.
muscle
c.
oxygen-rich blood
d.
blood that is under high pressure
Large blood vessels that return deoxygenated blood from the legs to the heart are a.
veins.
b.
capillaries.
c.
arteries.
d.
arteries and capillaries.
The blood vessels that allow diffusion between blood and nearby body cells are a.
veins.
b.
capillaries.
c.
arteries.
d.
veins and capillaries.
The pulmonary __________ carries __________ blood from the heart to the lungs. a.
vein; oxygen-rich
b.
artery; oxygen-rich
c.
vein; oxygen-poor
d.
artery; oxygen-poor
17.
18.
Blood flows rapidly within the arterial system but slows dramatically as it enters the capillaries. The benefit of having blood move slowly through the capillaries is that it a.
enables the capillaries to conserve the blood’s pressure gradient so that enough pressure remains to return the blood to the heart.
b.
provides the time needed for white blood cells to capture any bloodborne pathogens that might be present.
c.
ensures that the blood has enough time to exchange material with the surrounding cells.
d.
decreases the probability of frictional scarring on the capillary wall and the subsequent development of atherosclerosis.
The structure that is highlighted in the following figure is the
a.
diaphragm.
b.
bronchi.
c.
larynx.
d.
19.
20.
21.
22.
trachea.
For a human to inhale, the rib muscles and the diaphragm must __________ which __________ pressure inside the lungs. a.
contract; decreases
b.
relax; increases
c.
contract; increases
d.
relax; decreases
Which of the following sequences correctly describes the journey of a molecule of oxygen from the pharynx to an alveolus? a.
pharynx to trachea to bronchus to bronchiole to alveolus
b.
pharynx to bronchiole to bronchus to trachea to alveolus
c.
pharynx to trachea to bronchiole to bronchus to alveolus
d.
pharynx to bronchus to bronchiole to trachea to alveolus
During inhalation, a.
oxygen-rich air enters the alveoli.
b.
lung volume decreases.
c.
pressure in the lungs remains constant.
d.
the diaphragm relaxes.
Which of the following respiratory structures has the smallest diameter? a.
pharynx
b.
trachea
23.
24.
25.
c.
bronchi
d.
bronchioles
Air that is entering the lungs has a __________ concentration of __________ in an alveolus. a.
higher; carbon dioxide than air
b.
higher; both carbon dioxide and oxygen than air
c.
higher; oxygen and a lower concentration of carbon dioxide than air
d.
lower; oxygen but the same concentration of carbon dioxide as air
In cystic fibrosis, parts of the respiratory tract can become clogged with mucus, inhibiting gas exchange. The area(s) of the respiratory tract where gases are directly exchanged is/are the a.
alveoli.
b.
bronchi.
c.
diaphragm.
d.
trachea.
The breaking open of alveoli in people who have emphysema decreases their rate of gas exchange because a.
there is a decrease in the distance between the air they inhale and their blood.
b.
there is less pressure in the lungs to force the oxygen to dissolve in their blood.
c.
the concentration of oxygen in their lungs becomes much greater than the concentration of oxygen in their blood.
d.
their lungs have less surface area available for diffusion.
26.
27.
28.
29.
The concentration of oxygen in blood plasma near an alveolus is lowered when a.
nearby red blood cells release carbon dioxide.
b.
oxygen diffuses into red blood cells and binds to hemoglobin.
c.
carbon dioxide diffuses into the alveolus.
d.
oxygen diffuses into the alveolus.
Which of the following is a characteristic of an organ used for gas exchange? a.
limited surface area
b.
waterproofing layers
c.
dry surfaces
d.
very thin tissues
When blood arrives at an alveolus, the concentration of a.
oxygen is lower in the alveolus than in the blood.
b.
carbon dioxide is higher in the alveolus than in the blood.
c.
carbon dioxide is higher in the blood than in the alveolus.
d.
carbon dioxide in the blood is equal to the concentration of oxygen in the alveolus.
Which of the following statements accurately describes the movement of water and waste within a nephron? a.
Water and waste both filter through the glomerulus; additional water is later secreted from capillaries.
30.
31.
32.
b.
Water and waste both filter through the glomerulus; water is later reabsorbed from capillaries.
c.
Only waste filters through the glomerulus; water is secreted by capillaries along the length of the nephron.
d.
Only water filters through the glomerulus; waste is secreted by capillaries along the length of the nephron.
Comparing the filtrate that is leaving the glomerulus to urine that is exiting the body would show that some substances—such as hydrogen ions and toxins—are more concentrated in the urine. This process can be explained by the fact that hydrogen ions and toxins are a.
reabsorbed by capillaries.
b.
secreted from capillaries.
c.
not filtered in nephrons.
d.
stored in nephrons.
If the glomerulus remained intact but other capillaries were not in close physical contact with nephrons, which of the following functions would NOT be lost? a.
secretion of toxins
b.
reabsorption of water and sugars
c.
filtration of plasma
d.
concentration of urine
Which of the following functions occurs in the urinary bladder but NOT in nephrons? a.
urine storage
b.
filtration
33.
34.
35.
36.
c.
secretion
d.
reabsorption
Which of the following processes is NOT a function of nephrons? a.
filtration of plasma
b.
reabsorption of water
c.
secretion of some toxins
d.
diffusion of oxygen into body cells
As you take this exam, which part of your brain is helping you decide which answer is correct? a.
cerebellum
b.
pons
c.
thalamus
d.
cerebral cortex
The peripheral nervous system (PNS) may NOT a.
stimulate muscles.
b.
integrate and process information.
c.
inhibit endocrine cells.
d.
stimulate organs.
If you accidentally rest your hand on a hot stove, sensory information will ultimately be relayed to the appropriate part of your brain by the a.
thalamus.
37.
38.
39.
b.
hypothalamus.
c.
cerebrum.
d.
cerebellum.
As Ben is driving to school one morning, the driver in front of him suddenly slams on her brakes and turns right without using her turn signal. Despite the potentially irritating situation, Ben remains calm because his __________ helped him control his emotions. a.
cerebrum
b.
thalamus
c.
limbic system
d.
reticular formation
If a person were to step on a nail with the right foot, which of the following things would NOT happen? a.
Sensory input from the right foot would be processed in the central nervous system.
b.
Motor output would travel to both the legs; the right foot would be raised and the left leg would stiffen to prevent falling over.
c.
Motor output from the right leg would be interpreted by the brain as sensory input.
d.
The thalamus would filter and sort the sensory input that is entering the brain.
Which of the following sensory receptor types is NOT found in humans? a.
chemoreceptors
b.
mechanoreceptors
c.
magnetoreceptors
d.
40.
41.
42.
43.
thermoreceptors
The sensory receptor types that provide information about body position and balance to help a person coordinate dance moves are a.
chemoreceptors.
b.
mechanoreceptors.
c.
magnetoreceptors.
d.
electroreceptors.
Sensory neurons that contain specialized membrane channels activated by moderate temperatures are a.
thermoreceptors.
b.
chemoreceptors.
c.
pain receptors.
d.
electroreceptors.
When eating dessert, a person notices the sweetness of sugar when __________ are stimulated. a.
chemoreceptors
b.
photoreceptors
c.
thermoreceptors
d.
mechanoreceptors
The external signals and information that are received by an organism are called a.
sensory receptors.
44.
45.
46.
b.
dendrites.
c.
stimuli.
d.
nodes.
The branched structures on a nerve cell that receive information are called a.
dendrites.
b.
axons.
c.
neurons.
d.
synapses.
Which of the following sequences correctly describes the pathway that a signal travels in a neuron? a.
cell body to axon to dendrite
b.
axon to dendrite to cell body
c.
dendrite to axon to cell body
d.
dendrite to cell body to axon
The structures that carry signals away from the cell body of a neuron are called a.
dendrites.
b.
axons.
c.
nuclei.
d.
synapses.
47.
48.
The __________ of a neuron contain(s) all of the structures, such as a nucleus, that are common to animal cells. a.
dendrites
b.
axons
c.
synapses
d.
cell body
The arrow in the following figure indicates a(n)
a.
cell body.
b.
dendrite.
c.
target cell.
d.
axon.
49.
According to the following infographic, the greatest organ transplant need is for an organ that is part of the __________ system.
a.
cardiovascular
b.
respiratory
c.
integumentary
d.
urinary
50.
51.
52.
53.
When the human rib cage is pulled in and the diaphragm relaxes to move upward, these actions compress the space in the chest cavity, causing a(n) a.
increase in lung volume and increase in pressure, forcing air into the lungs.
b.
decrease in lung volume and increase in pressure, forcing air out of the lungs.
c.
increase in lung volume and decrease in pressure, forcing air out of the lungs.
d.
decrease in lung volume and decrease in pressure, forcing air into the lungs.
As the diaphragm contracts and pulls downward and the rib cage expands outward, the volume of the lungs increases, which results in a(n) a.
an increase in pressure in the lungs, forcing air out of the lungs.
b.
a decrease in pressure in the lungs, forcing air out of the lungs.
c.
a decrease in pressure in the lungs, pulling air into the lungs.
d.
an increase in pressure in the lungs, pulling air into the lungs.
If you consume an excess amount of water soluble calcium (more than your body can use for proper functioning), you would expect to see a.
a decrease in calcium ions in the glomerular filtrate.
b.
an increase in calcium ions in the glomerular filtrate.
c.
a stable or homeostatic level of calcium ions in the glomerular filtrate.
d.
no change in the concentration of calcium ions in the glomerular filtrate.
The central nervous system is composed of the
a.
brain, spinal cord, retina, optic and olfactory nerves.
b.
eyes, ears, and sensory nerves other than the optic and olfactory nerves.
c.
brain, eyes, nose, and ears.
d.
brain and reflex arc.
54.
List the path for blood flow through the body, beginning and ending in the heart chamber that receives oxygen-poor blood returning from the body. Your answer should include the specific heart chambers, the lungs, and the body.
55.
Explain how oxygen is transported within blood.
56.
Describe two ways in which the structure of capillaries allows for gas exchange.
57.
Iron is an important part of a hemoglobin molecule. An individual diagnosed with iron-deficiency anemia has a low level of hemoglobin. Why would irondeficiency anemia cause an individual to feel tired?
58.
Trace the pathway of air from the nose to the site of gas exchange in the lungs.
59.
Capillaries and alveoli both have similar walls. How is the structure of each related to a common function?
60.
Paralysis in which muscles cannot contract is a severe symptom of the disease polio. Which muscles would be paralyzed if breathing stopped? Would paralysis of these muscles primarily affect inhalation or exhalation?
61.
Blood pressure in the glomerulus is normally higher than blood pressure approaching a nephron. What would happen if the normally high blood pressure in the glomerulus decreased?
62.
Describe how the central nervous system (CNS) and the peripheral nervous system (PNS) work together as a coordinated unit.
63.
People who experience chronic pain might argue that they would be better off without pain receptors. Explain why it is important for humans to have pain receptors.
64.
A city has a chain of command with an elected chief of police, who initiates actions by sending commands to the captain. The captain receives commands from the chief of police and then passes orders on to three lieutenants. Which figure(s) in this metaphor best represent(s) a neuron? Explain your reasoning.
65.
A city has a chain of command with an elected chief of police, who initiates actions by sending commands to the captain. The captain receives commands from the chief of police and then passes orders on to three lieutenants, who act on the orders. Which figure(s) in the chain of command best represent(s) a muscle? Explain your reasoning.
66.
Explain how a reflex arc is integrated with both the PNS and CNS but could possibly occur without registering pain in the brain.
67.
When the __________ of the heart contracts, blood is pumped into the systemic circuit.
68.
The force of blood pushing against the walls of blood vessels is called
69.
A nurse reports that a patient’s blood pressure is 118/78. The top number in this reading is referred to as __________ and the bottom number is referred to as __________.
70.
The majority of carbon dioxide is carried in the blood component called
71.
Blood vessels that are designed to carry blood under high pressure are called __________. Blood vessels that have thin, porous walls are called __________.
72.
The process of expelling carbon dioxide from the lungs and taking oxygen into the lungs is known as
73.
Gases move from an area of __________ concentration to an area of __________ concentration.
74.
Valuable solutes, such as sugar and small proteins, that enter a nephron are __________ by capillaries.
75.
The thalamus is part of the __________ nervous system.
76.
Receptors in the eye that provide vision are called
77.
The arrow in the following figure indicates the __________ of a neuron.
78.
The floor of the chest cavity is formed by a thick muscle known as the
79.
Nephron tubules connect to collecting ducts that drain into the _________, which carries urine to the urinary bladder.
80.
Brain tissue is composed of _________ matter containing the cell bodies of neurons and __________ matter containing the neuronal dendrites and axons forming a network of connected neurons.
81.
The retina is a grouping of nerves that connects directly to the optic nerve. The optic nerve, in turn, connects to the __________ without any connective nerve tissue. Hence, the retina and optic nerve are considered part of the __________.
82.
Determine whether each of the following structures is part of the upper respiratory system or lower respiratory system. a.
upper respiratory system
b.
lower respiratory system __ 1. __ 2. __ 3. __ 4. __ 5.
83.
nasal cavity bronchi trachea larynx pharynx
Match each receptor type to the following sensory experiences. a.
You get into the bathtub and realize the water is moderately cold.
b.
You are cleaning your bathroom with undiluted bleach, which causes a burning sensation in your nose.
c.
You are eating dinner and enjoying both the taste and smell of your meal.
d.
You wake up in the morning and enjoy the sight of a beautiful sunrise.
e.
You hear thunder during a storm. __ 1. __ 2. __ 3. __ 4. __ 5.
chemoreceptors photoreceptors mechanoreceptors thermoreceptors pain receptors
Answer Key Chapter 24
1. Answer:
C
2. Answer:
B
3. Answer:
C
4. Answer:
C
5. Answer:
B
6. Answer:
C
7. Answer:
D
8. Answer:
C
9. Answer:
A
10. Answer:
D
11. Answer:
D
12. Answer:
A
13. Answer:
A
14. Answer:
A
15. Answer:
B
16. Answer:
D
17. Answer:
C
18. Answer:
D
19. Answer:
A
20. Answer:
A
21. Answer:
A
22. Answer:
D
23. Answer:
C
24. Answer:
A
25. Answer:
D
26. Answer:
B
27. Answer:
D
28. Answer:
C
29. Answer:
B
30. Answer:
B
31. Answer:
C
32. Answer:
A
33. Answer:
D
34. Answer:
D
35. Answer:
B
36. Answer:
A
37. Answer:
C
38. Answer:
C
39. Answer:
C
40. Answer:
B
41. Answer:
A
42. Answer:
A
43. Answer:
C
44. Answer:
A
45. Answer:
D
46. Answer:
B
47. Answer:
D
48. Answer:
D
49. Answer:
D
50. Answer:
B
51. Answer:
C
52. Answer:
B
53. Answer:
A
54. Answer:
Blood flows from the right atrium, then travels through the right ventricle, the lungs, the left atrium, the left ventricle, the body, and back to the right atrium.
55. Answer:
Oxygen is transported bound to hemoglobin molecules in red blood cells. Each hemoglobin molecule can carry up to four molecules of oxygen. Carbon dioxide levels, blood pH, body temperature, environmental factors, and diseases can all affect this process.
56. Answer:
Capillaries are well designed for diffusion because they have thin, porous walls that enable gases to move through them easily. Capillaries also have a large surface area. The large surface area causes blood flow to slow and enables more body cells to contact capillaries.
57. Answer:
Hemoglobin is the oxygen-binding molecule found in red blood cells. Low levels of hemoglobin decrease the oxygen-carrying capacity of red blood cells and limit the amount of oxygen reaching body cells. Body cells require oxygen for cellular respiration.
58. Answer:
Air flows from the nasal cavity to the pharynx to the larynx to the trachea to the bronchi to the bronchioles and, finally, to the alveoli, where gas exchange occurs.
59. Answer:
Capillaries and alveoli both allow for the diffusion of gases. Their structure of thin, porous walls and large surface area facilitates diffusion of gases.
60. Answer:
The muscles to be affected would be the diaphragm and rib muscles and inhalation would not occur. The diaphragm and rib muscles contract during inhalation and relax during exhalation.
61. Answer:
Blood pressure controls filtration of plasma through the glomerulus and into the tubule. If blood pressure in the glomerulus decreases, filtration decreases and the body will fail to get rid of waste.
62. Answer:
The PNS receives both external and internal stimuli, and it transmits that information to the CNS for processing and integration. The CNS then generates a response, such as a motor response.
63. Answer:
Pain receptors are important in preventing damage to tissues. Without pain receptors, we could sustain life-threatening injuries. Feeling pain is adaptive because it makes us aware of an injury, motivates us to remove ourselves from the cause of that injury, and makes us less likely to suffer additional injuries by making us protect the injured part.
64. Answer:
The captain represents a neuron. The captain is receiving a signal or stimulus and then relaying this information on to other cells.
65. Answer:
The three lieutenants represent a muscle. The muscles complete an action in response to a signal from a neuron.
66. Answer:
During a reflex arc, a sensory stimulus/input from the PNS is processed in the spinal cord and an immediate signal is sent to motor output. To register pain in the brain, the signal must also travel up through the spinal cord to the thalamus to be sorted to the sensory area of the brain responsible for perceiving pain. If there is an interruption in the signal to the brain, such as a spinal cord injury above the area of the reflex arc, the reflex arc can be activated without perceived pain registering in the brain.
67. Answer:
left ventricle
68. Answer:
blood pressure
69. Answer:
systole; diastole
70. Answer:
plasma
71. Answer:
arteries; capillaries
72. Answer:
breathing
73. Answer:
high; low higher; lower
74. Answer:
reabsorbed
75. Answer:
central
76. Answer:
photoreceptors
77. Answer:
axon
78. Answer:
diaphragm
79. Answer:
ureter
80. Answer:
gray; white
81. Answer:
brain; CNS brain; central nervous system
82. Answer:
83. Answer:
1.
A
2.
B
3.
B
4.
A
5.
A
1.
C
2.
D
3.
E
4.
A
5.
B
Name: ___________________________ Class: _________________ Date: __________
Chapter 25 1.
2.
Which of the following statements about hormones is true? a.
They are distributed primarily through the lymphatic system.
b.
They may regulate certain developmental periods of life.
c.
They can only enter target cells via endocytosis.
d.
They have generalized functions but no specific functions.
Which of the following statements accurately describes hormonal signaling, as depicted in the following figure?
a.
Each endocrine cell has the ability to make all of an organism’s hormones.
b.
Hormones act on specific target cells.
c.
Hormones may diffuse into the circulatory system, but they cannot diffuse out of it.
d.
3.
4.
5.
Target cells signal each other using hormones.
The steroid hormones testosterone, estradiol, and progesterone can cross the plasma membrane to enter target cells and bind intracellular receptors to regulate gene expression. Based on this information, steroid hormones must be a.
large and polar.
b.
hydrophilic.
c.
cationic or anionic and water soluble.
d.
mainly nonpolar and hydrophobic.
By what mechanism do most hormones travel through the organism that produces them? a.
circulatory system
b.
diffusion
c.
nervous system
d.
urinary system
A single hormone molecule can have dramatic effects on a target cell because it a.
causes the cell to produce thousands of copies of the hormone.
b.
initiates a chain of events that amplifies its effect.
c.
causes the nuclear membrane to break down and expose DNA directly to the hormone.
d.
becomes surrounded by enzymes that transport it to the nucleus.
6.
7.
8.
9.
Antidiuretic hormone (ADH) is produced by the pituitary gland when the brain detects lower-than-optimum levels of water in the body. In the kidneys, ADH promotes the uptake of water, creating more concentrated urine. ADH travels from the pituitary gland to the kidneys through the __________ system. a.
nervous
b.
circulatory
c.
endocrine
d.
digestive
Most hormones are able to produce their intended effects at extremely low concentrations in the body due to their a.
ability to bind to all cells in the body.
b.
production of copies of themselves within the bloodstream.
c.
specificity to receptors on target cells.
d.
production by exocrine glands in the body.
Once a hormone enters the bloodstream, it a.
is usually broken down within minutes.
b.
remains active for months.
c.
is broken down after it has performed its function on the target cells.
d.
produces enzymes that affect target cells.
Which of the following statements best explains how one hormone can regulate several different developmental events? a.
One hormone can affect different types of target tissues in different ways.
10.
b.
A hormone can migrate to a gland, where the endocrine system reshapes it for a different use.
c.
Once a steroid hormone attaches to a receptor on the surface of a cell, it becomes internalized and can alter gene expression.
d.
Hormones are made up of molecules that separate once they are inside the cell to signal the development of different aspects of sexual maturity.
Which of the following statements accurately describes how hormones can affect a cell, as illustrated in the accompanying figure?
a.
Hormones often trigger the shearing of DNA.
b.
Hormones must travel into the nucleus to effect gene expression.
11.
12.
13.
c.
Intracellular receptors increase the export of important signaling molecules when they are bound with hydrophilic hormones.
d.
Hormones can produce many changes in a target cell, even at low concentrations.
The primary role of the immune system’s first line of defense is to a.
mark pathogens for destruction.
b.
act as a barrier to prevent the entry of pathogens.
c.
kill intracellular pathogens.
d.
stimulate fever and inflammation.
Which of the following organs coordinate(s) communication between the endocrine system and the nervous system? a.
thyroid
b.
pancreas
c.
adrenal glands
d.
hypothalamus
A nursing human newborn receives some protection against pathogens because a.
newborns acquire memory cells during the birthing process.
b.
breastmilk provides preformed antibodies from the mother.
c.
breastmilk triggers an active immune response.
d.
newborns have more active innate immune responses than adults.
14.
15.
16.
17.
After receiving a vaccine a person, begins to produce antibodies. This demonstrates a(n) __________ immune response. a.
innate
b.
active
c.
secondary
d.
passive
The final event that would occur after an influenza virus has crossed a respiratory membrane in a vertebrate is a.
production of an antibody.
b.
movement of phagocytes into tissues.
c.
inflammation.
d.
production of memory cells.
Which of the following is an example of the immune system’s second line of defense? a.
the low pH environment of the stomach
b.
saliva containing antimicrobial enzymes
c.
macrophages engulfing pathogens during inflammation
d.
tears containing antimicrobial enzymes
Which of the following is a component of the immune system’s first line of defense? a.
antibodies
b.
histamine
c.
T cells
d.
18.
19.
20.
21.
earwax
A component of the immune system’s third line of defense is/are a.
T cells.
b.
mucus.
c.
macrophages.
d.
platelets.
A component of innate immunity is the a.
production of sensitized T cells.
b.
production of antibodies from B cells.
c.
administration of vaccinations.
d.
acidic environment in the digestive system.
What prevents pathogens from entering our bodies through the delicate tissues of the nose? a.
The lining of the nose has a low pH that creates an inhospitable environment for most pathogens.
b.
The tubes within the nose are lined with mucus that traps pathogens and is then removed from the respiratory system.
c.
The cells of the nose are covered by several layers of dead cells that prevent pathogens from reaching living lung tissue.
d.
Certain cells in the nose produce toxins that paralyze pathogens before they can infect the body.
In the vertebrate immune response to a pathogen, which of the following would occur first?
22.
23.
24.
a.
inflammation
b.
external defenses
c.
fever
d.
adaptive immunity
White blood cells of the innate immune response __________, whereas white blood cells of the adaptive immune response __________. a.
may function in inflammation; may secrete antibodies
b.
target infected cells; induce tear production
c.
produce memory cells; stimulate fever
d.
differentiate into T cells; reduce blood pressure
A puncture wound is difficult for the immune system to respond to because the a.
blood vessels will lose too much blood.
b.
first and second lines of defense have been bypassed.
c.
acidity of the skin is compromised.
d.
salty secretions of sweat glands cause infection.
Which of the following is likely to be first on the scene of a bacterial infection? a.
B cells
b.
neutrophils
c.
T helper cells
d.
killer T cells
25.
26.
27.
28.
Why is it important that white blood cells are able to travel outside the human circulatory system? a.
To form a complement, white blood cells must leave the circulatory vessels.
b.
White blood cells are the antibodies that target parasites.
c.
Pathogens may be found in other areas of the body besides the circulatory vessels.
d.
White blood cells must leave the circulatory system in order to return red blood cells to the circulatory vessels.
White blood cells of the adaptive immune response provide what advantage that is lacking in white blood cells of the innate immune response? a.
rapid response time
b.
memory
c.
decreased specificity
d.
barriers
The body innately responds to tissue damage by mounting an immediate and coordinated sequence of events called the __________ response. a.
specific immune
b.
prostaglandin
c.
inflammatory
d.
histamine
At the site of a wound or cut, platelets combine with proteins in our blood to form a.
macrophages.
29.
30.
31.
b.
antibodies.
c.
prostaglandins.
d.
blood clots.
Which of the following prevents both blood loss and the invasion of pathogens in vertebrates? a.
the formation of blood clots
b.
phagocytosis
c.
humoral immunity
d.
cell-mediated immunity
Which of the following events is the first to occur during inflammation? a.
Spaces form in blood vessels to enable phagocytes to pass.
b.
The wound is repaired to ease blood loss.
c.
Damaged cells release key signaling molecules.
d.
Phagocytes engulf and digest invading bacteria.
In the stage of inflammation that occurs after the one shown in the following image, a(n) __________ will arrive.
32.
a.
platelet
b.
T cell
c.
macrophage
d.
antibody
Which of the following is a molecule that makes blood vessels near a wound more porous so other cells can enter the area? a.
a platelet
b.
histamine
c.
a cytokine
d.
an adrenal hormone
33.
34.
35.
Substance A, circled in the following figure, is likely to be removed by which of the following?
a.
red blood cells
b.
cytokines
c.
lymphocytes
d.
macrophages
Which of the following is found in both invertebrates and vertebrates? a.
T cells
b.
B cells
c.
antibodies
d.
innate immunity
The most immediate response seen in a vertebrate when a pathogen invades is
36.
37.
38.
a.
the production of antibodies.
b.
an innate response.
c.
blood clotting.
d.
an increase in the number of T cells.
Which of the following statements correctly describes the immune response when the invading organism is a virus? a.
The antigen molecules on the viral DNA enable the immune system to prevent the infection.
b.
Lymphocytes are not involved in the immune response.
c.
The lack of nucleic acid in a virus complicates the immune response.
d.
Lymphocytes respond to infected human cells rather than to the virus itself.
Each T cell and each B cell binds to only one specific type of a.
antibody.
b.
antigen.
c.
neutrophil.
d.
histamine.
Which of the following is most likely to be the target of a human T cell? a.
antibodies
b.
pathogens suspended in lymph
c.
bacterial cells circulating through blood
d.
virally infected human cells
39.
40.
41.
42.
Which of the following organs would be LEAST likely to contain mature lymphocytes? a.
tonsils
b.
liver
c.
spleen
d.
appendix
Cell-mediated immunity is regulated by the activities of a.
antibodies.
b.
neutrophils.
c.
adrenaline.
d.
T cells.
Activated B cells are responsible for a.
producing antibodies that bind to pathogens.
b.
generating pathogens.
c.
increasing systemic body temperature.
d.
sealing breaks in the skin via clotting reactions.
Memory cells a.
include B cells and T cells that remain in the body for long periods of time after the first exposure to a pathogen.
b.
are macrophages that store copies of antibodies for decades.
c.
are T cells that continue to target and remove cells long after the primary response has ended.
d.
are removed from the body once the primary response is no longer needed.
43.
44.
45.
46.
Which of the following statements about immune response is correct? a.
The primary immune response develops slowly, over 2 weeks or more.
b.
Secondary immune responses lengthen the reaction time to the same pathogen during subsequent exposures.
c.
Primary immune responses involve the use of immune memory.
d.
The secondary immune response involves nonspecific mechanisms.
During a primary immune response, a.
antibodies are immediately made.
b.
nonspecific immunity may be of great benefit to the organism.
c.
the immune system has encountered the pathogen previously.
d.
the production of memory cells is blocked.
The term that is most closely associated with the secondary immune response is a.
“memory.”
b.
“slow.”
c.
“innate.”
d.
“weak.”
In the vertebrate immune response to a pathogen, which of the following events would happen last? a.
establishment of skin and mucous membranes
b.
neutrophils and macrophages engulfing pathogens
c.
elevation of body temperature in response to pathogens
d.
47.
48.
development of memory cells
Wim Hof, the “Iceman,” has successfully used cold exposure, breathing techniques, and meditation as a way to suppress an immune response in young, physically fit men. Which of the following individuals would be most likely to benefit from his techniques? a.
A 15-year-old female with an autoimmune disorder.
b.
A 45-year-old male with heart disease.
c.
An 18-year-old male with an autoimmune disorder.
d.
Any individual with an autoimmune disorder.
A young person with a known heart condition that is worsened by a rapid heartbeat decides to begin an exercise regime. Adrenaline is a stress hormone that has effects that include speeding up the heart rate. According to the information in the following infographic, what would be the best advice for this individual’s exercise regime?
49.
a.
Don’t exercise at all.
b.
Only exercise during the early morning hours.
c.
Only engage in low-intensity exercise.
d.
Only exercise during the mid-afternoon.
According to the information in the following infographic, an individual attempting to decrease cortisol levels to the lowest level possible should exercise for __________ minutes.
50.
a.
0
b.
30
c.
120
d.
150
In hormonal signaling, are target cells typically close to or far away from endocrine cells? Explain your answer.
51.
Hormones travel throughout the body and may potentially come in contact with any cell type. Why do some body cells respond to a particular hormone while other body cells do not?
52.
In preparation for your biology exam, you study endocrine signaling with a classmate. Your classmate suggests that all forms of signaling require receptors in order to affect target cells. Do you agree? Explain why or why not.
53.
Describe the location(s) of receptors for hormones that are hydrophilic. How does this differ from hormones that are hydrophobic? Explain your answer.
54.
Create a list of components of the immune system’s first, second, and third lines of defense. Each line of defense should include at least two components.
55.
How do phagocytes of the innate immune system differ in function from lymphocytes of the adaptive immune system?
56.
Based on the information provided in the following figure, explain the events that occur during inflammation and blood clotting. In addition, label the following structures in the figure: neutrophil, platelet, macrophage, and cytokine.
57.
What two white blood cell types play a role in adaptive immunity? Describe the two types of adaptive immunity that these cell types control.
58.
How do B cells and T cells differ in their responses to pathogens?
59.
Describe the two stages of adaptive immunity. How do these stages compare in terms of response time and the symptoms seen in an individual exposed to a pathogen?
60.
Explain how active immunity and passive immunity differ.
61.
When doctors administer the Mantoux skin test to determine whether a patient has tuberculosis (TB), they expose patients to small amounts of protein from the microorganism that causes TB and then check for a reaction to these proteins a few days later. Patients who have had previous
TB antigen exposure (and infection) will develop localized swelling at the site where the proteins were injected. The presence of swelling and amount of swelling are observed and measured to determine whether the test is positive. Explain why this test measures a secondary (versus primary) exposure to antigens. Which aspects of this test demonstrate secondary exposure?
62.
Explain how the vertebrate immune system works to prevent the entry of invading pathogens and then destroy them. Include the mechanisms of the first, second, and third lines of defense in your answer.
63.
The hormone-producing tissues of animals make up the __________ system.
64.
The cells with which a hormone interacts are called __________ cells.
65.
Hormones often alter __________ by turning a certain gene or group of genes on or off.
66.
Because steroid hormones are __________, they are able to pass through a cell’s plasma membrane without the assistance of membrane transport proteins.
67.
__________ are components of the immune system’s third line of defense that secrete antibodies.
68.
White blood cells that engulf and destroy pathogens in a nonspecific manner are called
69.
Before macrophages begin to phagocytize bacteria, __________ usually reach the wound site.
70.
Neutrophils and macrophages function in the process of __________, which traps and removes pathogens at the site of a wound.
71.
After the initial exposure to a disease-causing organism, __________ cells remain in the body and help the immune system recognize that particular organism during a second exposure.
72.
In a(n) __________ response, B cells and T cells only recognize one particular type of pathogen.
73.
On the first exposure to a pathogen, a(n) __________ immune response is triggered.
74.
Match the chemical, cell, or tissue with the function it performs in the immune response. a.
macrophages
b.
mucous membranes
c.
cytokines
d.
B cells
e.
lymph nodes
f.
platelets __ 1. secrete antibodies in response to foreign molecules __ 2. clotting factors that prevent excess blood loss
__ 3. phagocytize pathogens during inflammation __ 4. sites where trapped pathogens initiate adaptive immune responses __ 5. physical barriers lining the respiratory and digestive system that prevent the invasion of pathogens __ 6. molecules secreted by immune cells for initiation and regulation of immune responses
Answer Key Chapter 25
1. Answer:
B
2. Answer:
B
3. Answer:
D
4. Answer:
A
5. Answer:
B
6. Answer:
B
7. Answer:
C
8. Answer:
C
9. Answer:
A
10. Answer:
D
11. Answer:
B
12. Answer:
D
13. Answer:
B
14. Answer:
B
15. Answer:
D
16. Answer:
C
17. Answer:
D
18. Answer:
A
19. Answer:
D
20. Answer:
B
21. Answer:
B
22. Answer:
A
23. Answer:
B
24. Answer:
B
25. Answer:
C
26. Answer:
B
27. Answer:
C
28. Answer:
D
29. Answer:
A
30. Answer:
C
31. Answer:
C
32. Answer:
B
33. Answer:
D
34. Answer:
D
35. Answer:
B
36. Answer:
D
37. Answer:
B
38. Answer:
D
39. Answer:
B
40. Answer:
D
41. Answer:
A
42. Answer:
A
43. Answer:
A
44. Answer:
B
45. Answer:
A
46. Answer:
D
47. Answer:
C
48. Answer:
C
49. Answer:
D
50. Answer:
Endocrine cells are often located a considerable distance away from the target cells they affect. Chemical signaling molecules, called hormones, may be deposited in the bloodstream for delivery to target cells.
51. Answer:
In order to respond, a target cell must have receptors with which a particular hormone can bind. Cells that lack a receptor for a hormone will not respond.
52. Answer:
Your classmate is correct, because all signaling molecules will require a receptor to affect the target cells. Hydrophobic molecules such as sex hormones use internal receptors, called intracellular receptors, to send signals to the nucleus, whereas hydrophilic molecules interact with target cells using receptors located at the surface of the cell. Hydrophobic molecules may move directly through the plasma membrane, because they are nonpolar. The charge on hydrophilic hormones prevents their direct uptake by target cells.
53. Answer:
Hormones that are hydrophilic are not able to pass freely through the plasma membrane of a cell; receptors for hydrophilic hormones are found on the surface of the plasma membrane. Hydrophobic membranes can diffuse freely through the plasma and, therefore, interact with receptors found within a cell.
54. Answer:
First line of defense: skin, mucous membranes, tears containing antimicrobial enzymes, nose hairs, saliva, pH of gastric juices Second line of defense: inflammation, fever, phagocytosis Third line of defense: B cells, antibodies, T cells, memory cells
55. Answer:
Macrophages and neutrophils are phagocytic cells that engulf pathogens in a nonspecific manner. They do not have memory and they fail to elicit specificity in their responses. Lymphocytes, on the other hand, have memory and enact a specific response to a particular pathogen. In addition, their ability to respond to a particular pathogen improves with time.
56. Answer:
Inflammation may be initiated by a break in the skin, as shown in the figure. Tissue damage stimulates the release of cytokines and histamine, causing blood vessels near the site of damage to become leaky. Neutrophils, which are the first phagocytes to enter the tissue from blood vessels, begin to engulf and digest bacteria that are introduced by the wound. Macrophages arrive later and engulf even larger masses of agglutinated pathogens. Platelets that exit blood capillaries prevent blood loss, forming a clot at the wound.
57. Answer:
Adaptive immunity is divided into (1) antibody-mediated immunity, which is controlled by white blood cells called B cells and involves the production of antibodies, and (2) cell-mediated immunity, which is controlled by white blood cells called T cells and involves the recognition of cells that are infected by a virus or are cancer cells.
58. Answer:
B lymphocytes (B cells) and T lymphocytes (T cells) are components of the immune system’s third line of defense. In antibody-mediated immunity, activated B cells secrete antibodies that target external pathogens for destruction. T cells play diverse roles in cell-mediated immunity, but they generally act in targeting infected host cells. They protect the body from pathogens that are capable of entering and infecting cells.
59. Answer:
The first stage is a primary immune response. This stage occurs the first time an individual is exposed to a pathogen. The primary immune response is much slower than a secondary immune response and the individual will become ill. A secondary immune response occurs when an individual has already experienced a primary immune response and then comes in contact with the same pathogen. The secondary immune response is much quicker and will prevent symptoms of illness. The secondary immune response is due to the presence of “memory” cells.
60. Answer:
Active immunity occurs when an individual’s immune system responds to a pathogen and produces antibodies in response. Passive immunity occurs when an individual receives antibodies made by someone else. An individual with passive immunity does not produce the antibodies that are providing protection.
61. Answer:
The skin test measures secondary exposure to the pathogen since the result is “read” within a week of exposure. If significant swelling occurs at the site of TB protein injection on the skin, it indicates that the patient’s immune system has been exposed to the pathogen previously. A rapid immune response will ensue because the body has a pool of memory cells that recognize the TB antigens. Also, the size of the swelling is significant, since a large swelling demonstrates a robust immune response. This is another aspect of secondary exposure; the immune system provides a stronger response on subsequent exposure. A primary immune response would typically require two weeks or more to develop.
62. Answer:
The first line of defense provides a physical and chemical barrier to pathogens. In the second line of defense, the pathogen will result in inflammation, blood clotting, and a subsequent fever. Inflammation destroys pathogens that are walled off in tissues, using clotting factors and other substances. Molecules that are associated with the pathogens may stimulate the increase in body temperature (fever). This response may signal that an infection has occurred and may prepare cells to respond to potential circulating pathogens. In the third line of defense, exposure of pathogens to lymphocytes initiates adaptive immunity with the subsequent release of antibodies from activated B cells or the destruction of infected cells (cellmediated immunity).
63. Answer:
endocrine
64. Answer:
target
65. Answer:
gene expression
66. Answer:
hydrophobic
67. Answer:
B cells
68. Answer:
phagocytes
69. Answer:
neutrophils
70. Answer:
inflammation
71. Answer:
memory
72. Answer:
specific
73. Answer:
primary
74. Answer:
1.
D
2.
F
3.
A
4.
E
5.
B
6.
C
Name: ___________________________ Class: _________________ Date: __________
Chapter 26 1.
2.
3.
A cotyledon is the a.
embryonic leaf of a seedling.
b.
reproductive organ of a plant.
c.
food-storing organ found in the seeds of flowering plants.
d.
type of ground tissue in the mechanical reinforcement of stem structure.
Which of the following is NOT a function of stems? a.
positioning the leaves for photosynthesis
b.
supporting the overall shape of the plant
c.
water and mineral absorption
d.
vertical growth
Examine the following diagram of a root tip. Which letter in the diagram indicates the zone of cell division?
4.
a.
A
b.
B
c.
C
d.
D
Which combination of conditions will cause many plants’ stomata to open? a.
high moisture and daylight
5.
6.
7.
b.
high moisture and darkness
c.
dehydration and darkness
d.
dehydration and daylight
A tiny insect known as an aphid obtains nutrition by poking a mouthpart into the stem of a plant. Once the aphid’s mouthpart is inserted, fluid from the plant is pushed through the aphid’s digestive tract by pressure. The aphid’s mouthpart has most likely penetrated the plant’s a.
xylem.
b.
phloem.
c.
stomata.
d.
shoot system.
A botanist is asked to identify which plant organ is the source of an unknown sample. A cross section shows that the vascular tissue is found in a central column in the center of the structure, with the ground tissue outside the vascular cylinder. Which plant organ is the source of this sample? a.
bud
b.
leaf
c.
root
d.
stem
A florist places a cut white carnation into a glass in which red food coloring has been dissolved in water and the red color travels up the flower into the petals. The color is most likely moving through the a.
phloem.
b.
xylem.
8.
c.
dermal tissue.
d.
ground tissue.
Examine the plant in the following figure. The plant is most likely a dicot, based on the presence of
9.
10.
11.
a.
a taproot and the venation pattern in the leaves.
b.
a fibrous root system.
c.
five leaves.
d.
both root systems and shoot systems.
A plant has a flower with three petals and leaves with parallel veins. This plant can be classified as a a.
cotyledon.
b.
dicot.
c.
monocot.
d.
tricot.
Water and nutrients are absorbed from soil by a.
stomata.
b.
root hairs.
c.
root caps.
d.
xylem in taproots.
Worldwide, more than 80 percent of the calories consumed by humans come from a.
angiosperms.
b.
conifers.
c.
ferns.
d.
mosses.
12.
13.
14.
15.
Which of the following is NOT a plant hormone? a.
abscisic acid
b.
ethylene
c.
gibberellin
d.
nicotine
Which of the following plant hormones contributes most to fruit ripening? a.
auxins
b.
cytokinins
c.
abscisic acid
d.
ethylene
The gene-for-gene recognition immune response involves a.
plant alleles that attack matching alleles in pathogens.
b.
crossing-over between plant alleles and pathogen alleles.
c.
production of antibodies by plants in response to antigens produced by pathogens.
d.
production of proteins by plants that protect against pathogens with a particular genetic makeup.
The shoot of a plant that is tipped on its side will grow upward again because of the actions of a.
auxins.
b.
cytokinins.
c.
abscisic acid.
d.
ethylene.
16.
17.
18.
19.
Which of the following can help a plant deter herbivores, insects, or bacteria? a.
dermal hairs on the roots
b.
the production of auxin
c.
dermal hairs on the stem and leaves
d.
the production of cytokinin
A bean plant has a stem that does not grow in the same direction as those of all the other bean plants. This plant stem branches often, and the branches grow in random directions. This plant most likely lacks which of the following hormones? a.
auxins
b.
cytokinins
c.
abscisic acid
d.
ethylene
After a particularly hot and dry summer, plants are likely to contain elevated levels of a.
auxins.
b.
cytokinins.
c.
abscisic acid.
d.
ethylene.
Plant A produces more roots and fewer shoots than healthy plant B. Plant A most likely has a.
higher-than-normal concentrations of both auxins and cytokinins.
20.
21.
22.
b.
lower-than-normal concentrations of both auxins and cytokinins.
c.
higher-than-normal concentrations of auxins and lower-than-normal concentrations of cytokinins.
d.
lower-than-normal concentrations of auxins and higher-than-normal concentrations of cytokinins.
Plant growth aboveground can be accomplished by adding new __________ units. a.
leaf
b.
bud
c.
stem
d.
bud-stem-leaf
Diploid sporophytes that grow from a zygote formed by the union of sperm from anther-produced, wind-born pollen from one plant fertilizing the egg of another plant is likely to be genetically a.
unique from both the pollen-producing plant and the egg-producing plant.
b.
unique from the pollen-producing plant but not from the egg-producing plant.
c.
unique from the egg-producing plant but not from the pollen-producing plant.
d.
identical to both the pollen-producing plant and the egg-producing plant.
Which of the following plant types undergoes secondary growth? a.
both trees and grasses
b.
trees but not grasses
23.
24.
25.
c.
grasses but not trees
d.
neither trees nor grasses
Which of the following plants is a monocot? a.
carnation
b.
grass
c.
oak tree
d.
rose
Why is indeterminate growth beneficial to plants? a.
Indeterminate growth enables plants to respond to changing environmental conditions and produce new structures when it is beneficial to the plant.
b.
Animals commonly eat entire plants.
c.
Indeterminate growth enables plants to grow larger than needed for survival.
d.
Indeterminate growth enables plants to avoid reproducing when environmental conditions are unfavorable.
Most plants have indeterminate growth. This means that plant growth can respond to environmental conditions and that a.
they are perennials.
b.
they may complete their life cycles in one, two, or three years.
c.
they reach maturity at variable times based on external signals.
d.
the final form of the plant is not entirely predictable.
26.
27.
28.
29.
Copper is an example of a __________ by plants. a.
toxin produced
b.
hormone produced
c.
macronutrient needed
d.
micronutrient needed
Fertilizers that contain a variety of nutrients, are likely to a.
have higher concentrations of macronutrients than micronutrients.
b.
have lower concentrations of macronutrients than micronutrients.
c.
have equal concentrations of macronutrients and micronutrients.
d.
contain micronutrients but not macronutrients.
Plants get most of their micronutrients from a.
air.
b.
soil.
c.
photosynthesis.
d.
respiration.
A typical fertilizer contains no carbon, because carbon is a.
not a plant nutrient.
b.
plentiful in all soils.
c.
obtained from the atmosphere as carbon dioxide.
d.
produced when the plant metabolizes nitrogen.
30.
31.
32.
33.
Like other organisms, plants are composed of proteins, lipids, carbohydrates, and nucleic acids. Based on this information, which of the following would be a macronutrient? a.
zinc
b.
iron
c.
copper
d.
carbon
Fertilizers generally have three numbers on the label (for example, 20:10:20). These numbers refer to the three most essential plant nutrients, which are (in the order in which the numbers are listed) a.
nitrogen, phosphorus, and potassium.
b.
nitrogen, calcium, and magnesium.
c.
oxygen, hydrogen, and calcium.
d.
potassium, phosphorus, and iron.
Which of the following crops is likely to require the LEAST addition of fertilizers? a.
apples
b.
carrots
c.
tomatoes
d.
wheat
Pollen is produced in the a.
ovules.
b.
anthers.
c.
endosperm.
d.
34.
35.
36.
37.
cotyledon.
In the plant life cycle, meiosis occurs when the a.
gametophyte produces gametes.
b.
sporophyte produces spores.
c.
egg and the sperm fuse to form a zygote.
d.
germinating spore grows to become the gametophyte.
In plants, the diploid stage of the life cycle directly produces __________ through __________. a.
spores; meiosis
b.
spores; mitosis
c.
gametes; meiosis
d.
gametes; mitosis
After plant gametes fuse, the zygote that is formed undergoes mitosis to produce the a.
spores.
b.
sporophyte.
c.
gametophyte.
d.
flower.
The flower is an organ that is found on the __________ of a flowering plant. a.
cotyledon
b.
gametophyte
38.
39.
40.
41.
c.
sporophyte
d.
anther
Because its cells are diploid, the ovule is a part of the a.
gametophyte.
b.
sporophyte.
c.
carpel.
d.
anther.
During pollination, pollen is moved from a.
the endosperm to the ovary.
b.
the anther to the ovary.
c.
the ovary to the anther.
d.
the endosperm to the anther.
Anthers are typically attached to filaments and elevated within the flower to a.
improve the transfer of pollen to a pollinator.
b.
improve the transfer of pollen to the adjacent ovary.
c.
prevent pollen from becoming stuck in the nectar.
d.
prevent pollen from being blown away from the flower.
A flower may be specialized to attract bat pollinators and discourage insect pollinators by a.
opening at night.
42.
43.
44.
b.
producing a sweet scent.
c.
having a flat overall shape.
d.
having variegated petal colors.
The purpose of brightly colored flower petals is to a.
be aesthetically pleasing.
b.
help animals identify edible seeds.
c.
be the location of spore production.
d.
help pollinators find similar flowers.
Which of the following animals is LEAST likely to be a pollinator? a.
butterfly
b.
bat
c.
rattlesnake
d.
human
Flowers, like the ones in the following figures, display spectacular colors, shapes, and odors, in combination with food rewards such as nectar, to convince pollinating animals to visit several flowers of the same species and transfer pollen for reproduction. How might a flower be specialized to attract hummingbird pollinators (right) and discourage insect pollinators (left)?
45.
46.
a.
having brightly colored petals
b.
producing sugary nectar
c.
hanging downward from the branch tips
d.
organizing its petals into a flat landing surface
Horticulturists often remove the anthers from flowers. The purpose of this technique is to a.
promote branching.
b.
prevent self-fertilization.
c.
increase egg production.
d.
attract pollinators.
What is the mechanism of seed dispersal for the dandelion? a.
wind
b.
water
c.
animals
d.
humans
47.
48.
49.
A plant whose seeds are dispersed by animals most likely produces __________ seeds. a.
small, soft
b.
small, light
c.
large, dense
d.
large, sugary
Blackberry and cherry seeds are most likely dispersed far and wide because the seeds are encased in a.
a lightweight fruit that is dispersed on the wind.
b.
a sweet and tasty fruit that will be eaten by animals, which will cause the seeds to be dropped somewhere else later on.
c.
a lightweight floating fruit that is still rugged enough to float away to a far-off island.
d.
dry shells with sticky protrusions that become entangled in animal fur as the animal passes by. Later, the seeds fall off the animal in a new location.
Some fruits may produce low-density seeds that float on water because plants that produce those types of seeds live near or in a.
a very dry area, and producing seeds that fly away on the air would give them an advantage at dispersing their seeds.
b.
areas with large grazing animal populations that would easily consume large seeds and disperse the seeds later in a new location.
c.
water, and producing seeds that can float on the water gives them an advantage at dispersing their seeds in distant locations.
d.
grassy locations with short furry animals that pick up the prickly seeds in their fur. This would give them the advantage for seed dispersal and survival.
50.
51.
Genetically modified crops are similar to crops that were derived through selective breeding in that they both can
a.
provide humans with crops that have a unique set of desirable genetic characteristics.
b.
eliminate all undesirable genes from the crops.
c.
always produce the most abundant and long-lasting fruit.
d.
always create undesirable and even harmful characteristics in the fruit produced by the crops.
In a leaf, why is having the ground tissue—rather than the vascular tissue— directly under the dermal tissue a better strategy?
52.
The plant hormone auxin causes cells in the shoot to elongate (grow longer) faster. Auxin is involved in the phototropic response because it moves from one side of the plant to the other in response to light. Discuss the direction in which auxin moves (toward light or away from light) and how this brings about the phototropic response.
53.
What happens to ripening when a green banana is put in a paper bag?
54.
Explain why a fruit that produces abundant ethylene would be more likely to reproduce in a location away from the original plant.
55.
What is the source of the mass of carbon in a mighty oak tree? How does the carbon transition from its source to become the mass of the tree?
56.
Plants generally require having a root system that is approximately the same size as its shoot system. The hormones auxins and cytokinins work together to balance the root-to-shoot ratio in plants. Identify where each of these hormones is produced (in the root or in the shoot) and how they function to maintain this balance.
57.
Compare and contrast plant macronutrients and micronutrients and how plants obtain them.
58.
Compare and contrast the products of meiosis and mitosis in the plant life cycle.
59.
How do flowering plants benefit from forming diploid zygotes through the fertilization of two haploid gametes from different plants? How are these benefits passed on to new plants?
60.
What are the advantages and disadvantages of animal pollination versus wind pollination?
61.
Why would a horticulturist remove the anthers from some of flowers, thus preventing self-pollination and fertilization?
62.
By referring to the following images, discuss the similarities and differences between the ways some trees, like maples, disperse their seeds compared to plants like milkweed and dandelion.
63.
Propose why and how the seeds of some plants (such as corn, wheat, beans, and cherries) would be artificially selected for and dispersed by humans.
64.
Since 1996, the total land area used to grow genetically modified (GM) crops has expanded dramatically. Most of these crops are enhanced with the insertion of a gene that imparts insect resistance or herbicide tolerance. Broad scientific consensus has concluded that food derived from GM crops poses no greater risk to health than food from nonmodified crops. Discuss how inserting a gene that imparts insect resistance into a crop plant could be beneficial to the overall quality of the environment/ecosystem.
65.
Plants are protected from herbivores by __________ tissue, which also controls gas exchange.
66.
The bulk of the plant body is __________ tissues; these tissues perform a variety of functions such as physical support, wound repair, and photosynthesis.
67.
The hormone __________ is a gas produced by ripening fruit, and it can induce other fruits nearby to ripen.
68.
Increases in sporophyte length as a result of cell division and elongation at apical meristems are called __________ growth.
69.
The leaves of wild parsnip contain chemicals commonly called psoralens that cause people who have come in contact with it and then spent time in the sun to have “phyto-photo-dermatitis,” or a dramatic plant sunburn. The psoralens also appear to have an antifungal property. This is an example of plant __________ defenses.
70.
The repeated addition of bud-stem-leaf units above ground or new lateral roots below ground is referred to as __________ in plants.
71.
A plant’s physiological response to night length is called
72.
The nutrients nitrogen, phosphorus, potassium, calcium, sulfur, and magnesium are required in relatively large amounts; this group of nutrients is called the plant
73.
Spores undergo mitosis to form the haploid __________, one of the two stages in the life cycle of plants.
74.
Most people are familiar with the __________ generation of plants. This is the dominant form of flowering plant species and includes the rose bush, the oak tree, and the cornstalk.
75.
The transfer of the male gametophyte from an anther to a stigma is called
76.
Meiosis in the __________ of the flower produces male spores.
77.
Low-growing, flowering plants that produce seeds encased within a prickly covering, like a sandbur, are likely to use __________ to disperse their seeds.
78.
Plants such as cattails, coconut trees, and lotus live in wetlands, or near tropical beaches, ponds, or streams. They produce seeds that range in size
from small to large, but the seeds are not very dense. These seeds are most likely dispersed by
79.
Match each plant structure to the function that the structure performs. a.
This structure transports water.
b.
This structure transports sugars.
c.
This structure controls gas exchange.
d.
This structure is a protective outer covering.
e.
This structure conducts photosynthesis. __ 1. __ 2. __ 3. __ 4. __ 5.
80.
dermal tissue ground tissue phloem stomata xylem
Match each plant hormone with its primary function in the plant. a.
Involved in phototropism and gravitropism, these hormones are necessary for the cell elongation that results in growth toward or away from light or gravity .
b.
These hormones promote shoot formation and typically decline sharply just before plants drop their leaves in the fall.
c.
These hormones not only stimulate seeds to germinate, they increase stem growth by promoting cell elongation and increased cell division.
d.
This hormone helps plants survive drought, cold, heat, and other environmental stresses.
e.
This hormone stimulates the ripening of fruit and activates enzymes responsible for converting starches to sugars thus producing a sweeter fruit. __ 1. Abscisic acid (ABA) __ 2. Auxins __ 3. Cytokinins
__ 4. Ethylene __ 5. Gibberellins
Answer Key Chapter 26
1. Answer:
A
2. Answer:
C
3. Answer:
C
4. Answer:
A
5. Answer:
B
6. Answer:
C
7. Answer:
B
8. Answer:
A
9. Answer:
C
10. Answer:
B
11. Answer:
A
12. Answer:
D
13. Answer:
D
14. Answer:
D
15. Answer:
A
16. Answer:
C
17. Answer:
A
18. Answer:
C
19. Answer:
C
20. Answer:
D
21. Answer:
A
22. Answer:
B
23. Answer:
B
24. Answer:
A
25. Answer:
D
26. Answer:
D
27. Answer:
A
28. Answer:
B
29. Answer:
C
30. Answer:
D
31. Answer:
A
32. Answer:
A
33. Answer:
B
34. Answer:
B
35. Answer:
A
36. Answer:
B
37. Answer:
C
38. Answer:
B
39. Answer:
B
40. Answer:
A
41. Answer:
A
42. Answer:
D
43. Answer:
C
44. Answer:
C
45. Answer:
B
46. Answer:
A
47. Answer:
D
48. Answer:
B
49. Answer:
C
50. Answer:
A
51. Answer:
Leaves are the main site of photosynthesis, which is conducted by the cells of the ground tissue. Having the ground tissue close to the surface helps these cells absorb sunlight. If the vascular tissue was between the dermal tissue and the ground tissue, it would reduce the amount of sunlight getting to the photosynthetic cells.
52. Answer:
Phototropism causes stems to bend toward light. This means that the cells on the dark side of the plant must elongate faster than those on the light side of the plant. Because auxin causes cells in the shoot to elongate, it must move away from the light.
53. Answer:
Putting unripe fruit, like green bananas, in a paper bag helps to speed up the ripening process. This happens because the bag will trap ethylene gas produced by the fruit. The trapped ethylene gas becomes more concentrated in the air present in the bag and stimulates the fruit to ripen faster and produce even more ethylene.
54. Answer: Ethylene is produced by fruit and stimulates the ripening of fruit and activates enzymes responsible for converting starches into sugars; this results in a sweeter fruit that is more likely to be eaten by animals. The seeds will survive passing through the digestive system of the animal and be expelled in a location farther away from the original plant. This is helpful to spread the plant’s seeds and possibly broaden the plant’s range.
55. Answer: The source of carbon mass in an oak tree is carbon dioxide in the air. The carbon dioxide enters the leaves through their stomata and then the cells in the leaves photosynthesize to produce sugars from the CO2 and water using sunlight as an energy source. These sugars and their chemical derivatives are then used to construct polysaccharides and other structural components of the tree. 56. Answer:
Auxins promote root production, and cytokinins promote shoot production. Auxins must be produced in the shoot system because a plant with more shoots needs to produce more roots. Cytokinins are produced in the root system because a plant with more roots needs to produce more shoots.
57. Answer:
Macronutrients are needed in relatively large quantities by plants and include sulfur, phosphorus, carbon, hydrogen, oxygen, calcium, and nitrogen. Plants obtain their carbon, hydrogen, and oxygen from the air surrounding the plant. Through their roots, they absorb the majority of their sulfur, phosphorus, calcium, and nitrogen from the soil. Plants require micronutrients in relatively small quantities. Characteristic micronutrients such as iron, zinc, and copper are absorbed from the soil through the plant roots.
58. Answer:
In diploid plants, meiosis produces haploid spores, which grow into multicellular structures called gametophytes through mitosis. Through mitosis, the gametophytes produce gametes, which will fuse to form a new diploid zygote. The zygote divides by mitosis to form the new sporophyte.
59. Answer:
The fertilization of haploid gametes from different plants to form a new, unique diploid zygote is advantageous to plants because it produces new genetic combinations in the resulting sporophyte plant. As this flowering sporophyte grows, its cells will reproduce through mitosis until some of its cells undergo meiosis to form haploid spores that divide by mitosis to form gametophytes in the ovary and anthers of the plant. Cells in the gametophyte undergo meiosis to produce gametes, which then fertilize one another to produce new diploid zygotes.
60. Answer:
Animal pollination is more precise than wind pollination because animals often visit the same types of plants, but it requires energy expenditure on the part of the plant (for the production of nectar or similar substances). Wind pollination is essentially random, but it requires a smaller energy expenditure on the part of the plant.
61. Answer:
The horticulturist probably wants to control which flowers are pollinated with which pollen and exercise some control over which genes are passed on to the next generation of plants. By removing the anthers from some flowers, the horticulturist can increase the chances that the new generation of plants that grow from the seeds have particular genetic traits such as flower color and shape or stem length and texture.
62. Answer:
All three of these plants disperse their seeds through the wind. Maple seeds look heavier, but because they are tall plants, their seeds are more likely to be picked up by the wind and travel some distance before fluttering to the ground. Milkweed and dandelions are small plants that grow closer to the ground; their seeds appear to be much lighter, with feathery structures suitable for picking up any puff of wind to send them flying to a new location.
63. Answer:
Humans would first recognize that a particular plant has some beneficial quality, such as being nutritious or tasty. Humans would then select the most nutritious or tastiest of these plants to eat and also pollinate them with other plants most similar to them, followed by planting the seeds to grow more of these plants with the desired trait(s). If the humans move to a new location, they are likely to take their favorite seeds with them to plant in their new home; this would extend the range of the plant.
64. Answer:
If crop plants can be genetically modified to produce their own chemical resistance (or more of their own chemical resistance) to insects, then those plants will be more likely to grow successfully without the use of pesticides on the crops. When pesticides are put on crops in the field, the pesticides can drift in the wind or dissolve and run off in rain water to surrounding areas. The broadcasting of pesticides affects not only the pests that might destroy the crops but also other insects in the area and becomes concentrated in the local food chain. This could do harm to organisms all the way up the food chain in that ecosystem.
65. Answer:
dermal
66. Answer:
ground
67. Answer:
ethylene
68. Answer:
primary
69. Answer:
chemical
70. Answer:
modular growth
71. Answer:
photoperiodism
72. Answer:
macronutrients
73. Answer:
gametophyte
74. Answer:
sporophyte
75. Answer:
pollination
76. Answer:
anther anthers
77. Answer:
animals
78. Answer:
water
79. Answer:
80. Answer:
1.
D
2.
E
3.
B
4.
C
5.
A
1.
D
2.
A
3.
B
4.
E
5.
C