OpenStax Microbiology Test Bank All Chapters ( Updated 2023/2024)

Chapter 1: An Invisible World * = Correct answer Multiple Choice

1. Which of the following is true of the microbial world?

A. All microbes are harmful.

B. Humans could survive without microbes.

C. Many microbes are helpful.* D. Most microbes are pathogenic.

Difficulty: Easy ASM Standard: 23, 24 2. Which of the following is when humans first suspected the existence of microbes?

A. during the Industrial Revolution B. in prehistoric times* C. in the last century D. within the last 500 years Difficulty: Easy ASM Standard: 23 3. Which individual first observed unicellular organisms, which he called “animalcules,” using a microscope he developed?

A. Robert Koch B. Louis Pasteur C. Thucydides D. Antonie van Leeuwenhoek* Difficulty: Easy ASM Standard: 6 4. To reduce the risk of open flame from Bunsen burners, microbiologists are increasingly using which of the following devices for easy, rapid benchtop sterilization of small pieces of equipment?

A. autoclaves B. ethylene oxide C. incubators

D. microincinerators* Difficulty: Easy ASM Standard: 36

5. The Swedish botanist known for having developed an important biological classification system is which of the following people?

A. Ernst Haeckel B. Carolus Linnaeus* C. Louis Pasteur D. Robert Whittaker Difficulty: Easy ASM Standard: N/A 6. Which kingdom was the only one found in Empire Prokaryota?

A. Animalia B. Fungi C. Monera* D. Protista Difficulty: Easy ASM Standard: N/A 7. Which are the three currently accepted domains?

A. Archaea, Bacteria, and Eukarya* B. Archaea, Prokaryota, and Eukaryota C. Bacteria, Fungi, and Protista D. Bacteria, Prokaryota, and Eukarya Difficulty: Easy ASM Standard: N/A 8. Which two taxonomic units are typically used to identify an organism when using binomial nomenclature?

A. domain and kingdom B. genus and family C. genus and species* D. phylum and class Difficulty: Easy ASM Standard: N/A 9. Which of the following is not true about the process of fermentation?

A. It can help preserve foods, preventing spoilage.

B. It converts sugars to organic acids, alcohols, and/or gases such as carbon dioxide.

C. It is carried out exclusively by unicellular eukaryotes such as yeast.* D. It is used to make foods such as cheese and bread.

Difficulty: Moderate ASM Standard: 11, 23, 26

10. The Romans may have reduced their risk of waterborne infectious diseases by using which of the following?

A. a variety of pharmaceutical products B. aqueducts and a sewer system* C. prophylactic antibiotics D. quarantine of people with leprosy Difficulty: Moderate ASM Standard: 23 11. For which of the following is Thucydides known?

A. developing an effective sewer system in ancient Greece, helping to reduce levels of disease in cities B. observing microbes, using a microscope, for the first time, even distinguishing between bacteria and fungi C. proposing that disease was caused by microorganisms D. realizing that people who had been infected by the Athenian plague had immunity to reinfection* Difficulty: Moderate ASM Standard: 23, 31 12. Ernst Haeckel proposed a classification system consisting of which of the following subgroups?

A. five kingdoms B. four kingdoms* C. two domains and three kingdoms D. two domains and five kingdoms Difficulty: Moderate ASM Standard: N/A 13. Viruses not included in phylogenetic trees for which of the following reasons?

A. It is too difficult to observe their characteristics.

B. They are acellular and nonliving.* C. They do not have any genes, which prevents genetic analysis.

D. They lack a nucleus.

Difficulty: Moderate ASM Standard: 5 14. Which is the best description of the primary purpose of a phylogeny?

A. Phylogenies show all the alterative names for each species.

B. Phylogenies show all the common names for each species.

C. Phylogenies show evolutionary relatedness between organisms.*

D. Phylogenies show interactions between species in a shared habitat.

Difficulty: Moderate ASM Standard: 5 15. Current phylogenetic analyses include which of the following?

A. information from a range of sources, including morphological, genetic, and biochemical data* B. information on visible similarities only C. information regarding how to classify organisms on the basis of external morphological characteristics and visible behaviors D. varied morphological and structural characteristics, with preference for leaving historical classifications to prevent confusion Difficulty: Moderate ASM Standard: 5 16. Diatoms are classified within which of the following domains?

A. Archaea B. Bacteria C. Eukarya* D. Prokaryota Difficulty: Moderate ASM Standard: N/A 17. Horizontal gene transfer involves which of the following?

A. any transfer of genes in a laboratory setting B. the transfer of genes from a virus to a bacterium or vice versa but not any other form of gene transfer C. the transfer of genes from one individual to another, including from one species to another, but not from parent to offspring* D. the transfer of genes from parent to offspring Difficulty: Moderate ASM Standard: 2, 4 18. Bacteria are generally identified to species by using which of the following?

A. a combination of genetic, biochemical, and microscopic approaches* B. a combination of microscopic and physiological approaches, but not genetics C. primarily characteristics such as motility that can be visualized using microscopy D. primarily morphological characteristics of individual cells Difficulty: Moderate ASM Standard: 34, 36

19. For taxonomic classification of microbes, serological tests typically are used to do which of the following?

A. determine complete genome sequences for microbes B. identify proteins on the basis of their reaction with specific antibodies* C. run analyses to identify whether particular genes are present D. visualize microbial external morphology Difficulty: Moderate ASM Standard: 34, 36 20. Which of the following is true of bacterial strains?

A. They are closely related subtypes within a bacterial species that may or may not have similar properties.* B. They are informal bacterial groupings used for medical distinctions but not recognized for classification purposes.

C. They are more distantly related to each other than are members of a single bacterial species.

D. They are very similar bacteria with almost identical properties.

Difficulty: Moderate ASM Standard: 5 21. Bergey’s Manual of Systematic Bacteriology is used primarily as which of the following?

A. a guide to bacterial shapes B. a historical account of changes in classification techniques C. a list and characterization of all known medically relevant microbes D. a reference for bacterial classification* Difficulty: Moderate ASM Standard: 34 22. Which of the following indicates how bacteria and viruses typically compare in size?

A. Bacteria are indistinguishable from viruses.

B. Bacteria are much larger than viruses.* C. Bacteria are much smaller than viruses.

D. Bacteria are similar in size to viruses.

Difficulty: Easy ASM Standard: N/A 23. Viruses are classified as which of the following?

A. Archaea B. Bacteria C. Eukarya D. distinct from the three-domain system*

Difficulty: Moderate ASM Standard: 4 24. Which of the following is not a curved bacterial shape?

A. bacillus* B. spirillum C. spirochete D. vibrio Difficulty: Easy ASM Standard: 34 25. Based just on the name, which of the following groups of bacteria contains entirely species that consume organic compounds for food?

A. cyanobacteria B. green nonsulfur bacteria C. green sulfur bacteria D. nonphotosynthetic bacteria* Difficulty: Moderate ASM Standard: 11, 13, 20 26. Chitin cell walls are characteristic of which taxonomic group?

A. algae B. archaea C. bacteria D. fungi* Difficulty: Moderate ASM Standard: 20 27. Yeasts are which of the following?

A. a type of algae B. a type of protist C. any unicellular microbe D. unicellular fungi* Difficulty: Moderate ASM Standard: 20 28. The cell walls of archaeans often contain which of the following substances?

A. cellulose B. chitin C. peptidoglycan D. pseudopeptidoglycan*

Difficulty: Moderate ASM Standard: 20 29. Which of the following is not true of archaeans?

A. Some species live on the human body.

B. They are genetically distinct from bacteria.

C. They are only found in extreme environments.* D. They have substantial metabolic differences from bacteria.

Difficulty: Difficult ASM Standard: 20 30. Which of the following is not true of algae?

A. All the algae are classified together in one similar group closely related to green plants.*

B. Ingredients made from algae, including carrageenan, are used in food products.

C. They are being used to develop biofuels.

D. They are sometimes multicellular.

Difficulty: Moderate ASM Standard: 20, 23, 26 31. Oral thrush is caused by which type of organism?

A. algae B. bacteria C. fungi* D. protists

Difficulty: Moderate ASM Standard: 23 32. Mycotoxins are produced by which type of organism?

A. archaeans B. heterotrophic protists C. molds* D. protozoans Difficulty: Moderate ASM Standard: 23 33. Which of the following is not a common use of fungi?

A. the production of alcoholic beverages B. the production of carrageenan* C. the production of cyclosporine D. the production of penicillin

Difficulty: Moderate ASM Standard: 20, 23, 26 34. The guinea worm is best described as which of the following?

A. a helminthic parasite transmitted by consuming contaminated water* B. a type of mold that grows into a worm-like shape and produces antimicrobial chemicals

C. a type of protist found in water that has not been properly treated D. a type of protozoan that is unusual because it is multicellular Difficulty: Moderate ASM Standard: 23 35. Which of the following is true of the genetics of viruses?

A. Viruses always contain DNA and force host cells to produce RNA. B. Viruses always contain DNA and RNA. C. Viruses always contain RNA and force host cells to produce DNA. D. Viruses can contain either DNA or RNA, but not both.* Difficulty: Moderate ASM Standard: N/A True/False 36. All organisms studied in the field of microbiology are visible only with a microscope. Answer: False Difficulty: Easy ASM Standard: N/A 37. Older scientific names are typically derived from Latin. Answer: True Difficulty: Easy ASM Standard: N/A 38. Animal cells are generally about the same size as bacterial cells. Answer: False Difficulty: Easy ASM Standard: N/A 39. Researchers studying a 5300-year-old mummy discovered in the 1990s think he may have been trying to use a fungus to treat his illnesses.

Answer: True Difficulty: Easy

ASM Standard: 23, 26 40. Analyses of rRNA genes suggest that Archaea, Bacteria, and Eukarya evolved from a common ancestor.

Answer: True Difficulty: Moderate ASM Standard: 5 41. The average size of a typical virus is approximately 100 nm. Answer: True Difficulty: Moderate ASM Standard: N/A 42. When a scientific name is used repeatedly, both the genus and species must always be written out in full to avoid confusion.

Answer: False Difficulty: Moderate ASM Standard: N/A 43. Taenia saginata is a type of fungus that causes disease. Answer: False Difficulty: Moderate ASM Standard: 23 Matching 44. Match each type of microbiological tool with the best definition.

A. loop i. tool used to transfer microbes from one location to another B. media ii. liquid, solid, or gel that contains nutrients to aid microbial growth C. microincinerator iii. tool used to sterilize equipment D. Petri plate iv. container used to grow microbial cultures Answers: A. i., B. ii., C. iii., D. iv.

Difficulty: Easy ASM Standard: 36 45. Match the bacterial shape with the illustration.

(credit micrograph “i”: modification of work by Janice Haney Carr, Centers for Disease Control and Prevention; credit micrograph “iii”: modif ication of work by Centers f or Disease Control and Prevention)

Answers: A. v., B. i., C. iv., D. iii., E. ii.

Difficulty: Easy ASM Standard: 34 46. Match each type of microbe with the best description.

A. algae i. a very broad, informal grouping of organisms that do not fit into other eukaryotic kingdoms and that may be photosynthetic or nonphotosynthetic B. fungi ii. a diverse, informal subgroup of organisms that may move using cilia, flagella, or pseudopodia C. protists iii. a group of photosynthetic organisms with cellulose cell walls D. protozoa iv. a group of nonphotosynthetic organisms that usually have cell walls containing chitin Answers: A. iii., B. iv., C. i., D. ii.

Difficulty: Moderate ASM Standard: 2 47. Match each subfield of microbiology with the most appropriate example.

A. bacteriology i. the study of how antibodies are released in response to a pathogen B. immunology ii. the study of how fungi cause disease in plants C. mycology iii. the study of the classification of bacilli D. parasitology iv. the study of how to reduce the rate of guinea worm infections E. protozoology v. the study of heterotrophic protists

Answers: A. iii., B. i., C. ii., D. iv., E. v.

Difficulty: Moderate ASM Standard: 23 48. Match each taxonomic group with its domain. You will use some options more than once.

A. algae i. Archaea B. halophiles ii. Bacteria C. helminths iii. Eukarya D. spirochetes Answers: A. iii., B. i., C. iii., D. ii.

Difficulty: Moderate ASM Standard: 2 49. Match each causative agent with the associated classification.

A. Dracunculus medinensis i. protist B. Ebola ii. fungus C. Giardia lamblia iii. helminth D. yeast iv. virus Answers: A. iii., B. iv., C. i., D. ii.

Difficulty: Difficult ASM Standard: 23 Fill in the Blank 50.

was a Greek physician who posited that natural causes, not supernatural forces, caused disease.

Answer: Hippocrates Difficulty: Easy ASM Standard: 23

51.

is the science of identifying, naming, and classifying living organisms. Answer: Taxonomy Difficulty: Easy ASM Standard: N/A

52. Fermentation by yeast produces ethanol and gas. Answer: carbon dioxide Difficulty: Moderate ASM Standard: 11, 26

53. Carl Woese and George Fox sequenced and analyzed wide range of organisms to build their phylogenetic tree.

Answer: rRNA (or ribosomal RNA)

from a

Difficulty: Moderate ASM Standard: 4, 5 54. The archaebacteria are now called . Answer: Archaea Difficulty: Moderate ASM Standard: N/A 55. The genus of Halobacterium salinarum is . Answer: Halobacterium Difficulty: Easy ASM Standard: N/A 56. is the standard reference book that provides guidance onidentifying and classifying prokaryotes.

Answer: Bergey’s Manual of Determinative Bacteriology Difficulty: Moderate ASM Standard: 34 57. There are nanometers in 520 meters. Answer: 520,000,000,000 Difficulty: Moderate ASM Standard: 29 58. The thermophilic genus Thermoproteus includes extremophiles classified in the domain .

Answer: Archaea

Difficulty: Difficult ASM Standard: 5 59. The cytoplasmic extensions used by some protists to move are called . Answer: pseudopods Difficulty: Moderate ASM Standard: N/A Short Answer

60. What is horizontal gene transfer?

Sample Answer: Horizontal gene transfer is the transfer of genetic material between two organisms that are not related as parent and offspring.

Difficulty: Easy ASM Standard: 2 61. How are newly discovered organisms named?

Sample Answer: Newly discovered organisms are usually given names that describe their characteristics and/or that honor a particular individual. The names are generally Latin, Greek, or English.

Difficulty: Easy ASM Standard: 5 62. How do protozoa move?

Sample Answer: Protozoa can move using structures such as pseudopods, flagella, and cilia. They may also be carried by the water in which they live.

Difficulty: Easy ASM Standard: N/A 63. Why are formal scientific names based on a standardized system more useful than simple names that just describe characteristics, such as “orange cat-like animal”?

Sample Answer: Organisms may have similar characteristics, especially in closely related species. By having a formal naming system, it is possible to clearly distinguish organisms so that people around the world can identify exactly which organism is being discussed.

Difficulty: Moderate ASM Standard: N/A 64. What are at least four types of products made using fermentation?

Sample Answer: Fermentation is used to make alcoholic products, cheese, yogurts, pickled vegetables, and bread.

Difficulty: Easy ASM Standard: 11, 23, 26 65. What is the Hippocratic Oath?

Sample Answer: The Hippocratic Oath is an oath taken by new doctors to pledge their willingness to follow certain ethical guidelines, such as avoiding causing harm to their patients.

Difficulty: Moderate ASM Standard: N/A31

66. Which famous scientist developed a vaccine for rabies? Sample Answer: Louis Pasteur developed a vaccine for rabies.

Difficulty: Moderate ASM Standard: 14, 23 67. Why is most milk pasteurized before it is sold?

Sample Answer: Pasteurization helps reduce the number of microbes associated with spoilage and disease, keeping milk safe to drink longer than if it is not pasteurized.

Difficulty: Moderate ASM Standard: 14, 23 68. What are helminths and why are they medically important?

Sample Answer: Helminths are worms. They are eukaryotes. They can be human parasites.

Difficulty: Moderate ASM Standard: 14, 23 69. Why is it often preferable to use a microincinerator rather than a Bunsen burner? Sample Answer: Bunsen burners have an open flame, whereas microincinerators do not; therefore, it is safer to use a microincinerator.

Difficulty: Moderate ASM Standard: 14, 36 70. How do scientists decide how to organize organisms in a phylogenetic tree?

Sample Answer: Phylogenies show evolutionary relationships. To develop a phylogenetic tree, scientists examine a variety of characteristics, including biochemical, morphological, and genetic characteristics, to determine the most likely relationships between organisms. Genetic data are especially important in determining these relationships in modern phylogenetic trees.

Difficulty: Moderate ASM Standard: 5 71. What is the difference in how DNA is stored within the cells of prokaryotes versus eukaryotes?

Sample Answer: Eukaryotes have a true membrane-bound nucleus and prokaryotes do not.

Difficulty: Moderate ASM Standard: 9

72. What does it m ean to say that som e photosynthetic bacteria, including som e green sulfur bacteria, are anoxygenic? Consider the word parts in “anoxygenic” if you are not sure. Sample Answer: Anoxygenic means that they do not generate oxygen.

Difficulty: Difficult ASM Standard: 11 73. Who published Systema Naturae and what did it present?

Sample Answer: Systema Naturae was published by Carolus Linnaeus to present his taxonomic system.

Difficulty: Difficult ASM Standard: N/A 74. Of the three domains, which is/are known to contain some human pathogens?

Sample Answer: Bacteria and Eukarya contain some species that are human pathogens. No known archaeal pathogens have been identified.

Difficulty: Moderate ASM Standard: 23 Brief Essay Essay Question Rubric RATING Failing Criteria for evaluati on

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is poor and contains numerous grammatical mistakes and misspellings.

Below Average Answer fails to provide examples to support an argument.

Writing is poor and grammatical errors are common.

Answer is somewhat incoherent.

Competent

Advanced

Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

3

0 1 2 POINT VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

75. Explain why some scientists think that it may be more appropriate to describe a “web of life” instead of a “tree of life.”

Answer: Student answers will vary but should include components of the following.

A tree suggests straightforward pathways of evolution from one branch to another.

Because horizontal gene transfer is common, this does not fully represent the complexity involved in evolution. A web would better show ways genes can be transferred from one taxonomic group to another.

Difficulty: Moderate ASM Standard: 5 76. Halobacterium salinarum is classified in the domain Archaea. Why does its name suggest it is a bacterium? This answer is not in the textbook chapter, so you should speculate based on your understanding of taxonomy.

Answer: Student answers will vary but should include the following. This species was identified before the domain Archaea was recognized. As a result, it was previously considered a bacterium and given a bacterial name.

Difficulty: Moderate ASM Standard: N/A 77. Consider the phylogenetic tree below. Explain how it shows the relationships between Bacteria, Archaea, and Eukarya, and their common ancestor. Of these three groups, which two are more closely related and how can you tell from the figure?

(credit: modification of work by Eric Gaba) Answer: Student answers will vary but should include the following. The lines leading to Bacteria, Archaea, and Eukarya branch from the same root, meaning they all share a common ancestor. Archaea and Eukarya branch more closely together than either branches with

Bacteria, suggesting that they diverged from each other more recently than they diverged from a common ancestor that had previously branched from Bacteria.

Difficulty: Difficult ASM Standard: 5 78. In the textbook chapter, there is information about efforts to eradicate the guinea worm.

What are some factors that have allowed these efforts to be relatively successful, with only 126 cases reported in 2014, compared with efforts to eradicate other diseases such as hantavirus, carried by rodents, and rabies, carried by a variety of wild animals?

Answer: Student answers will vary but should include components of the following.

Guinea worm is transmitted in contaminated water. Thus, efforts to improve water sanitation can be very effective in reducing infections. Other diseases have different mechanisms of transmission. Diseases such as rabies are found in wild animals and it would be difficult to treat or vaccinate all infected animals.

Difficulty: Difficult ASM Standard: 14, 23, 31

This file is copyright 2017, Rice University. All rights reserved.

Chapter 2: How We See the Invisible World * = Correct answer Multiple Choice 1. Which term is used to refer to a wave’s rate of vibration?

A. amplitude B. frequency* C. trough D. wavelength Difficulty: Easy ASM Standard: N/A 2. On the figure, which letter represents a refracted ray of light?

A. A B. B C. C D. D* Difficulty: Easy ASM Standard: N/A 3. On the electromagnetic spectrum, which type of wave has the shortest wavelength?

A. cosmic ray* B. infrared ray C. ultraviolet ray D. visible light Difficulty: Moderate ASM Standard: N/A 4. Dyes are often used during microscopy to increase which of the following?

A. contrast* B. magnification

C. motility D. resolution Difficulty: Easy ASM Standard: 32 5. Which of the following was the first to use the term “cells”?

A. Robert Hooke* B. Robert Koch C. Carolus Linnaeus D. Antonie van Leeuwenhoek Difficulty: Easy ASM Standard: N/A 6. Which of the following is the typical magnification of an object viewed using a 10× ocular lens and a 100× objective lens on a brightfield microscope?

A. 1× B. 10× C. 100× D. 1000×* Difficulty: Moderate ASM Standard: 32 7. Most modern microscopes have two eyepieces, meaning that they are which of the following?

A. binocular* B. monocular C. oil immersion D. trinocular Difficulty: Easy ASM Standard: 32 8. An annular stop is used for which type of microscopy?

A. confocal B. darkfield C. fluorescence D. phase contrast* Difficulty: Easy ASM Standard: 32 9. Which of the following is the specific name for a stain that colors the background but not the specimen?

A. acid-fast stain B. counterstain C. differential stain D. negative stain* Difficulty: Easy ASM Standard: 32 10. Which type of microscopy would work best for viewing internal cell structures?

A. atomic force microscopy B. scanning electron microscopy C. scanning tunneling microscopy D. transmission electron microscopy* Difficulty: Moderate ASM Standard: 32 11. The Gram-staining procedure is best described as which of the following?

A. complex staining B. differential staining* C. negative staining D. simple staining Difficulty: Easy ASM Standard: 32 12. When there is a substantial difference in refractive index between two materials, which of the following describes what will happen to light passing from one material to the other?

A. It will fail to be refracted.

B. It will undergo a large amount of refraction.* C. It will undergo a small amount of refraction.

D. It will undergo a variable amount of refraction.

Difficulty: Moderate ASM Standard: N/A 13. In microscopy, the focal length refers to which of the following?

A. a description of the wavelength needed for an image to be in focus B. a measure of the amount of refraction produced by a lens C. a measure of the thickness of the lens needed for an image to be in focus D. the distance to the image point (at which all light entering a lens is parallel)* Difficulty: Moderate ASM Standard: 32 14. Which of the following are pigments used in microscopy to absorb and reflect light?

A. chromatographs

B. chromophores* C. oilophores D. photophores Difficulty: Easy ASM Standard: N/A 15. Negative staining is the standard approach used to visualize which structure(s)?

A. capsules* B. endospores C. flagella D. nucleoid regions Difficulty: Moderate ASM Standard: 6, 32 16. Which is a standard mordant used in flagella staining?

A. basic fuchsin B. iodine C. safranin D. tannic acid* Difficulty: Moderate ASM Standard: 6, 32 17. Which of the following pairs are common acid-fast staining techniques?

A. Gram and Kinyoun B. negative and Schaeffer-Fulton C. Ziehl-Neelsen and Kinyoun* D. Ziehl-Neelsen and Schaeffer-Fulton Difficulty: Moderate ASM Standard: 32 18. Which is the primary stain used in the Ziehl-Neelsen technique?

A. acid-alcohol B. carbolfuchsin* C. crystal violet D. methylene blue Difficulty: Moderate ASM Standard: 32 19. Which is the correct order of steps in Gram staining?

A. crystal violet stain, ethanol decolorization, Gram’s iodine mordant, safranin counterstain B. crystal violet stain, Gram’s iodine mordant, ethanol decolorization, safranin counterstain*

C. ethanol stain, crystal violet rinse, safranin counterstain, Gram’s iodine mordant D. safranin stain, Gram’s iodine mordant, ethanol decolorization, crystal violet counterstain Difficulty: Easy ASM Standard: 32 20. It is important to fix bacterial smears on a slide for which of the following reasons?

A. to attach them to the slide* B. to cause swelling of the cell to make interior structures more visible C. to enhance the uptake of stains D. to provide a nutrient medium to sustain the bacteria Difficulty: Easy ASM Standard: 32 21. Which of the following is not commonly used for chemical fixation?

A. acetic acid B. ethanol C. glutaraldehyde D. iodine* Difficulty: Moderate ASM Standard: 32 22. Which of the following is not involved in preparing a bacterial slide for Gram staining?

A. allowing the sample to dry on the slide B. fixing the specimen to the slide C. placing a smear on the slide D. preparing a wet mount* Difficulty: Moderate ASM Standard: 32 23. Which of the following most specifically refers to stains with positively charged chromophores?

A. acid-fast dyes B. acidic dyes C. basic dyes* D. positive dyes Difficulty: Moderate ASM Standard: 32 24. Which of the following most specifically refers to a stain that dyes a specimen rather than the background?

A. counterstain

B. mordant C. negative stain D. positive stain* Difficulty: Moderate ASM Standard: 32 25. Which of the following describes the difference between the Ziehl-Neelsen and Kinyoun acid-fast staining techniques?

A. The Ziehl-Neelsen technique uses a counterstain and the Kinyoun technique does not.

B. The Ziehl-Neelsen technique uses an acidic dye and the Kinyoun technique does not.

C. The Ziehl-Neelsen technique uses heat and the Kinyoun technique does not.* D. The Ziehl-Neelsen technique uses two dyes and the Kinyoun technique does not.

Difficulty: Moderate ASM Standard: 32 26. Which of the following described the difference between gram-positive and gram-negative cells that causes them to stain differently after Gram staining?

A. Gram-positive cells have a mycolic acid layer in their cell walls that holds in stain, whereas gram-negative cells lack this layer.

B. Gram-positive cells have capsules and gram-negative cells have S layers.

C. Gram-positive cells have thicker cell membranes than gram-negative cells.

D. Gram-positive cells have thicker peptidoglycan layers in their cell walls than do gramnegative cells.* Difficulty: Moderate ASM Standard: 7, 32, 34, 36 27. Which of the following would not potentially cause a gram-positive cell to appear gramnegative after Gram staining?

A. counterstaining with crystal violet instead of safranin* B. exposing the cells to ethanol for too long C. using older bacterial cultures D. using safranin as a primary stain Difficulty: Moderate ASM Standard: 32, 34, 36 28. Which of the following does not cause the probe to move up and down above the specimen in atomic force microscopy?

A. chemical bonding B. electrostatic forces C. van der Waals forces D. variations in current*

Difficulty: Difficult ASM Standard: 32 29. Quantum tunneling of electrons is important in the mechanism underlying which microscope type?

A. AFM B. SEM C. STM* D. TEM Difficulty: Moderate ASM Standard: 32 30. Which of the following is the chemical in some bacterial cells’ walls that makes themresist decolorization after acid-fast staining?

A. acetic acid B. mycolic acid* C. peptidoglycan D. phospholipid Difficulty: Moderate ASM Standard: 32 31. Gram staining is useful for bacterial identification. Which of the following is another way it is most useful?

A. Knowing Gram staining results allows a researcher to know which organisms abacterium can infect.

B. Knowing Gram staining results allows a researcher to select the appropriate growth medium for optimal bacterial growth.

C. Knowing Gram staining results is helpful in choosing an effective antibiotic.* D. Knowing Gram staining results is helpful in understanding a bacterium’s metabolic requirements.

Difficulty: Difficult ASM Standard: 7, 23 32. Which of the following is not true regarding capsule staining?

A. Capsules are typically stained using basic dyes.* B. Capsule staining does not require heat fixation in advance.

C. Capsule staining requires careful selection of a stain that can stain the capsule itself.

D. Capsule staining typically involves negative staining.

Difficulty: Difficult ASM Standard: 7, 23 33. Because endospores are difficult to stain, which of the following is generally needed?

A. Heat must be used to make the endospore take up stain.

B. Mycolic acid must be added to encourage the endospore to take up stain.

C. Negative staining must be used to stain endospores because they do not absorb stain.* D. The cells must be cooled to make the endospore more brittle prior to staining.

Difficulty: Difficult ASM Standard: 7, 32 34. When endospores are stained using the Schaeffer-Fulton method, which of the following correctly describes how they appear after staining?

A. The endospore appears green within a pink cell, because only the endospore retained the primary stain.* B. The entire cell appears green because the endospore surrounds all the vegetative material.

B. The entire cell appears pink because the endospore surrounds all the vegetative material.

C. The entire cell appears pink except for a clear area representing the endospore.

Difficulty: Moderate ASM Standard: 6, 7, 32 35. Specimens for TEM are prepared by doing which of the following?

A. dehydrating the specimen in ethanol and then coating it in a material that will repel electrons B. sputter coating with a substance such as gold to repel electrons C. using an ultramicrotome to cut very thin sections from samples embedded in plastic resin* D. using chemical fixation, followed by standard staining techniques such as the Gram stain Difficulty: Difficult ASM Standard: 32 True/False 36. In fluorescence, emitted photons have the same amount of energy as absorbed photons.

Answer: False Difficulty: Easy ASM Standard: N/A 37. A microscope with very high magnification and low resolution would allow you toclearly see small structures.

Answer: False Difficulty: Easy ASM Standard: 6 38. The difference between a simple microscope and a compound microscope is that the latter only has one lens.

Answer: False Difficulty: Easy ASM Standard: N/A 39. Flagella staining is very useful for diagnostic purposes in medical settings.

Answer: False Difficulty: Moderate ASM Standard: 7, 32 40. The transmission electron microscope and scanning electron microscope produce very similar images, but the former can be show three-dimensional external structures.

Answer: False Difficulty: Moderate ASM Standard: 6, 32 41. Differential interference contrast microscopy produces three-dimensional images of specimens.

Answer: True Difficulty: Moderate ASM Standard: 32 42. During specimen preparation for transmission electron microscopy, the specimensare dehydrated in alcohol and embedded in plastic resin.

Answer: True Difficulty: Difficult ASM Standard: 32 43. In atomic force microscopy, the movement of the probe tip is determined using Hooke’slaw of elasticity.

Answer: True Difficulty: Difficult ASM Standard: 32 Matching 44. Match each term with the best definition.

A. amplitude i. electromagnetic radiation within certain parameters B. frequency ii. the height of a wave peak or depth of a wave trough C. visible light iii. the rate of vibration of a wave D. wavelength iv. the distance between two wave peaks

Answers: A. ii., B. iii., C. i., D. iv.

Difficulty: Easy ASM Standard: N/A 45. Match each term with the best definition.

A. absorbance i. Light waves change direction when they enter a new medium.

B. diffraction ii. Two waves interact.

C. interference iii. A wave travels through something.

D. refraction iv. A material captures light energy.

E. transmission v. Light bends or scatters as it interacts with objects or openings.

Answers: A. iv., B. v., C. ii., D. i., E. iii.

Difficulty: Moderate ASM Standard: N/A 46. Match each type of microscope with a common use for that microscope type.

A. brightfield i. commonly used clinically; helpful in distinguishing living from dead cells, finding molecules within a cell, and for immunostaining B. darkfield ii. widely used and easily available; used for examining common protists, bacteria, and tissues; stains are often needed C. fluorescence iii. uses an annular stop, refraction, and interference to produce relatively high-resolution images without stains D. phase contrast iv. used to examine an image produced with light that hits a specimen indirectly owing to the use of an opaque light stop; often used to view living microorganisms without stains E. two-photon v. often used to penetrate thick specimens, such as biofilms, with long-wavelength light Answers: A. ii., B. iv., C. i., D. iii., E. v.

Difficulty: Difficult ASM Standard: 32 47. Match each type of microscopy with the best description.

A. atomic force microscopy i. measures changes in current as a probe is moved at a constant height over a specimen B. scanning electron ii. measures variations in the height of a probe moving microscopy over the specimen; height variations occur to maintain a constant current C. scanning tunneling iii. yields images from electrons produced by an electron microscopy beam hitting the surface of a sputter-coated specimen D. transmission electron iv. produces images from electrons that pass through a microscopy very thin specimen, allowing internal structures to be visualized Answers: A. ii., B. iii., C. i., D. iv.

Difficulty: Moderate

ASM Standard: 32 48. Match the staining procedure with the chemicals used.

A. acid-fast stain i. crystal violet, iodine, ethanol, safranin B. capsule stain ii. tannic acid or potassium alum, pararosaniline or basic fuchsin C. endospore stain iii. carbolfuchsin, acid alcohol, and methylene blue D. flagella stain iv. malachite green, safranin E. Gram stain v. India ink or nigrosin, sometimes with positive staining Answers: A. iii., B. v., C. iv., D. ii., E. i.

Difficulty: Moderate ASM Standard: 32 49. The choices describe possible scenarios and outcomes from Gram staining with standard stains (e.g., crystal violet and safranin). Match the scenario with the most likely outcome.

A. A gram-negative cell is stained, but i. The cell will probably appear pink, which will the ethanol step is skipped. not correctly indicate its cell wall structure.

B. A gram-positive cell with a severely ii. The cell will appear pink. damaged cell wall is stained.

C. A healthy gram-negative cell is iii. The cell will appear purple/violet. stained.

D. A healthy gram-positive cell is iv. The cell will probably appear purple/violet, stained. which will not correctly indicate its cell wall structure.

Answers: A. iv., B. i., C. ii., D. iii.

Difficulty: Difficult ASM Standard: 6, 32 Fill in the Blank 50. Compared with air, water has a(n) Answer: higher

refractive index.

Difficulty: Easy ASM Standard: N/A 51. The electron microscope produces high-resolution images of three-dimensional surface structures of sputter-coated specimens.

Answer: scanning Difficulty: Moderate ASM Standard: 32 52. Robert Hooke published compound microscopes.

Answer: Micrographia

, in which he described his observations of cork via

Difficulty: Easy ASM Standard: N/A 53.

microscopy uses an opaque stop, is useful for viewing living organisms without using stains, and produces images with a dark background.

Answer: Darkfield Difficulty: Moderate ASM Standard: 32

54. Acid-fast bacteria have Answer: mycolic acids

in their cell walls that retain carbolfuschin stain.

Difficulty: Moderate ASM Standard: 6, 7, 32 55. In acid-fast staining, cells that are not acid-fast usually appear Answer: blue

.

Difficulty: Moderate ASM Standard: 32 56. During preparation of specimens for scanning electron microscopy, specimens areoften sputter coated with or a similar material.

Answer: gold Difficulty: Moderate ASM Standard: 32 57. Negative staining of capsules is commonly done using India ink or Answer: nigrosin

.

Difficulty: Moderate ASM Standard: 6 32 58. An acid-fast staining technique similar to the Ziehl-Neelsen technique is called the technique.

Answer: Kinyoun Difficulty: Moderate ASM Standard: 32 59. When an object is relatively small relative to a wavelength of light, diffraction is than if an object is relatively large.

Answer: larger

Difficulty: Difficult ASM Standard: 32 Short Answer 60. Why is the resolution of a microscope image important?

Sample Answer: A high-resolution image is clear because you can distinguish between points. If the image is low resolution, then it is fuzzy and individual structures are more difficult to see.

Difficulty: Easy ASM Standard: 32 61. Who is believed to have developed the first microscopes that allowed microbes to be viewed?

Sample Answer: Antonie van Leeuwenhoek is believed to have developed the first microscopes that allowed microscopes to be viewed.

Difficulty: Easy ASM Standard: N/A 62. What is the name of the lens that focuses light from a microscope light source onto the specimen on the stage?

Sample Answer: The lens that focuses light on the slide is called the condenser.

Difficulty: Easy ASM Standard: N/A 63. Would you use immersion oil at high magnification or low magnification?

Sample Answer: Immersion oil is used to view specimens at high magnification with a light microscope and only with objective lenses that are designed for oil immersion.

Difficulty: Easy ASM Standard: 32 64. What is the difference between fluorescence and phosphorescence?

Sample Answer: In both fluorescence and phosphorescence, a material absorbs energy from light and then emits it again at a lower energy level. However, there is a delay between light absorbance and the emission of lower energy photons in phosphorescence that does not occur in fluorescence.

Difficulty: Difficult ASM Standard: N/A 65. Which lens will produce an image with greater resolution: one with a higher numerical aperture or one with a lower numerical aperture? Why?

Sample Answer: A higher numerical aperture produces an image with greater resolution, because more light can be gathered by the lens.

Difficulty: Moderate ASM Standard: 32 66. How does immersion oil improve the resolution of a microscope image?

Sample Answer: Immersion oil has a similar refractive index to glass. When light passes from the specimen into air, it is refracted and some is lost rather than passing through the objective. When there is oil between the specimen and the objective lens, more light enters the objective lens rather than being lost, and the image resolution is greater.

Difficulty: Moderate ASM Standard: N/A 67. For what type of microscopy is an opaque light stop used, and what is its function?

Sample Answer: In darkfield microscopy, an opaque stop is placed between the light source (illuminator) and the condenser lens. The stop blocks light from the illuminator from hitting the specimen directly. This means light does not hit the specimen directly and only refracted or reflected light reaches the objective, producing a bright specimen on a dark background.

Difficulty: Moderate ASM Standard: N/A 68. Why is it sometimes advantageous to avoid using stains when viewing microorganisms?

Sample Answer: Most stains or the process of staining can kill the specimen. It is often advantageous to view microorganisms without stains when one wishes to observe them alive (e.g., to observe their motility).

Difficulty: Moderate ASM Standard: N/A 69. What is another name for differential interference contrast microscopy?

Sample Answer: Differential interference contrast microscopy is also called Nomarski optics.

Difficulty: Moderate ASM Standard: N/A 70. What are some common fluorochromes used in fluorescence microscopy?

Sample Answer: Some common fluorochromes are Texas red, FITC, DAPI, and acridine orange.

Difficulty: Moderate ASM Standard: 32 71. In immunofluorescence, what are secondary antibodies used for?

Sample Answer: Secondary antibodies bind to primary antibodies, which bind to a an antigen (i.e., a protein, sometimes as part of a pathogen) in indirect immunofluorescence assays.

Difficulty: Moderate ASM Standard: 32 72. Why is it important to embed specimens in plastic resin during their preparation for TEM? Sample Answer: TEM specimens must be very thin for internal structures to be visible. An ultramicrotome is used to cut thin sections for this purpose. By embedding the specimens in plastic before cutting them, it is easier to prevent them from being damaged and compressed while being cut. Ethanol is used to help the plastic resin penetrate the cell.

Difficulty: Difficult ASM Standard: 32 73. Why can electron microscopes achieve higher resolutions than light microscopes?

Sample Answer: Resolution is higher when there are shorter wavelengths. The beams of electrons used by electron microscopes have shorter wavelengths than the light waves used by light microscopes.

Difficulty: Difficult ASM Standard: 32 74. Why do microscopes have rheostats? What is adjusted by adjusting a microscope’s rheostat?

Sample Answer: A microscope rheostat is used to adjust the amount of light on the specimen.

This is important to have the optimal amount of light to view the specimen. Having too much or too little light makes the specimen difficult to see clearly.

Difficulty: Difficult ASM Standard: 32 Brief Essay Essay Question Rubric RATING Failing Criteria for evaluati on

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is poor and contains numerous grammatical

Below Average Answer fails to provide examples to support an argument.

Writing is poor and grammatical errors are common.

Answer is

Competent

Advanced

Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

mistakes and misspellings.

somewhat incoherent.

two grammatical mistakes or misspellings.

Answer is well organized and free of grammatical errors and misspellings.

0 1 2 3 POINT VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

75. Explain how direct and indirect immunofluorescence assays differ, including an explanation of why indirect immunofluorescence is more commonly used.

Answer: Student answers will vary but should include the following. Direct immunofluorescence involves the use of an antibody that is attached to a fluorochrome.

When the antibody binds to an antigen, the fluorochrome is visible under the fluorescence microscope and allows the location of the antigen to be visualized. In indirect immunofluorescence, a primary antibody lacking a fluorochrome binds to an antibody. Then, a secondary antibody containing a fluorochrome binds to the primary antibody. Because more than one secondary antibody may bind to a primary antibody, indirect immunofluorescence increases sensitivity and can make it easier to visualize the specimen.

This is an important reason to choose indirect immunofluorescence even though direct immunofluorescence requires fewer steps.

Difficulty: Moderate ASM Standard: 32, 36 76. You prepare a slide of a bacterial sample by placing bacteria on a slide and examining it under a brightfield microscope. However, it is difficult to see the bacteria because the contrast is low. What are at least two ways you could increase the contrast?

Answer: Student answers will vary but should include the following. There are several ways you could increase the contrast. You could add a stain, choosing one that would likely stain the structures or cells of interest. You could also use a different form of microscopy, such as darkfield or phase contrast. Another option is to adjust the amount of light on the slide using the diaphragm and/or rheostat. Other options are also possible.

Difficulty: Moderate ASM Standard: 32 77. Explain some advantages of two-photon microscopy, and explain why this typeof microscopy is not more commonly used.

Answer: Student answers will vary but should include the following. Two-photon microscopy is especially valuable for penetrating thicker materials, such as biofilms. It also uses lower-energy light that is less damaging to living tissues than some other forms of microscopy. This means it can be used to obtain high-resolution images of living organisms and tissues. However, the technology is still not widely used because it is very expensive.

Difficulty:

Moderate ASM Standard: 32 78. There is some debate over who invented the microscope. Explain why this debate exists and what factors help some individuals get more credit for their roles than others.

Answer: Student answers will vary but should include components of the following.

Multiple people worked on early microscopes, including Galileo. Antonie van Leeuwenhoek and Robert Hooke receive considerable credit for their microscopes and observations. However, it is possible that Hans Janssen and Zaccharias Janssen should receive more credit. There is considerable uncertainty about their exact work. A major reason for this is that Leeuwenhoek and Hooke published their work. Because the Janssens did not, much less is known about their work.

Difficulty: Difficult ASM Standard: 31 79. Many microbes live in biofilm communities and understanding these communities is important for a variety of reasons. For example, understanding biofilm formation within wounds and medical devices is important for improving patient outcomes. What are ways that light microscopy, confocal microscopy, fluorescence microscopy, electron microscopy, and two-photon microscopy can be used to study biofilms?

Answer: Student answers will vary but should include components of the following.

Although light microscopes are easily available, biofilm architecture is difficult to examine under light microscopy because biofilms are too thick to easily examine throughout their structure with light microscopes without cutting and disrupting the biofilm. Confocal microscopy can be helpful in providing three-dimensional images of thicker structures, such as biofilms, but still have lower resolution than two-photon microscopes. Additionally, fluorescent stains can be used with confocal microscopy to enhance visibility with these three-dimensional images. Even without the depth of confocal microscopy, fluorescence microscopy is helpful in identifying the locations of specific molecules or cells. Electron microscopy allows high magnifications, but the specimens are distorted and can’t be viewed alive. Two-photon microscopes are especially useful because thick biofilm specimens can be viewed without distortion, but these microscopes are too expensive for general use.

Difficulty: Difficult ASM Standard: 32 This file is copyright 2017, Rice University. All rights reserved.

Page 35 of 17

Chapter 3: The Cell * = Correct answer Multiple Choice 1. The idea that life could appear from nonliving materials was called which of the following?

A. the cell theory B. the cellular genesis theory C. the theory of biogenesis D. the theory of spontaneous generation* Difficulty: Easy ASM Standard: N/A 2. The first known use of epidemiology to trace the source of a disease outbreak was the identification of contaminated water as the cause of cholera transmission in London.

Which of the following was the physician who accomplished this?

A. Joseph Lister B. John Needham C. Ignaz Semmelweis D. John Snow* Difficulty: Easy ASM Standard: N/A 3. Which of the following is a series of steps for determining the causative agent of a particular disease?

A. Koch’s postulates* B. Lister’s checklists C. Pasteur’s principles D. Semmelweis’ guidelines Difficulty: Easy ASM Standard: 23 4. Which scientist performed an elegant series of experiments that finally and definitively disproved the theory of spontaneous generation?

A. John Needham B. Louis Pasteur* C. Francesco Redi D. Jan Baptista van Helmont Difficulty: Easy Page 36A of S M17Standard:

N/A

5. Prokaryotes are classified into which domain(s)?

A. Domain Archaea only B. Domain Bacteria only C. Domains Archaea and Bacteria only* D. Domains Bacteria and Eukarya only Difficulty: Moderate ASM Standard: N/A 6. Which term refers to a curved rod?

A. bacillus B. coccus C. spirillum D. vibrio* Difficulty: Easy ASM Standard: N/A 7. When a bacterial cell with a cell wall is placed in salt water with a higher-solute concentration than the cell cytoplasm, the cell will undergo which of the following?

A. crenation B. crenolysis C. lysis D. plasmolysis* Difficulty: Moderate ASM Standard: 8, 22 8. The bacterial chromosome located in which of the following?

A. the capsule B. the nucleoid region* C. the nucleus D. the thylakoids Difficulty: Easy ASM Standard: N/A 9. Which scientist thought spontaneous generation had occurred in flasks of broth after the broth had been boiled?

A. John Needham* B. Louis Pasteur C. Francesco Redi D. Jan Baptista van Helmont Difficulty: Moderate ASM Standard: N/A Page 37 of 17

10. Which of the following is not evidence for the endosymbiotic theory?

A. Chloroplasts and mitochondria contain ribosomes that resemble prokaryotic ribosomes.

B. Chloroplasts and mitochondria contain their own DNA that resembles prokaryotic DNA. C. Chloroplasts and mitochondria have structures that resemble prokaryotic cell walls.* D. Chloroplasts and mitochondria reproduce using binary fission, like prokaryotic cells.

Difficulty: Moderate ASM Standard: 1 11. Which physician realized that doctors were causing maternal deaths by failing to wash their hands while assisting during childbirth?

A. Girolamo Fracastoro B. Joseph Lister C. Louis Pasteur D. Ignaz Semmelweis* Difficulty: Easy ASM Standard: 23 12. How did Joseph Lister dramatically improve surgical outcomes?

A. by developing new antibiotics B. by developing new ways to circulate air within surgical facilities C. by using phenol as an antiseptic and disinfectant during surgery* D. by using vaccination against communicable diseases Difficulty: Easy ASM Standard: 14, 23 13. Sporulation generally occurs under which of the following circumstances?

A. when conditions are unfavorable or there are insufficient nutrients* B. when microbes are exposed to a new, favorable environment C. when microbes are under little stress and can become dormant D. when resources become highly abundant Difficulty: Moderate ASM Standard: 8, 22 14. Which of the following is not a difference between endospores and vegetative cells?

A. Vegetative cells are metabolically active, whereas endospores are dormant.

B. Vegetative cells are more resilient due to their metabolic activities, whereas endospores are more sensitive to change.* C. Vegetative cells normally have enzyme activity, whereas endospores do not show enzymatic activity.

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D. Vegetative cells stain easily using normal staining protocols, whereas endospores are difficult to stain without special endospore stains.

Difficulty: Moderate ASM Standard: 8 15. Immediately following asymmetric cell division during sporulation, which of the following structures contains the DNA and goes on to develop into an endospore?

A. cortex B. forespore* C. hindspore D. spore coat Difficulty: Moderate ASM Standard: 8 16. Which of the following gives the correct order of the stages of sporulation?

A. Cortex formation, formation of a double layer of membrane, DNA replication, spore release B. DNA replication, formation of a double layer of membrane, cortex formation, spore release* C. DNA replication, spore release, cortex formation, formation of a double layerof membrane D. Formation of a double layer of membrane, DNA replication, spore release, cortex formation Difficulty: Moderate ASM Standard: 8 17. Which of the following is not a clinically significant, spore-forming bacterium?

A. Bacillus anthracis B. Clostridium botulinum C. Clostridium difficile D. Escherichia coli* Difficulty: Moderate ASM Standard: 8 18. All cells have which of the following?

A. capsule B. cell membrane* C. cell wall D. nucleus Difficulty: Moderate ASM Standard: 8 Page 39 of 17

19. Which term refers to proteins that extend across the plasma membrane from one side to the other?

A. glycoproteins B. lipoproteins C. peripheral proteins D. transmembrane proteins* Difficulty: Moderate ASM Standard: N/A 20. In which types of organisms are phospholipids with branched chains common?

A. archaea* B. bacteria C. eukaryotes D. all of the above Difficulty: Moderate ASM Standard: N/A 21. The lipopolysaccharide molecule is an important component of the cell membranes of which organisms?

A. archaeans B. eukaryotes C. gram-negative bacteria* D. gram-positive bacteria Difficulty: Moderate ASM Standard: 8, 23 22. Capsules and slime layers are examples of which type of structure?

A. cell walls B. glycocalyces* C. peptidoglycan layers D. S-layers Difficulty: Moderate ASM Standard: 8 23. Bacteria use flagella to move purposefully toward or away from a chemical by which of the following?

A. having alternating runs and tumbles of equal lengths B. increasing the length of runs and decreasing the length of tumbles* C. increasing the length of tumbles and decreasing the length of runs D. using only runs

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Difficulty: Moderate ASM Standard: 8, 22 24. Which of the following is not a typical difference between eukaryotes and prokaryotes?

A. Eukaryotes have ester-linked phospholipids, whereas prokaryotes have ether-linked or ester-linked phospholipids.

B. Eukaryotic cell walls lack peptidoglycan in their cell walls (if present), whereas many prokaryotes use peptidoglycan in their cell walls.

C. Eukaryotic cells have histones for DNA organization, whereas prokaryotic cellshave histone-like proteins or nucleoid-associated proteins involved in DNA organization.

D. Eukaryotic cells typically have circular chromosomes, whereas prokaryotic cells typically have linear chromosomes.* Difficulty: Moderate ASM Standard: N/A 25. In eukaryotic cells, the function of the nucleolus is which of the following?

A. It is where all the nuclear DNA is located.

B. It is where cellular respiration takes place.

C. It is where ribosomal RNA is synthesized and ribosome assembly begins.* D. It is where transcription and translation of all gene products take place.

Difficulty: Moderate ASM Standard: 9 26. Microfilaments are composed of which structure?

A. actin* B. desmin C. keratin D. tubulin Difficulty: Moderate ASM Standard: N/A 27. Which of the following are not types of inclusions in bacterial cells?

A. carboxysomes B. magnetosomes C. thylakoids* D. volutin granules Difficulty: Difficult ASM Standard: 8 28. Which of the following is not true of archaeal membranes?

A. They are sometimes monolayers.

B. They have branched phospholipids.

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C. They have ether linkages instead of ester linkages.

D. They have peptidoglycan linkages attaching their membranes to their cell walls.* Difficulty: Difficult ASM Standard: N/A 29. Which cell would best be able to survive in a hypotonic environment?

A. a gram-positive bacterium in a medium containing penicillin B. a gram-positive bacterium in a medium without antibiotics* C. an animal red blood cell D. an archaeal cell lacking a cell wall Difficulty: Difficult ASM Standard: 8, 22 30. For a peritrichously flagellated bacterium, which of the following results in a run?

A. alternating beating of flagella B. alternating whip-like movements of flagella C. clockwise flagellar rotation D. counterclockwise flagellar rotation* Difficulty: Difficult ASM Standard: 8 31. Which of the following is true of ribosomes?

A. All prokaryotic ribosomes are 70S and eukaryotic cytoplasmic ribosomes are 80S. B. Bacterial ribosomes are 70S, whereas archaeal and eukaryotic cytoplasmic ribosomes are 80S. C. Organelle ribosomes and prokaryotic ribosomes are 70S, whereas eukaryotic cytoplasmic ribosomes are 80S.* D. Prokaryotic ribosomes are 80S, but eukaryotic cytoplasmic ribosomes are variable in size.

Difficulty: Difficult ASM Standard: 1 32. Which of the following is not part of the endomembrane system?

A. lysosomes B. mitochondria* C. the Golgi apparatus D. the rough endoplasmic reticulum Difficulty: Difficult ASM Standard: N/A 33. Which of the following are anchored into the plasma membrane by a basal body composed of nine triplets of microtubules?

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A. eukaryotic cilia only B. eukaryotic flagella only C. eukaryotic cilia and flagella only* D. prokaryotic flagella only Difficulty: Difficult ASM Standard: 8 34. Which best describes the function of cristae?

A. They aid in the proper trafficking of vesicles around eukaryotic cells.

B. They are compartments for digestive enzyme storage in eukaryotic cells.

C. They increase the surface area for reactions associated with cellular respiration.* D. They provide a location for the light reactions of photosynthesis in plant cells.

Difficulty: Moderate ASM Standard: 8 True/False 35. One of the first recorded proponents of spontaneous generation was Aristotle.

Answer: True Difficulty: Easy ASM Standard: N/A 36. All bacterial cells can form endospores.

Answer: False Difficulty: Easy ASM Standard: 8 37. Some bacterial inclusions are surrounded by a phospholipid monolayer membrane.

Answer: True Difficulty: Moderate ASM Standard: 8 38. The S-layer can function as a cell wall in some archaeans.

Answer: True Difficulty: Moderate ASM Standard: 8 39. Prokaryotic and eukaryotic flagella have the same structure.

Answer: False

Page 43 of 17

Difficulty: Moderate ASM Standard: 8, 9 40. Mitochondria contain their own DNA but chloroplasts do not.

Answer: False Difficulty: Moderate ASM Standard: 1 41. Specialized organelles called hydrogenosomes are used by some eukaryotes to produce hydrogen anaerobically.

Answer: True Difficulty: Difficult ASM Standard: 9 42. The extracellular matrix of animal cells generally consists mostly of phospholipids.

Answer: False Difficulty: Difficult ASM Standard: N/A Matching 43. Match each term for bacterial cell arrangement with the correct illustration.

Answers: A. iii., B. v., C. ii., D. iv., E. i.

Difficulty: Easy ASM Standard: N/A 44. Match each type of solution with its best description.

A. hypertonic i. a solution with a lower solute concentration than that inside the cell B. hypotonic ii. a solution with a concentration equivalent to that inside of the cell C. isotonic iii. a solution with a higher solute concentration than that inside the Page 44 of 17

cell Answers: A. iii., B. i., C. ii.

Difficulty: Moderate ASM Standard: 20 45. Match each organelle with its best description.

A. chloroplast i. is acidic; contains digestive enzymes B. Golgi apparatus ii. synthesizes proteins C. lysosome iii. has its own DNA; is site of cellular respiration D. mitochondrion iv. has its own DNA; is site of photosynthesis E. rough endoplasmic reticulum v. modifies materials and packages them into vesicles Answers: A. iv., B. v., C. i., D. iii, E. ii.

Difficulty: Moderate ASM Standard: N/A 46. Match each organelle with its best description.

A. nucleus i. used for lipid synthesis and detoxification B. peroxisome ii. used to transport materials C. smooth endoplasmic reticulum iii. contains DNA D. vesicle iv. produces and degrades hydrogen peroxide; involved in lipid biosynthesis Answers: A. iii., B. iv., C. i., D. ii.

Difficulty: Moderate ASM Standard: N/A 47. Match each cytoskeletal component with its best description.

A. intermediate filaments i. contain tubulin; found in cilia and flagella; move materials and organelles in the cell B. microfilaments ii. composed of a variety of materials; important in nuclear lamina, joining cells, and other functions C. microtubules iii. contain actin and work with motor proteins; used for amoeboid motion, cell motility, cell division, and muscle contraction in animals Answers: A. ii., B. iii., C. i.

Difficulty: Moderate ASM Standard: 9 48. Match each cell’s characteristics with the correct domain or domains. Some domains may be used more than once.

A. have 70S ribosomes as the major i. Archaea ribosome type (no 80S ribosomes) B. have ether linkages in phospholipids ii. Bacteria C. have histones or histone-like proteins iii. Eukarya Page 45 of 17

D. have peptidoglycan cell walls E. have sterols in the cell membrane Answers: A. i. and ii, B. i., C. i. and iii., D. ii., E. iii.

Difficulty: Difficult ASM Standard: 8, 9 Fill in the Blank 49. The is the outermost portion of an endospore.

Answer: exosporium Difficulty: Easy ASM Standard: 8 50. The plasma membrane is a(n) Answer: phospholipid

bilayer.

Difficulty: Easy ASM Standard: N/A 51. Microtubules are filaments composed of Answer: Tubulin

dimers.

Difficulty: Easy ASM Standard: N/A 52. The theory that states chloroplasts and mitochondria arose from prokaryotes that lived within other cells is the theory.

Answer: endosymbiotic Difficulty: Moderate ASM Standard: 1 53. The model is the model currently used to explain the structure of the plasma membrane.

Answer: fluid mosaic Difficulty: Moderate ASM Standard: N/A 54. The general term for molecules that bind to structures such as receptors, including the molecules that bind to receptors in cell-mediated endocytosis, is .

Answer: ligand Difficulty: Moderate ASM Standard: N/A Page 46 of 17

55. Most cell membranes are phospholipid bilayers, but archaeans sometimes have phospholipid .

Answer: monolayers Difficulty: Moderate ASM Standard: 8 56. The first known epidemiological study found that the disease from wells in London.

Answer: cholera

was being spread

Difficulty: Moderate ASM Standard: 23 57. Some large molecules, viruses, and bacteria enter eukaryotic cells using endocytosis.

Answer: receptor-mediated Difficulty: Moderate ASM Standard: N/A 58. If a protozoan cell (with no cell wall) is placed into distilled water (with all solutes removed), water would flow the cell and the cell would .

Answer: into, lyse Difficulty: Difficult ASM Standard: 22 59.

is a form of transport used by bacteria, but not by eukaryotic cells, to move materials across the cell membrane and into the cell.

Answer: Group translocation Difficulty: Difficult ASM Standard: 22

Short Answer 60. What two terms describe molecules that consist of protein and carbohydrate?

Sample Answer: A protein with a sugar component is called a glycoprotein or proteoglycan, depending on its specific structure.

Difficulty: Easy ASM Standard: N/A

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61. What type of organisms sometimes have a plasma membrane that is a monolayer?

Sample Answer: Some archaeans have a plasma membrane that is amonolayer.

Difficulty: Easy ASM Standard: 8 62. What is an extracellular matrix and what functions can it perform?

Sample Answer: Cells that lack a cell wall, such as animal cells, often have an extracellular matrix of carbohydrate and protein (proteoglycans). This helps provide structure and stability, among other functions.

Difficulty: Easy ASM Standard: N/A 63. What is a hydrogenosome?

Sample Answer: Hydrogenosomes are organelles found in some anaerobic eukaryotes. They resemble mitochondria, are used to produce hydrogen anaerobically, and typically do not have DNA or ribosomes.

Difficulty: Easy ASM Standard: N/A 64. What is the difference between phagocytosis and pinocytosis?

Sample Answer: Phagocytosis is a type of endocytosis in which large particles are engulfed.

In contrast, small molecules or liquids are taken up through pinocytosis.

Difficulty: Moderate ASM Standard: N/A 65. Both prokaryotes and eukaryotes have ribosomes, but some antibiotics specifically target prokaryotic ribosomes. How is it possible to use these antibiotics to treat human diseases and how do they affect eukaryotic cells?

Sample Answer: All medications can potentially have harmful effects, but it is possible to target prokaryotic ribosomes without targeting eukaryotic cytoplasmic ribosomes, because they are different. Prokaryotes have 70S ribosomes and eukaryotes have 80S cytoplasmic ribosomes. However, eukaryotic organelle ribosomes are 70S ribosomes and these can potentially be harmed by these antibiotics, resulting in negative side effects.

Difficulty: Moderate ASM Standard: 7, 14, 23 66. Why is the plasma membrane considered a fluid mosaic?

Sample Answer: The phospholipids in the plasma membrane are considered fluid in that they can move within the membrane. Proteins are embedded in the membrane in a mosaic and are also often capable of movement although they may be anchored in place.

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Difficulty: Moderate ASM Standard: N/A 67. What is the difference between facilitated transport and active transport?

Sample Answer: Facilitated transport and active transport both use proteins as carriers or channels to transport materials across the cell membrane. However, facilitated transport moves materials down their concentration gradient without requiring energy, whereas active transport moves materials up their concentration gradient (i.e., from low to high concentration), which requires energy to power the process.

Difficulty: Moderate ASM Standard: 22 68. How do the components of bacterial cell walls differ from the components of archaeal cell walls?

Sample Answer: Bacterial cell walls commonly contain peptidoglycan, whereas archaeal cell walls do not. There is more diversity in archaeal cell wall composition. Archaeal cell walls may contain pseudopeptidoglycan, glycopeptide, polysaccharide, or protein.

Difficulty: Moderate ASM Standard: 8 69. How do eukaryotic cell wall components differ from bacterial cell wall components?

Sample Answer: The major component of bacterial cell walls is peptidoglycan. Many eukaryotes lack cell walls. In eukaryotes that have cell walls, the major components are cellulose, chitin, silica, agar, calcium carbonate, or carrageenan.

Difficulty: Moderate ASM Standard: 9 70. Prokaryotes do not have chloroplasts, but some are photosynthetic. What structures do cyanobacteria use for photosynthesis?

Sample Answer: Cyanobacteria use sections of their plasma membrane, where it is folded into thylakoids, for photosynthesis.

Difficulty: Moderate ASM Standard: 8 71. How do prokaryotic flagella differ from eukaryotic flagella?

Sample Answer: Prokaryotic flagella are rigid and made up of different material (i.e., flagellin or the archaeal equivalent [students may use the term “archaellin,” but it is not in the text]). Eukaryotic flagella are more flexible and consist of tubulin, with microtubules that are arranged in pairs in a 9+2 array. In contrast, prokaryotic flagella consist of stiff spiral filaments. The movement of the flagella differs: Prokaryotes have a propeller-like motionand eukaryotes have a whiplike motion.

Difficulty: Moderate Page 49 of 17

ASM Standard: 8 72. Lysosomes are used for digestion in eukaryotes.What is an advantage of having a specialized structure for this purpose?

Sample Answer: Lysosomes are acidic and contain digestive enzymes. By having these in a compartment, it prevents the lysosomal contents from damaging other parts of the cell.

Difficulty: Moderate ASM Standard: 9 73. Giardia lamblia is a protist that causes gastrointestinal disease in humans. It hasmitosomes, which appear to be reduced mitochondria. It also has reduced endoplasmic reticulum and Golgi apparati. Why do you think this species is able to survive with reduced cellular components?

Sample Answer: Giardia lamblia is a parasite, so it can rely on its host for many functions.

Because it can obtain these functions from its host, it no longer needs the machinery to make them itself.

Difficulty: Difficult ASM Standard: 9 74. Penicillin inhibits cell wall synthesis in bacteria. Under certain conditions, bacteria can survive without a cell wall. Why is penicillin often effective in killing pathogenic bacteriaby inhibiting cell wall synthesis? Under what conditions would bacteria be able to survive penicillin treatment?

Sample Answer: Penicillin damages growing cell walls by inhibiting cell wall synthesis.

Once the cell wall is damaged, the bacterial cell can survive in an isotonic solution. However, bacteria often live in hypotonic environments, so water would flow into cells lacking cell walls and the cells would burst. Bacteria could survive penicillin treatment if they were in an isotonic solution. (Students may also mention that bacteria could survive better if they were not actively growing and synthesizing penicillin).

Difficulty: Difficult ASM Standard: 7, 14, 23 Brief Essay Essay Question Rubric RATING Failing Criteria for evaluati on

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is

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Below Average Answer fails to provide examples to support an argument.

Writing is poor and

Competent

Advanced

Answer provides an argument with one or two examples that support it.

Writing is

Answer clearly provides an argument with two or more excellent examples that support it;

poor and contains numerous grammatical mistakes and misspellings.

grammatical errors are common.

Answer is somewhat incoherent.

acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

0 1 2 3 POINT VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

75. Mitochondria are unable to survive outside of eukaryotic cells. If they originated from ancestral prokaryotes, as proposed by the endosymbiotic theory, then why can’t they survive independently?

Answer: Student answers will vary but should include components of the following. Over time, mitochondria and their host cells evolved to be dependent on each other. For example, many mitochondrial genes transferred to the cell nucleus. This means that the mitochondrion does not have all its genes; therefore, it cannot perform all its functions if it is removed from the eukaryotic cell.

Difficulty: Moderate ASM Standard: 1 76. Explain what happens during sporulation.

Answer: Student answers will vary but should include the following. When conditions become unfavorable, some bacterial cells can form endospores. First, they copy their DNA and a membrane forms around it. A septum divides the cell, forming a forespore that will form the core of the endospore. A cortex containing calcium and dipicolinic acid is formed surrounding the forespore. As a protein spore coat forms, the outer cell develops into an exosporium, which is released from the parent cell. (This is summarized in Figure 3.20).

Difficulty: Moderate ASM Standard: 8 77. In osmosis, water moves across a semipermeable membrane in response to a concentration gradient. For example, osmosis could occur if a cell were placed into a solution of concentrated NaCl. Why don’t the sodium and chloride ions cross the membrane instead of just water?

Answer: Student answers will vary but should include the following. The cell membrane has a hydrophobic layer at the middle of its phospholipid bilayer. Charged ions cannot easilypass through this layer, even if they are very small. Because the sodium and chloride ions are charged, they do not pass through the membrane unless transported through a protein.

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Instead, water moves through the membrane through osmosis in response to the concentration difference.

Difficulty: Difficult ASM Standard: 22 78. You discover a new species of microbe and begin to study its characteristics. It lacks any mitochondria but has some membranous internal structures. It lacks a cell wall; however, it has a nucleus with a very small quantity of DNA. What do you think is the best classification for this organism? How can it function?

Answer: Student answers will vary but should include components of the following. This species must be eukaryotic because it has a nucleus. It is probably parasitic and able to use resources from its host, allowing it to survive without its own mitochondria, with fewer genes, and with reduced organelles.

Difficulty: Difficult ASM Standard: 9, 22, 28

This file is copyright 2017, Rice University. All rights reserved.

Chapter 4: Prokaryotic Diversity * = Correct answer Multiple Choice 1. Which is the best example of a population?

A. all the microbes living in a particular area B. all the microbes of a particular domain living in a particular area C. all the microbes of a single species living in a particular area* D. all the microbes living within the same host Difficulty: Moderate ASM Standard: 20 2. Microbial ecology is defined as the study of which of the following?

A. competitive interactions between microbes B. cooperative interactions between microbes C. interactions between individuals of a single species D. interactions between microbial populations and their environment* Difficulty: Easy ASM Standard: 20 3. Which term best describes the relationship between pathogenic bacteria and humans?

A. amensalism B. commensalism C. parasitism* D. predation Difficulty: Moderate ASM Standard: 23 4. Which of the following is not a class within the phylum Proteobacteria?

A. Alphaproteobacteria B. Betaproteobacteria C. Deltaproteobacteria D. Omegaproteobacteria* Difficulty: Easy ASM Standard: N/A 5. Which of the following correctly characterizes Epsilonproteobacteria?

A. They are atypical (not gram positive or gram negative).

B. They are gram negative.* C. They are gram positive.

D. They are gram variable.

Difficulty: Easy ASM Standard: 34 6. Which describes bacteria that require low concentrations of oxygen to survive (less than that in the current atmosphere)?

A. facultative anaerobes B. microaerophiles* C. obligate aerobes D. obligate anaerobes Difficulty: Easy ASM Standard: 11, 22 7. Cyanobacteria produce which of the following?

A. hydrogen sulfide gas B. large quantities of ammonia C. oxygen* D. sulfuric acid Difficulty: Easy ASM Standard: 11, 22 8. Which of the following bacterial groups is thought to be most closely related to the last universal common ancestor?

A. Alphaproteobacteria B. cyanobacteria C. deeply branching bacteria* D. green filamentous bacteria Difficulty: Easy ASM Standard: 5 9. Which of the following is a phylum in Domain Archaea?

A. Crenarchaeotae* B. Deinococcus C. Mycoplasma D. Thermotogae Difficulty: Easy ASM Standard: 5 10. Which genus contains the nitrogen-fixing bacteria that live in legume nodules?

A. Bacillus B. Escherichia

C. Rhizobium* D. Vibrio Difficulty: Moderate ASM Standard: 11, 24 11. Approximately what percentage of prokaryotes are thought to be pathogens?

A. <1%* B. 12% C. 26% D. 48% Difficulty: Moderate ASM Standard: 23 12. Two species of bacteria live in near each other and use similar food resources. Which type of biological interaction does this describe?

A. a competitive interaction* B. a cooperative interaction C. a mutualistic interaction D. a parasitic interaction Difficulty: Moderate ASM Standard: 23

13. Which of the following is a source of vitamin K for humans?

A. Bacteroides thetaiotetraiotamicron digests foods, which release vitamin K. B. Escherichia coli in their digestive tract produces vitamin K.* C. S. epidermidis releases vitamin K from dead cells.

D. their diet only Difficulty: Moderate ASM Standard: 23, 24 14. The human microbiome consists of which of the following?

A. all microbes present on or in the body* B. pathogenic microbes only C. resident microbes only D. transient microbes only Difficulty: Moderate ASM Standard: 23

15. The most common bacterial genus found in plaque on teeth is which of the following?

A. Fusobacterium* B. Haemophilus C. Lactobacillus D. Streptococcus Difficulty: Moderate ASM Standard: 23 16. Who authored A Manual in Determinative Bacteriology, published in 1923?

A. David Bergey* B. Robert Koch C. Barry Marshall and Robin Warren D. Louis Pasteur Difficulty: Moderate ASM Standard: N/A 17. Which of the following cannot be classified as either gram positive or gram negative on the basis of the Gram staining protocol?

A. Bacillus B. Escherichia C. Mycoplasma* D. Vibrio Difficulty: Moderate ASM Standard: N/A 18. Bordetella pertussis is an example of which group of organisms?

A. Cytophaga-Flavobacterium-Bacteroides B. high G+C bacteria C. Proteobacteria* D. spirochetes Difficulty: Moderate ASM Standard: N/A 19. Treponema pallidum, the causative agent of syphilis, is an example of which group of organisms?

A. CFB group B. planctomycetes C. proteobacteria D. spirochetes* Difficulty:

Moderate ASM Standard: N/A 20. Which of the following correctly describes the microscopic morphology of Bacteroides?

A. gram-negative bacilli* B. gram-negative cocci C. gram-positive bacilli D. gram-positive cocci Difficulty: Moderate ASM Standard: N/A 21. Which best describes the metabolic activities of purple sulfur bacteria?

A. They are capable of nitrogen fixation, fixing nitrogen gas into nitrates and ammonia.

B. They are heterotrophic and break down organic compounds to obtain energy.

C. They use light energy to oxidize hydrogen sulfide, producing sulfur and sulfuric acid.* D. They use light energy to oxidize organic compounds such as sugars.

Difficulty: Moderate ASM Standard: 11 22. How do Archaea differ from Bacteria?

A. Archaea are found exclusively in extreme habitats.

B. Archaea have ether linkages in their cell membranes.* C. Archaea have peptidoglycan cell walls.

D. Archaea lack a nucleus.

Difficulty: Moderate ASM Standard: 8 23. Which of the following correctly describes the metabolism of methanogens?

A. They oxidize CO 2 .

B. They oxidize H 2 S. C. They produce CH4 .* D. They produce N 2 gas.

Difficulty: Moderate ASM Standard: 11 24. Which best describes Halobacterium salinarum?

A. It is a type of methanogen.

B. It is abundant in temperate environments.

C. It is an example of the deeply branching bacteria.

D. It is one of the oldest archaea.* Difficulty: Moderate ASM Standard: 5 25. Which of the following is the correct classification for the methanogens?

A. Archaea* B. low G+C bacteria

C. Proteobacteria D. spirochetes Difficulty: Moderate ASM Standard: 11 26. Which best describes Crenarchaeota?

A. aquatic archaea abundant in oceans* B. aquatic bacteria abundant in oceans C. archaea that cause dental disease D. pathogenic bacteria that infect animals Difficulty: Moderate ASM Standard: 11 27. The LPSN refers to which of the following?

A. a guide to bacterial identification B. a list of approved bacterial names* C. a taxonomic key to aid identification of bacteria D. an overview of current bacterial systematics Difficulty: Difficult ASM Standard: N/A 28. Which of the following is not a genus of Betaproteobacteria?

A. Bordetella B. Chlamydia* C. Leptothrix D. Thiobacillus Difficulty: Difficult ASM Standard: N/A 29. Which of the following bacterial genera is microaerophilic?

A. Bdellovibrio B. Campylobacter* C. Klebsiella D. Pseudomonas Difficulty: Difficult ASM Standard: 11, 20, 22 30. Rhodospirillum, a genus capable of fixing nitrogen, is a type of which of the following?

A. green nonsulfur bacteria B. green sulfur bacteria purple nonsulfur bacteria*

C. purple sulfur bacteria Difficulty: Difficult ASM Standard: 11 31. Which genus, believed to be the deepest-branching archaeal genus, has flagella and is strictly anaerobic?

A. Methanosarcina B. Pyrolobus C. Sulfolobus D. Thermoproteus* Difficulty: Difficult ASM Standard: 5, 20 32. Which best describes the class Halobacteria?

A. archaeans that require highly saline environments* B. archaeans that require methane-rich environments C. bacteria that require highly arid environments D. bacteria that require highly saline environments Difficulty: Difficult ASM Standard: 20 33. Methanobrevibacter oralis is an example of which type of organism?

A. a bacterium that takes advantage of the conditions caused by immunosuppression, as can occur during cancer treatment B. a pathogenic archaean C. a pathogenic bacterium D. an archaean that takes advantage of the conditions caused by periodontal disease to grow; may or may not affect disease progression* Difficulty: Difficult ASM Standard: 23 34. A toga is which of the following?

A. a structure produced by the fungus Tolypocladium inflatum that has medicinal uses B. an outer membrane found in a taxon within the deeply branching bacteria* C. an outer peptidoglycan layer found in a taxon within the proteobacteria D. an unusual cell wall found in some archaeans Difficulty: Difficult ASM Standard: 8 True/False

35. The bacterial species found associated with the human body are very similar from one individual to another.

Answer: False Difficulty: Easy ASM Standard: 21, 23 36. The phototrophic bacteria do not form a distinct taxonomic group.

Answer: True Difficulty: Easy ASM Standard: 5, 11 37. Although Archaea cannot be classified as gram positive or gram negative, all Bacteria can be classified into one of these two categories.

Answer: False Difficulty: Moderate ASM Standard: 5 38. Spirochetes are generally easy to culture in the laboratory.

Answer: False Difficulty: Moderate ASM Standard: 11, 36 39. The deeply branching bacteria contain species that have evolved most recently.

Answer: False Difficulty: Moderate ASM Standard: 5 40. All the bacteria classified within the genus Bacillus are capable of forming endospores.

Answer: True Difficulty: Moderate ASM Standard: 8 41. Mycoplasmas are bacteria that lack cell walls.

Answer: True Difficulty: Moderate ASM

Standard: 8 42. Phototrophic bacteria may have carotenoids, which are the red and orange pigments also used as accessory pigments by plants.

Answer: True Difficulty: Difficult ASM Standard: 11 43. The class Bacilli includes both rod-shaped and spherical bacterial species.

Answer: True Difficulty: Difficult ASM Standard: N/A Matching 44. Match each type of association with the best definition.

A. amensalism i. neither organism affects the other B. commensalism ii. both organisms benefit C. mutualism iii. one organism benefits and the other is harmed D. neutralism iv. one organism is harmed and the other is not affected E. parasitism v. one organism benefits and the other is not affected Answers: A. iv., B. v., C. ii., D. i., E. iii.

Difficulty: Moderate ASM Standard: 20, 23 45. Match each type of association with the best example.

A. amensalism i. A mold produces a chemical that kills bacteria without apparently benefiting.

B. commensalism ii. A helminth takes up residence in a human digestive tract, consuming nutrients.

C. mutualism iii. Flagellates live in the gut of termites, feeding on the wood consumed by the termite and allowing the termite access to nutrition and energy in wood that they could not otherwise digest.

D. parasitism iv. Aerobic bacteria in the human colon consume oxygen, making it possible for anaerobic species to survive.

Answers: A. i., B. iv., C. iii., D. ii.

Difficulty: Moderate ASM Standard: 20, 23 46. Match each genus with the appropriate class of Proteobacteria.

A. Alphaproteobacteria i. Myxobacterium B. Betaproteobacteria ii. Rickettsia C. Deltaproteobacteria iii. Neisseria

D. Epsilonproteobacteria E. Gammaproteobacteria

iv. Escherichia v. Helicobacter

Answers: A. ii., B. iii., C. i., D. v., E. iv.

Difficulty: Moderate ASM Standard: N/A 47. Match each low G+C bacterial genus with the best description of its morphology.

A. Clostridium i. chains or pairs of cocci B. Enterococcus ii. pairs of cocci, not chains C. Mycoplasma iii. gram-positive rods D. Streptococcus iv. relatively small, pleomorphic Answers: A. iii., B. ii., C. iv., D. i.

Difficulty: Moderate ASM Standard: 34 48. Match each genus of Actinobacteria with its best description.

A. Actinomyces i. facultative anaerobes; can live in soil and can be associated with periodontal disease B. Bifidobacterium ii. found in the human vagina and associated with vaginosis C. Corynebacterium iii. associated with legumes and fix nitrogen D. Frankia iv. can be aerobes or facultative anaerobes; form palisades E. Gardnerella . aAnN aeKroSbE icLbLacEtR er. iaCcO om STvB Mmon in the human gut Answers: A. i., B. v., C. iv., D. iii., E. ii.

Difficulty: Moderate ASM Standard: 20, 23 49. Match each group of bacteria with its best description.

A. deeply branching bacteria i. large group of gram-negative bacteria that includes five diverse classes B. high G+C bacteria ii. gram-positive group that includes the Actinobacteria C. low G+C bacteria iii. gram-positive group that includes the Bacilli D. nonproteobacteria iv. many thrive at high temperatures and in harsh environments; believed to have similarities with ancient bacteria E. Proteobacteria v. gram-negative bacteria including the spirochetes, GFC group, and planctomyces Answers: A. iv., B. ii., C. iii., D. v., E. i.

Difficulty: Difficult ASM Standard: 34 Fill in the Blank 50.

is the domain that includes the Crenarchaeota and Euryarchaeota.

Answer: Archaea Difficulty: Easy ASM Standard: N/A

51. The class consists of high G+C bacteria.

Answer: Actinobacteria Difficulty: Easy ASM Standard: N/A 52. Green and purple bacteria perform photosynthesis using green, purple, or blue pigments called .

Answer: bacteriochlorophylls Difficulty: Moderate ASM Standard: 11 53. Purple sulfur bacteria use Answer: carbon dioxide

as their source of carbon.

Difficulty: Moderate ASM Standard: 23, 24 54. Variability in cellular shape, as exemplified by mycoplasmas, is described by the term .

Answer: pleomorphic Difficulty: Moderate ASM Standard: N/A 55. The is a class of Proteobacteria characterized by oligotrophy and that includes chlamydias and the rickettsias.

Answer: Alphaproteobacteria Difficulty:

Moderate ASM Standard: N/A 56. Organisms that must live within the cells of their hosts are Answer: obligate intracellular

pathogens.

Difficulty: Moderate ASM Standard: N/A 57. The Halobacteria are classified within the archaeal phylum Answer: Euryarchaeota

.

Difficulty: Moderate ASM Standard: N/A 58. A special growth medium called Neisseria.

Answer: chocolate

agar is required to culture members of the genus

Difficulty: Moderate ASM Standard: 33, 36 59. The medically important genus Salmonella is classified within the Gammaproteobacteria.

Answer: Enterobacteriaceae

family of the

Difficulty: Difficult ASM Standard: N/A Short Answer 60. What is the term for different strains within a bacterial species, also called serotypes?

Sample Answer: Different strains within a bacterial species are called serovars.

Difficulty: Easy ASM Standard: N/A 61. Which genus of Gammaproteobacteria is associated with infections in patients with cystic fibrosis?

Sample Answer: Pseudomonas spp. is especially important as a cause of infections associated with cystic fibrosis.

Difficulty: Easy ASM Standard: 23

62. What is unusual about the morphology of myxobacteria?

Sample Answer: Myxobacteria are social and capable of forming multicellular structures called fruiting bodies.

Difficulty: Easy ASM Standard: N/A 63. How do cyanobacteria obtain energy?

Sample Answer: Cyanobacteria are photosynthetic and can convert light energy from the sun to chemical energy they can use.

Difficulty: Easy ASM Standard: 11 64. What is the major way that purple nonsulfur and purple sulfur bacteria differ?

Sample Answer: Purple sulfur bacteria use hydrogen sulfide for oxidation and purple nonsulfur bacteria use hydrogen for oxidation.

Difficulty: Moderate ASM Standard: 11 65. Why are bacteria in the CFB group classified together even though they are phylogenetically diverse?

Sample Answer: Although this group is phylogenetically diverse and not monophyletic, they share important similarities. They share some DNA sequences, are gram-negative rods, and grow anaerobically by fermentation.

Difficulty: Moderate ASM Standard: N/A 66. What is the role of Bacteroides in the human gut and what are the effects of antibiotic use on them?

Sample Answer: Bacteroides lives in a mutualistic relationship with humans. Humans provide nutrients and the Bacteroides help prevent the establishment of pathogenic bacteria in the human gut. When Bacteroides populations are decreased because of antibiotic use, AN the risk increases of harmful specTieEsSbT e cB om i nK gSmEoL reLaE buRn.dC anOt.M Difficulty: Moderate ASM Standard: 14, 22, 23 67. Describe the classification and characteristics of Helicobacter pylori. Why is it of medical importance?

Sample Answer: Helicobacter pylori is classified in the Epsilonproteobacteria and is a gram- negative, spiral-shaped rod. It is of medical importance because it is associated with gastritis, stomach ulcers, and cancer of the stomach and duodenum.

Difficulty: Moderate ASM Standard: 14, 23 68. Which taxonomic groups of bacteria are considered phototrophic groups? List the groups and provide examples.

Sample Answer: The phototrophic bacteria include Proteobacteria and nonproteobacteria.

Phototrophic bacteria are found in the Proteobacteria and the nonproteobacteria. They include the green sulfur bacteria, the green nonsulfur bacteria, the purple sulfur bacteria, the purple nonsulfur bacteria, and the cyanobacteria.

Difficulty: Moderate ASM Standard: 22 69. What is the difference between oxygenic and anoxygenic photosynthesis?

Sample Answer: Oxygenic photosynthesis produces oxygen and anoxygenic photosynthesis does not. The cyanobacteria use oxygenic photosynthesis, but most prokaryotes use anoxygenic photosynthesis.

Difficulty: Moderate ASM Standard: 11, 22 70. What are chlorosomes?

Sample Answer: Chlorosomes are structures that resemble organelles and are used for photosynthesis in green sulfur and green nonsulfur anoxygenic phototrophic bacteria.

They contain bacteriochlorophyll and are found in bacteria such as members of the genera Chlorobium and Chloroflexus.

Difficulty: Moderate ASM Standard: 11 71. What are at least two differences between Archaea and Bacteria??

Sample Answer: Archaeans have ether-linked phospholipids in their cell membranes, whereas bacteria have ester-linked phospholipids. Also, most bacteria have peptidoglycan in their cell walls, whereas archaeans have other materials, such as pseudopeptidoglycan.

Difficulty: Moderate ASM Standard: N/A 72. In which environment would purple sulfur bacteria more likely live: acidic, alkaline, or neutral environment? Explain why.

Sample Answer: Purple sulfur bacteria oxidize hydrogen sulfide, producing sulfur and sulfuric acid as products. Unless other processes remove or neutralize the acid, their surroundings will tend to be acidic from the sulfuric acid produced.

Difficulty: Difficult ASM Standard: 11, 22 73. Why are myxobacteria useful in studying intercellular communication?

Sample Answer: Myxobacteria can form multicellular structures known as fruiting bodies. Understanding how the cells communicate with each other to form this complex structure requires understanding intercellular communication. Therefore, myxobacteria provide a system that may be helpful in understanding intercellular communication in other species.

Difficulty: Difficult ASM Standard: 22, 25 74. Why do purple sulfur bacteria require sulfites?

Sample Answer: These bacteria need sulfites as sources of electrons.

Difficulty: Difficult ASM Standard: 11, 22 Brief Essay Essay Question Rubric Failin Below RATING g Average Criteria Answer does Answer fails to for not provide an provide evaluatio argument. examples to Answer contains support an n inaccuracies. argument.

Writing is Writing is poor poor and and grammatical contains errors are numerous common. grammatical Answer is mistakes and somewhat misspellings. incoherent.

Competen t Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

POINT 0 1 2 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Advance d Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

3

75. The Epsilonbacteria include two genera of particular medical importance. What are these two genera and why are they important?

Answer: Student answers will vary but should include components of the following. The two genera are Campylobacter and Helicobacter. C. jejuni is associated with food poisoning that causes enteritis. H. pylori can be asymptomatic but is also associated with gastritis, ulcers, and cancer of the stomach and duodenum.

Difficulty: Moderate ASM Standard: 22, 23 76. The term “neutralism” technically means an interaction in which two species do not affect each other. Is this likely to occur when two organisms exist in the same location? Explain why this particular type of interaction is difficult to identify and why some argue that it may not exist in nature.

Answer: Student answers will vary but should include components of the following.

Organisms that live in the same location may have indirect effects on each other that are not easily observable or measured, especially if they use the same resources and space. Even when organisms appear distinct, all the organisms in the community are likely interconnected in some direct or indirect ways. This makes it difficult to conclude that a relationship is completely neutral, with neither organism having any effect on the other.

Difficulty: Moderate ASM Standard: 20, 22, 23 77. Mycoplasmas are considered atypical, rather than gram positive or gram negative. Why is it not possible to use a standard Gram stain technique to classify these bacteria? What color would they appear if stained using a Gram stain technique?

Answer: Student answers will vary but should include components of the following.

Mycoplasmas do not have a cell wall. The Gram stain technique differentially stains bacteria on the basis of whether they have a relatively thick peptidoglycan layer that holds in the crystal violet stain (gram positive) or a thinner peptidoglycan layer with an outer membrane that lets out crystal violet when decolorized with ethanol. Mycoplasmas do not fit into either of these categories because they do not have a cell wall. If stained using a Gram stain technique, they would not have a thick peptidoglycan layer to hold in the crystal violet stain and, therefore, would show the color of the counterstain (usually pink from safranin).

Difficulty: Moderate ASM Standard: 32, 34 78. Methanobrevibacter oralis is an archaean that has been identified in patients with periodontal disease. Explain how this finding does not necessarily mean causation and what would be needed to conclude that an archaean was responsible for a particular disease.

Answer: Student answers will vary but should include the following. These archaeans have

been found in patients with periodontal disease, but research suggests they are taking advantage of the environment produced by the disease rather than being a cause of the CeOmMber that finding a correlation is disease. This is an example ofTE whSyTiB t iA sN imKpS oE rtaLnL t E t oRr. em not the same as showing causation. So far, no archaean has been found to cause disease. If needed, Koch’s postulates could be used to examine a possible pathogenic archaean. If the organism could be isolated from individuals with the disease, and infecting other individuals with the organism caused the disease, then that would provide more substantial evidence of a causal relationship. It is not always possible to use Koch’s postulates. For example, it would be unethical to infect someone with a potentially dangerous pathogen. In those cases, it would be important to carefully look for the pathogen in individuals with and without the disease and to examine changes over time associated with having the microbe present, including differences in disease outcomes.

Difficulty: Difficult ASM Standard: 23, 28 79. When scientists first proposed that Helicobacter pylori might be associated with stomach ulcers, other scientists were very skeptical of their conclusions. One of the researchers eventually consumed a sample and documented the effects, dramatically showing that the bacterium could cause gastrointestinal symptoms. Why do you think scientists were initially skeptical that a bacterium, rather than stress and lifestyle factors, could be responsible for gastritis, ulcers, and stomach cancer?

Answer: Student answers will vary but should include components of the following. The stomach is very acidic, containing digestive enzymes as well, and it had seemed unlikely that bacteria could survive in such a hostile environment. The findings regarding H. pylori led to further research demonstrating that H. pylori and other species can survive in the stomach through a variety of mechanisms. For example. H. pylori modifies its immediate surroundings using enzymes.

Difficulty: Difficult ASM Standard: 14, 22, 23

This file is copyright 2017, Rice University. All rights reserved.

OpenStax Microbiology Test Bank Chapter 5: The Eukaryotes of Microbiology

Chapter 5: The Eukaryotes of Microbiology * = Correct answer Multiple Choice 1. Protozoa are best described as being: A. nonphotosynthetic multicellular microorganisms B. nonphotosynthetic unicellular microorganisms* C. photosynthetic multicellular microorganisms D. photosynthetic unicellular microorganisms Difficulty: Easy ASM Standard: 9 2. Which of the following best describes zooplankton?

A. eukaryotes that are nonphotosynthetic and motile* B. eukaryotes that are photosynthetic and motile C. prokaryotes that are nonphotosynthetic and nonmotile D. prokaryotes that are photosynthetic and nonmotile Difficulty: Easy ASM Standard: 9 3. Where is the pellicle found within a protozoan?

A. as part of cilia B. beneath the cell membrane* C. surrounding the nucleus D. within chloroplasts Difficulty: Easy ASM Standard: 13 4. Which of the following is not a structure used for locomotion by protists?

A. cilia B. contractile vacuoles* C. flagella D. pseudopods Difficulty: Moderate ASM Standard: 9 5. Which structures associated with locomotion in protists can be described as short, hair-like structures that extend from the surface of the cell?

A. cilia* B. contractile vacuoles

Page 1 of 14

OpenStax Microbiology Test Bank Chapter 5: The Eukaryotes of Microbiology

C. flagella D. pseudopods Difficulty: Easy ASM Standard: 9 6. Pseudopod formation requires which cytoskeletal component?

A. actin filaments* B. collagen fibers C. intermediate filaments D. microtubules Difficulty: Moderate ASM Standard: 9 7. The organelle in protists that regulates osmolarity is known as which of the following?

A. contractile vacuole* B. hydrogenosome C. kinetoplasmid D. plasmalemma Difficulty: Easy ASM Standard: 12 8. Cytoprocts are specialized structures that carry out which cellular process?

A. endocytosis B. exocytosis* C. phagocytosis D. syngamy Difficulty: Moderate ASM Standard: 12 9. Which organism is best known as the “brain-eating amoeba”?

A. Acanthamoeba keratitis B. Entamoeba histolytica C. Giardia lamblia D. Naegleria fowleri* Difficulty: Moderate ASM Standard: N/A 10. An important slime mold used in research is Dictyostelium discoideum. In this species, individual amoeboid cells that aggregate into multicellular mobile slugs, each forming a fruiting body that produces haploid spores, are known as which of the following?

A. cellular slime molds*

Page 2 of 14

OpenStax Microbiology Test Bank Chapter 5: The Eukaryotes of Microbiology

B. plasmodium slime molds C. pseudohyphae D. sporangia Difficulty: Moderate ASM Standard: N/A 11. During the asexual life cycle described in the textbook, cellular slime molds produce which of the following?

A. gametes B. spores* C. gametes and spores D. neither gametes nor spores Difficulty: Moderate ASM Standard: N/A 12. Plasmodial slime molds produce which of the following: A. gametes but no spores B. gametes that divide into spores C. spores but no gametes D. spores that divide into gametes* Difficulty: Moderate ASM Standard: 13 13. The apical complex of Apicomplexans such as Plasmodium is involved in which cellular process?

A. binary fission B. entry into host cells* C. phagocytosis D. photosynthesis Difficulty: Moderate ASM Standard: 23 14. Which of the following is a parasitic ciliate?

A. Balantidium coli* B. Escherichia coli C. Paramecium caudatum D. Stentor coeruleus Difficulty: Moderate ASM Standard: 23 15. The stigma (eyespot) in members of Euglenozoa functions in which of the following?

Page 3 of 14

OpenStax Microbiology Test Bank Chapter 5: The Eukaryotes of Microbiology

A. chemotaxis B. conjugation C. photosynthesis D. phototaxis* Difficulty: Moderate ASM Standard: N/A 16. African sleeping sickness is caused by which pathogen?

A. Giardia lamblia B. Plasmodium falciparum C. Toxoplasma gondii D. Trypanosoma bruceii* Difficulty: Moderate ASM Standard: 23 17. Cestodes are often transmitted via which of the following?

A. aerosols B. open wounds in the skin C. undercooked meats* D. water Difficulty: Moderate ASM Standard: 23 18. The cell walls of fungi are largely composed of which of the following?

A. cellulose B. chitin* C. peptidoglycan D. starch Difficulty: Easy ASM Standard: N/A 19. Which of the following includes fungi used as food (such as truffles), bread molds, and pathogenic fungi such as Trichophyton?

A. Ascomycota* B. Basidiomycota C. Chytridiomycota D. Zygomycota Difficulty: Easy ASM Standard: 5 20. Most mushrooms and puffballs are members of which fungal phylum?

Page 4 of 14

OpenStax Microbiology Test Bank Chapter 5: The Eukaryotes of Microbiology

A. Ascomycota B. Basidiomycota* C. Chytridiomycota D. Zygomycota Difficulty: Easy ASM Standard: 5 21. Which of the following include fungi that are obligate intracellular pathogens?

A. Ascomycota B. Basidiomycota C. Microsporidia* D. Zygomycota Difficulty: Easy ASM Standard: N/A 22. Which fungus is common in the microbiota of a healthy individual?

A. Aspergillus aculeatus B. Candida albicans* C. Histoplasma capsulatum D. Rhizopus stolonifera Difficulty: Moderate ASM Standard: 23, 24 23. The mode of reproduction for chytrids (Chytridiomycota) uses which of the following?

A. asci B. basidia C. motile gametes* D. zygospores Difficulty: Easy ASM Standard: N/A 24. To produce spores, some fungi use club-shaped structures called which of the following?

A. asci B. basidia* C. plastids D. zygospores Difficulty: Easy ASM Standard: N/A 25. Fungi have an important role in nutrient cycling as which of the following?

A. decomposers*

Page 5 of 14

OpenStax Microbiology Test Bank Chapter 5: The Eukaryotes of Microbiology

B. primary consumers C. producers D. secondary consumer Difficulty: Easy ASM Standard: 24 26. Which of the following statements is incorrect?

A. Fungi can be autotrophic or heterotrophic.* B. Fungi can be pathogenic, mutualistic, or neither.

C. Fungi can be unicellular or multicellular.

D. Fungi have eukaryotic cells.

Difficulty: Medium ASM Standard: 24 27. The types of algae are mainly grouped according to which of the following?

A. the size of their cells B. their chloroplast types C. their pigment types* D. where they are found Difficulty: Easy ASM Standard: 5 28. A lichen results from the mutualistic relationship between fungi and which of the following?

A. cyanobacteria or algae* B. green plants C. heterotrophic bacteria D. protozoans Difficulty: Easy ASM Standard: 23 29. The source of agar, which is typically used in the microbiology laboratory, is which of the following?

A. brown algae B. green algae C. red algae* D. lichen Difficulty: Easy ASM Standard: 26 30. Lichens attach to a surface using which structure?

A. capsules Page 6 of 14

OpenStax Microbiology Test Bank Chapter 5: The Eukaryotes of Microbiology

B. cilia C. flagella D. rhizines* Difficulty: Moderate ASM Standard: 9 True/False 31. The feeding and growth portion of a protozoan’s life cycle is known as the cyst stage.

Answer: False Difficulty: Easy ASM Standard: 13 32. Saprozoic fungi feed on dead organisms by ingesting small soluble food particles.

Answer: True Difficulty: Easy ASM Standard: 12, 24 33. Amoeba spp. use cilia as a means of locomotion.

Answer: False Difficulty: Easy ASM Standard: 9 34. All protozoans can reproduce sexually and asexually.

Answer: False Difficulty: Easy ASM Standard: 13 35. Plasmodial slime molds are individual amoeboids that aggregate into a mobile slug.

Answer: False Difficulty: Easy ASM Standard: N/A 36. Apicomplexans are parasitic protists.

Answer: True Difficulty: Easy ASM Standard: 23

37. The fusion of cytoplasmic contents from two separate cells during the fungal sexual life cycle is known as karogamy.

Answer: False Difficulty: Easy ASM Standard: N/A 38. Conidia are asexual fungal spores produced by members of the Ascomycota.

Answer: True Difficulty: Moderate ASM Standard: 9 39. The green algae that are most closely related to land plants are known as the Chlorophyta.

Answer: False Difficulty: Moderate ASM Standard: 5 40. One of the earliest truly multicellular green algae is Volvox.

Answer: False Difficulty: Easy ASM Standard: 5 Matching

41. Match the subgroup with its distinguishing feature.

A. apicomplexans i. commonly known as water molds B. Chlorophyta ii. have cell walls with substantial cellulose C. euglenozoans iii. may be photosynthetic or heterotrophic and have flagella D. Foraminifera iv. intracellular parasites with apical organelles E. oomycetes v. have calcium carbonate shells Answers: A. iv., B. ii., C. iii., D. v., E. i.

Difficulty: Moderate ASM Standard: 9 42. Match the pathogenic protist to the most relevant mechanism of transmission.

A. Cryptosporidium i. being bitten by mosquitoes B. Plasmodium ii. drinking contaminated water C. Toxoplasma iii. sexual transmission D. Trichomonas iv. exposure to contaminated cat feces Answers: A. ii., B. i., C. iv., D. iii.

Difficulty: Moderate ASM Standard: 23

43. Match the pathogenic nematode to the most relevant mechanism transmission.

A. Dirofilaria i. ingestion of undercooked meat B. Enterobius ii. exposure to contaminated dogs and cats C. Schistosoma iii. being bitten by a contaminated mosquitos D. Trichinella iv. exposure to freshwater snails Answers: A. iii., B. ii., C. iv., D. i.

Difficulty: Moderate ASM Standard: 23 44. Put the generalized sexual life cycle of fungi in order, starting with two hyphae beginning to “mate.”

A. Step 1 i. dikaryon formation B. Step 2 ii. karogamy C. Step 3 iii. meiosis and sporangia formation D. Step 4 iv. plasmogamy E. Step 5 v. spore release and germination Answers: A. iv., B. i., C. ii., D. iii., E. v.

Difficulty: Moderate ASM Standard: N/A Fill in the Blank

45. Cytostomes are specialized protozoan structures for the process of . Answer: phagocytosis Difficulty: Moderate ASM Standard: N/A 46.

is a protozoal mechanism of asexual reproduction whereby the nucleus of a cell divides repeatedly before the cytoplasm of the cell divides.

Answer: Schizogony Difficulty: Easy ASM Standard: 9

47. The feeding and growth portion of the protozoan life cycle is known as the stage. Answer: trophozoite Difficulty: Easy ASM Standard: 9 48. The dormant stage of the protozoan life cycle is known as the stage. Answer: cyst Difficulty: Moderate ASM Standard: 9 49. Genetic diversity can be obtained in the ciliates through a process known as which micronuclei are exchanged.

Answer: conjugation

, in

Difficulty: Easy ASM Standard: 15 50. Fungal fruiting bodies store and release Answer: spores

_.

Difficulty: Easy ASM Standard: N/A 51. In the United States, the most common infection caused by nematodes is Answer: pinworm (Enterobius vermicularis is also an acceptable answer) Difficulty: Moderate ASM Standard: 23 52. Fungi consist of filaments known as N/A Answer: hyphae Difficulty: Easy ASM Standard:

.

.

53. Chloroplasts can contain Answer: pyrenoids

that synthesize and store starch.

Difficulty: Moderate ASM Standard: 9 54. According to the endosymbiotic theory, chloroplasts found in algae originally evolved from .

Answer: cyanobacteria Difficulty: Easy ASM Standard: 1 Short Answer 55. Name three methods of locomotion used by various groups of protozoans.

Sample Answer: Protozoans may use cilia, flagella, or pseudopodia for locomotion.

Difficulty: Easy ASM Standard: 9 56. What are the two ways that heterotrophic protozoans bring in food particles?

Sample Answer: Some are holozoic and use phagocytosis to engulf large particles; others are saprozoic and ingest small soluble particles.

Difficulty: Easy ASM Standard: N/A 57. Briefly describe the differences between cellular and plasmodial slime molds, using examples from the specific cellular and plasmodial slime molds mentioned in the chapter.

Sample Answer: Cellular slime molds have individual cells. They may exist as individual amoebae or join together to form a mobile slug, then a fruiting body. Plasmodial slime molds can exist as individual cells but also have a part of their life cycle in which these cells join to form large, multinucleate cells. They can form reproductive stalks to produce spores that divide into gametes.

Difficulty: Moderate ASM Standard: N/A 58. Ciliates contain two types of nuclei. Briefly describe what they are and how many sets of chromosomes they contain.

Sample Answer: Ciliates contain a micronucleus and macronucleus. The micronucleus is diploid (with two copies of chromosomes) and is used for conjugation. The macronucleus is polyploid (with multiple copies of chromosomes) and contains metabolic genes.

Difficulty: Difficult ASM Standard: 9 59. What are the four phyla of fungi that are important causes of human mycoses?

Sample Answer: The four phyla of fungi that are most important for human disease are Ascomycota, Basidiomycota, Microsporidia, and Zygomycota.

Difficulty: Moderate ASM Standard: 23 60. What unique molecules are found in the cell wall and membrane of fungi, and serve as targets for antifungal agents?

Sample Answer: The fungal cell wall contains chitin and the fungal cell membrane contains ergosterol.

Difficulty: Easy ASM Standard: 7, 14

61. Dimorphic fungi can grow in different forms at different temperatures. How could this cause a change in a fungus that infected a human (i.e., would be at a higher temperature than in the surrounding environment)?

Sample Answer: Fungi such as Histoplasma capsulatum, which causes histoplasmosis, is found as a mold at lower temperatures and as a yeast at higher temperatures. In nature, it grows as a mycelium. Within the human body, it grows as a yeast.

Difficulty: Moderate ASM Standard: 14 62. What is the most potent natural carcinogen known and what organism produces it?

Sample Answer: The chemical is aflatoxin, which is produced by the fungus Aspergillus flavus.

Difficulty: Easy ASM Standard: 23 63. What is a zygospore?

Sample Answer: A zygosopore is hard-walled structure produced by members of the Zygomycota during sexual reproduction.

Difficulty: Easy ASM Standard: 9

64. What are plasmogamy and karogamy, and what does each event produce in the fungal life cycle?

Sample Answer: Plasmogamy is the fusion of the cytoplasm of two haploid cells of differing mating types, resulting in the formation of a dikaryotic cell containing two distinct nuclei.

The nuclei then fuse during the process of karyogamy and produce a diploid zygote that immediately undergoes meiosis to form haploid spores.

Difficulty: Moderate ASM Standard: N/A 65. What is the function of microsporidia’s polar tubule?

Sample Answer: Microsporidia are obligate intracellular pathogens. The polar tubule allows the fungus to penetrate and enter host cells.

Difficulty: Moderate ASM Standard: 9, 23 66. How did chloroplasts in eukaryotes arise?

Sample Answer: They arose from the engulfment of cyanobacteria (secondary endosymbiosis).

Difficulty: Moderate ASM Standard: 1 67. How do red tides harm marine life?

Sample Answer: Red algae produce toxins.

Difficulty: Moderate ASM Standard: 23 68. What are the two types of green algae? Which is more closely related to today’s land plants?

Be sure to explain your answer.

Sample Answer: The two types are Chlorophyta and Charophyta. The Charophyta are more closely related to modern land plants. Charophyta share a mechanism of cell division and an important biochemical pathway with land plants, whereas the other green algae do not.

Difficulty: Moderate ASM Standard: 5 69. How do the three types of lichens differ from each other?

Sample Answer: Crustose lichens are tightly attached to their substrate and have a crusty appearance. Foliose lichens have leaf-like lobes; they may be attached at only one point and may have a second cortex below the medulla. Fruticose lichens have structures that are more rounded and appear branched overall.

Difficulty: Moderate ASM Standard: N/A Brief Essay Essay Question Rubric RATING Failing

Below Average

Competent

Advanced

Criteria for evaluation

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is poor and contains numerous grammatical mistakes and misspellings.

Answer fails to provide examples to support an argument.

Writing is poor and grammatical errors are common. Answer is somewhat incoherent.

Answer provides an argument with one or two examples that support it. Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

POINT 0 1 2 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently. Answer is well organized and free of grammatical errors and misspellings.

3

70. Compare and contrast endospores and cysts. In what ways are they similar? In what ways are they different?

Sample Answer: Students should identify the following similarities: The process occurs when environmental conditions are not favorable; both ensure survival of the cell's genetic information; both structures have a thick protective wall; both are nonreproductive cells; only certain bacteria or protists produce these types of structures. Students should identify the following differences: Cyst formation occurs in some protists; endospore formation occurs only in some bacteria (Clostridium and Bacillus spp.); the composition of the cell walls differs: cysts (protists) have chitin or cellulose; endospores, which are produced by bacteria, have a cortex (which contains peptidoglycan) and a spore coat.

Difficulty: Difficult ASM Standard: 9 71. Briefly describe how conjugation occurs in Paramecium.

Sample Answer: In conjugation, the micronuclei of both cells undergo meiosis. The macronucleus and all but one haploid micronuclei from each cell disintegrate. The remaining micronuclei undergo mitosis. The two cells exchange one micronucleus each, which fuses with the remaining micronucleus to form a new, genetically different, diploid micronucleus.

Difficulty: Moderate ASM Standard: 16

72. Describe how Trypanosoma brucei, which causes the disease known as African sleeping sickness, is transmitted to the host.

Sample Answer: T. brucei replicates in the blood and lymph of infected individuals. The tsetse fly takes a blood meal and ingests T. brucei, which replicates in the midgut of the fly into the infectious stage and then enters the fly’s salivary glands. When the fly takes another blood meal from a new host, it injects T. brucei into that host.

Difficulty: Moderate ASM Standard: 23 73. There is a wide variety of eukaryotic algae, including seaweeds. Are these true plants?

Why or why not?

Sample Answer: Plants and algae are photosynthetic, contain pigments, and have cell walls. Some algae are multicellular, like plants (although no plants are unicellular).

However, algae do not have specialized tissues and organs like those found in plants.

Additionally, unlike plants, algae do not have a waxy cuticle to prevent desiccation.

Difficulty: Difficult ASM Standard: N/A

This file is copyright 2017, Rice University. All rights reserved.

Chapter 6: Acellular Pathogens * = Correct answer Multiple Choice 1. Which of the following is not a property of a virus?

A. It is an infectious cellular pathogen.* B. It is an obligate intracellular pathogen.

C. Its genome consists of DNA or RNA. D. Its genome is surrounded by a protein capsid.

Difficulty: Easy ASM Standard: 10, 13 2. Which of the following is the scientist responsible for first discovering viruses (specifically, tobacco mosaic virus)?

A. Dimitri Ivanovski* B. Edward Jenner C. Henrietta Lacks D. Stanley Prusiner Difficulty: Easy ASM Standard: N/A

3. The protein subunits that surround the nucleic acid of a virus are known as which of the following?

A. amino acids B. capsomeres* C. chromatins D. telomeres Difficulty: Easy ASM Standard: N/A 4. Arthropods typically serve as which mechanism of transmission for viruses?

A. biological vector* B. fomite C. mechanical vector D. both as fomites and as vectors Difficulty: Medium ASM Standard: 10, 13, 23 5. Which unit of length best describes the average size of a virion?

A. mm B. µm C. nm* D. pm Difficulty: Easy ASM Standard: 6 6. Viruses can be visualized using which method?

A. compound light microscope B. electron microscope* C. the naked eye D. ultraviolet rays Difficulty: Easy ASM Standard: 6, 32, 36 7. The Baltimore Classification system describes viruses according to which characteristic?

A. capsid shape B. host-cell susceptibility C. the presence or absence of an envelope D. the viral genome* Difficulty: Easy ASM Standard: 10 8. Which of the following properly lists (in order) the steps of viral replication?

A. Attachment → Lysis → Penetration → Biosynthesis → Maturation B. Attachment → Penetration → Biosynthesis → Maturation → Lysis * C. Biosynthesis → Attachment → Penetration → Lysis → Maturation

D. Penetration → Biosynthesis → Lysis → Attachment → Maturation

Difficulty: Easy ASM Standard: 10 9. In the lysogenic cycle of bacteriophages, the integrated phage genome is known as which of the following?

A. prophage* B. provirus C. virioid D. virion Difficulty: Easy ASM Standard: 10 10. In retroviruses, the integrated phage genome is known as which of the following?

A. prophage B. provirus* C. virioid D. virion Difficulty: Easy ASM Standard: 10 11. Which mechanism of horizontal gene transfer relies on the use of viruses?

A. conjugation B. mutation C. transduction* D. transformation Difficulty: Easy ASM Standard: 2, 4 12. A bacteriophage infects a host cell and the genome integrates itself into the host chromosome. Sometime later, the phage is excised along with a short piece of DNA adjacent to the insertion point. Both the phage DNA and the host DNA are packaged into the same capsid. The bacteriophage then infects a new cell, delivering both phage and bacterial DNA. Which process is being described in this scenario?

A. The lysogenic cycle, reactivating as the lytic cycle, followed by generalized transduction B. The lysogenic cycle, reactTivEaS t inTgBaAs N thKeSlyEtiL cL cyEcR le. , fCoO lloMwed by specialized transduction* C. The lytic cycle, reactivating as the lysogenic cycle, followed by generalized transduction D. The lytic cycle, reactivating as the lysogenic cycle, followed by specialized transduction Difficulty: Medium ASM Standard: 2, 4, 10

13. (−)ssRNA is transcribed into (+)ssRNA using which of the following?

A. DNA polymerase encoded by the host cell B. DNA polymerase encoded by the virus C. RNA polymerase encoded by the host cell D. RNA polymerase encoded by the virus* Difficulty: Easy ASM Standard: 16, 18 14. Which of the following is a novel enzyme found in retroviruses?

A. forward transcriptase B. retrotranscriptase C. reverse transcriptase* D. Taq polymerase Difficulty: Easy ASM Standard: 16, 18, 26 15. Reverse transcriptase is used to generate which nucleic acid from RNA? A. cDNA* B. dsRNA C. (+)ssRNA D. (−)ssRNA Difficulty: Easy ASM Standard: 26 16. Which of the following is the host-cell receptor that recognizes human immunodeficiency virus (HIV)?

A. CD4* B. CD8 C. Gp120 D. sialic acid Difficulty: Hard ASM Standard: 10 17. Which of the following viruses does not cause latent infections?

A. adenovirus* B. Epstein-Barr virus C. herpes simplex virus D. varicella-zoster virus Difficulty: Medium ASM Standard: 23

18. Chicken pox can reemerge as which disease?

A. cowpox B. genital warts C. shingles* D. smallpox Difficulty: Easy ASM Standard: 23 19. The excision of the viral genome from the host chromosome is known as which of the following?

A. induction * B. lysogeny C. phage conversion D. transduction Difficulty: Medium ASM Standard: 10 20. Which statement regarding the introduction of virus in eggs is true?

A. Pox can form on the embryo.* B. The virus cannot be introduced into the yolk sac.

C. The virus will not kill the embryo if it is introduced early in development.

D. Virus introduction will not disrupt embryonic development.

Difficulty: Medium ASM Standard: 33 21. The liquid portion of blood that does not contain clotting factors is known as which of the following?

A. erythrocytes B. plasma C. platelets D. serum* Difficulty: Easy ASM Standard: N/A 22. Which method cannot be used to detect virus in a patient’s serum?

A. EIA B. hemagglutinin assay C. growth in pure culture* D. RT-PCR Difficulty: Medium ASM Standard: 34

23. You are a nurse and you suspect that you may have been exposed to a particular virus. You and your health care provider decide to perform a hemagglutinin assay. A sample of your serum is taken and added to a sample of virus. Next, the virus and serum sample are added to erythrocytes. Upon examination, you do not see any agglutination occurring. Which can you conclude from these results?

A. The test result suggests you may have been exposed to the virus, and your serum contains antibodies against the virus.* B. The test result suggests you may have been exposed to the virus, but your serum does not contain antibodies against the virus.

C. The test result suggests you may not have been exposed to the virus.

D. You cannot make a conclusion from the information given.

Difficulty: Medium ASM Standard: 28b, 34, 36 24. Which effect does tomato planta macho viroids have on the crop?

A. browning of fruit B. crown-gall formation C. loss of chlorophyll* D. lysis of root cells Difficulty: Medium ASM Standard: 23 25. Which scientist first discovered prions?

A. Dimitri Ivanovski B. Edward Jenner C. Henrietta Lacks D. Stanley Prusiner* Difficulty: Easy ASM Standard: N/A 26. Transmissible spongiform encephalopathies, such as Creutzfeldt-Jakob disease, are caused by which of the following?

A. bacterium B. fungus C. prion* D. virus Difficulty: Easy ASM Standard: 23

27. How is kuru transmitted?

A. bloodborne transmission B. contaminated neurosurgical instruments C. eating contaminated cattle meat D. eating infected meat through cannibalism* Difficulty: Medium ASM Standard: N/A 28. An acellular entity composed of a small circular RNA molecule without a capsid and capable of replicating its genome is known as which of the following?

A. satellite RNA B. virion C. viroid* D. virusoid Difficulty: Easy ASM Standard: 10, 16 29. An acellular entity composed of a small circular RNA molecule without a capsid and is not capable of replicating its genome is known as which of the following?

A. provirus B. virion C. viroid D. virusoid* Difficulty: Easy ASM Standard: 10, 16 30. Although there are no current treatments for prion infections, which of the following could be used?

A. antibiotics B. nucleases C. proteases* D. sulfa drugs Difficulty: Medium ASM Standard: N/A True/False 31. Viruses are facultative intraceTllE ulS arTpBaA t hN ogKeS nE s. LLER.COM Answer: False Difficulty: Easy ASM Standard: 10, 13, 18 32. A zoonosis can only be transmitted from animals to humans. Answer: False Difficulty: Medium ASM Standard: 23

33. Most plant viruses do not kill their host. Answer: True Difficulty: Medium ASM Standard: 23 34. (+)ssRNA can be directly used in translation at the ribosome. Answer: True Difficulty: Medium ASM Standard: 16 35. Any virus can infect any host cell.

Answer: False Difficulty: Easy ASM Standard: 16, 23

36. Satellite RNAs can encode for protein.

Answer: True Difficulty: Medium ASM Standard: 16 37. There is a cure for transmissible spongiform encephalopathies.

Answer: False Difficulty: Easy ASM Standard: 23, 27 38. Prion diseases cannot be transmitted from one generation to the next.

Answer: False Difficulty: Hard ASM Standard: 23

39. RT-PCR relies on an enzyme encoded by retroviruses.

Answer: True Difficulty: Easy ASM Standard: 26 40. The hemagglutinin assay can only identify infectious virus particles.

Answer: False Difficulty: Medium ASM Standard: 34 Matching 41. Match the virus family to its clinical features: A. Herpesviridae i. penile and/or cervical cancer B. Papillomaviridae ii. cold sores and/or genital warts C. Parvoviridae iii. respiratory tract infections D. Picornaviridae iv. skin lesions E. Poxviridae v. hepatitis Answers: A. ii., B. i., C. iii., D. v., E. iv.

Difficulty: Medium ASM Standard: 23 42. Match the virus family to its genome (as defined by the Baltimore classification): A. (+)ssRNA naked i. reovirus B. (+)ssRNA enveloped ii. HIV C. (−)ssRNA enveloped iii. hepatovirus D. dsDNA naked iv. herpes simplex virus E. dsDNA envelope v. influenza virus Answers: A. iv., B. i., C. ii., D. v., E. iii.

Difficulty: Hard ASM Standard: 23 43. Put the steps of HIV infection in order by matching the correct events with each step: A. Step 1 i. New virus particles are released.

B. Step 2 ii. Provirus appears.

C. Step 3 iii. HIV RNA and other viral proteins enter the cell.

D. Step 4 iv. Viral DNA is transcribed into viral RNA. E. Step 5 v. Viral DNA is synthesized.

Answers: A. iii., B. v., C. ii., D. iv., E. i.

Difficulty: Medium ASM Standard: 16, 23 44. Match the virus detection method to its proper description: A. EIA i. using antibodies to detect viral antigens (proteins) B. Hemagglutinin ii. using primers to amplify DNA C. PCR iii. making cDNA from RNA D. RT-PCR iv. isolating antibodies from a patient, adding them to a virus, and seeing if the virus can clump erythrocytes Answers: A. i., B. iv., C. ii., D. iii.

Difficulty: Medium ASM Standard: 34, 36 Fill in the Blank 45. All viruses are composed of Answer: protein and nucleic acid

and

.

Difficulty: Easy ASM Standard: 6 46. Viruses that infect bacterial cells are known as

.

Answer: bacteriophages Difficulty: Easy ASM Standard: 7, 18 47.

is an enzyme used by retroviruses to produce complementary DNA from RNA. Answer: Reverse transcriptase Difficulty: Medium ASM Standard: 16, 23

48. The lipid content of an enveloped virus is produced from the Answer: host cell

.

Difficulty: Medium ASM Standard: 10, 18 49. The protein content of an enveloped virus is produced from the Answer: viral genome

.

Difficulty: Medium ASM Standard: 10, 18 50.

occurs when a randToE mSpTieBcA e fKbS acEteLrL iaE l cRh. roCmOoM som al DNA is transferred by the phage during the lytic cycle.

Answer: Generalized transduction Difficulty: Easy ASM Standard: 2, 10, 18

51. The integrated genome of a retrovirus in a host cell is known as Answer: provirus

.

Difficulty: Easy ASM Standard: 10, 23 52. The number of virions per unit volume is known as the Answer: viral titer Difficulty: Easy

.

ASM Standard: 35 53. When a lawn of bacteria is grown on semisolid medium and those cells are lysed, the clear zones produced are known as .

Answer: plaque Difficulty: Easy ASM Standard: 35 54. Proteinaceous infectious particles are known as Answer: prions

.

Difficulty: Easy ASM Standard: 23 Short Answer 55. Name two possible shapes for viral capsids.

Sample Answer: Helical and polyhedral (icosahedral) Difficulty: Easy ASM Standard: 6 56. Define the term “tissue tropism.”

Sample Answer: Viruses can only infect certain types of cells.

Difficulty: Medium ASM Standard: 10, 18

EaSl TviBruAsNreKpSliE 57. List, in order, the stages of anT im caL tiL onE. R.COM Sample Answer: Attachme nt → Penetration (entry)

→ Uncoating → Biosynthe sis → Assembly → Release

Difficulty: Easy ASM Standard: 10 58. What two methods can an enveloped animal virus use to enter a host cell?

Sample Answer: Receptor-mediated endocytosis or membrane fusion Difficulty: Medium ASM Standard: 10 59. Why are naked animal viruses unable to enter host cells through membrane fusion?

Sample Answer: Naked viruses do not have lipid envelopes (only a protein capsid), so it cannot fuse with the host-cell membrane; rather, it enters via receptor-mediated endocytosis.

Difficulty: Hard ASM Standard: 10, 18 60. Identify which type of virus is shown in the diagram below. Additionally, indicate what the labels A, B, C, and D represent.

Page 11 of 16

OpenStax Microbiology Test Bank Chapter 6: Acellular Pathogens

Sample Answer: Virus shown is a bacteriophage. A. capsid; B. viral genome; C. sheath; D. tail fibers.

Difficulty: Medium ASM Standard: 6 61. On the axes below, sketch the multiplication curve for a bacteriophage population. Be sure to indicate each of the four stages.

TESTBANKSELLER.COM

Sample Answer: Graph shown below:

Difficulty: Medium ASM Standard: 35 62. What is a provirus? How does it compare to a prophage?

Sample Answer: A provirus is the integrated genome from a retrovirus, whereas a prophage is the integrated genome from a bacteriophage.

Difficulty: Medium ASM Standard: 10, 23 63. Briefly describe the difference between the lytic and lysogenic cycles.

Sample Answer: In the lytic cycle, the bacteriophage causes the death of the bacterium host cell. In the lysogenic cycle, the bacteriophage DNA integrates into the host-cell chromosome (known as a prophage). This prophage can then be excised, and the lytic cycle (the new bacteriophage being manufactured and being released via cell lysis) can be resumed.

Difficulty: Easy ASM Standard: 10 64. From where were HeLa cells first isolated? Why are they used in virology?

Sample Answer: HeLa cells were tumor cells isolated from Henrietta Lacks. They were used to develop the first continuous tissue-culture cell line (cells that can be continually grown indefinitely). Because viruses are obligate intracellular entities, these types of cell lines allow scientists to culture and study viruses.

Difficulty: Easy ASM Standard: 23, 33 65. Describe three cytopathic effects of viruses on eukaryotic cells.

Sample Answer: Answers can include inclusion bodies, cell swelling, cytoplasmic stranding, rounding, “grape-like” clustering, change in cell shape, cytoplasmic membrane fusion, multinucleated syncytia, cell lysis.

Difficulty: Easy ASM Standard: 23 66. What is the difference between plasma and serum?

Sample Answer: Plasma is the liquid portion of blood. Serum is the liquid portion of blood with clotting factors removed.

Difficulty: Medium ASM Standard: 36 67. What is the difference between viroids and virusoids?

Sample Answer: A viroid is a short strand of circular single-stranded RNA without a capsid (protein coat). Like viruses, viroids can replicate their genome in host cells. Virusoids (a type of satellite virus) are circular, single-stranded RNAs that require a helper virus for replication.

Difficulty: Easy ASM Standard: 10, 16, 18 68. What are the two spike proteins of influenza virus?

Sample Answer: Hemagglutinin and neuraminidase.

Difficulty: Easy ASM Standard: 6, 23 69. When there was an outbreak of mad cow disease (bovine spongiform encephalopathy) in 2003, everyone was concerned about eating certain beef products but not about eating steak.

Why? Sample Answer: Bovine spongiform encephalopathy is caused by a prion. Prions are misfolded proteins in neural tissue. There was concern about acquiring Creutzfeldt-Jakob disease (a human variant of mad cow disease) by eating food containing neural tissue. Steaks do not contain a high proportion of neural tissue.

Difficulty: Hard ASM Standard: 23 Brief Essay Essay Question Rubric RATING Failing

Below Average

Competent

Advanced

Criteria for evaluation

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is poor and contains numerous grammatical mistakes and misspellings.

Answer fails to provide examples to support an argument.

Writing is poor and grammatical errors are common. Answer is somewhat incoherent.

Answer provides an argument with one or two examples that support it. Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

POINT 0 1 2 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently. Answer is well organized and free of grammatical errors and misspellings.

3

70. Compare and contrast bacteriophages and animal viruses. In what ways are they the same and in what ways are they different?

Sample Answer: Both viruses demonstrate host-cell specificity. During penetration, the bacteriophage does not uncoat its nucleic acid. Rather, it injects its genome into the host cell.

Animal cells enter host cells either through membrane fusion or receptor-mediated ytoplasm, viral DNA or RNA can be replicated. Viral component endocytosis. Once in the c are synthesized. In some cases (lysogenic phages or retroviruses), the viral DNA can be integrated into the host chromosome (known as prophages and proviruses, respectively).

During bacteriophage infections, the cell lyses to release new phage particles due to the action of viral enzymes. For animal viruses, release from the host cell can occur either by cell lysis or through budding off of the cell membrane. Therefore, host-cell destruction of bacteriophage-infected cells (if going through the lytic cycle) is immediate, whereas in animal cells, it may be prolonged.

Difficulty: Medium ASM Standard: 10, 23 71. Chicken pox and shingles are distinctly different diseases but are due to the actions of the same virus. Which virus causes both these diseases? Discuss why different signs and symptoms are observed during the two diseases.

Sample Answer: Both chicken pox and shingles are caused by the varicella-zoster virus.

This virus can infect different cells throughout the body. At first, a rash of blisters covers the skin (chicken pox). The virus then becomes dormant and lives within nerve cells. The virus can be reactivated and cause a new disease called shingles. Shingles is specific to nerve cells. Pain, burning, tickling, tingling, and/or numbness occurs in the area around the affected nerves several days or weeks before a rash appears. Next, a rash will appear (typically on one side of the body) along with burning and pain. [Source: WebMD.com].

Difficulty: Medium

ASM Standard: 23

72. When studying bacterial genomes, it is common to find prophages that have never been reactivated. Some of them are also known as “defective prophages,” which can never be reactivated. Genome scientists use these defective prophages to study the ways viruses have shaped the genomes of bacteria. Based on this information, answer the following questions. (a) Define what a prophage is. (b) Explain how prophages normally become activated and what might cause a prophage to become “defective.” (c) Discuss other ways viruses have contributed to the evolution of the genomes of bacteria.

Sample Answer: Prophage is the integrated genome of a bacteriophage in the host bacterial cell chromosome (the lysogenic cycle). During induction, the viral genome is excised from the host chromosome. Environmental stresses, cell damage, or the presence of chemicals or ultraviolet light can trigger induction, allowing the lytic cycle to resume. The maintenance of the prophage or the induction of prophage is under the control of viral regulatory genes. Loss of the functions of these regulatory genes (either through mutations or evolutionary stresses) may result in the inability of the prophage to be excised and the lytic cycle to resume. These defective prophages have now become an integral part of the bacterium's chromosome and may even be necessary for survival. These defective prophages have introduced important virulence factors for pathogens, including biofilm production ability and antibiotic resistance. Another way that viruses can contribute to the evolution of bacteria is through the horizontal gene-transfer method of transduction (either generalized, in which a random piece of DNA from one bacterium is carried by a virus to another bacterium, or specialized, in which DNA next to the prophage site is transferred).

[Source: http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2958.2003.03580.x/pdf] Difficulty: Hard ASM Standard: 2, 10, 16, 23

This file is copyright 2017, Rice University. All rights reserved.

Chapter 7: Microbial Biochemistry * = Correct answer Multiple Choice 1. Which of the following is the best definition of a macronutrient?

A.a trace element B. a vitamin C. an organic molecule necessary for life D. the most abundant elements found in living cells* Difficulty:Easy ASM Standard: N/A 2. Amino groups are an important component of which of the following macromolecules?

A.carbohydrates B.lipids C.nucleic acids D. proteins* Difficulty: Easy ASM Standard: N/A 3. The building blocks of polymers are called which of the following?

A. inorganic molecules B.macromolecules C.monomers* D. nucleic acids Difficulty: Easy ASM Standard: N/A 4. Which of the following is not one of the four major types of carbon-based macromolecules found in cells?

A. carbohydrates B. lipids C. macronutrients* D. nucleic acids Difficulty: Easy ASM Standard: N/A 5. Which of the following is the typical, stable shape of glucose in cells?

A.a branched chain A. a doublering

C. a ring* D.a tetrahedron Difficulty: Easy ASM Standard: N/A 6. In which form do plants generally store sugar molecules? A.cellulose B. chitin C. glycogen D.starch* Difficulty: Easy ASM Standard: N/A 7. Which term specifically describes fatty acids that do not have any double bonds, triple bonds, or rings?

A. esterified B. polyunsaturated C. saturated* D.unsaturate d Difficulty: Easy ASM Standard: N/A 8. Which of the following best describes the difference between steroids and sterols?

A. Steroids are the most common type of sterol.

B. Steroids contain rings, whereas sterols do not. C.Sterols are a type of steroid with an OH group.* D. Sterols are present in prokaryotes and steroids are not.

Difficulty:Moder ate ASM Standard: N/A 9. Which best describes oligopeptides?

A. a molecule consisting of two amino acids B. long chains of amino acids C. polymers of about 20 amino acids* D.polymers of about 50 amino acids

Difficulty: Easy ASM Standard: N/A 10. Which of the following is not a lipid?

A. a fatty acid B. a glyceraldehyde* C. a wax D. an isoprenoid Difficulty: Easy ASM Standard: N/A 11. How many single covalent bonds can oxygen form?

A.one B.two* C.three D.four Difficulty: Moderate ASM Standard: N/A 12. Which of the following molecules is an organic molecule?

A.CO 2 B. CaCO 3 C. CH 3 OH* D. H 2 O Difficulty:Moderate ASM Standard: N/A 13. Which of the following is the best example of a micronutrient?

A.carbon B. nitrogen C.phosphorus D. potassium* Difficulty:Easy ASM Standard: N/A 14. Which of the following best describes glucose, fructose, and galactose?

A.achiral B. enantiomers C. stereoisomers D.structural isomers* Difficulty:Moderate

ASM Standard: N/A 15. Why does it matter which enantiomer of a molecule is used for a medication?

A.Enantiomers can have different pharmacologic effects and only one may be effective.* B. It is usually easier to prepare one enantiomer than mixtures of both.

C. The D form is typically more effective than the L form.

D. The L form is typically more effective than the D form.

Difficulty:Moderate ASM Standard: N/A 16. Which of the following shows a ketone?

A. a carboxylic acid B. anester C. an internal carbonyl group* D. an internal ether Difficulty:Moderate ASM Standard: N/A 17. Which of the following types of bonds joins monosaccharides together to form a polysaccharide?

A. glycosidic bonds* B. hydrogen bonds C. peptide bonds D.phosphodiester bonds Difficulty: Moderate ASM Standard: N/A 18. Which of the following best describes the molecule lactose?

A.disaccharide* B.monosaccharide C.polysaccharide D. trisaccharide Difficulty: Moderate ASM Standard: N/A 19. Which of the following is an important component of insect exoskeletons?

A.cellulose B. chitin* C. glycogen D. starch

Difficulty: Moderate ASM Standard: N/A 20. Which describes the hydrocarbon tails in the plasma membrane?

A.amphipathic B. hydrophilic C.hydrophobic* D.polar Difficulty: Moderate ASM Standard: N/A 21. In a protein, which type of chemical linkage joins the amino acids?

A. disulfide linkages B. glycosidic linkages or bonds C. hydrogen bonds D. peptide bonds* Difficulty: Moderate ASM Standard: N/A 22. Which is a common type of secondary structure of proteins?

A. the α helix* B. the β helix C. the Δ helix D. the ω helix Difficulty: Moderate ASM Standard: N/A 23. Disulfide bridges are most important inwhich of the following?

A.primary structure of proteins B. secondary structure of proteins C. structure of carbohydrates D. tertiary structure of proteins* Difficulty: Moderate ASM Standard: N/A 24. Which enantiomers rotate plane polarized light in a clockwise direction?

A.+ or d* B. + or l C. – or d D. – or l Difficulty: Moderate ASM Standard: N/A

25. C6 H12 O6 is an example of which type of molecule?

A. amino acid B. fatty acid C. monosaccharide* D. nucleotide Difficulty: Moderate ASM Standard: N/A 26. The phospholipid molecules in the plasma membrane are which of the following?

A.amphipathic* B.hydrophilic only C.hydrophobic only D.in the shape of micelles Difficulty: Moderate ASM Standard: N/A 27. Amylose is a component of which of the following?

A. cellulose B. disaccharides C. nucleotides C.starch* Difficulty:Moderate ASM Standard: N/A 28. Chitin is a polymer of which of the following?

A. amylase and amylopectin B. glycosaminoglycan B. N-acetyl glucosamine* C. N-acetyl muramic acid Difficulty: Difficult ASM Standard: N/A 29. Dextromethorphan and levomethorphan are best described as which of the following?

A. achiral B. biologically identical C.enantiomers* D.structural isomers Difficulty: Difficult ASM Standard: N/A 30. Which type of molecule is CH3 (CH 2 )14 COOH?

A. amino acid B. fatty acid* C. monosaccharide D. nucleotide Difficulty: Difficult ASM Standard: N/A 31. A triglyceride contains which subcomponents?

A. a glycerol and two fatty acids B. a glycerol and two sugars C. a glycerol and three fatty acids* D. a glycerol and three sugars Difficulty:Moderate ASM Standard: N/A 32. The phospholipids of the plasma membrane contain which subcomponents?

A. a wax, a glycerol, and a phosphate group B. two fatty acids, a glycerol, and a phosphate group* C. three fatty acids, a glycerol, and a phosphate group D. four sphingolipids and a phosphate group Difficulty: Difficult ASM Standard: N/A 33. Which monomers make up lipids?

A.amino acids B.fatty acids C. lipids do not consist of monomers* D.monosaccharides Difficulty: Difficult ASM Standard: N/A 34. Which are the components found in starch?

A. amylose and amylopectin* B. amylose and glycogen C. cellulose and glycogen D.glucosamine and muramic acid Difficulty: Difficult ASM Standard: N/A 35. Which of the following is not true of triglycerides?

A. They are a type of phospholipid.* B. They are considered simple lipids.

C. They are hydrophobic.

D. They contain glycerol and three fatty acids.

Difficulty: Difficult ASM Standard: N/A 36. FAME analysis involves which of the following?

A. gas chromatography* B. high-pressure liquid chromatography C.immunological testing D. mass spectrometry Difficulty: Difficult ASM Standard: N/A True/False 37. Polysaccharides generally have a sweet taste.

Answer:False Difficulty: Easy ASM Standard: N/A 38. Cellulose is an important structural component of plant cell walls.

Answer: True Difficulty: Easy ASM Standard: N/A 39. A denatured protein has lost its primary structure.

Answer: False Difficulty: Moderate ASM Standard: N/A 40. The MALDI-TOF method includes irradiation of the sample.

Answer:True Difficulty: Moderate ASM Standard: N/A 41. Proteins embedded within the plasma membrane are called integral proteins.

Answer: True Difficulty: Moderate ASM Standard: N/A

42. Disulfide bridges are a major component of the secondary structure of a protein.

Answer: False Difficulty: Moderate ASM Standard: N/A 43. The structure of β-pleated sheets is maintained by covalent bonds and ionic interactions.

Answer:False Difficulty: Moderate ASM Standard: N/A 44. The presence of poly-β-hydroxybutyrate granules is used in the classification of species of Pseudomonas bacteria.

Answer: False Difficulty: Difficult ASM Standard: N/A 45. Some plants use leghemoglobin to bind oxygen.

Answer: True Difficulty: Difficult ASM Standard: N/A 46. Xanthophylls are a type of isoprenoid.

Answer: True Difficulty: Difficult ASM Standard: N/A Matching 47. Match each term with the best definition.

A. primary protein structure i. created from localized folding that creates helices and sheets primarily stabilized by hydrogen bonding B. secondary protein structure ii.produced by joining more than one polypeptide chain by interactions including hydrogen bonding, hydrophobic interactions, disulfide bonds, and ionic interactions C. tertiary protein structure iii.created from interactions between relatively distant amino acids, including hydrogen bonding, hydrophobic interactions, disulfide bonds, and ionic interactions D. quaternary protein structure iv.refers to the sequence of amino acids connected by peptide bonds Answers: A. iv., B. i., C. iii., D. ii.

Difficulty: Easy

ASM Standard: N/A

48. Match each molecule with the best description.

A. FAME i. uses saponification to release fatty acids for further analysis to produce gas chromatograms B. MALDI-TOF ii.produces gas chromatograms of fatty acids to compare with references C. PLFA iii.uses HPLC, digestion, then mass spectrometry D. proteomic analysis iv.produces a mass spectrum to compare with references without requiring HPLC Answers: A. ii., B. iv., C. i., D. iii.

Difficulty: Difficult ASM Standard: N/A 49. Match each molecule with type of monomer it exemplifies.

A. adenosine triphosphate i. amino acid B. alanine ii.lipid C. cholesterol iii.monosaccharide D. ribose iv.nucleotide Answers: A. iv., B. i., C. ii., D. iii.

Difficulty:Moderate ASM Standard: N/A 50. Match each molecule with a type of functional group it contains. i. ketone A. NH 2 CH2 CH3 ii.carboxylic acid B. CH 3 COCH 3 iii.amino C. CH 3 CH 2 OH CH CH COOH iv. sulfhydryl D. 3 2 v. hydroxyl E. CH 3 CH 2 SH Answers: A. iii., B. i., C. v., D. ii., E. iv.

Difficulty: Moderate ASM Standard: N/A 51. Match each molecule with the class of macromolecules it exemplifies.

A. β-carotene i. protein B. chitin ii. lipid C. hemoglobin iii. nucleic acid D. RNA iv. carbohydrate Answers: A. ii., B. iv., C. i., D. iii.

Difficulty: Difficult ASM Standard: N/A Fill in the Blank 52.

tissue stores energy in the form of triglycerides.

Answer:Adipose (fat) Difficulty: Easy ASM Standard: N/A 53.

fatty acids are usually liquid at room temperature.

Answer:Unsaturated Difficulty: Easy ASM Standard: N/A

54. Another term for triglyceride is Answer:triacylglycerol

.

Difficulty: Moderate ASM Standard: N/A 55. Sulfhydryl groups in amino acids join together to form Answer:disulfide bridges (disulfide bonds)

.

Difficulty: Moderate ASM Standard: N/A 56. Sebum contains wax esters, triacylglycerol, and Answer: squalene

.

Difficulty:Difficult ASM Standard: N/A 57.

is a branched lipid that is a building block of β-carotene.

Answer:Isoprene Difficulty: Moderate ASM Standard: N/A

58. Fungi produce in their cell membranes,which serves a similar function as cholesterol in animal cell membranes.

Answer:ergosterol Difficulty: Moderate ASM

Standard: N/A 59.

is a hormone produced in response to stress; it is marketed in a synthetic form as hydrocortisone to reduce skin irritation and inflammation.

Answer:Cortisol

Difficulty: Moderate ASM Standard: N/A 60. The presence or absence of the storage molecule species of Pseudomonas.

Answer:poly-β-hydroxybutyrate

can be used to identify some

Difficulty: Difficult ASM Standard: N/A 61.

is an important globular protein that has four subunits, including two α peptides and two βpeptides.

Answer:Hemoglobi n Difficulty: Difficult ASM Standard: N/A

Short Answer 62. Some lipid molecules have a distinctive four-ringed structure and often function as hormones. What is the name for this group of hormones, and what are two examples of molecules in this group?

Sample Answer:Steroids, including sterols, have this structure. Cholesterol and steroid hormones are examples.

Difficulty: Easy ASM Standard: N/A 63. What is the difference between a steroid and a sterol?

Sample Answer: Steroids lack an –OH group present in sterols.

Difficulty: Easy ASM Standard: N/A 64. What is a unit membrane?

Sample Answer: A unit membrane is the standard membrane of plasma membranes and eukaryotic organelles. Unit membranes have a phospholipid bilayer structure.

Difficulty:Moderat e ASM Standard: N/A

65. Draw an example of a type of dehydration reaction (a chemical reaction) important in living organisms.

Sample Answer:Polymers are often made using dehydration reactions. For example, amino acids are joined together by removing water (a dehydration reaction).

Difficulty: Easy ASM Standard: N/A 66. What is the function of cholesterol in cell membranes?

Sample Answer:Cholesterol makes cell membranes more resilient. [While the chapter onlymentions that cholesterol strengthens cell membranes, students may also say that cholesterol helps regulate membrane fluidity.]

Difficulty: Moderate ASM Standard: N/A 67. How many glycosidic linkages are in the molecule below?

Sample Answer:There are two glycosidic linkages in this molecule.

Difficulty: Moderate ASM Standard: N/A 68. What type of chemical reaction is needed to separate this molecule into three fatty acids and glycerol?

Sample Answer: To break down this molecule, water must be added (i.e., a hydrolysis reaction).

Difficulty: Moderate ASM Standard: N/A 69. Indicate the α carbon on the amino acid below.

Sample Answer:The α carbon is the carbon to which the amino group, carboxyl group, hydrogen, and R group are joined.

Difficulty: Moderate ASM Standard: N/A 70. Consider the molecule below. Of the four major types of important biological molecules, which type is this? How can you tell? Explain why it fits into that group and then explain why it does not fit into each of the other three groups.

Sample Answer: This molecule is a lipid. It is nonpolar and consists of only carbon and hydrogen. It is not a monosaccharide, because it does not have –OH groups. Sugars do have –OH groups and an aldehyde or ketone (when linear).They can also form rings. It is not an

amino acid, because it lacks an amino group and a carboxyl group. Finally, it is not a

nucleotide, because it lacks a phosphate group, a sugar, and a nitrogenous base (let alone any nitrogen). It does not contain a sugar for the reasons already discussed.

Difficulty: Moderate ASM Standard: N/A 71. Identify the functional group or groups in this molecule: CH 3 CH 2 CHO Sample Answer: This molecule contains an aldehyde.

Difficulty: Moderate ASM Standard: N/A 72. Why is glucose usually found in nature as a ring rather than as a linear structure?

Sample Answer: Sugars can form a ring through the interaction of a hydroxyl group and a carbonyl group. When the ring is the right size for maintaining appropriate bond angles (reducing ring strain), then a ring is more stable than the linear molecule. Glucose has six carbons and can form either a six-membered ring or a five-membered ring.

Difficulty: Moderate ASM Standard: N/A 73. Compare the structures of starch, glycogen, and cellulose. Explain why humans cannot use cellulose as a major source of energy even though it contains glucose molecules.

Sample Answer:Although starch, glycogen, and cellulose are all polymers of glucose, they have different structures, resulting in different properties. Starch consists of two types of chains, a straightchain (amylose) and a branched chain (amylopectin). Glycogen consists of one type of chain, which is more branched than amylopectin. Cellulose is not branched but has linkages between its linear chains that make it strong. Because cellulose has different glycosidic linkages than those of starch and glycogen, a different enzyme is needed to break it down and human do not produce this enzyme.

Difficulty:Difficult ASM Standard: N/A 74. What are micelles and why is it energetically favorable for them to form?

Sample Answer:Micelles are spherical structures that assemble from phospholipids with the phosphate groups toward the outside and the lipid tails toward the inside. This is energetically favorable because the lipid tails are hydrophobic and it would take more energy to keep them in contact with water than in contact with each other.

Difficulty: Difficult ASM Standard: N/A 75. Is the α carbon of this molecule chiral? Explain.

Sample Answer:Yes, the α carbon of this molecule is chiral because it has four different groups attached to it and, therefore, has two mirror image forms.

Difficulty: Difficult ASM Standard: N/A Brief Essay Essay Question Rubric RATING Failing Criteria for evaluati on

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is poor and contains numerous grammatical mistakes and misspellings.

Below Average Answer fails to provide examples to support an argument.

Writing is poor and grammatical errors are common.

Answer is somewhat incoherent.

Competent

Advanced

Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

POINT 0 1 2 3 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

76. When a plasma membrane is damaged, it reseals to keep the lipid bilayer intact. Explain how this process happens and why it is energetically favorable.

Answer: Student answers will vary but should include components of the following. The middle of the plasma membrane is a hydrophobic lipid layer. It is energetically favorable for the hydrophobic molecules to contact each other rather than being in contact with the watery material inside and outside the cell. For this reason, it is energetically favorable for the membrane to reseal itself when damaged.

Difficulty: Moderate

ASM Standard: N/A 77. Explain how the structure of the plasma membrane affects what can pass through it.

Answer: Student answers will vary but should include components of the following. The middle of the membrane is hydrophobic, so only small, uncharged molecules can pass through easily. Molecules that are polar, such as water, may pass through if they are sufficiently small. However, even very small ions, such as Na+, are unable to pass without assistance (e.g., by passing through a protein channel). Larger, nonpolar molecules, such as steroid hormones, can pass through the membrane.

Difficulty: Moderate ASM Standard: N/A 78. Compare the types of interactions that are responsible for the four different levels of protein structure.

Answer: Student answers will vary but should include components of the following. Primary protein structure is determined by the sequence of amino acids, which are joined together by peptide bonds. Secondary structure results from hydrogen bonding between amino acids that are relatively close together, forming α-helices and β-pleated sheets. Tertiary structure involves interactions between amino acids that are farther apart and results from hydrogen bonding, hydrophobic interactions, disulfide bonds, and ionic interactions. Quaternary structure results from the same interactions as tertiary structure but involves more than one polypeptide chain.

Difficulty: Moderate ASM Standard: N/A 79. Look at the phospholipid molecule below. Compare the shape of saturated and unsaturated fatty acids and think about what would happen if you packed together many phospholipids with a saturated fatty acids compared with packing together many phospholipids with unsaturated fatty acids. How do you think the plasma membrane might act differently if it has a higher proportion of saturated fatty acids versus a higher proportion of unsaturated fatty acids?

Answer: Student answers will vary but should include the following. Saturated fatty acids can pack tightly because they are straight. In contrast, unsaturated fatty acids are kinked and this causes them to pack less tightly. If the temperature were increased without any changes in the composition of the membrane, then the membrane would become too fluid if it had a high proportion of unsaturated fatty acids. By increasing the amount of saturation in the membrane, organisms can make the membrane more solid as the temperature increases.

Organisms can also make the membrane more flexible as the temperature drops by increasing the amount of unsaturation.

Difficulty: Moderate ASM Standard: N/A 80. Think about the structure of the plasma membrane and about how proteins form threedimensional structures. How do you think hydrophobic interactions affect an integral membrane protein? Where would hydrophobic amino acids be located on the protein? How would this differ from the location of hydrophobic amino acids in a protein that is loose in the cytoplasm, such as an enzyme?

Answer: Student answers will vary but should include the following. Hydrophobic interactions make it energetically favorable for nonpolar amino acids to be in the center of a protein in the cytoplasm, where they will interact with each other instead of with the watery cytoplasm of the cell. The inner layer of the cell membrane is composed of the fatty acid tails of the phospholipids, so it is nonpolar.Therefore, hydrophobic amino acids would tend to be located where they would contact the fatty acid tailsin center of the cell membrane rather than the polar phosphate groups on the inner and outer sides of the membrane.

Within the hydrocarbon portion of the membrane, nonpolar amino acids would be toward the outside of the protein and polar amino acids may be inside in the case of a protein channel. For parts of the protein toward the outside of the membrane, which interact with the polar heads of the phospholipids and extend into the cell, polar amino acids would be predicted to be on the outside and nonpolar amino acids would be toward the inside of the folded protein.

Difficulty: Difficult ASM Standard: N/A 81. People often think of fats as unhealthy and something that they should avoid. What are some reasons that fats are important in the human diet? Give at least three reasons.

Answer: Student answers may vary but should include at least some of the following. Fats are important in building cell membranes. There are phospholipids forming the membrane bilayer and cholesterol within the membrane. Adipose (fat) tissue provides insulation, cushioning, and contouring. Fats are important in energy storage. Because fat is hydrophobic, it can be very tightly packed and takes up less space than glycogen (which associates with water molecules). Animals obtain energy by oxidizing organic molecules.

Because fats are more reduced than carbohydrates or proteins, more energy can be extracted from them. Fats also serve additional purposes while storing energy, such as providing cushioning and insulation.

Difficulty: Difficult ASM Standard: N/A 82. What are similarities between cholesterol and hopanoids? What types of organisms use them? What are some other molecules with similar functions?

Answer: Student answers will vary but should include components of the following. Both cholesterol and hopanoids are used to stabilize the cell membrane. Hopanoids are found in prokaryotic cell membranes and cholesterol is found in eukaryotic cell membranes. Other molecules with similar functions are phytosterols, used by plants, and ergosterols, used by fungi.

Difficulty:Moderate ASM Standard: N/A

This file is copyright 2017, Rice University. All rights reserved.

Chapter 8: Microbial Metabolism * = Correct answer Multiple Choice 1. Which of the following refers to the term metabolism?

A. all the reactions in a cell or organism* B. all the reactions in a cell that break down molecules only C. all the reactions in a cell that build new molecules only D. all the reactions in a cell that decompose molecules only Difficulty: Easy ASM Standard: N/A 2. Which of the following best describes an endergonic reaction?

A. absorbs energy from the environment* B. is coupled with another reaction C. is involved in biosynthesis D. releases energy into the environment Difficulty: Easy ASM Standard: N/A 3. Chemotrophs obtain their energy from which of the following?

A. inorganic chemical reactions only B. light energy C. organic chemical reactions only D. organic and inorganic chemical reactions* Difficulty: Easy ASM Standard: 11 4. Which of the following describes a molecule that had an electron removed?

A. anabolized B. electronated C. oxidized* D. reduced Difficulty: Easy ASM Standard: N/A 5. Which of the following best describes the subcomponents of pyrophosphate?

A. two inorganic phosphate molecules* B. two organic phosphate molecules C. three inorganic phosphate molecules

D. three organic phosphate molecules Difficulty: Easy ASM Standard: N/A 6. Which molecule is often called the cell’s energy currency?

A. adenosine triphosphate* B. flavin adenine dinucleotide C. nicotinamide adenine dinucleotide D. nicotinamide adenine dinucleotide phosphate Difficulty: Easy ASM Standard: N/A 7. Which site on an enzyme is where substrates bind?

A. the activation site B. the active site* C. the catalyst site D. the lock and key site Difficulty: Easy ASM Standard: N/A 8. Which of the following are inorganic molecules that bind to enzymes?

A. apoenzymes B. coenzymes C. cofactors* D. holoenzymes Difficulty: Easy ASM Standard: N/A 9. Which of the following best describes catabolic pathways?

A. They always absorb energy.

B. They break down large molecules into smaller components.* C. They build up large molecules from smaller components.

D. They must be coupled with the breakdown of ATP. Difficulty: Moderate ASM Standard: N/A 10. Which group comprises all lithotrophs?

A. algae B. autotrophs C. microbes* D. plants Difficulty: Moderate ASM Standard: 11, 20, 22 11. Which is a common electron acceptor in catabolic reactions?

A. ATP B. FADH 2 C. NAD +* D. NADPH Difficulty: Moderate ASM Standard: N/A 12. The reaction that breaks down ATP to form ADP and inorganic phosphate is classified as which of the following?

A. endergonic B. exergonic* C. nonspontaneous D. reduction Difficulty: Moderate ASM Standard: N/A 13. Which of the following is an inhibitor that binds to the active site of an enzyme?

A. a competitive inhibitor* B. a noncompetitive inhibitor C. an allosteric inhibitor D. an uncompetitive inhibitor Difficulty: Moderate ASM Standard: N/A 14. Glycolysis produces a net gain of which of the following?

A. two ATP, two NADH, and two pyruvates* B. two ATP, two NADH, and four pyruvates C. two ATP, four NADH, and two pyruvates D. four ATP, two NADH, and two pyruvates Difficulty: Easy

ASM Standard: N/A 15. Which of the following is a pathway that breaks down glucose in some microbes?

A. the Calvin cycle B. the Entner-Doudoroff pathway* C. the Krebs cycle D. the tricarboxylic acid cycle Difficulty: Moderate ASM Standard: 11, 22 16. Which of the following best describes a transition reaction?

A. a reaction that converts pyruvate to acetyl CoA with the release of carbon dioxide* B. a series of reactions that convert citric acid to oxaloacetate C. an optional reaction that transports pyruvate into the mitochondrion D. the reaction that converts glucose to glucose-6-phosphate in glycolysis Difficulty: Moderate ASM Standard: N/A 17. Which of the following is not a product of the Krebs cycle?

A. carbon dioxide B. GTP, which is converted to ATP C. NADH D. pyruvate* Difficulty: Moderate ASM Standard: 20, 22 18. The Krebs cycle begins with the addition of acetyl CoA to which of the following?

A. citric acid B. oxaloacetate* C. ribulose bisphosphate D. succinate dehydrogenase Difficulty: Moderate ASM Standard: NA 19. Which of the following is the step in which CO 2 enters the light-independent reactions (Calvin cycle)?

A. fixation* B. reduction C. regeneration D. transition

Difficulty: Moderate ASM Standard: 20, 22 20. Carotenoids are pigments that are which of the following colors?

A. blue/green B. green/orange C. orange/yellow/red* D. purple/blue Difficulty: Moderate ASM Standard: N/A 21. Which of the following are enzymes that break down proteins?

A. amylases B. oxidases C. oxygenases D. proteases* Difficulty: Easy ASM Standard: N/A 22. Fatty acids are often degraded using which set of reactions?

A. β-oxidation* B. glycolysis C. photophosphorylation D. the tricarboxylic acid cycle Difficulty: Moderate ASM Standard: N/A 23. Triglycerides are broken down by which of the following?

A. lipases* B. nitrogenases C. phospholipases D. proteases Difficulty: Moderate ASM Standard: N/A 24. During the Krebs cycle, FAD is reduced to which of the following?

A. FADH B. FADH 2 *

C. NADH D. NADH 2 Difficulty: Moderate ASM Standard: N/A 25. Which of the following is the purpose of fermentation?

A. to produce carbon dioxide B. to produce large quantities of additional energy C. to regenerate NAD +* D. to regenerate oxygen Difficulty: Moderate ASM Standard: 11, 20, 22 26. ATP is produced through oxidative phosphorylation when which of the following occurs?

A. FADH 2 donates electrons to succinate dehydrogenase B. H+ moves through ATP synthase* C. NADH donates electrons to NADH dehydrogenase D. the light-independent reactions fix CO2 Difficulty: Moderate ASM Standard: N/A 27. Each pyruvate molecule contains how many carbon atoms?

A. two B. three* C. four D. six Difficulty: Moderate ASM Standard: N/A 28. When is the pentose phosphate pathway favored over other pathways to break down glucose?

A. when biosynthesis is not needed B. when phospholipids are needed D. when the cell has a severe energy deficit and needs energy rapidly C. when the synthesis of nucleic acids and proteins is needed* Difficulty: Difficult ASM Standard: 11, 22 29. Which of the following occurs when molecules are broken down using β-oxidation?

A. Carbon dioxide is removed.

B. Three carbon propyl groups are removed.

C. Two carbon acetyl groups are removed.* D. Two carbon acyl groups are removed.

Difficulty: Difficult ASM Standard: N/A 30. Which of the following best defines chemiosmosis?

A. the disruption of the inner mitochondrial membrane, which dissipates energy B. the movement of electrons from one acceptor to another C. the movement of hydrogen ions through ATP synthase* D. the series of reactions that regenerate oxaloacetate Difficulty: Difficult ASM Standard: N/A 31. Which of the following is the most acidic location in a mitochondrion?

A. the intermembrane space* B. the matrix C. within the outer membrane D. within the thylakoid Difficulty: Difficult ASM Standard: N/A 32. Which of the following is not a common electron acceptor in anaerobic respiration?

A. Fe3+ B. H 2 S C. NO3 – D. PO 4 3– * Difficulty: Difficult ASM Standard: N/A 33. Why is the actual ATP yield of aerobic respiration often less than the maximum possible yield of 38 ATP? A. Aerobic respiration competes with anaerobic respiration for energy.

B. Aerobic respiration competes with fermentation for energy.

C. In eukaryotes, energy is used to move molecules across membranes.

D. No organisms complete all parts of aerobic respiration.

Difficulty: Difficult ASM

Standard: N/A 34. How can enteropathogenic O157:H7 E. coli strain be recognized from other E. coli strains?

A. Unlike other E. coli, it cannot ferment lactose.

B. Unlike other E. coli, it cannot ferment mannose.

C. Unlike other E. coli, it cannot ferment pyruvate.

D. Unlike other E. coli, it cannot ferment sorbitol.* Difficulty: Difficult ASM Standard: 34 True/False 35. Glycolysis cannot occur in an anaerobic environment. Answer: False Difficulty: Easy ASM Standard: 20, 22 36. Nitrogen is fixed to ammonia by cyanobacteria and other microbes.

Answer: True Difficulty: Easy ASM Standard: 11, 20, 22, 23, 24 37. The light reactions of photosynthesis include an electron transport chain.

Answer: True Difficulty: Moderate ASM Standard: N/A 38. Fermentation is necessary because it provides additional energy compared with glycolysis alone.

Answer: False Difficulty: Moderate ASM Standard: N/A 39. E. coli can be distinguished from some if its close gram-negative relatives because it can ferment lactose.

Answer: True Difficulty: Moderate ASM Standard: 11, 34 40. Oxygen is necessary for an electron transport chain to function.

Answer: False Difficulty: Moderate ASM Standard: N/A 41. Mycobacterium tuberculosis can degrade cholesterol, making it more virulent.

Answer: True Difficulty: Difficult ASM Standard: 11, 23 42. Cyclic photophosphorylation produces only ATP, but noncyclic photophosphorylation produces ATP and NADH. Answer: True Difficulty: Difficult ASM Standard: N/A

Matching 43. Match each description with the best definition.

A. chemoautotroph i. uses light energy and an inorganic carbon source B. chemoheterotroph ii. uses chemical energy and an inorganic carbon source C. photoautotroph iii. uses light energy and an organic carbon source D. photoheterotroph iv. uses chemical energy and an organic carbon source Answers: A. ii., B. iv., C. i., D. iii.

Difficulty: Easy ASM Standard: 11, 20, 22 44. Match each term with its best example.

A. chemoautotroph i. animals B. chemoheterotroph ii. iron-oxidizing bacteria C. photoautotroph iii. purple sulfur bacteria D. photoheterotroph iv. green nonsulfur bacteria Answers: A. ii., B. i., C. iii., D. iv.

Difficulty: Moderate ASM Standard: 11, 20, 22 45. Match each word with the best definition.

A. apoenzyme i. an inorganic enzyme helper molecule B. coenzyme ii. an active enzyme with its coenzyme or cofactor C. cofactor iii. an inactive enzyme lacking its coenzyme or cofactor D. holoenzyme iv. an organic enzyme helper molecule Answers: A. iii., B. iv., C. i., D. ii.

Difficulty: Moderate ASM Standard: N/A 46. Match each reaction with the place that it occurs in eukaryotic cells.

A. electron transport chain of cellular respiration i. stroma of chloroplast B. glycolysis ii. cytoplasm C. Krebs cycle iii. thylakoid membrane D. light-independent reactions (Calvin cycle) iv. inner mitochondrial membrane E. light reactions of photosynthesis v. mitochondrial matrix Answers: A. iv., B. ii., C. v., D. i., E. iii.

Difficulty: Moderate ASM Standard: 11, 20, 22 47. Match each process with the best definition.

A. aerobic respiration i. uses an electron transport chain with an inorganic molecule such as SO 4 2– as the terminal electron acceptor

B. anaerobic respiration C. fermentation

ii. regenerates NAD + for glycolysis by donating an electron to an endogenous organic molecule, often pyruvate iii. uses an electron transport chain with O 2 as the terminal electron acceptor

Answers: A. iii., B. i., C. ii.

Difficulty: Moderate ASM Standard: 11, 20, 22 48. Match each type of fermentation with some of its end products.

A. alcohol i. acetic acid and other products B. butanediol ii. succinic acid and other products C. mixed acid iii. formic acid, lactic acid, and other products iv. ethanol and CO2 only D. propionic acid Answers: A. iv., B. iii., C. ii., D. i.

Difficulty: Moderate ASM Standard: 11, 20, 22 49. Match each type of fermentation with a microbe that uses it.

A. acetone-butanol-ethanol i. Candida, Saccharomyces B. alcohol ii. Escherichia, Shigella C. butanediol iii. Klebsiella, Enterobacter D. lactic acid iv. Clostridium acetobutylicum E. mixed acid v. Streptococcus, Lactobacillus Answers: A. iv., B. i., C. iii., D. v., E. ii.

Difficulty: Difficult ASM Standard: 11 Fill in the Blank 50. Another name for the Embden-Meyerhof-Parnas pathway is Answer: glycolysis

.

Difficulty: Moderate ASM Standard: N/A 51. Cyclic photophosphorylation produces Answer: ATP

.

Difficulty: Easy ASM Standard: 23 52. In oxygenic photosynthesis, oxygen is released because

electron to replace one

that absorbs a photon of light.

is split to provide an

Answer: water Difficulty: Easy ASM Standard: N/A 53. The light-independent reactions of photosynthesis are also known as the .

Answer: Calvin-Benson cycle (the names Calvin cycle or dark reactions may also be used, although the latter is not a preferred name) Difficulty: Moderate ASM Standard: N/A 54. Cyclic photophosphorylation uses only photosystem Answer: I [PSI or P700]

.

Difficulty: Moderate ASM Standard: N/A 55. The enzyme that brings CO2 into the light-independent reactions of photosynthesis, catalyzing the first reaction, is .

Answer: ribulose bisphosphate carboxylate oxidase (RuBisCO) Difficulty: Moderate ASM Standard: N/A 56. are bacteria and archaea that use methane as a carbon source.

Answer: Methanotrophs Difficulty: Moderate ASM Standard: 11, 20, 22 57. Approximately 78% of the atmosphere is Answer: nitrogen gas [N 2 ]

.

Difficulty: Easy ASM Standard: N/A 58. Rhizobia are bacteria that live in the root nodules of plants known as Answer: legumes Difficulty: Moderate ASM Standard: 11, 20 59. The is another name for the flow of electrons in noncyclic photophosphorylation.

Answer: Z scheme Difficulty: Difficult ASM Standard: N/A

.

60. Acetate fermentation is used by .

Answer: methanogens (students may also use acetogens, but that term is not in the chapter) Difficulty: Difficult ASM Standard: 11, 20, 22 Short Answer 61. Provide a basic overview of the major steps of the sulfur cycle.

Sample Answer: Hydrogen sulfide is oxidized to elemental sulfur and then to sulfate.

Difficulty: Easy ASM Standard: 24 62. What characteristics cause an organism to be classified as a chemoheterotroph?

Sample Answer: Chemotrophs get their energy from chemical reactions. Heterotrophs obtain preformed organic molecules and cannot build organic molecules from inorganic molecules.

Organisms that consume food (organic molecules) to get energy and organic molecules are chemoheterotrophs.

Difficulty: Easy ASM Standard: N/A 63. What are xenobiotics?

Sample Answer: Xenobiotics are chemicals produced by humans and released into the environment.

Difficulty: Easy ASM Standard: N/A 64. In terms of water and electron donors, what is the difference between oxygenic and anoxygenic photosynthesis?

Sample Answer: Oxygenic photosynthesis produces oxygen and anoxygenic photosynthesis does not. Oxygenic photosynthesis involves the use of water to donate an electron, releasing oxygen. In anoxygenic photosynthesis, other electron donors are used.

Difficulty: Easy ASM Standard: 11, 20, 22 65. Describe an example of a microbe being used for bioremediation.

Sample Answer: Rhodococcus and Pseudomonas are used to break down harmful compounds, such as those that could be released during an oil spill.

Difficulty: Moderate ASM Standard: 11, 26, 23, 31 66. Compare the energy produced by fermentation with that produced by aerobic respiration.

Sample Answer: Fermentation produces a net gain of two ATP molecules. In contrast, aerobic respiration produces a maximum of 38 ATP molecules.

Difficulty: Moderate ASM Standard: 11, 20, 22 67. Compare the photosystems used in cyclic and noncyclic photophosphorylation, as well as the products of each.

Sample Answer: Cyclic photophosphorylation uses photosystem I only (PSI or P700). It produces ATP. In contrast, noncyclic photophosphorylation uses photosystem I (PSI or P700) and photosystem II (PSII or P680). Noncyclic photophosphorylation produces ATP and NADPH. Difficulty: Moderate ASM Standard: 11 68. What is produced by the light-independent reactions (the Calvin cycle) of photosynthesis?

Sample Answer: The light-independent reactions of photosynthesis produce glyceraldehyde3-phosphate. These reactions consume ATP and NADPH, producing ADP, Pi , and NADP+ that can be used for the light reactions. (Note that the last sentence is not explained clearly in the text, although the text mentions that ATP and NADPH are used.)

Difficulty: Moderate ASM Standard: N/A 69. During glycolysis, how many ATP molecules are consumed and how many are produced?

Sample Answer: During glycolysis, two ATP molecules are consumed and four ATP molecules are produced. There is a net gain of two ATP molecules.

Difficulty: Easy ASM Standard: 11 70. What are the electron carrier molecules that deliver electrons to the electron transport chain in aerobic respiration?

Sample Answer: In aerobic respiration, electrons are provided by NADH and FADH 2 .

Difficulty: Easy ASM Standard: 11 71. What electron carrier in the electron transport chain can be used to distinguish similar bacterial species?

Sample Answer: Cytochrome oxidase, the electron carrier that donates electrons to oxygen, differs among species and can be used in identification.

Difficulty: Moderate ASM Standard: 11, 34

72. Where does the transition reaction occur in prokaryotic cells, compared with eukaryotic cells?

Sample Answer: Prokaryotic cells do not have mitochondria, so the transition reaction takes place in the cytoplasm. In contrast, in eukaryotic cells, the transition reaction takes place in the mitochondrial matrix.

Difficulty: Moderate ASM Standard: 9, 11, 20, 22 73. In prokaryotic cells, where does the electron transport chain of aerobic respiration take place?

Sample Answer: In prokaryotic cells, the electron transport chain takes place on the cell membrane because these cells do not have mitochondria.

Difficulty: Moderate ASM Standard: 9, 11, 22 74. The figure shows a chemical reaction. Explain whether the reaction is endergonic or exergonic.

Sample Answer: The reaction is endergonic. The amount of energy in the products is higher than the amount of energy in the reactants, meaning that energy was absorbed from the environment during the reaction. You can tell that the amount of energy is higher in the products because the line is higher on the y-axis of the graph for the products.

Difficulty: Difficult ASM Standard: N/A 75. Based on what you know about different metabolic types of microbes, what would be the carbon, energy, and electron requirements for a chemoorganoautotroph?

Sample Answer: A chemoorganoautotroph would be an organism that used chemical reactions of organic molecules to gain energy and electrons but is also capable of fixing inorganic molecules to produce organic molecules.

Difficulty: Difficult ASM Standard: 20, 22 76. Explain redox potential and why it is important in understanding the electron transport chain.

Sample Answer: Redox potential describes how easily a molecule acquires electrons. A molecule with a more positive redox potential will more readily accept an electron from

another molecule, being reduced in the process. In the electron transport chain, an electron is passed from one acceptor to another, with each having a more positive redox potential than the last.

Difficulty: Difficult ASM Standard: N/A Brief Essay Essay Question Rubric RATING Failing Criteria for evaluati on

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is poor and contains numerous grammatical mistakes and misspellings.

Below Average Answer fails to provide examples to support an argument.

Writing is poor and grammatical errors are common.

Answer is somewhat incoherent.

Competent

Advanced

Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

POINT 0 1 2 3 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

77. Compare the Embden-Meyerhof-Parnas, Entner-Doudoroff, and pentose phosphate pathways for breaking down glucose.

Sample Answer: Student answers will vary but should include components of the following.

The Embden-Meyerhof-Parnas pathway (EMP), or glycolysis, is the most common pathway and is found in most cells. The Entner-Doudoroff pathway (ED) can coexist with the EMP pathway in some cells. Other organisms use only the ED pathway. The pentose phosphate pathway occurs in all cells and is useful in biosynthesis. It is especially important when

molecules with an odd number of carbons, proteins, and nucleic acids are needed.

Difficulty: Moderate ASM

Standard: 11 78. Explain the difference between substrate level phosphorylation and oxidative phosphorylation.

Sample Answer: Student answers will vary but should include the following. Substrate level phosphorylation occurs when two reactions are coupled, one that releases energy and one that uses that energy to form ATP. Oxidative phosphorylation occurs when an electron transport chain is used to perform multiple oxidation reactions, providing the energy to produce ATP. Difficulty: Moderate ASM Standard: N/A 79. Explain at least three reasons why some cells may not use aerobic respiration even though it produces more energy than other forms of respiration.

Sample Answer: Student answers will vary but should include the following. One possible reason is that a cell lacks an appropriate cytochrome oxidase to use in an electron transport chain. Cytochrome oxidase is needed to transfer electrons to oxygen.

Another possible reason is that the cell may not have mechanisms to protect itself from damage caused by the presence of oxygen. When oxygen is present, reactive oxygen species, such as hydrogen peroxide and the superoxide radical, are present and can damage cells if the cells do not have mechanisms to protect themselves. Finally, the cell may be in an environment in which there is not enough oxygen for it to perform cellular respiration.

Difficulty: Difficult ASM Standard: 11, 20, 22 80. Describe some ways that differences in metabolic abilities can be used to identify microbes.

Sample Answer: Student answers will vary but should include components of the following. There are many ways that differences in metabolic abilities can be used to identify microbes. Multiple examples are included in the chapter. For example, an oxidase test can be used to distinguish Pseudomonas aeruginosa and Vibrio cholerae from negative Enterobacteriaceae because they use different cytochrome oxidases. The ability to ferment lactose distinguishes Escherichia coli from some other gram-negative bacteria.

Additionally, O157:H7 E. coli can be distinguished from other E. coli strains because it cannot ferment sorbitol. Staphylococcus aureus can be distinguished from other staphylococci because it can ferment mannitol.

Difficulty: Difficult ASM Standard: 22, 33, 34

This file is copyright 2017, Rice University. All rights reserved.

Chapter 9: Microbial Growth * = Correct answer Multiple Choice Bacteria most commonly reproduce using which of the following methods?

A. binary fission* B. budding C. meiosis D. mitosis Difficulty: Easy ASM Standard: N/A 1. Which structure separates new daughter cells in binary fission?

A. the crescent B. the division septum* C. the FtsZ D. the spindle apparatus Difficulty: Easy ASM Standard: N/A 2. Which of the following is another term for generation time?

A. doubling time* B. growth rate C. mitotic index D. replication index Difficulty: Easy ASM Standard: N/A 3. Which of the following best describes culture density?

A. another term for a batch culture B. the number of cells per unit volume* C. the reproducible pattern of growth D. the total number of cells Difficulty: Easy ASM Standard: 36 4. Which of the following is the correct order of phases of growth in the growth curve of a batch culture? lag phase log phase stationary phase A. death/decline phase log phase stationary phase death/decline phase * B. lag phase

lag phase stationary phase C. log phase D. stationary phase log phase lag phase

death/decline phase death/decline phase

Difficulty: Easy ASM Standard: 36 Which of the following is not a common way bacteria divide?

A. binary fission B. budding C. fragmentation D. sporulation* Difficulty: Moderate ASM Standard: N/A 5. Which of the following is the term for free-living bacteria?

A. biofilms B. pathogenic C. planktonic* D. sessile Difficulty: Easy ASM Standard: 21 6. Which of the following is not a reactive oxygen species?

A. atmospheric oxygen* B. peroxides C. singlet oxygen D. superoxide Difficulty: Easy ASM Standard: 14 7. Which of the following best describes FtsZ? A. a cytoskeletal protein in eukaryotic cells B. the protein that assembles the Z ring, which forms a divisome before division by binary fission* C. the protein that forms within the central structure of the new cell wall and septum that separates the daughter cells during binary fission D. the protein that gives structure to spirochetes, contributing to their unusual shape and motility Difficulty: Moderate ASM Standard: N/A 8. Which microbial pathogen has an unusually long doubling time?

A. Bacillus subtilis B. Escherichia coli C. Mycobacterium leprae*

D. Salmonella typhimurium Difficulty: Moderate ASM Standard: N/A 9. The initial cells added to a batch culture are called which of the following?

A. the batch B. the culture C. the inoculum* D. the lagging cells Difficulty: Moderate ASM Standard: 36 10. Which best describes bacterial growth during the log phase of the growth curve?

A. exponential* B. linear C. S-shaped D. stationary Difficulty: Moderate ASM Standard: N/A 11. Which best defines the term “persisters?”

A. cells that form endospores rapidly when environmental conditions become unfavorable, allowing them to survive in a dormant state without causing disease symptoms B. cells that persist in the log phase for much longer than other cells C. cells that rapidly colonize new environments by releasing virulence factors and moving through tissues, allowing them to contribute to severe systemic infections.

D. cells with relatively slow metabolic rates that survive longer than others during the death phase and that can cause chronic infections* Difficulty: Moderate ASM Standard: 14, 23 12. Which type of system is used to maintain bacteria in a relatively constant environment, allowing them to stay in the log phase of growth?

A. bacteriostat B. chemostat* C. maintenance state D. stable state Difficulty: Moderate

ASM Standard: 36 13. Which of the following is an indirect method of measuring numbers of bacterial cells?

A. a Coulter counter B. a Petroff-Hausser chamber C. microscopic cell count D. turbidity measurements* Difficulty: Moderate ASM Standard: 35, 36 14. Which of the following is not a common step in preparing a pour plate to make a count of microbial numbers?

A. A serial dilution is performed.

B. Bacteria are spread across the agar, using a sterile spreader.* C. Bacteria are mixed with warm agar and poured onto a Petri plate, then swirled.

D. The sample is allowed to grow, then colonies are counted.

Difficulty: Moderate ASM Standard: 33, 35, 36 15. Which of the following best describes why extracellular polymeric substances are important?

A. They are chemicals produced as part of the immune response to microbial invasion.

B. They are components of a biofilm secreted by the host cells as an immune response to wall off the pathogens.

C. They are components of a biofilm secreted by the microbes present.* D. They are secreted by free-living bacteria as virulence factors to allow them to penetrate the bloodstream.

Difficulty: Moderate ASM Standard: 20, 21, 22 16. Which of the following media is commonly used to determine the oxygen requirements of a bacterial species?

A. chocolate agar medium B. Mueller-Hinton agar medium C. thioglycolate medium* D. tryptic soy medium Difficulty: Moderate ASM Standard: 11, 35, 36

17. Which of the following best describes how a microaerophile would grow in a thioglycolate tube culture?

A. a short distance below the top of the medium, but not at the top* B. at the bottom of the medium only, with no growth in the middle or top C. near and at the top of the medium, with no growth at the bottom D. throughout the medium Difficulty: Moderate ASM Standard: 20, 22 18. Which of the following is not an example of an enzyme used to detoxify reactive oxygen species?

A. catalase B. permeases* C. peroxidases D. superoxide dismutases Difficulty: Moderate ASM Standard: 11, 20, 22 19. A candle jar is often used to grow which type of bacteria?

A. capnophiles* B. microaerophiles C. obligate aerobes D. obligate anaerobes Difficulty: Moderate ASM Standard: 14, 20, 22, 36 20. Which of the following is the most common category of bacteria?

A. acidophiles B. alkaliphiles C. extreme alkaliphiles D. neutrophiles* Difficulty: Easy ASM Standard: 13, 14, 20, 22, 36 21. Human pathogens are generally which type of microbe?

A. mesophiles* B. psychrophiles C. psychrotrophs D. thermophiles Difficulty: Moderate ASM Standard: 14, 20, 22, 26

22. Food spoilage is often caused by which type of microbe?

A. mesophiles B. psychrophiles

C. psychrotrophs* D. thermophiles Difficulty: Moderate ASM Standard: 14, 20, 22, 36 23. Which type of microbes thrive in the Great Salt Lake?

A. barophilic B. barotolerant C. extreme halophiles* D. halotolerant Difficulty: Easy ASM Standard: 11, 20, 22 24. Which type of organism can survive at great depths in the ocean?

A. acidophilic B. barophilic C. barotolerant* D. halophilic Difficulty: Moderate ASM Standard: 11, 20, 22 25. Which range of the electromagnetic spectrum is considered photosynthetically active radiation?

A. from ultraviolet to near infrared B. from visible light to near infrared* C. in near infrared only D. in visible light only Difficulty: Difficult ASM Standard: 11, 20, 22 26. In batch culture, how does the log phase of the bacterial growth curve appear?

A. exponential on a semi-log scale B. linear on a semi-log scale* C. logarithmic on an arithmetic scale D. logarithmic on a semi-log scale Difficulty: Difficult ASM Standard: N/A 27. Which of the following best describes the enzymes of extreme alkaliphiles?

A. They have many acidic amino acids.

B. They have relatively high isoelectric points.* C. They have relatively high numbers of negatively charged surface amino acids.

D. They have the ability to pump protons out of cells.

Difficulty: Difficult ASM Standard: 11, 20, 22 28. Capnophiles are bacteria that grow best under which of the following conditions?

A. relatively high CO2 and relatively low oxygen concentrations* B. relatively high oxygen and relatively low CO2 concentrations C. relatively low CO2 and oxygen concentrations D. relatively low oxygen and CO 2 concentrations Difficulty: Difficult ASM Standard: 11, 20, 22 29. Which of the following best describes the cell membranes of microbes that thrive at low temperatures?

A. They have only one layer.

B. They have relatively even amounts of saturated and unsaturated fatty acids.

C. They have relatively high amounts of saturated fatty acids.

D. They have relatively high amounts of unsaturated fatty acids.* Difficulty: Difficult ASM Standard: 11, 20, 22 30. If you grow two species of bacteria on mannitol salt agar to determine which can ferment mannitol, and you know both species can grow on the medium, which type of medium is the agar?

A. differential* B. selective C. both a differential medium and a selective medium D. neither a differential medium nor a selective medium Difficulty: Difficult ASM Standard: 20, 22, 33, 34 31. Which of the following pigments are especially useful at great depths, where less light penetrates?

A. bacteriorhodopsin and carotenoids B. carotenoids and chlorophylls C. fucoxanthin and carotenoids D. fucoxanthin and phycobilins* Difficulty: Difficult ASM Standard: 11, 20, 22

32. Which of the following microbes uses light energy to pump hydrogen and sodium?

A. Bacteriodetes B. Campylobacter C. Chlamydomonas D. Halobacterium* Difficulty: Difficult ASM Standard: 34 33. Which of the following is true of using a Petroff-Hausser chamber to do a direct cell count?

A. Identical squares, all the same size, are etched into the slide.

B. If the sample was diluted, then the concentration must be corrected accordingly.* C. It is not necessary to know the volume of the sample added to the slide.

D. The chamber does not resemble a hemocytometer.

Difficulty: Moderate ASM Standard: 35, 36 34. Which of the following would be the best choice for distinguishing living and dead bacteria in a cell count?

A. using a Coulter counter or other electronic counting method B. using a streak plate, spread plate, or pour plate C. using gram staining or a similar method D. primary and secondary fluorescent stains* Difficulty: Moderate ASM Standard: 35, 36 35. What is the goal number of CFUs on a spread plate if a serial dilution is done correctly?

A. 1–10 per plate B. 30–300 per plate* C. 400–900 per plate D. 1000 or more per plate Difficulty: Easy ASM Standard: 35, 36 True/False 36. The largest component of the dry weight of a biofilm is usually extracellular polymeric substances.

Answer: True Difficulty: Easy ASM Standard: 21

37. Generation time in prokaryotes refers to the amount of time required for the doubling of the population through a single round of binary fission.

Answer: True Difficulty: Easy ASM Standard: N/A 38. Estimates of coliforms in water are often made using most probable number techniques.

Answer: True Difficulty: Moderate ASM Standard: 36 39. Quorum sensing always occurs between members of the same species.

Answer: False Difficulty: Moderate ASM Standard: 12 40. Halotolerant microbes cannot grow without high concentrations of salt. Answer: False Difficulty: Moderate ASM Standard: 11, 13, 20, 22 41. Fungi can generally thrive in drier environments than can bacteria.

Answer: True Difficulty: Moderate ASM Standard: 11, 20, 22 42. MacConkey agar can be used to select for the growth of gram-positive bacteria, making it especially useful to study Enterobacteriaceae.

Answer: False Difficulty: Difficult ASM Standard: 11, 20, 22, 33, 34, 36 43. Some halotolerant microbes are important causes of food poisoning.

Answer: True Difficulty: Difficult ASM Standard: 11, 20, 22, 23

Matching 44. Match each type of organism with the best description of its oxygen requirements.

A. aerotolerant anaerobes i. an organism that requires an oxygen-free environment B. facultative anaerobe ii. an organism that requires oxygen to survive C. microaerophile iii. an organism that requires a low concentration of oxygen (less than the oxygen concentration in the atmosphere) D. obligate aerobe iv. an organism that grows equally well with or without oxygen E. obligate anaerobe v. an organism that can grow without oxygen but that grows best with oxygen Answers: A. iv., B. v., C. iii., D. ii., E. i.

Difficulty: Easy ASM Standard: 11, 20, 22 45. Match each type of microbe with the best example.

A. aerotolerant i. Streptococcus B. facultative anaerobe ii. Clostridium difficile C. microaerophile iii. Campylobacter pylori D. obligate anaerobe iv. Staphylococcus Answers: A. i., B. iv., C. iii., D. ii.

Difficulty: Difficult ASM Standard: 11, 14, 20, 22 46. Match each type of microbe with the best description.

A. hyperthermophile i. temperature range for growth: approximately 0–15 °C B. mesophile ii. temperature range for growth: approximately 80–110 °C C. psychrophile iii. temperature range for growth: approximately 50–80 °C D. psychrotroph iv. optimal temperature range for growth: approximately 20–40 °C E. thermophile v. grows well between 4 °C and 25 °C Answers: A. ii., B. iv., C. i., D. v., E. iii.

Difficulty: Moderate ASM Standard: 11, 14, 20, 22 47. Match each type of medium with the best description.

A. chemically defined medium i. a medium with growth factors added to promote the growth of fastidious organisms B. complex medium ii. a medium made from the digests of yeasts, meats, or plants, meaning that the exact composition is unknown C. differential medium iii. a medium that favors the growth of some organisms over others D. enriched medium iv. a medium for which the entire composition is exactly known E. selective media v. a medium that allows colonies of bacteria to be

distinguished based on one or more characteristics

Answers: A. iv., B. ii., C. v., D. i., E. iii.

Difficulty: Moderate ASM Standard: 11, 20, 22, 33, 34 48. Match each microbe with the best description.

A. Bacillus firmus i. acidophile B. Ferroplasma ii. alkaliphile C. Geobacillus iii. halotolerant D. Halomonas iv. thermophile Answers: A. ii., B. i., C. iv., D. iii.

Difficulty: Difficult ASM Standard: 11, 20, 22, 33, 34 Fill in the Blank 49. The process of division by which cells split from a parent filament is called Answer: fragmentation

.

Difficulty: Easy ASM Standard: 22 50. The generation time for a particular bacterial species in a particular batch culture is called the .

Answer: intrinsic growth rate Difficulty: Easy ASM Standard: N/A 51. Turbidity is measured using a Answer: spectrophotometer

.

Difficulty: Easy ASM Standard: 36 52. When a spread plate is used to estimate bacterial numbers, the numbers are reported as .

Answer: colony forming units per milliliter (CFU/mL) Difficulty: Moderate ASM Standard: 36 53.

organisms do not require high salt concentrations for growth but can grow in salty environments.

Answer:

Halotolerant

Difficulty: Moderate ASM Standard: 11, 20, 22 54.

is a measure of available moisture.

Answer: Water activity Difficulty: Moderate ASM Standard: N/A

55.

is when the cell membrane moves away from the cell wall due to osmosis occurring within the cytoplasm.

Answer: Plasmolysis Difficulty: Moderate ASM Standard: N/A

56. At low temperatures, membranes become composition.

Answer: less

fluid unless they are able to modify their

Difficulty: Moderate ASM Standard: 11, 20, 22 57. The pigment used by Halobacteria to absorb light is called Answer: bacteriorhodopsin

.

Difficulty: Moderate ASM Standard: 11, 20, 22 58. The process of freeze-drying microbes so they can be stored until needed is called Answer: lyophilization Difficulty: Difficult ASM Standard: 36 59.

is an important accessory pigment used by brown algae to aid photosynthesis at low light levels.

Answer: Fucoxanthin Difficulty: Difficult ASM Standard: 11, 20, 22

.

Short Answer 60. Which group of bacteria commonly divides using fragmentation?

Sample Answer: The Actinomycetes commonly divide using fragmentation.

Difficulty: Easy ASM Standard: 11, 20, 22 61. Where are barophilic organisms found?

Sample Answer: Barophilic organisms require high pressures to grow, so they are found deep in the ocean.

Difficulty: Easy ASM Standard: 11, 20, 22 62. What happens during plasmolysis and what causes it?

Sample Answer: When a cell is exposed to a high osmotic pressure, the protoplasm moves away from the cell wall. (More detailed answer students may give if they remember the information from Chapter 3: Plasmolysis occurs when an organism with a cell wall is placed in a hypertonic solution. Water leaves the cell through osmosis, causing the plasma membrane to pull away from the cell wall, containing the reduced contents of the cell.)

Difficulty: Easy ASM Standard: 11, 20, 22 63. What is the difference between the optimum oxygen concentration and the maximum permissive oxygen concentration?

Sample Answer: The optimum oxygen concentration is the concentration at which a microbe grows best. In contrast, the maximum permissive oxygen concentration is the maximum concentration at which a microbe can grow.

Difficulty: Easy ASM Standard: 11, 14, 20, 22 64. What is the following equation used for and what do the variables n, N n , and N 0 refer to?

Nn = N0 2n Sample Answer: This equation is used to calculate the number of cells in a population undergoing binary fission for a particular starting population size. The initial number of cells is N 0 ; n represents the number of generations; and Nn represents the number of cells after n generations.

Difficulty: Moderate ASM Standard: 35 65. Why do researchers often work with bacteria in the log phase of bacterial growth in a batch culture, rather than in other phases?

Sample Answer: Bacteria in the log stage are most commonly used because of their relatively consistent characteristics (i.e., growth and metabolism) and susceptibility to disinfectants and antibiotics.

Difficulty: Moderate ASM Standard: 11, 20, 22, 36 66. What are the most important signaling molecules for quorum sensing in gram-negative bacteria? How does this compare with the signaling molecules used by gram-positive bacteria?

Sample Answer: N-acetylated lactones are the most important signaling molecules used for quorum sensing by gram-negative bacteria. In contrast, the most important signaling molecules used by gram-positive bacteria are small peptides.

Difficulty: Moderate ASM Standard: 12 67. What is the standard way to grow obligate anaerobes in the laboratory?

Sample Answer: Obligate anaerobes are killed by oxygen, so they need to be maintained in an oxygen-free environment. This can be accomplished using an anaerobic jar or anaerobic chamber. A candle jar is generally used for capnophiles, specifically because it contains a high CO 2 concentration. The oxygen concentration decreases as the candle burns, so it is not completely devoid of oxygen, which is the condition needed for strict anaerobes.

Difficulty: Moderate ASM Standard: 11, 20, 22, 36 68. Why is MacConkey agar considered both a selective and a differential medium?

Sample Answer: MacConkey agar is selective because the bile salts and crystal violet included in the medium favor the growth of gram-negative bacteria while interfering with the growth of gram-positive bacteria. It is differential because bacteria that are able to grow cause the medium to turn red if they ferment lactose, whereas nonfermenters do not cause a color change. In this way, fermenters can be distinguished from nonfermenters.

Difficulty: Moderate ASM Standard: 11, 34, 36 69. Why might you need to enrich media?

Sample Answer: Fastidious microbes need particular specialized vitamins, growth factors, or other nutrients added to media. When these are added, the medium is called an enriched medium.

Difficulty: Moderate ASM Standard: 11, 34, 36 70. Give an example of a halotolerant species that can cause food poisoning.

Sample Answer: Staphylococcus aureus and Bacillus cereus are halotolerant and can cause food poisoning. Vibrio cholerae, the causative agent of cholera, is also halotolerant.

Difficulty: Difficult ASM Standard: 11, 34 71. Mixed bacterial infections can occur that include both facultative anaerobes and obligate anaerobes. What happens when these species coexist?

Sample Answer: When facultative anaerobes and obligate anaerobes coexist, the facultative anaerobes use up any oxygen present, which allows the obligate anaerobes to thrive.

Difficulty: Moderate ASM Standard: 11, 14, 20, 22 72. Staphylococci thrive on human skin. What does this tell you about their environmental requirements?

Sample Answer: Organisms that thrive on human skin are generally mesophiles, because the optimal temperature range for these species includes human body temperature. They also need to be able to tolerate salt from sweat, so they are generally halotolerant. Water availability varies on different parts of the skin, as do other environmental factors.

Difficulty: Moderate ASM Standard: 11, 20, 22, 23 73. Explain how you would do a serial dilution beginning with 1 mL of your bacterial culture.

Sample Answer: If you have 1 mL of culture, then you would add 9 mL to have 10 mL total (a 1:10 dilution). You then take 1 mL of the first dilution and add 9 mL of water to get a 1:100 dilution. You repeat this process as many times as needed to obtain the dilution required.

Difficulty: Moderate ASM Standard: 35, 36 74. Why are microbes in the stationary phase of growth less susceptible to antibiotics?

Sample Answer: Microbes at this stage have slower metabolic activities, so they are less susceptible to antibiotics that target those activities.

Difficulty: Difficult ASM Standard: 7, 14 75. Which enzymes that detoxify reactive oxygen species are present or absent in obligate anaerobes and aerotolerant organisms?

Sample Answer: The three major types of enzymes used to detoxify reactive oxygen species are catalases, peroxidases, and superoxide dismutases. Aerotolerant organisms usually have superoxide dismutase, but obligate anaerobes usually lack all these enzymes.

Difficulty: Difficult ASM Standard: 11, 14, 20, 22

76. Why is an enzyme from Thermus aquaticus especially useful for PCR? Sample Answer: Thermus aquaticus is a thermophile; its enzymes function well at high temperatures, making it useful for PCR. Difficulty: Difficult ASM Standard: 11, 20, 22, 26 Brief Essay Essay Question Rubric RATING Failing Criteria for evaluati on

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is poor and contains numerous grammatical mistakes and misspellings.

Below Average Answer fails to provide examples to support an argument.

Writing is poor and grammatical errors are common.

Answer is somewhat incoherent.

Competent

Advanced

Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

POINT 0 1 2 3 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

77. Using the standard equation to calculate number of cells at each generation, how many cells would be present after four generations in a population undergoing exponential growth that started with a population of two cells? How does this compare with the size after four generations of a similar population that started with eight cells?

Sample Answer: Student answers will vary but should include components of the following.

After four generations, a population of two cells would have grown to 32 cells. After four generations, a population of eight cells would have grown to 128 cells.

Difficulty: Moderate ASM Standard: 35 78. Explain what factors influence the length of the lag phase in a batch culture, and why.

Sample Answer: Student answers will vary but should include the following. The species present, health of the cells, type of medium, and other factors influence the length of the lag phase. When microbes are first placed into a new culture, they must adjust and repair damage before beginning the log phase of growth. They must produce any enzymes necessary to grow in the new medium, although this will be more rapid if the medium and growth conditions are very similar to their previous growth medium. Damaged cells need to undergo repair before rapid growth can begin.

Difficulty: Moderate ASM Standard: 36 79. Why is it helpful for some bacteria, such as Staphylococcus aureus, to produce virulence factors during the stationary phase of growth in a batch culture?

Sample Answer: Student answers will vary but should include the following. Cells enter the stationary phase because their environment has become less favorable for growth because of increased concentrations of waste products and/or reduced availability of nutrients and oxygen. By producing virulence factors, bacteria may increase their ability to spread to new locations. For example, S. aureus produces enzymes that help it break down tissues to more easily move to new locations.

Difficulty: Difficult ASM Standard: 13 80. There has been considerable concern about finding good ways to treat infections involving biofilms, such as those that develop on medical devices. What characteristics of biofilms complicate the treatment of infections involving biofilms?

Sample Answer: Student answers will vary but should include components of the following.

The proposed hypotheses include at least three possibilities. First, microbes in biofilms may be less metabolically active and bacteria that are less metabolically active are generally affected less by medications. Second, the extracellular polymeric substances may inhibit the ability of medications and other chemicals to penetrate the biofilm to affect the deeper cells.

In addition, microbes in biofilms may have metabolic abilities that help to counteract medications. For example, they may be able to pump out antibiotics using efflux pumps.

Finally, microbes in biofilms can exchange resistance genes through horizontal gene transfer.

Difficulty: Difficult ASM Standard: 2, 14, 21 81. What are some ways in which the structures of thermophiles and hyperthermophiles differ in order to help them thrive at high temperatures?

Sample Answer: Student answers will vary but should include components of the following.

These organisms have greater proportions of unsaturated fatty acids in their membranes, which reduces membrane fluidity. They also have higher proportions of guanine–cytosine

nitrogenous bases in their DNA to strengthen hydrogen bonding between the two strands, as well as additional bonds (ionic and covalent) to stabilize their protein structure.

Difficulty: Difficult ASM Standard: 11, 14, 20, 22 This file is copyright 2017, Rice University. All rights reserved.

OpenStax Microbiology Test Bank Chapter 10: Biochemistry of the Genome

Chapter 10: Biochemistry of the Genome * = Correct answer Multiple Choice 1. Gregor Mendel conducted his revolutionary work on patterns of inheritance using which organism?

A. fruit flies B. pea plants* C. roundworms D. snapdragons Difficulty: Easy ASM Standard: N/A 2. Which best describes true-breeding organisms?

A. They are heterozygous at multiple loci.

B. They have been produced through hybridization.

C. They produce offspring identical to themselves when self-fertilized.* D. They produce offspring of the same species when self-fertilized.

Difficulty: Easy ASM Standard: N/A 3. In a monohybrid cross, the first generation of offspring is called which of the following?

A. dihybrid generation B. first filial generation* C. parental generation D. second filial generation Difficulty: Easy ASM Standard: N/A 4. When Mendel published his work, most people believed which of the following about inheritance?

A. A fully formed, miniature human was transmitted from the father.

B. Blending of traits from both parents produces the traits of the offspring.* C. Genes are transmitted in DNA. D. Information from the mother provides the entire blueprint for the offspring.

Difficulty: Easy ASM Standard: N/A 5. A DNA nucleotide contains which of the following?

A. a deoxyribose sugar and a nitrogenous base B. a deoxyribose sugar, a phosphate, and a nitrogenous base* C. a ribose sugar and a nitrogenous base D. a ribose sugar, a phosphate, and a nitrogenous base

Difficulty: Easy ASM Standard: N/A 6. A nucleoside contains which of the following components?

A. a phosphate and a base B. a phosphate and a sugar C. a sugar and a base* D. a sugar, a phosphate, and a base Difficulty: Easy ASM Standard: N/A 7. Which of the following is a name for nitrogenous bases with a double-ring structure?

A. nucleosides B. nucleotides C. purines* D. pyrimidines Difficulty: Easy ASM Standard: N/A 8. Where in the DNA structure do DNA-binding proteins generally bind?

A. in the center of the helix, between the bases B. in the major grooves C. in the minor grooves D. in the major and minor grooves* Difficulty: Easy ASM Standard: N/A 9. Which of the following is not an example of an organism’s phenotype?

A. a behavioral response to certain conditions B. an organism’s observable characteristics C. the DNA sequence of a cellular genome* D. which enzymes are being synthesized Difficulty: Moderate ASM Standard: N/A 10. Who identified the nucleotide bases of DNA and RNA? A. Richard Altmann B. Albrecht Kossel* C. Gregor Mendel D. Friedrich Miescher Difficulty: Moderate ASM Standard: N/A 11. Mendel published his work in which of the following books?

A. Experiments in Plant Hybridization* B. On the Origin of Species C. The Double Helix

D. The Physical Basis of Heredity Difficulty: Moderate ASM Standard: N/A 12. Whose work provided the first experimental evidence for the Chromosomal Theory of Inheritance?

A. Theodor Boveri’s work with sea urchins B. Barbara McClintock’s work with maize C. Gregor Mendel’s work with pea plants D. Thomas Hunt Morgan’s work with Drosophila* Difficulty: Moderate ASM Standard: N/A 13. Which alga provided an important model to demonstrate the location of genetic information in the nucleus?

A. Acetabularia* B. Chlamydomonas C. Ulva D. Volvox Difficulty: Moderate ASM Standard: N/A 14. The one gene–one enzyme hypothesis that developed into the one gene–one polypeptide hypothesis was proposed by which of the following?

A. George Beadle, Edward Tatum, and colleagues* B. Gregor Mendel C. Matthew Meselson and Franklin Stahl D. Thomas Hunt Morgan Difficulty: Easy ASM Standard: N/A

15. Evidence that DNA was the genetic material rather than protein was provided by which of the following?

A. Oswald Avery, Colin MacLeod, and Maclyn McCarty B. George Beadle, Edward Tatum, and colleagues C. Alfred Hershey and Martha Chase* D. Matthew Meselson and Franklin Stahl Difficulty: Moderate ASM Standard: N/A 16. Who first demonstrated horizontal transmission of genetic information?

A. Oswald Avery B. Frederick Griffith* C. Barbara McClintock D. Thomas Hunt Morgan

Difficulty: Moderate ASM Standard: N/A 17. Which of the following correctly describes the number and type of bond(s) that stabilize an adenine–thymine base pair?

A. one hydrogen bond B. one phosphodiester bond C. two hydrogen bonds* D. three hydrogen bonds Difficulty: Moderate ASM Standard: N/A 18. Which of the following describes the relationship in which the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine in doublestranded DNA? A. Chargaff’s rules* B. Griffith’s rules C. Mendel’s laws D. Pauling’s principles Difficulty: Moderate ASM Standard: N/A 19. Which researchers published the first description of DNA as a double helix?

A. Francis Crick and Linus Pauling B. Rosalind Franklin and Linus Pauling C. Rosalind Franklin and Maurice Wilkins D. James Watson and Francis Crick*

Difficulty: Moderate ASM Standard: N/A 20. Which researcher produced X-ray diffraction images of DNA that were critical to determining its structure but did not receive a Nobel prize with colleagues because it is not awarded posthumously?

A. Francis Crick B. Rosalind Franklin* C. James Watson D. Maurice Wilkins Difficulty: Moderate ASM Standard: N/A 21. One strand of DNA runs from 5′ to 3′ and the opposing strand runs 3′ to 5′, meaning that the strands are oriented in which way?

A. antiparallel* B. conservative C. helical D. semiconservative

Difficulty: Moderate ASM Standard: N/A 22. The rejoining of two previously separated strands of DNA is called which of the following?

A. denaturation B. hydrogenation C. reannealing* D. semiconservative replication Difficulty: Moderate ASM Standard: N/A 23. DNA strands are often denatured in the laboratory using which method?

A. adding restriction enzymes B. freezing the sample C. raising the temperature* D. using a cold calcium chloride solution Difficulty: Moderate ASM Standard: N/A 24. Transmission of genetic information from parent to offspring is called which of the following?

A. horizontal gene transfer B. phage transfer C. transposition D. vertical gene transfer* Difficulty: Moderate ASM Standard: N/A 25. Which of the following is not a difference between DNA and RNA? A. DNA is used for shorter-term functions than RNA.* B. DNA is usually double stranded and RNA is usually single stranded.

C. RNA contains uracil and DNA contains thymine.

D. RNA is usually less stable than DNA. Difficulty: Moderate ASM Standard: N/A 26. Which process produces an RNA copy of a DNA molecule?

A. replication B. transcription* C. transformation D. translation Difficulty: Moderate ASM Standard: N/A 27. In which cellular location in a eukaryote do rRNA synthesis and ribosome assembly occur?

A. at ribosomes attached to the rough endoplasmic reticulum B. in the cytoplasm C. in the nucleolus* D. in the pores of the nuclear envelope Difficulty: Moderate

ASM Standard: N/A 28. Which of the following is located on the 5′ end of a DNA strand?

A. a phosphate group* B. the amino group of a nitrogenous base C. the hydroxyl group of a deoxyribose sugar D. the hydroxyl group of a ribose sugar Difficulty: Difficult ASM Standard: N/A 29. What happens to pyrophosphate released during phosphodiester bond formation?

A. It forms hydrogen bonds with nitrogenous bases.

B. It forms phosphodiester bonds with RNA. C. It is hydrolyzed to release energy.* Genome

D. It is immediately joined to another nucleotide.

Difficulty: Difficult ASM Standard: N/A 30. Who suggested that the DNA molecule may have three strands?

A. Francis Crick B. Rosalind Franklin C. Linus Pauling* D. James Watson Difficulty: Difficult ASM Standard: N/A 31. Streptococcus mutans only expresses the genes for slime-layer production when which of the following occurs?

A. constitutive genes are activated B. sucrose is present* C. the environment is strongly acidic D. the temperature is sufficiently high Difficulty: Difficult ASM Standard: 17, 20, 22

32. Which enzymes help prevent supercoiling?

A. histones B. polymerases C. primases D. topoisomerases* Difficulty: Difficult ASM Standard: N/A

33. Which describes a stable change in gene expression without changing the base sequence?

A. epigenetics* B. mutation C. replication D. transformation Difficulty: Difficult ASM Standard: N/A 34. Which term best describes the DNA in chloroplasts?

A. extrachromosomal* B. noncoding C. single stranded D. viral Difficulty: Difficult ASM Standard: N/A 35. Which best describes the mitochondrial DNA chromosome?

A. It is circular.* B. It is identical to chloroplast DNA. C. It is viral.

D. It lacks thymine.

Difficulty: Difficult ASM Standard: 34 True/False 36. DNA is important contributor to the physical structure of components throughout the cell.

Answer: False Difficulty: Easy ASM Standard: N/A 37. Extrachromosomal DNA can be viral.

Answer: True Difficulty: Easy ASM Standard: N/A 38. The presence of double-stranded RNA suggests a viral infection.

Answer: True Difficulty: Moderate ASM Standard: N/A 39. An organism’s genotype describes its appearance and genetic makeup.

Answer: False Difficulty: Moderate ASM Standard: N/A

40. Noncoding DNA appears to have very few functions and is known as “junk DNA.” Answer: False Difficulty: Moderate ASM Standard: N/A

41. Prokaryotes are generally haploid.

Answer: True Difficulty: Moderate ASM Standard: N/A 42. Ribosomal RNA is shorter than messenger RNA and transfer RNA. Answer: False Difficulty: Difficult ASM Standard: N/A 43. The peptidyl transferase enzymatic activity of ribosomes is due to rRNA. Answer: True Difficulty: Difficult ASM Standard: N/A Matching 44.

Match each scientist or scientists with their work.

A. George Beadle, Edward Tatum, and colleagues i. described a double-helix model of DNA structure SE B. Alfred Hershey and Martha T CE haSseTBA ii.NdK em onLstLraEteRd.thCaO tM X-ray exposure causes mutations C. Hermann Mueller iii. used bacteriophages to show that DNA was the genetic material D. James Watson and Francis Crick iv. developed the “one gene–one enzyme” hypothesis Answers: A. iv., B. iii., C. ii., D. i.

Difficulty: Easy ASM Standard: N/A 45. Match each type of RNA with the best description.

A. messenger RNA i. short, unstable, single-stranded RNA that encodes genetic information B. ribosomal RNA ii. short, stable RNA with extensive intramolecular base pairing C. transfer RNA iii. relatively long, stable RNA involved in catalyzing bond formation and stabilizing the structures involved in translation Answers: A. i., B. iii., C. ii.

Difficulty:

Moderate ASM Standard: N/A 46. Match the scientist with his work.

A. Frederick Griffith

i. worked with Acetabularia to show that the nucleus contains the genetic material B. Joachim Hämmerling ii. found evidence for the Chromosomal Theory of inheritance and is known for work with fruit flies C. Gregor Mendel iii. examined inheritance patterns and showed that inheritance does not result from the blending of traits D. Thomas Hunt Morgan iv. demonstrated transformation in Streptococcus pneumoniae Answers: A. iv., B. i., C. iii., D. ii.

Difficulty: Moderate ASM Standard: N/A 47. Match each molecule with its description.

A. chromatin i. an enzyme that helps prevent overwinding of the DNA during DNA replication B. histone ii. an RNA enzyme that catalyzes bond formation during translation C. peptidyl transferase iii. protein around which DNA is wrapped D. topoisomerase iv. DNA and the proteins around which it is arranged Answers: A. iv., B. iii., C. ii., D. i.

Difficulty: Moderate ASM Standard: N/A 48. Match each base with the best description.

A. adenine i. a purine that binds with cytosine B. cytosine ii. a purine that binds with thymine C. guanine iii. a pyrimidine that binds with adenine D. thymine iv. a pyrimidine that binds with guanine Answers: A. ii., B. iv., C. i., D. iii.

Difficulty: Easy ASM Standard: N/A 49. Match each scientist with his or her work.

A. Richard Altmann i. isolated chemicals from pus that are now known to be DNA and RNA B. Erwin Chargaff ii. developed the rules that A=T and C=G in doublestranded DNA C. Rosalind Franklin iii. first used the term “nucleic acid” for DNA and RNA D. Barbara McClintock iv. used X-ray diffraction to produce images that were critical to determining the structure of DNA E. Friedrich Miescher v. identified transposons Answers: A. iii., B. ii., C. iv, D. v., E. i.

Difficulty: Difficult

ASM Standard: N/A Fill in the Blank 50. The type of chemical bonds that hold together the two strands of a DNA double helix are called bonds.

Answer: hydrogen Difficulty: Easy ASM Standard: N/A 51. Thomas Hunt Morgan worked with the model organism Answer: Drosophila melanogaster (fruit flies)

.

Difficulty: Easy ASM Standard: N/A 52.

are a type of topoisomerase in prokaryotes.

Answer: Gyrases Difficulty: Easy ASM Standard: N/A

53.

TsEtShT is a purine that form reB eA hyNdK roSgE enLbLoE nR d s.wCiO t hMits complementary pyrimidine.

Answer: Guanine Difficulty: Moderate ASM Standard: N/A

54. The DNA nucleotides in a single strand of DNA are connected by a type of covalent bond called a .

Answer: phosphodiester bond Difficulty: Moderate ASM Standard: N/A 55.

are also known as jumping genes.

Answer: Transposons Difficulty: Moderate ASM Standard: N/A

56. The alga that was useful in determining that the genetic material is located in the nucleus is .

Answer: Acetabularia Difficulty: Moderate ASM Standard: N/A 57. Frederick Griffith showed that horizontal gene transfer can occur through a process he called .

Answer: transformation Difficulty: Moderate ASM Standard: N/A 58. A molecule with a sugar and base but no phosphate is called a . Answer: nucleoside Difficulty: Moderate ASM Standard: N/A 59. Ribose has five carbons, so it is referred to as a sugar. Answer: pentose Difficulty: Moderate ASM Standard: 20 60. Hershey and Chase showed that DNA carries genetic information using the bacteriophage. Answer: T2 Difficulty: Difficult ASM Standard: 11, 20, 22 Short Answer 61. Why is it important that Mendel used true-breeding plants?

Sample Answer: True-breeding plants are homozygous, meaning that the two alleles are the same for each trait. This makes crosses easier to interpret because the researcher knows what alleles are carried by all gametes for a trait of interest.

Difficulty: Moderate ASM Standard: N/A 62. What are proteases, such as the proteases used by Oswald Avery, Colin MacLeod, and Maclyn McCarty?

Sample Answer: Proteases are enzymes that digest proteins, breaking them down so that they can no longer function.

Difficulty: Easy ASM Standard: N/A

63. What are phages? Why are they useful for genetic studies?

Sample Answer: Phages, or bacteriophages, are viruses that infect bacteria. They are useful for genetic studies because they have a simple structure and are easy to manipulate. They infect bacteria, which are easy to grow in the laboratory.

Difficulty: Easy

ASM Standard: N/A 64. What are transposons?

Sample Answer: Transposons are DNA segments that can move from one place to another within the genome.

Difficulty: Easy ASM Standard: N/A 65. What is the difference between the rough and smooth strains of Streptococcus pneumoniae and what is the significance of this difference in the virulence of S. pneumoniae?

Sample Answer: The rough strain of S. pneumoniae produces colonies that have a rough appearance because they lack capsules. The smooth strain produces colonies that appear smooth because they have capsules. The capsule is important in allowing S. pneumoniae to cause disease, because it helps protect the bacteria from phagocytosis.

Difficulty: Moderate ASM Standard: N/A

66. The “one gene–one enzyme” hypothesis was later modified. Give an example of something encoded by a gene that is not an enzyme.

Sample Answer: Answers may vary. Some genes encode polypeptides that form structural proteins in the cell. Additionally, some genes encode rRNA molecules or tRNA molecules.

Difficulty: Moderate ASM Standard: N/A 67. If you radioactively labeled the phosphorus in a cell, would RNA become radioactive? Sample Answer: Yes. Phosphorus is found in RNA, so the RNA would become radioactive.

Difficulty: Moderate ASM Standard: N/A 68. DNA replication is semiconservative. What does this mean?

Sample Answer: When DNA is replicated, a DNA molecule splits into two single parental strands. Each parental strand serves as a template for the synthesis of a complementary daughter strand, resulting in two double-stranded DNA molecules. Therefore, one of the two strands in each new DNA molecule is conserved from the parental DNA molecule, whereas the other strand is newly synthesized.

Difficulty: Moderate ASM Standard: N/A 69. Explain complementary base pairing in DNA and RNA. Sample Answer: The complementary base pairing rules are 1) adenine always forms hydrogen bonds with thymine and 2) cytosine always forms hydrogen bonds with guanine in DNA. In RNA, there is no thymine, so adenine instead bonds with uracil.

Difficulty: Moderate ASM Standard: N/A 70. Prokaryotic cells are generally haploid. How does this affect their utility as model organisms to study inheritance patterns, such as those studied by Mendel?

Sample Answer: Because they are haploid, they do not have alleles that are not expressed, such as the recessive alleles that are hidden by dominant alleles in eukaryotic organisms.

This can make them very useful for certain types of genetic studies but means that they would not be useful for doing crosses like those that Mendel did using pea plants.

Difficulty: Moderate ASM Standard: N/A 71. Compare the amount of noncoTdEinSgTDBNAANK inSpE roLkL arE yoRt. esCaO ndMeukaryotes.

Sample Answer: Eukaryotes have much more noncoding DNA than prokaryotes. Although the amounts vary considerably by species, the average amount of noncoding DNA is 12% for prokaryotes and 98% for eukaryotes.

Difficulty: Moderate ASM Standard: N/A 72. How would an antibiotic that targeted a gyrase kill a bacterial cell?

Sample Answer: Gyrases prevent overwinding during DNA replication. If they are inactivated, the DNA can become damaged by becoming packed too tightly, DNA replication stops, and cells will die.

Difficulty: Moderate ASM Standard: 14 73. Think carefully about the structure of DNA, including that in viruses. Does the amount of adenine always equal the amount of thymine in a DNA sample? Explain.

Sample Answer: The amount of adenine always equals the amount of thymine in doublestranded DNA. However, even though DNA is usually double stranded, it is not always double stranded. If your sample happened to contain single stranded DNA (e.g., if you had denatured it with heat and then taken out some material for further analysis), then the amounts of adenine and thymine may not be equal. Viruses have varied genomes. Some have single-stranded DNA instead of double-stranded DNA in their genome. In these cases, the amount of adenine may not be equal to the amount of thymine.

Difficulty: Difficult ASM Standard: N/A 74. How are epigenetic changes able to influence phenotypes without changing the sequence of nitrogenous bases in DNA? Sample Answer: Epigenetic changes affect gene expression. For example, methylation of nucleotides can affect the expression of those nucleotides by affecting DNA packaging. By changing the expression of genes, it is possible to change phenotypes without changing the sequence of bases.

Difficulty: Difficult ASM Standard: N/A Brief Essay Essay Question Rubric RATING Failing

Below Average

Competent

ESTBANKSEL E R.COM

Advanced

Criteria for evaluation

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is poor and contains numerous grammatical mistakes and misspellings.

Answer fails to Answer provides provide examples an argument with to support an one or two argument. examples that Writing is poor and support it. Writing grammatical errors is acceptable for the college level are common.

Answer is somewhat but may contain one or two incoherent. grammatical mistakes or misspellings.

POINT 0 1 2 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently. Answer is well organized and free of grammatical errors and misspellings.

3

75. What are some reasons that fruit flies, pea plants, and microbes such as Acetabularia are good model systems for studying genetics?

Answer: Student answers may vary. Some reasons, for example, are that these organisms are used to study genetics because they have relatively short generation times, are easy to raise in the laboratory, and are easy to breed in a controlled way so parent crosses are known.

Difficulty: Moderate ASM Standard: 25 76. Compare and contrast the pros and cons of using bacteria versus fruit flies for genetic studies.

Genome

Answer: Student answers will vary but should include the following. Many species of bacteria are easy to raise in the laboratory, as are fruit flies, and generation times are short.

Therefore, both types of organisms are easy to work with in the laboratory. However, they differ in that bacteria are prokaryotes and fruit flies are eukaryotes, meaning they have different numbers of chromosomes and cellular machinery relating to DNA. In addition, bacteria are haploid and fruit flies are diploid. Because bacteria are haploid, they do not have alleles that don’t get expressed, such as the recessive alleles that are hidden by dominant alleles in eukaryotic organisms. Therefore, genetic experiments, such as those performed by Mendel, cannot be performed with bacteria. In addition, bacteria reproduce using binary fission, whereas fruit flies use sexual reproduction. Because binary fission is a form of cloning, the offspring of bacteria are usually identical to the parent. This is not true with sexual reproduction, where offspring contain the DNA of both parents Difficulty: Moderate ASM Standard: 25 77. How would the results of Avery, MacLeod, and McCarty’s experiment have differed if RNA

had been the molecule of inheritance instead of DNA? Answer: Student answers will vary but should include the following. In this experiment, Avery, MacLeod, and McCarty inactivated different cellular molecules to see which one was responsible for bacterial transformation, thereby identifying the molecule of heredity. They found that using deoxyribonucleases prevented transformation from occurring because these enzymes digested DNA. If RNA had actually been the critical genetic material for TaEtiSonTB transformation, then transform wA o uNldKS haE vL e L ocEcuRr. reC d OafMter the use of deoxyribonucleases as long as the RNA was intact. Instead, ribonucleases would degrade the RNA, thus preventing transformation from occurring.

Difficulty: Difficult ASM Standard: N/A 78. Explain how some disease-causing microbes may cause epigenetic changes that can help protect them from the host’s immune system. Give at least one specific example.

Answer: Student answers will vary but should include components of the following. Some bacteria, such as Helicobacter pylori and Shigella flexneri, can remodel the chromatin in the host cells. If the chromatin is made more tightly packed, then RNA polymerase cannot access the DNA to express the genes. This turns off the tightly packed genes and can affect the immune response.

Difficulty: Difficult ASM Standard: 23

This file is copyright 2017, Rice University. All rights reserved.

Chapter 11: Mechanisms of Microbial Genetics * = Correct answer Multiple Choice 1. Gene expression includes which of the following?

A. DNA replication B. replication, transcription, and translation C. transcription and translation* D. translation only Difficulty: Easy ASM Standard: N/A 2. The central dogma describes which of the following?

A. the process by which enzymes are modified after translation B. the steps of gene expression* C. the way DNA is replicated D. the way RNA is used as a template to make DNA Difficulty: Easy ASM Standard: N/A 3. During bacterial DNA replication, which of the following holds open the replication bubble?

A. DNA polymerases B. helicases C. primers D. single-strand binding proteins* Difficulty: Easy ASM Standard: N/A 4. Telomeres found in which of the following?

A. all microbes B. animal cells only, not in unicellular organisms C. fungal, protist, plant, and animal chromosomes* D. microbes only, including all domains Difficulty: Easy ASM Standard: 16

5. Which of the following best describes the direction in which lagging strands are added?

A. as 5′ to 3′ Okazaki fragments in an overall 3′ to 5′ direction only* B. as 5′ to 3′ Okazaki fragments in an overall 5′ to 3′ direction only C. in the 3′ to 5′ or 5′ to 3′ direction D. in variable directions depending on the species Difficulty: Easy ASM Standard: N/A 6. Which of the following correctly describes uracil and where is it found?

A. It is a nitrogenous base found in DNA and RNA. B. It is a nitrogenous base found in DNA only.

C. It is a nitrogenous base found in RNA only.* D. It is a nitrogenous base found only in nucleotides of molecules other than RNA and DNA. Difficulty: Easy ASM Standard: N/A 7. Which of the following is another name for the template strand (the strand of DNA that is transcribed)?

A. anticodon strand B. antisense strand* C. sense strand D. transcription strand Difficulty: Moderate ASM Standard: N/A 8. Which of the following correctly describes events that occur during transcription?

A. DNA polymerase binds to the site of initiation.

B. RNA polymerase binds to the core enzyme.

C. RNA polymerase binds to the operator.

D. RNA polymerase binds to the promoter.* Difficulty: Easy ASM Standard: N/A 9. Which of the following correctly explains why DNA replication is described as semiconservative?

A. Each daughter strand contains one old strand and one new strand.* B. Each daughter strand contains two new strands.

C. The nucleotides used in replication are recycled multiple times.

D. The nucleotides used in replication contain old and new components.

Difficulty:

Moderate ASM Standard: N/A 10. During DNA replication in bacteria, which of the following enzymes adds DNA nucleotides to the growing strand?

A. DNA polymerase I B. DNA polymerase II C. DNA polymerase III* D. DNA polymerase IV Difficulty: Moderate ASM Standard: 16 11. Topoisomerase II in bacteria is also called which of the following?

A. gyrase* B. helicase C. primase D. topoisomerase β Difficulty: Moderate ASM Standard: 16 12. DNA polymerase III adds DNA nucleotides in which of the following direction(s)?

A. in the 3′ to 5′ direction only B. in the 3′ to 5′ direction and in 5′ to 3′ direction C. in the 5′ to 3′ direction on one strand and in the 3′ to 5′ direction on the complementary strand D. in the 5′ to 3′ direction only* Difficulty: Moderate ASM Standard: 16 13. Which of the following removes the primers during DNA replication in bacteria?

A. DNA polymerase I* B. DNA polymerase II C. DNA polymerase III D. DNA polymerase IV Difficulty: Moderate ASM Standard: 16 14. The noncoding, repetitive sequences at the end of eukaryotic chromosomes are called which of the following?

A. bubbles B. forks

C. lagging strands D. telomeres* Difficulty: Easy ASM Standard: 16 15. During DNA replication, the lagging strand is formed from which of the following?

A. helicases B. leading strands C. Okazaki fragments* D. single strand binding proteins Difficulty: Moderate ASM Standard: N/A 16. Which of the following is the maximal rate of growth of a new bacterial DNA strand?

A. 10 nucleotides per second B. 100 nucleotides per second C. 1000 nucleotides per second* D. 10,000 nucleotides per second Difficulty: Moderate ASM Standard: N/A 17. Which statement best describes DNA polymerase I? A. It acts as a ligase.

B. It has exonuclease activity.* C. It joins fragments together.

D. It prevents supercoiling.

Difficulty: Moderate ASM Standard: 16 18. Which describes one difference between prokaryotic and eukaryotic DNA replication?

A. Eukaryotes have more origins of replication than prokaryotes.* B. The chromosomes are usually circular in eukaryotes and usually linear in prokaryotes.

C. The DNA is not tightly complexed with histones in eukaryotes.

D. The RNA primer is removed by ribonuclease H instead of a DNA polymerase I in prokaryotes Difficulty: Moderate ASM Standard: 16 19. Telomerase in humans is generally active in which cells?

A. all cells B. all cells during childhood, but not during adulthood C. in stem cells and germ cells* D. stem cells only Difficulty: Moderate ASM Standard: N/A 20. Which of the following uses rolling circle replication?

A. some bacteria only B. some bacteria and some viruses C. some bacteria, some plasmids, and some viruses* D. some bacteria, some plasmids, some viruses, and some eukaryotic main chromosomes Difficulty: Moderate ASM Standard: 16 21. Which of the following defines a sigma () factor?

A. a subunit of eukaryotic RNA polymerase that is important in binding to DNA B. a subunit of eukaryotic RNA polymerase that is important in binding to RNA B. a subunit of prokaryotic RNA polymerase that is important in binding to DNA* C. a subunit of prokaryotic RNA polymerase that is important in binding to RNA Difficulty: Easy ASM Standard: 16 22. Which sequences of eukaryotic genes code for proteins?

A. exons* B. introns C. invariant D. the spliceosome Difficulty: Moderate ASM Standard: 16 23. Which of the following is one important distinction between prokaryotic and eukaryotic mRNA? A. Eukaryotic mRNA is generally monocistronic.* B. Eukaryotic mRNA is generally polycistronic.

C. Eukaryotic mRNA is equally likely to be monocistronic or polycistronic.

D. Eukaryotic mRNA is often both monocistronic and polycistronic within an operon.

Difficulty: Moderate ASM Standard: 16

24. Stop codons are also known as which of the following?

A. antisense codons B. missense codons C. nonsense codons* D. sense codons Difficulty: Moderate ASM Standard: N/A 25. Which researchers provided evidence that DNA replication was semiconservative?

A. B. George Beadle, Edward Tatum, and colleagues C. Alfred Hershey and Martha Chase D. Matthew Meselson and Franklin Stahl* E. James Watson and Francis Crick Difficulty: Moderate ASM Standard: N/A 26. Quinolones are medications that target which of the following?

A. DNA gyrase and topoisomerase IV* B. ligase and topoisomerase III C. primase and topoisomerase I D. replicase and topoisomerase V Difficulty: Difficult ASM Standard: 14 27. Following DNA replication, bacterial chromosomes become which of the following?

A. concatenated* B. linear C. plasmids D. single stranded Difficulty: Difficult ASM Standard: 16 28. Human telomeres contain 100 to 1000 copies of which nucleotide sequence?

A. AATAT B. TATATA C. TTAGGG* D. TTTTTT Difficulty:

Difficult ASM Standard: N/A 29. Which enzyme(s) elongate the lagging strand during replication in eukaryotes?

A. DNA polymerases I and III B. DNA polymerase III C. DNA polymerase δ* D. DNA polymerase ε Difficulty: Difficult ASM Standard: 16 30. What does the σ factor recognize?

A. the – 10 consensus sequence in eukaryotes B. the – 10 consensus sequence in prokaryotes C. the – 35 consensus sequence in prokaryotes* D. the TATA box in eukaryotes Difficulty: Difficult ASM Standard: 16 31. Which of the following is the function of the σ factor?

A. It allows DNA polymerase to recognize a specific promoter in eukaryotes.

B. It allows RNA polymerase to bind to a specific promoter in eukaryotes.

C. It allows RNA polymerase to recognize a specific promoter in prokaryotes.* D. It allows RNA polymerase to terminate transcription in prokaryotes.

Difficulty: Difficult ASM Standard: 16 32. Which statement best describes selenocysteine and pyrrolysine?

A. They are amino acids commonly found in eukaryotic proteins.

B. They are amino acids commonly found in proteins in all microbes.

C. They are unusual amino acids found in some archaea.

D. They are unusual amino acids found in some bacteria and archaea.* Difficulty: Difficult ASM Standard: 16 33. Which statement best describes polyribosomes?

A. They are only found in archaea.

B. They can occur in archaea, bacteria, and eukaryotes during transcription.

C. They can only form after RNA has left the nucleus in eukaryotes, but are found in all domains.* D. They can only form in eukaryotes, not in other organisms, and can only form once the

RNA has been fully processed.

Difficulty: Difficult ASM Standard: 16 34. Which amino acid is attached to a tRNA? A. aminoacyl tRNA synthetase B. an activated amino acid C. a charged amino acid D. a cognate amino acid* Difficulty: Difficult ASM Standard: N/A True/False 35. A particular genotype always produces the same phenotype.

Answer: False Difficulty: Moderate ASM Standard: N/A 36. Prokaryotes usually have a single origin of replication, whereas eukaryotes usually have multiple origins of replication.

Answer: True Difficulty: Easy ASM Standard: 16 37. Archaea, Bacteria, and Eukarya use different DNA polymerases.

Answer: True Difficulty: Moderate ASM Standard: 16 38. RNA primases require a free 3′-OH group to add nucleotides to a growing strand.

Answer: False Difficulty: Moderate ASM Standard: N/A 39. The termination of DNA replication is understood far better than the initiation of DNA replication.

Answer: False Difficulty: Moderate ASM Standard: N/A 40. At 100 nucleotides per second, replication of eukaryotic DNA is faster than replication of prokaryotic DNA. Answer: False Difficulty: Moderate ASM Standard: 16 41. Prokaryotic RNA transcripts undergo splicing.

Answer: False Difficulty: Difficult ASM Standard: 16 42. Matthew Meselson and Franklin Stahl used radiolabeled phosphorus to determine that DNA replication is semiconservative.

Answer: False Difficulty: Difficult ASM Standard: N/A Matching 43. Match each molecule with its function.

A. mRNA i. brings in amino acids during translation.

B. rRNA ii. carries encoded information from DNA C. tRNA iii. contributes to ribosome structure Answers: A. ii., B. iii., C. i.

Difficulty: Easy ASM Standard: N/A 44. Match each molecule with its role in prokaryotic DNA replication.

A. helicase i. helps hold open the double helix by preventing hydrogen bonding between the separated strands of the replication bubble B. ligase heK lpSsE hL o lL d E DR N. ACpOoM lymerase III in the proper position TESTBiiA. N

C. primase

iii. synthesizes small pieces of RNA to start the synthesis of new DNA strands D. single-strand binding proteins iv. breaks hydrogen bonds between bases to open the double helix E. sliding clamp v. joins Okazaki fragments together Answers: A. iv., B. v., C. iii., D. i., E. ii.

Difficulty: Moderate ASM Standard: 16 45. Match the enzyme with its role in prokaryotic DNA replication.

A. DNA polymerase I i. relaxes supercoils and relieves stress on DNA B. DNA polymerase III ii. an exonuclease that removes RNA primers C. topoisomerase II iii. adds nucleotides in the 5′ to 3′ direction to produce the new complementary strand of DNA during replication D. topoisomerase IV iv. cuts DNA to release concatenated chromosomes and reseals the DNA Answers: A. ii., B. iii., C. i., D. iv.

Difficulty: Moderate ASM Standard: 16 46. Match the process that contributes to prokaryotic genetic diversity with the best description.

A. conjugation i. DNA is transferred through a pilus.

B. transduction ii. DNA is picked up from the environment.

C. transformation iii. DNA is transferred by a bacteriophage.

D. transposition iv. DNA excises from one location and inserts in another.

Answers: A. i., B. iii., C. ii., D. iv.

Difficulty: Moderate ASM Standard: 2 47. Match each part of the operon with its best description.

A. operator i. site where RNA polymerase binds B. promoter ii. site where a repressor can bind C. structural genes iii. code for proteins with related functions Answers: A. ii., B. i., C. iii.

Difficulty: Easy ASM Standard: 17 48. Match each mutagen with its effect on DNA. A. 2-aminopurine i. strand breaks or conversion of GC to AT pairs B. ethidium bromide ii. conversion of GC pairs to AT pairs

C. nitrous oxide

iiiE. S d iT stB orA tiN onKoSfEthLeLdE ouRb.leChOeM lix, leading to small insertions T and deletions

D. X-rays and γ rays iv. conversion of AT pairs to GC pairs Answers: A. iv., B. iii., C. ii., D. i.

Difficulty: Difficult ASM Standard: 2 Fill in the Blank 49.

expression occurs when genes are continuously expressed.

Answer: Constitutive Difficulty: Easy ASM Standard: 17

50. The structure formed by an mRNA with multiple attached ribosomes is called a(n) Answer: polyribosome Difficulty: Easy ASM Standard: 16 51.

mRNA codes for multiple polypeptides.

Answer: Polycistronic Difficulty: Moderate ASM Standard: N/A

52. The subunit of prokaryotic RNA polymerase helps it bind to the –35 consensus sequence.

Answer: sigma (σ) Difficulty: Moderate ASM Standard: 16 53.

are transcription factors that can bind to the regulatory region of an operon to increase transcription levels above basal levels.

Answer: Activators Difficulty: Moderate ASM Standard: 17

54. The tryptophan operon is turned off when there is an excess of tryptophan, making it a(n)

.

operon.

Answer: repressible Difficulty: Moderate ASM Standard: 17 55. When lactose is present but there is no regulatory region of the lac operon.

Answer: glucose

, the CAP–cAMP complex binds to the

Difficulty: Moderate ASM Standard: 17 56.

are nucleotide derivatives that change gene expression in response to stress and are especially important in pathogenic bacteria.

Answer: Alarmones Difficulty: Moderate ASM Standard: 23

57. A molecule that influences regulation of prokaryotic gene expression found in the 5′ end of mRNA is called a(n) .

Answer: riboswitch Difficulty: Difficult ASM Standard: 17 58. The trp operon in Escherichia coli can be regulated by the type of stem loop structures formed, which is a type of regulation called ?

Answer: attenuation Difficulty: Difficult ASM Standard: 17 Short Answer 59. What is the term for horizontal gene transmission by a virus?

Sample Answer: The term for horizontal gene transmission by a virus is transduction.

Difficulty: Easy ASM Standard: 2 60. What is a riboswitch?

Sample Answer: A riboswitch is found in the 5′ end of prokaryotic mRNA and regulates transcription and translation.

Difficulty: Easy ASM Standard: 17 61. What is the term for the process by which mRNA is used to make a protein?

Sample Answer: The processTbE yS wT hiB chAN mK RS NE ALisLuEsR ed.tC oO mMake a protein is called translation.

Difficulty: Easy ASM Standard: N/A 62. What is another term for the genetic elements often called “jumping genes?”

Sample Answer: Jumping genes are also known as transposons.

Difficulty: Easy ASM Standard: 2 63. Why is a primase required for DNA replication, instead of just using DNA polymerase?

Sample Answer: DNA polymerase cannot add to free 3′-OH groups, but primase can.

Difficulty: Moderate ASM Standard: 23, 24 64. Will the structural genes of the lac operon be expressed when there is plenty of lactose and glucose? Will the repressor be bound to the operator? Why or why not?

Sample Answer: The repressor will not be bound to the operator because of the presence of lactose, but the high concentration of glucose will mean that there is only a low level of CAP–cAMP complex bound in the regulatory region. The structural genes will only be expressed at low levels.

Difficulty: Moderate ASM Standard: 17 65. What is epigenetic regulation?

Sample Answer: Epigenetic regulation is a type of regulation that occurs when DNA is modified in a way that does not affect the nucleotide sequence. This is often accomplished by methylation.

Difficulty: Moderate ASM Standard: 17

66. Explain what a frameshift mutation is and why frameshift mutations often have severe consequences.

Sample Answer: Frameshift mutations involve the addition or deletion of one or two bases and, therefore, cause a shift in the reading frame, meaning that all of the codons downstream are affected. These can potentially affect large parts of a protein and have very severe effects.

Difficulty: Moderate ASM Standard: 2 67. What can cause a thymine dimer and what are the consequences of one forming?

Sample Answer: Thymine dimers often result from nonionizing radiation exposure, such as exposure of the skin to UV raT diE atSioTnB .A ThNeKrS adE iaL tiL onEcRa. usCeO s tMwo adjacent thymines to form a covalent link, forming a dimer. The dimer causes DNA replication and transcription to stall at its location. Replication will then proceed either with a point mutation or a frameshift mutation.

Difficulty: Moderate ASM Standard: 2 68. How does horizontal gene transfer differ from vertical gene transfer?

Sample Answer: Vertical gene transfer involves the transfer of genes from parents to offspring. When organisms exchange genes, it is called horizontal gene transfer.

Horizontal gene transfer can take place through a variety of mechanisms and even between species that are not closely related.

Difficulty: Moderate ASM Standard: 2 69. Why is the error rate for bacterial DNA replication very low?

Sample Answer: Some forms of DNA polymerase are capable of proofreading.

Difficulty: Moderate ASM Standard: 2 70. How many of the 64 codons are stop codons?

Sample Answer: There are three stop codons.

Difficulty: Moderate ASM Standard: N/A 71. What does it mean to say that the genetic code is degenerate?

Sample Answer: The genetic code is degenerate because there is more than one codon for most of the amino acids.

Difficulty: Difficult ASM Standard: N/A 72. In eukaryotes, RNA produced by transcription is not immediately ready for translation. What steps have to take place before translation can occur?

Sample Answer: For translation to occur, a 5′ cap and a polyA tail must be added. Next, RNA splicing takes place. Finally, the transcript must move from the nucleus to the cytoplasm because transcription takes place in the nucleus and translation takes place in the cytoplasm.

Difficulty: Difficult ASM Standard: 16 73. What chemical reaction is catT alE yzSeT dB byAN DK NS AEliLgL a sE e?R.COM Sample Answer: DNA ligase joins fragments of DNA together during DNA replication.

This is accomplished by forming phosphodiester linkages between the 5′ phosphate end of one fragment and the 3′-OH end of the other fragment.

Difficulty: Difficult ASM Standard: N/A Brief Essay Essay Question Rubric RATING Failing

Below Average

Competent

Advanced

Criteria for evaluatio n

Answer does Answer fails to not provide an provide argument. examples to Answer contains support an inaccuracies. argument.

Writing is Writing is poor poor and and grammatical contains errors are numerous common. grammatical Answer is mistakes and somewhat misspellings. incoherent.

Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

POINT 0 1 2 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

3

74. Describe one way in which a transposon could cause a mutation. Be sure also to explain how transposons work.

Answer: Student answers will vary but should include components of the following.

Transposons produce transposase and are able to move from one location to another, sometimes by producing a copy and sometimes by simply moving. If they insert into another gene, they can inactivate it. Alternatively, they could insert a promoter and activate a gene LuLtaEtiRon.C that had previously been turnTdEoSffT. B ThAeNt K erS mEm deOscMribes any change in DNA that can be inherited, so this is a type of mutation.

Difficulty: Moderate ASM Standard: 2 75. A transposon inserts structural genes (the genes that code for proteins) into the lac operon.

What would happen if the bacterium were inoculated onto medium containing lactose?

Explain what would happen by describing how each part of the operon would be affected (i.e., whether it would or would not be affected) and then whether the bacterium would metabolize lactose.

Answer: Student answers will vary but should include components of the following. When the transposon inserts into a gene, the gene is likely to be mutated. The product probably will not be produced normally. In this case, one of the structural genes would be affected and the bacterium would not be able to produce all the proteins needed to metabolize lactose. The repressor would not bind to the operator because of the presence of lactose.

RNA polymerase would bind to the promoter and begin transcription. However, one or more of the proteins probably would not be produced properly during translation and, therefore, the bacterium probably could not metabolize lactose.

Difficulty:

Moderate ASM Standard: 2 76. Ethidium bromide is commonly used to stain DNA on electrophoresis gels. However, ethidium bromide is a mutagen. Explain how ethidium bromide causes mutations in DNA. Answer: Student answers will vary but should include the following. Ethidium bromide is an intercalating agent, meaning that it inserts between DNA nucleotides. This distorts the double helix and can easily lead to insertions and deletions during DNA replication, because the bases are not paired up properly. Deletions and insertions of one or two bases can have severe consequences if they cause frameshift mutations, because all the codons downstream of the mutations will likely be incorrect, resulting in an incorrect sequence of amino acids in the translated polypeptide.

Difficulty: Moderate ASM Standard: 2 77. Why is it necessary to have a control group when you use an Ames test?

Answer: Student answers will vary but should include the following. The Ames test examines whether a particular chemical or other treatment causes mutations. Because mutations can occur spontaneously, it is important to have a control group so you can compare whether mutations increased in the treatment group (i.e., the bacteria exposed to the chemical of interest). If you just look for mutations, they will be present, to some extent, even if the chemical is not mutagenic.

Difficulty: Moderate ASM Standard: 2 78. Explain the major differences in gene expression between prokaryotes and eukaryotes.

Include at least three differences.

Answer: Student answers will vary but should include components of the following and at least three of the examples given. Transcription and translation can occur simultaneously in prokaryotes, but the two processes occur separately in eukaryotes. In eukaryotes, RNA must be processed through the addition of a methyl cap, poly A tail, and splicing before translation. Additionally, the RNA must be transported from the nucleus to the cytoplasm before it can be translated. Ribosome structure differs in prokaryotes and eukaryotes as well. Prokaryotes have a 70S ribosome with a 30S subunit and a 50S subunit, whereas eukaryotes have an 80S ribosome with a 40S subunit and a 60S subunit. The first amino acid brought to the ribosome during translation is fMet in prokaryotes and Met in eukaryotes. Finally, the Shine-Dalgarno sequence is present in prokaryotes but not in eukaryotes. Additional differences (e.g., consensus sequences in DNA) also exist. (See Figures 11.16 and Table 11.17.)

Difficulty: Difficult ASM Standard: 16 79. Mutations may be harmful but may also be beneficial or neutral. Explain some examples of

neutral and beneficial mutations.

Answer: Student answers will vary but should include components of the following.

Neutral mutations have no effect on fitness (i.e., the ability of an organism to reproduce).

They are

not harmful or helpful. If the mutation occurs in the third base of a codon, the amino acid may not be changed (a silent mutation). Even if a single amino acid is changed, the protein may still function in some cases. Additionally, mutations may occur in noncoding regions and be neutral. Beneficial mutations may give an organism a new ability, such as antibiotic resistance. The text describes how a mutation may help to protect against HIV in the Micro Connections box “A Beneficial Mutation.” In this case, a mutation in the gene for a receptor causes an abnormal receptor to be produced and this interferes with the ability of HIV to bind to the cell.

Difficulty: Difficult ASM Standard: 2, 23

This file is copyright 2017, Rice University. All rights reserved.

Chapter 12: Modern Applications of Microbial Genetics * = Correct answer Multiple Choice 1. Which of the following is the definition of biotechnology?

A. The alteration of DNA in a cell B. The use of living systems to benefit humankind* C. Using computers to synthesize biomolecules D. Using DNA for solving mathematical problems Difficulty: Easy ASM Standard: 26 2. Which of the following is the definition of genetic engineering?

A. The alteration of DNA in a cell* B. The use of living systems to benefit humankind C. Using computers to synthesize biomolecules D. Using DNA for solving mathematical problems Difficulty: Easy ASM Standard: 15, 19, 26, 31 3. The first set of genes to be introduced into E. coli came from which of the following?

A. Arabidopsis B. Haemophilus C. Mycobacterium D. Xenopus* Difficulty: Easy ASM Standard: 15, 19

4. Which of the following is a palindrome sequence that could be recognized by a restriction enzyme?

A. 5′ – GAAAAG – 3′ 3′ – CTTTTC – 5′ B. 5′ – GAATTC – 3′ * 3′ – CTTAAG – 5′ C. 5′ – GACT – 3′ 3′ – CTGA – 5′ D.

5′ – GCCCC – 3′ 3′ – CGGGG – 5′

Difficulty: Moderate ASM Standard: 26, 36

5. Restriction enzymes (endonucleases) are produced by bacteria as a means of protection against which infectious agent?

A. antibiotics B. antibodies C. bacteriophages* D. prions Difficulty: Easy ASM Standard: 18, 26 6. Which of the following enzymes rejoins two sugar-phosphate backbones of DNA? A. helicase B. ligase* C. restriction enzyme D. reverse transcriptase Difficulty: Easy ASM Standard: 26, 36 7. Genes to be cloned into a plasmid are typically inserted in which location?

A. in a location disrupting the antibiotic selective marker B. oriC (origin of replication) C. polylinker site* D. randomly Difficulty: Easy ASM Standard: 19, 26, 36 8. Which genus of bacterium is naturally competent?

A. Bacillus* B. Escherichia C. Listeria D. Yersinia Difficulty: Moderate ASM Standard: 11, 19 9. Which of the following regarding pUC19 and blue/white screening is NOT true?

A. Colonies that appear white have the gene of interest inserted into the plasmid pUC19.

B. pUC19 confers antibiotic resistance.

C. The gene of interest being cloned disrupts the lacI gene.* D. X-gal is a chromogenic agent used in blue/white screening to test for -galactosidase activity.

Difficulty: Moderate ASM Standard: 19, 26, 36

10. You are in the process of cloning a gene of interest into pUC19 using blue/white screening.

You complete your cloning and transform E. coli with your cloned plasmid. You plate your transformation on two media. One medium agar plate contains X-gal only. The second medium agar plate contains X-gal and ampicillin (an antibiotic), in the hope of using blue/white screening. You examine your plates and see a mixture of blue and white colonies.

Which of the following colonies should be picked?

A. the blue colonies that are resistant to ampicillin B. the blue colonies that are sensitive to ampicillin C. the white colonies that are resistant to ampicillin* D. the white colonies that are sensitive to ampicillin Difficulty: Moderate ASM Standard: 15, 19, 26, 28b, 36, 38 11. Which plasmid encodes the genes for its own conjugation?

A. an F-plasmid* B. any plasmid C. Plasmids cannot be transferred by conjugation.

D. pUC19 only Difficulty: Easy ASM Standard: 2, 19, 26, 36 12. Which of the following methods can be used to transfect protoplast plant cells?

A. Agrobacterium tumefaciens B. electroporation C. gene gun D. All these options can be used.* Difficulty: Easy ASM Standard: 19, 26, 36 13. Which virus is typically used as mechanism to transfect eukaryotic cells?

A. adenovirus* B. bacteriophage C. influenza virus D. retrovirus Difficulty: Easy ASM Standard: 2, 19, 26, 36 14. For gel electrophoresis, the matrix used for separation of DNA fragments is whereas the matrix used for separation of proteins is .

A. agarose; polyacrylamide* B. arabinose; sodium dodecyl sulfate C. polyacrylamide; agarose

,

D. sodium dodecyl sulfate; arabinose Difficulty: Easy ASM Standard: 36 15. Which charge does a molecule of DNA have?

A. positive B. neutral C. negative* D. depends on what the sequence of DNA is Difficulty: Easy ASM Standard: 36 16. A

blot is used to identify specific sequences of DNA on a membrane, whereas a blot is used to identify specific sequences of RNA on a membrane.

A. Northern; Southern B. Northern; Western C. Southern; Northern* D. Western; Eastern Difficulty: Easy ASM Standard: 36

17. A two-dimensional PAGE separates molecules according to which two properties?

A. charge at various pHs and hydrophobicity B. charge at various pHs and size* C. hydrophobicity and presence of disulfide bonds D. size and hydrophobicity Difficulty: Moderate ASM Standard: 36 18. For protein electrophoresis to function, which of the following can be added to the protein to impart a uniform negative charge?

A. ammonium persulfate B. phosphate C. polyacrylamide D. sodium dodecyl sulfate* Difficulty: Easy ASM Standard: 36 19. You are interested in determining which genes are upregulated in HeLa cells during intracellular infection with a newly discovered pathogen. You prepare a microarray

experiment as shown in the diagram below and examine the gene expression of three genes (labeled A through C). Which gene’s expression is not altered during intracellular infection?

A. gene A* B. gene B C. gene C D. cannot conclude from this experiment; more information is needed Difficulty: Difficult ASM Standard: 28b, 36, 38 20. Which technique can be used to amplify DNA? A. Genomic libraries B. PCR* C. Sanger method D. Southern blot Difficulty: Easy ASM Standard: 26, 36 21. Which of the following are the three steps (in order) of PCR? A. annealing, denaturation, extension B. denaturation, annealing, extension* C. denaturation, extension, annealing

D. extension, annealing, denaturation Difficulty: Moderate ASM Standard: 36 22. Which of the following correctly explains why primers are used in PCR? A. DNA replication requires a free 3′ hydroxyl group.* B. DNA replication requires a free 3′ phosphate group.

C. DNA replication requires a free 5′ hydroxyl group.

D. DNA replication requires a free 5′ phosphate group.

Difficulty: Easy ASM Standard: 36 23. The Sanger method/chain termination reaction relies upon using which unique nucleotide?

A. a nucleotide that is missing a 5-carbon sugar B. a nucleotide that is missing a hydroxyl group* C. a nucleotide that is missing a nitrogenous base D. a nucleotide that is missing a phosphate group Difficulty: Moderate ASM Standard: 36 24. Which of the following is a next-generation sequencing technique in which fragmented DNA has DNA adapters attached, is amplified by PCR, is attached to a bead, and then is placed into a well with sequencing reagents. The flash of light produced by the release of pyrophosphate on addition of a nucleotide is monitored.

A. pyrosequencing* B. Sanger method C. Southern blot D. transformation Difficulty: Moderate ASM Standard: 36 25. The study of all the DNA of an entire microbial community is known as which ofthe following?

A. genomics B. metagenomics* C. metatranscriptomics D. toxicogenomics Difficulty: Moderate ASM Standard: 20, 21, 36

26. In RNAi technology, the dsRNA molecule first combines with which endonuclease that then cleaves it into smaller fragments?

A. DICER* B. Ligase C. RecA D. RISC Difficulty: Hard ASM Standard: 17, 36 27. Which of the following is/are completely complementary to the target mRNA in RNAi technology?

A. miRNA B. siRNA* C. both miRNA and siRNA D. Neither method cleaves mRNA. Difficulty: Easy ASM Standard: 17, 36 28. Which disease has been effectively controlled by gene therapy?

A. bacterial meningitis B. cystic fibrosis* C. ornithine transcarbamylase D. sickle cell anemia Difficulty: Moderate ASM Standard: 19, 26, 31, 36 29. Which agency does not oversee gene therapy?

A. FDA B. NIH C. OHRP D. WHO* Difficulty: Moderate ASM Standard: 31 30. Genomics would not be an effective method to detect which type of pathogen?

A. bacteria B. helminths C. prions* D. viruses Difficulty: Moderate ASM Standard: 27

True/False 31. DNA that has been cut with a restriction enzyme, resulting in sticky ends, can be moreeasily ligated than DNA that has been cut with a restriction enzyme resulting in blunt ends.

Answer: True Difficulty: Easy ASM Standard: 19, 26, 36 32. For cloning purposes using transduction, lytic bacteriophages are used.

Answer: False Difficulty: Easy ASM Standard: 10, 26 33. Lambda ( ) bacteriophages can be used to make genomic libraries.

Answer: True Difficulty: Moderate ASM Standard: 10, 26 34. The uptake of a plasmid by a prokaryotic cell is known as transfection.

Answer: False Difficulty: Moderate ASM Standard: 2, 19, 26, 36 35. DNA probes can be used to locate any gene within a cell.

Answer: False Difficulty: Moderate ASM Standard: 32, 36 36. Blue/white screening works on the basis of disrupting the lacZ gene in cloning.

Answer: True Difficulty: Moderate ASM Standard: 15, 19, 26, 34, 36 37. Reverse transcriptase-PCR amplifies molecules of RNA. Answer: False Difficulty: Easy ASM Standard: 10, 26, 36

38. cDNA is made by reverse transcriptase, which is found in all viruses.

Answer: False Difficulty: Moderate ASM Standard: 10, 26, 36 39. Due to concerns about gene transfer, genetically engineered microbes cannot be used to manufacture vaccines.

Answer: False Difficulty: Easy ASM Standard: 15, 19, 31 40. RNAi is a natural process used by cells as a means of gene regulation.

Answer: True Difficulty: Easy ASM Standard: 17 Matching 41. Match the different steps of molecular cloning to their function.

A. DNA ligase i. cuts both DNA containing gene of interest and vector DNA B. PCR ii. amplifies gene of interest C. plasmid iii. chromogenic substrate used for blue/white screening D. restriction endonuclease iv. joins together sugar-phosphate backbone of DNA E. X-gal v. small circular DNA used for cloning Answers: A. iv., B. ii., C. v., D. i., E. iii.

Difficulty: Easy ASM Standard: 19, 26, 36

42. Match the technique to its primary function.

A. microarray i. used to detect sequences of DNA B. Northern blot ii. used to compare gene expression between different cells C. PCR iii. used to amplify DNA D. Southern blot used to detect sequences of RNA Answers: A. ii., B. iv., C. iii., D. i.

Difficulty: Easy ASM Standard: 36 43. Match the genetically engineered pharmaceutical to what it can treat.

A. DNase i. cancers and viral infections B. factor VIII ii. hemophilia C. interferons iii. cystic fibrosis D. plasminogen activator iv. myocardial infarctions Answers: A. iii., B. ii., C. i., D. iv.

Difficulty: Moderate ASM Standard: 26, 31 44. Match the mechanism of horizontal gene transfer to its appropriate description.

A. conjugation i. uptake of DNA by a eukaryotic cell B. transduction ii. uptake of free DNA by a prokaryotic cell C. transfection iii. transfer of DNA usingpili D. transformation iv. transfer of DNA using bacteriophage Answers: A. iii., B. iv., C. i., D. ii.

Difficulty: Easy ASM Standard: 2, 26, 36 Fill in the Blank 45.

is DNA composed from different organisms.

Answer: Recombinant Difficulty: Easy ASM Standard: 19, 26, 36

46.

are enzymes produced by bacteria that are used in molecular cloning to cut DNA. Answer: Restriction enzymes (endonucleases) Difficulty: Easy ASM Standard: 26, 36

47.

are plasmids that have phage sequences so they can be packaged into bacteriophages.

Answer: Phagemids Difficulty: Moderate ASM Standard: 10, 18, 26, 36

48.

is the technique of using radioactive phosphorous to identify and track sequences of DNA in gel electrophoresis.

Answer: Autoradiography Difficulty: Moderate ASM Standard: 36

49.

compares DNA banding patterns of different DNA samples after being incubated with restriction enzymes and subjected to agarose gel electrophoresis.

Answer: Restriction fragment length polymorphism (RFLP) Difficulty: Easy ASM Standard: 26, 36

50.

is a bacterium that causes crown-gall disease and can be used as a molecular biology tool.

Answer: Agrobacterium tumefaciens Difficulty: Moderate ASM Standard: 23, 26, 36

51.

is the DNA polymerase that is most commonly used in PCR. Answer: Taq polymerase Difficulty: Easy ASM Standard: 26

52. In proteomics, a disease.

Answer: biomarker Difficulty: Easy

is the name given to a protein whose expression is affected by

ASM Standard: 17, 23, 31, 36 53. A noncoding RNA sequence that is complementary to mRNA is known as

.

Answer: antisense Difficulty: Easy ASM Standard: 16, 17 54. In gene therapy, genes need to be introduced into to the next generation.

to ensure they will be passed on

Answer: germ-line cells Difficulty: Easy ASM Standard: 19, 31, 36 Short Answer 55. Why is it possible for bacteria to produce human proteins such as insulin?

Sample Answer: The genetic code is universal and DNA and RNA can be transcribed and translated in any organism.

Difficulty: Difficult ASM Standard: 16, 19, 26, 56. Why do bacteria produce restriction enzymes (endonucleases)?

Sample Answer: to protect against bacteriophages Difficulty: Easy ASM Standard: 7, 18, 26 57. How can a molecular biologist tell the difference between a chromosome and a commercial plasmid?

Sample Answer: Various answers are correct. Chromosomes are typically larger than plasmids. Chromosomes are essential for the survival of the cell (i.e., they contain housekeeping genes), whereas commercial plasmids are not essential. Commercial plasmids will contain a polylinker or multiple cloning site with restriction enzyme recognition sites in the same region, whereas chromosomes lack this site.

Difficulty: Difficult ASM Standard: 2, 8, 19, 36 58. What is a reporter gene? Give an example of one.

Sample Answer: Reporter genes encode an easily observable characteristic used to track gene expression. Examples of reporter genes include lacZ (which would require a chromogenic agent in the medium) and gfp.

Difficulty: Easy ASM Standard: 17, 19, 26, 36 59. How can bacterial cells become chemically competent?

Sample Answer: Chemical treatment can increase the permeability of the cell membrane by neutralizing charges on the cell membrane.

Difficulty: Moderate ASM Standard: 36 60. How does electroporation make bacterial cells competent to receive foreign molecules of DNA? Sample Answer: A brief electric pulse results in the formation of transient pores in the phospholipid bilayers of cells. The electric pulse generates a short-lived positive charge on one side of the cell’s interior to attract the negatively charged DNA molecule (plasmid) into the cell.

Difficulty: Moderate ASM Standard: 19, 36 61. Why are phages preferred in making a genomic library?

Sample Answer: Phages can hold a larger insert of foreign DNA, as compared with a plasmid.

Difficulty: Moderate ASM Standard: 26, 36 62. What is the difference between a genomic library and a cDNA library?

Sample Answer: A genomic library contains a copy of all the DNA of an organism. A cDNA library contains a copy of all the genes that are actively being expressed (i.e., genes being currently transcribed into mRNA).

Difficulty: Moderate ASM Standard: 26, 36 63. Name two molecular techniques one can use to examine gene expression in a bacterial cell.

Sample Answer: Reverse transcriptase-PCR (RT-PCR), DNA microarrays, or Northern blotting Difficulty: Easy ASM Standard: 17, 26, 36

64. Why is Taq polymerase used in PCR and not E. coli DNA polymerase?

Sample Answer: Taq polymerase is heat stable, which is important because, during PCR, the temperature is raised to 95 °C to denature the DNA template.

Difficulty: Easy ASM Standard: 26, 36 65. Explain how qPCR is quantitative. What is it measuring?

Sample Answer: qPCR uses a fluorescence probe to monitor the increase in double-stranded template over time. Based upon the kinetics of this, one can determine the amount of original template.

Difficulty: Moderate ASM Standard: 36 66. Why is GFP used in the field of proteomics?

Sample Answer: The gene encoding GFP is a common reporter gene that can be fused to a gene of interest. In this way, the scientist can track the location and timing of the expression of the gene of interest.

Difficulty: Easy ASM Standard: 36 67. Which type of disease could be a candidate for treatment using gene therapy?

Sample Answer: Human diseases that result from genetic mutations due to abnormalities in a patient’s genome.

Difficulty: Moderate ASM Standard: 17, 19, 31 68. What are the three steps to PCR? Sample Answer: denaturation, primer annealing, and primer extension Difficulty: Easy ASM Standard: 26, 36 69. What are the ways transfection can occur?

Sample Answer: Electroporation, gene guns, microinjection, shuttle vectors, and viral vectors Difficulty: Easy ASM Standard: 19, 36 Brief Essay Essay Question Rubric RATING Failing

Below Average

Competent

Advanced

Criteria for evaluati on

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is poor and contains numerous grammatical mistakes and misspellings.

Answer fails to provide examples to support an argument.

Writing is poor and grammatical errors are common.

Answer is somewhat incoherent.

Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

0 1 2 3 POINT VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

70. Discuss how you can genetically engineer an E. coli cell to produce human insulin. Be sure to include in your answer the use of restriction enzymes, ligase, pUC19, X-gal, selective media, and a method for determining that your transgenic E. coli contains the insulin gene and that it is producing insulin.

Answer: Student answers may vary but should include components of the following. You begin by taking the gene for insulin and the pUC19 plasmid (vector) and digest them both with the same restriction enzymes (choosing a restriction enzyme site in the polylinker or multiple cloning site). After digestion, the insulin gene is inserted into the digested pUC19 using DNA ligase. The plasmid is then introduced into E. coli that is competent. The most common method would be to use chemical transformation or electroporation. The E. coli is then plated on selective media containing X-gal. The selective media should contain an antibiotic to which the plasmid confers resistance. Since X-gal is used in blue/white screening, one would allow the E. coli to grow. E. coli that appear white on the media contain the plasmid with the PCR product inserted into it. You can verify the presence of ins in E. coli using either PCR or using DNA probes (i.e., Southern blot). To verify the transgenic E. coli is producing insulin, grow the bacterium, collect the supernatant, perform polyacrylamide gel electrophoresis, and compare with the supernatant of E. coli that has not been genetically altered. The insulin protein band should be seen only in the proteome of the transgenic E. coli.

Difficulty: Moderate ASM Standard: 15, 16, 19, 26, 31, 33, 36

71. An outbreak has occurred at a local banquet. You determine that the causative agent was Listeria monocytogenes, which was found in the cold cut meats. You have been asked to further determine from which ribotype the identified L. monocytogenes is. The results of your experiment are shown in the gel diagram below. Answer the questions below the image.

a. What is ribotyping and how is it performed? b. Which ribotype was found in the cold cut meats? c. Why do the DNA molecules appear as they do on the gel? Identify where largemolecules and small molecules of DNA would be found on this gel.

Answer: Student answers may vary but should include components of the following. (a) Ribotyping is a technique in which a short sequence of DNA between the 16S and 23S rRNA gene sequences is used for restriction fragment length polymorphism (RFLP). In RFLP, a segment of DNA is digested using restriction enzymes (endonucleases). The fragments are then resolved using agarose gel electrophoresis. Because restriction enzymes recognize specific DNA sequences, differences in DNA sequences between bacterial strains will lead to different banding patterns after agarose gel electrophoresis. (b) In this ribotyping, we see that the bands from the cold cut meats match L. monocytogenes ribotype R-2. (c) DNA is negatively charged and is pulled toward the positive electrode in agarose gel electrophoresis.

The DNA bands you see are located in the gel according to their size. Large molecules of DNA cannot move quickly through the agarose gel matrix, so they would be found at the top of the gel. Small molecules of DNA can move more quickly through the agarose gel matrix, so they would be found toward the bottom of the gel.

Difficulty: Moderate ASM Standard: 5, 26, 28b, 31, 34, 36, 38

72. You wish to amplify a segment of DNA from the genome of the bacterium Haemophilus influenzae. You decide to use PCR. You prepare your PCR using the following reagents and temperatures. What will be the result of each of these? Be sure to explain why these reactions will work or will not work. (a) You add DNA template, DNA primers (forward and reverse), nucleotides, and E. coli DNA polymerase. You set the denaturing temperature for 95 C, annealing temperature for 50 C, and the extension temperature for 72 C. You repeat this for 30cycles. (b) You add DNA template, nucleotides, and Taq polymerase. You set the denaturing temperature for 95 C, annealing temperature for 50 C, and the extension temperature for 72 C. You repeat this for 30 cycles. (c) You add DNA template, DNA primers (forward and reverse), nucleotides, and Taq polymerase. You set the denaturing temperature for 95 C, annealing temperature for70 C, and the extension temperature for 72 C. You repeat this for 30 cycles.

Answer: Student answers may vary but should include components of the following.

In all cases, the PCR would not work. In (a), you are using E. coli DNA polymerase.

This is not a heat-stable polymerase. Therefore, when you heat the reaction to 95 °C for the denaturation reaction, the polymerase will no longer be functional and will be unable to synthesize the complementary strand of DNA. In (b), there are no DNA primers added. DNA synthesis requires a primer to synthesize the complementary strand of DNA (i.e., it cannot perform de novo synthesis). In (c), the annealing temperature is too high, so the DNA primer will not attach. Since the primer doesn’t attach, then the complementary strand of DNA cannot be synthesized.

Difficulty: Difficult ASM Standard: 26, 28b, 36 73. Discuss the similarities and differences between miRNA and siRNA. Sample Answer: Student answers may vary but should include components of the following. Both are methods of gene silencing using RNA (RNAi). Both these RNA molecules are double stranded. siRNAs are completely complementary to the mRNA transcript of a specific gene of interest, whereas miRNAs are mostly complementary.

They both bind to the endonuclease DICER forming RISC. The siRNA-RISC complex binds to mRNA and cleaves it. In miRNA, only one of the two strands binds to RISC; the miRNA-RISC complex then binds to mRNA, inhibiting translation.

Difficulty: Difficult ASM Standard: 17, 26, 36

This file is copyright 2017, Rice University. All rights reserved.

OpenStax Microbiology Test Bank Chapter 13: Control of Microbial Growth

Chapter 13: Control of Microbial Growth * = Correct answer Multiple Choice 1. Which of the following is not an example of a fomite?

A. catheter B. doorknob C. mosquitoes* D. towels Difficulty: Easy ASM Standard: 13, 14, 23 2. HEPA filters are required for which Biological Safety Level (BSL)?

A. BSL 1 B. BSL 2 C. BSL 3 D. BSL 4* Difficulty: Easy ASM Standard: 14, 37 3. From a clinical perspective, aseptic technique is carried out to do which of the following?

A. clean fomites B. contaminate fomites C. introduce contamination in living tissue D. prevent contamination in living tissue* Difficulty: Easy ASM Standard: 36, 37 4. The autoclave uses which of the following mechanism(s) for sterilization?

A. pressure B. temperature C. pressure and temperature* D. pressure, temperature, and pH Difficulty: Easy ASM Standard: 14, 36, 37 5. Autoclaves are designed to kill which of the following heat-resistant microbes?

A. endospores* B. prions C. vegetative bacterial and fungal cells Page 226 of

OpenStax Microbiology Test Bank Chapter 13: Control of Microbial Growth

D. viruses Difficulty: Easy ASM Standard: 14, 36, 37 6. The decimal reduction time (D-value) is how long it takes to kill which percentage of a microbial population?

A. 10% B. 50% C. 90%* D. 100% Difficulty: Moderate ASM Standard: 14 7. Which of the following actions would be most clearly considered bacteriostatic rather than bactericidal?

A. autoclaving bacterial cultures B. placing a bacterial culturein the −80 C freezer* C. spraying 70% alcohol on a laboratory bench D. treating a mattress with ethylene oxide Difficulty: Moderate ASM Standard: 14 8. Microbial death follows which type of trend?

A. linear B. logarithmic* C. power series D. variable Difficulty: Moderate ASM Standard: 14 9. Which of the following are the standard conditions for an autoclave?

A. 100 C, 1 psi, 60 minutes B. 121 C, 1 psi, 60 minutes C. 121 C, 15 psi, 20minutes* D. 212 C, 15 psi, 10 minutes Difficulty: Moderate ASM Standard: 14, 36, 37 10. Which of the following is not a milkborne pathogen?

A. Escherichia coli O157:H7 Page 227 of

OpenStax Microbiology Test Bank Chapter 13: Control of Microbial Growth

B. Listeria monocytogenes

Page 228 of

OpenStax Microbiology Test Bank Chapter 13: Control of Microbial Growth

C. Salmonella enterica D. Yersinia pestis* Difficulty: Moderate ASM Standard: 23 11. For appropriate food storage in refrigerators, the temperature should be set to no higher than which of the following?

A. 5 C B. 7 C* C. 9 C D. 11 C Difficulty: Easy ASM Standard: 14 12. How does pascalization control microbial growth?

A. by cross-linking proteins B. by damaging DNA C. by denaturing proteins* D. by disrupting membrane integrity Difficulty: Moderate ASM Standard: 14 13. X-rays and gamma rays are examples of which type of radiation?

A. beta emission radiation B. ionizing radiation* C. nonionizing radiation D. nonpenetrating radiation Difficulty: Easy ASM Standard: 14 14. Ultraviolet light is an example of which type of radiation?

A. beta emission radiation B. ionizing radiation C. nonionizing radiation* D. penetrating radiation Difficulty: Easy ASM Standard: 14 15. To sterilize packaged intravenous tubing, which method would not be acceptable?

A. ethylene oxide Page 229 of

OpenStax Microbiology Test Bank Chapter 13: Control of Microbial Growth

B. freezing

Page 230 of

OpenStax Microbiology Test Bank Chapter 13: Control of Microbial Growth

C. ionizing radiation D. nonionizing radiation* Difficulty: Moderate ASM Standard: 14, 36 16. Liquid growth media that contain antibiotics should be sterilized using which method?

A. autoclaving B. boiling C. HEPAfiltration D. membrane filtration* Difficulty: Easy ASM Standard: 14, 36 17. Which method of microbial control introduces double-strand breaks into DNA? A. alcohols B. autoclaving C. ionizing radiation* D. nonionizing radiation Difficulty: Easy ASM Standard: 14 18. Which method of microbial control does not rely on denaturing proteins and/or disrupting the integrity of the cell membrane?

A. autoclaving B. lyophilization* C. treatment with alcohols D. treatment with phenolics Difficulty: Moderate ASM Standard: 14 19. Phenolic compounds can be found naturally in which group of organisms?

A. animals B. bacteria C. fungi D. plants* Difficulty: Easy ASM Standard: N/A 20. Which phenolic compound has commonly been added to soap and raises concerns about Page 231 of

OpenStax Microbiology Test Bank Chapter 13: Control of Microbial Growth

selection for more antimicrobial-resistant bacteria?

A. capsaicin

Page 232 of

OpenStax Microbiology Test Bank Chapter 13: Control of Microbial Growth

B. carbolic acid C. o-phenylphenol D. triclosan* Difficulty: Moderate ASM Standard: 3, 14 21. Which best describes how heavy metals can control microbial growth?

A. by binding to sulfur-containing amino acids* B. by cross-linking proteins C. by introducing double-strand breaks into DNA D. by inserting pores in the cell membrane Difficulty: Moderate ASM Standard: 14 22. What is argyria?

A. a buildup of silver in the body resulting in blue-gray skin* B. a form of skin necrosis due to topical use of phenolics C. inadequate blood supply resulting in chest pain D. microorganisms growing in the blood Difficulty: Moderate ASM Standard: N/A 23. Which halogen or halogen-containing compound is typically used as a form of topical antisepsis?

A. bromine B. chloramine C. fluorine D. iodophor* Difficulty: Easy ASM Standard: 14, 37 24. All but which of the following may be used to disinfect water to make it potable?

A. bleach B. chloramine C. fluoride D. sodium dichloroisocyanurate* Difficulty: Easy ASM Standard: 14, 23 25. Contact lens cleaners commonly use which type of chemical agent to control microbial Page 233 of

OpenStax Microbiology Test Bank Chapter 13: Control of Microbial Growth

growth?

Page 234 of

OpenStax Microbiology Test Bank Chapter 13: Control of Microbial Growth

A. alkylating agents B. peroxygen* C. quats D. supercritical fluid Difficulty: Easy ASM Standard: 14 26. Which of the following is not an alkylating agent?

A. chlorhexidine* B. ethylene oxide C. formalin D. o-phenylphenol Difficulty: Moderate ASM Standard: 14 27. Many chemical preservatives, such as potassium sorbate, preserve food products in which of the following ways?

A. by altering the pH* B. by binding to pathogens C. by changing the osmolarity D. by drying foods Difficulty: Easy ASM Standard: 14 28. Nisin is an antimicrobial peptide produced by which bacterium?

A. Lactobacillus acidophilus B. Lactococcus lactis* C. Listeria monocytogenes D. Streptomyces natalensis Difficulty: Easy ASM Standard: 14, 26 29. Examine the disk-diffusion assay shown below. Which antimicrobial agent is the least effective?

Page 235 of

OpenStax Microbiology Test Bank Chapter 13: Control of Microbial Growth

A. A B. B C. C D. D* Difficulty: Moderate ASM Standard: 14, 28b 30. Which of the following is used to determine if a solution of disinfectant actively used in the clinical setting is contaminated?

A. the disk-diffusion method B. the in-use test* C. the phenol coefficient test D. the use-dilution test Difficulty: Moderate ASM Standard: 14, 36 True/False 31. Commercial sterilization kills all microbes.

Answer: False Difficulty: Easy ASM Standard: 14 32. Pasteurized foods cannot spoil.

Answer: False Difficulty: Easy ASM Standard: 14 33. Autoclaves use moist heat to sterilize materials.

Page 236 of

OpenStax Microbiology Test Bank Chapter 13: Control of Microbial Growth

Answer: True Difficulty: Easy ASM Standard: 14 34. X-rays and gamma rays are examples of ionizing radiation and cause the formation of thymine dimers.

Answer: False Difficulty: Moderate ASM Standard: 14 35. Mercury compounds may be dissolved in alcohol and used as tinctures.

Answer: True Difficulty: Easy ASM Standard: 14 36. HEPA filters are able to filter many airborne virions.

Answer: True Difficulty: Easy ASM Standard: 14 37. Quats are not effective against endospores and prions.

Answer: True Difficulty: Difficult ASM Standard: 14 38. Quats are anionic compounds.

Answer: False Difficulty: Moderate ASM Standard: 14 39. Soaps with no added ingredients are bactericidal.

Answer: False Difficulty: Easy ASM Standard: 14 40. Sonication causes cavitation in cells.

Answer: True Difficulty: Easy Page 237 of

OpenStax Microbiology Test Bank Chapter 13: Control of Microbial Growth

ASM Standard: 14 Matching 41. Match the medical instrument to its proper classification.

Note than an answer may be used more than once.

A. catheter i. critical B. colonoscope ii. semicritical C. duodenoscope iii. noncritical D. sonogram probe E. sphygmomanometer (blood pressure cuff) Answers: A. i., B. ii., C. ii., D. iii., E. iii.

Difficulty: Moderate ASM Standard: N/A 42. Match the microbial growth control term with its correct definition.

A. antisepsis i. a technique used to prevent contamination to maintain sterility B. asepsis ii. a chemical process used to control microbial growth on body surfaces C. disinfection iii. a process that kills nonspore-forming pathogenic pathogens D. pasteurization iv. lowering microbial load to public health standards E. sanitization v. a chemical process used to control microbial growth on inanimate objects Answers: A. ii., B. i., C. v., D. iii., E. iv.

Difficulty: Moderate ASM Standard: 14 43. Match the agent to its mechanism of action.

A. alcohols i. physically remove a microbe from a surface B. gamma rays ii. damage DNA molecules C. heavy metals iii. bind to sulfur-containing amino acids to inhibit enzyme activity D. soaps iv. denature proteins and disrupt membrane integrity Answers: A. iv., B. ii., C. iii., D. i.

Difficulty: Moderate ASM Standard: 14 44. Match the agent to the mechanism of action.

A. alkylating agent i. affect proteins and nucleic acids.

B. nitric acid ii. inhibit catalases and peroxidases C. quat iii. may disrupt ferredoxin in the electron transport chain D. sorbic acid iv. disrupt membrane integrity Answers: A. i., B. iii., C. iv., D. ii.

Difficulty: Moderate

ASM Standard: 14 Fill in the Blank 45. The complete removal of vegetative cells, endospores, and viruses is known as Answer: sterilization

.

Difficulty: Easy ASM Standard: 14 46. Traditional pasteurization kills pathogens and reduces the number of maintaining food quality.

Answer: spoilage-causing microbes

while

Difficulty: Easy ASM Standard: 14, 23 47. A microbiology laboratory that works with many indigenous environmental samples would be classified as a Biological Safety Lab (BSL) .

Answer: 2 Difficulty: Moderate ASM Standard: 37 48.

is the appropriate method to pasteurize milk for areas where the milk cannot be refrigerated.

Answer: Ultra-high temperature (UHT) pasteurization Difficulty: Moderate ASM Standard: 14

49. Food items are irradiated using Answer: ionizing (also accept gamma)

radiation.

Difficulty: Moderate ASM Standard: 14 50. Prior to the use of antibiotics, newborns were routinely treated with

upon birth as

protection against bacterial infection they may have acquired during passage through the birth canal.

Answer: silver nitrate Difficulty: Easy ASM Standard: 14, 23 51. Recently, the heavy metal reduce diarrheal diseases.

Answer: copper

has been used in designing pots for water storage to

Difficulty: Easy ASM Standard: 14, 23 52.

is a gaseous alkylating agent used to sterilize objects, like bed mattresses, that cannot be autoclaved.

Answer: Ethylene oxide Difficulty: Moderate ASM Standard: 14

53. Some bacteria and other organisms produce the enzyme reaction

H2O2

H2O + O2 .

, which catalyzes the

Answer: catalase Difficulty: Easy ASM Standard: 14 54. A recently developed method of antisepsis that can be used on skin before transplantation is .

Answer: scCO 2 (also accept supercritical fluids) Difficulty: Moderate ASM Standard: 14 Short Answer 55. What is the difference between a disinfectant and an antiseptic?

Sample Answer: Disinfectants are used on inanimate surfaces, whereas antiseptics are used on living tissue.

Difficulty: Easy ASM Standard: 14 56. Which heat method (dry or moist) is more effective? Why? Sample Answer: Moist heat is more effective because moisture is able to penetrate cells better.

Difficulty: Easy ASM Standard: 14 57. Name two quality-control methods/indicators used to determine if something has been autoclaved properly.

Sample Answer: Heat-sensitive autoclave tape, a biological indicator spore test, or a Diack tube can be used to determine if something has been autoclaved properly.

Difficulty: Easy ASM Standard: 36, 37 58. Is desiccation a “-cidal” mechanism and what effect does it have on microbes?

Sample Answer: Desiccation is not “-cidal.” It is “-static.” Water is removed, hence inhibiting metabolic pathways (because metabolism requires water).

Difficulty: Moderate ASM Standard: 13, 14 59. Why is it rare to hear about foodborne disease outbreaks from the consumption of candy bars?

Sample Answer: Candy contains a high sugar concentration, which provides an environment of high osmotic pressure. In these conditions, cells will lose water, inhibiting their metabolic pathways.

Difficulty: Moderate ASM Standard: 13, 14 60. An experiment is conducted to see how many bacteria remain in a culture at different times and temperatures. The data are shown below. (a) What is the lowest temperature that represents the thermal death point? (b) What is the thermal death time at 67 °C? 0 minutes 5 × 109 cells 5 × 109 cells 5 × 109 cells 5 × 109 cells

5 minutes 3 × 107 cells 1 × 103 cells 100 cells 0 cells

57 °C 67 °C 77 °C 87 °C Sample Answer: (a) 77 °C; (b) 15 minutes.

10 minutes 100 cells 5 cells 0 cells 0 cells

15 minutes 5 cells 0 cells 0 cells 0 cells

Difficulty: Moderate ASM Standard: 13, 14, 28b 61. How does nonionizing radiation cause mutations in DNA? Sample Answer: Nonionizing radiation causes the formation of thymine dimers between adjacent thymines in a DNA strand. If the strand is not repaired, then during DNA replication, DNA polymerase does not always incorporate the correct complementary nucleotides, thus leading to mutations.

Difficulty: Moderate ASM Standard: 14 62. What is the mode of action for iodine?

Sample Answer: Iodine oxidizes cellular components (including sulfur-containing amino acids, nucleotides, and fatty acids) and destabilizes macromolecules.

Difficulty: Moderate ASM Standard: 14 63. What is the mode of action for alcohols?

Sample Answer: Alcohols denature proteins and disrupt membrane integrity.

Difficulty: Moderate ASM Standard: 14 64. Name two chemical food preservatives that are naturally produced by microorganisms.

Sample Answer: Two examples of chemical food preservatives naturally produced by

microorganisms are natamycin and nisin.

Difficulty: Easy ASM Standard: 14, 26 65. Name one benefit of using quats.

Answers will vary. Quats are stable, nontoxic, inexpensive, colorless, odorless, and tasteless.

They are also active against fungi, protozoans, and enveloped viruses. They may be used as antiseptics or disinfectants.

Difficulty: Moderate ASM Standard: 14 Questions 66 and 67 are based on the following experiment: Different disinfectants are soaked on sterile pads that are then placed on a lawn of bacteria. The photo below shows the results after 24 hours of incubation.

66. What assay is being shown here?

Sample Answer: Disk diffusion assay (also accept Kirby-Bauer) Difficulty: Easy ASM Standard: 14, 36 67. Which antimicrobial agent (A through F) is the most effective against the bacteria that were plated?

Sample Answer: A Difficulty: Easy ASM Standard: 28b, 38 Questions 68 and 69 are based on the following experiment: You wish to test the efficacy of a disinfectant that has been used to clean hospital rooms. The diagram below shows the experimental setup and the results.

68. What assay is being shown here? Sample Answer: This is the in-use assay.

Difficulty: Easy ASM Standard: 14, 36 69. What conclusion can you draw from the results of this experiment?

Sample Answer: The disinfectant is contaminated. This is evident because of the growth of five or more colonies on either plate.

Difficulty: Moderate

ASM Standard: 28b, 38 Brief Essay Essay Question Rubric RATING Failing Criteria for evaluati on

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is poor and contains numerous grammatical mistakes and misspellings.

Below Average Answer fails to provide examples to support an argument.

Writing is poor and grammatical errors are common.

Answer is somewhat incoherent.

Competent

Advanced

Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

POINT 0 1 2 3 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

70. A simple example of controlling microbial growth is based on how we handle our food products. Name three food preparation methods that counter microbial growth. Be sure to discuss the mode of action for each method.

Answer: Student answers will vary but should include components of the following. ● Heat. We cook our foods to certain temperatures to ensure that microbial growth is killed. Heat denatures proteins and disrupts membrane integrity. ● Smoking. Meats are smoked with moist heat. Moist heat can easily penetrate cells.

Like heating, smoking would denature proteins and disrupt membrane integrity of microbes. ● Pickling. Pickling lowers the pH of food. Lowered pH inhibits enzyme activity in microbes. ● Drying. Meats are cooked and dried (i.e., beef jerky). The removal of water inhibits metabolic pathways in microbes. ● Salting. Similar to drying, salt removes water, inhibiting metabolic pathways in microbes.

Difficulty: Difficult ASM Standard: 14

71. A company has hired you and your laboratory to test the efficacy of a new alkylating agent, “Substance X.” You prepare a culture of endospores and add Substance X. Every 5 minutes, you plate the endospores to see if they are still viable. The data from this experiment are shown below.

Time (minutes) 0 5 10 15 20 25 30 35 40

Number of viable endospores 50,000 25,500 5000 3000 500 400 50 20 5

A. What is the mode of action for Substance X? B. State the independent and dependent variables of this experiment.

C. Prepare a graph of these data using a logarithmic scale for the y-axis and a linear sale for the x-axis.

D. What is the approximate decimal reduction time (D-value) of Substance X against the endospores used?

E. Would you classify Substance X as a high-, intermediate- or low-level germicide? Why? Answer: Student answers will vary but should include components of the following.

A. Alkylating agents replace hydrogen atoms with alkyl groups. These chemicals cross-link proteins.

B. The independent variable is time (minutes) and the dependent variable is the number of endospores.

C. Graph shown below.

D. It takes approximately 10 minutes to decrease 10-fold or 1 log unit.

E. Substance X is a high-level germicide because it effectively kills endospores.

Intermediate-level germicides are less effective at killing endospores, and low-level

level germicides are ineffective against endospores.

Difficulty: Difficult ASM Standard: 14, 28b, 29, 29a, 38 72. Explain how hyperbaric oxygen therapy works. What types of bacterial infections can be treated with hyperbaric oxygen?

Answer: Student answers will vary but should include components of the following. A patient is placed in a chamber with a higher oxygen concentration/pressure or is supplied pressurized oxygen through a breathing tube. This method is used to treat pathogens that are either oxygen-sensitive microbes or obligate anaerobic microorganisms (including Clostridium spp.). The increased oxygen assists with increasing the activities of certain lymphocytes like neutrophils and macrophages. The increased oxygen also produces toxic-free radicals that can target anaerobic or oxygen-sensitive pathogens. Hyperbaric therapy may also increase the effectiveness of certain antibiotics.

Difficulty: Moderate ASM Standard: 13, 14, 23 73. Name two chemical preservatives and state their modes of action. Be sure to indicate whether they target bacteria and/or fungi.

Answer: Student answers will vary but should include components of the following. ● Sorbic acid inhibits enzyme activity by reducing intracellular pH. It also inhibits catalase/peroxidase. Acts on both bacteria and fungi. ● Benzoic acid/propionic acid inhibits enzyme activity by reducing intracellular pH. It inhibits oxidative phosphorylation and acts on both bacteria and fungi. ● Sulfites interfere with protein structure by disrupting disulfide bonds. They act on both bacteria and fungi. ● Nitrites react with ferredoxin (an electron transport-chain carrier), preventing ATP synthesis. They act on both bacteria and fungi. ● Nisin targets cell wall production against gram-positive bacteria. ● Natamycin is an antifungal believed to target ergosterol in the cell membrane Difficulty: Difficult ASM Standard: 13, 14 This file is copyright 2017, Rice University. All rights reserved.

Chapter 14: Antimicrobial Drugs * = Correct answer Multiple Choice 1. Which was the first antimicrobial agent discovered to treat syphilis?

A. chloramphen icol B. compound 606* C. penicillin D. sulfonamide Difficulty: Easy ASM Standard: 14, 23 2. Who is credited for first finding an antimicrobial agent? A. Paul Ehrlich* B. Alexander Fleming C. Edward Jenner D. Joseph Lister Difficulty: Moderate ASM Standard: 14 3. Who is credited for first finding a naturally occurring antimicrobial agent?

A. Paul Ehrlich B. Alexander Fleming* C. Edward Jenner D. Joseph Lister Difficulty: Moderate ASM Standard: 14, 26 4. Alexander Fleming first observed a mold (now known as Penicillium notatum) that was able to inhibit which organism?

A. Escherichia B. Listeria C. Staphylococcus* D. Streptococcus Difficulty: Easy ASM Standard: 14, 26 5. Which of the following is a semisynthetic antimicrobial agent?

A. actinom ycin B. ampicillin*

C. streptomycin D. neomycin Difficulty: Moderate ASM Standard: 14 6. Which describes the difference between a secondary infection and a superinfection?

A. A secondary infection is a type of superinfection that develops when antibiotics arenot given.

B. A superinfection is a type of secondary infection that can develop when antibioticskill much of the patient’s normal flora.* C. A superinfection is a type of secondary infection that develops when antibiotics takento treat a particular pathogen do not completely kill all of that original pathogen.

D. A secondary infection is a type of superinfection that develops when the pathogenmutates in response to the antimicrobial agent.

Difficulty: Difficult ASM Standard: 14, 23 7. Life-threatening diseases caused by bacterial pathogens should be treated with which of the following?

A. bactericidal agents only* B. bacteriostatic agents only C. both bacteriostatic and bactericidal agents D. neither bacteriostatic nor bactericidal agents Difficulty: Moderate ASM Standard: 14, 23 8. Which of the following is a -lactam antibiotic?

A.

*

B.

C.

D. Difficulty: Moderate ASM Standard: 14, 26 9. Which of the following is not a -lactam antibiotic?

A. carbapenem B. cephalosporin C. penicillin D. tetracycline* Difficulty: Easy ASM Standard: 14, 26 10. How does penicillin work?

A. Penicillin binds to penicillin-binding proteins, thus inhibiting the transglycosylation reaction during cell wall synthesis.

B. Penicillin binds to penicillin-binding proteins, thus inhibiting the transpeptidation reaction during cell wall synthesis.* C. Penicillin blocks the movement of peptidoglycan subunits from the cytoplasm to the exterior of the cell.

D. Penicillin inserts into the plasma membrane, causing cell lysis.

Difficulty: Moderate ASM Standard: 7, 14, 26 11. How does bacitracin work?

A. Bacitracin binds to penicillin-binding proteins, thus inhibiting the transglycosylation reaction during cell wall synthesis.

B. Bacitracin binds to penicillin-binding proteins, thus inhibiting the transpeptidation reaction during cell wall synthesis.

C. Bacitracin blocks the movement of peptidoglycan subunits from the cytoplasm to the exterior of the cell.* D. Bacitracin inserts into the plasma membrane, causing cell lysis.

Difficulty: Moderate ASM Standard: 7, 14, 26 12. The penicillins act on which type of bacteria?

A. gram-negative bacteria only B. gram-positive bacteria only C. mostly gram-negative bacteria and some gram-positive bacteria D. mostly gram-positive bacteria and some gram-negative bacteria* Difficulty: Moderate ASM Standard: 7, 14, 26 13. The aminoglycosides directly target which structure of the bacterial cell?

A. 30S ribosomal subunit* B. 50S ribosomal subunit C. cell wall D. plasma membrane Difficulty: Easy ASM Standard: 7, 14, 26 14. The macrolides target which feature of the bacterial cell?

A. 30S ribosomal subunit B. 50S ribosomal subunit* C. cell wall D. plasma membrane

Difficulty: Easy ASM Standard: 7, 14, 26 15. Which of the following was the first broad-spectrum antibiotic to be approved by the FDA? A. chloramphenicol* B. compound 606 C. penicillin D. tetracycline Difficulty: Easy ASM Standard: 7, 14, 26 16. Which of the following commonly results from most antibiotic classes that bind to the 50S ribosomal subunit?

A. Peptide bond formation is inhibited.* B. Proteins made from this ribosome insert into the plasma membrane.

C. The proofreading mechanism of the ribosome is inhibited.

D. tRNAs charged with an amino acid cannot enter the ribosome.

Difficulty: Difficult ASM Standard: 7, 14, 26 17. Congratulations! You have discovered a new antibiotic. It is lipophilic and detergent-like. On the basis of this information, its target is most likely which of the following?

A. peptidoglycan B. the bacterial ribosome C. the plasma membrane* D. nucleic acid synthesis machinery Difficulty: Moderate ASM Standard: 7, 14 18. Which is the target of the antimicrobial drug known as rifampin?

A. DNA gyrase B. DNA polymerase C. helicase D. RNA polymerase* Difficulty: Easy ASM Standard: 7, 14, 26 19. Which is the target of the class of antimicrobial drugs known as fluoroquinolones?

A. DNA gyrase* B. DNA polymerase C. helicase

D. RNA polymerase Difficulty: Moderate ASM Standard: 7, 14, 26 20. Sulfa drugs (sulfonamides) inhibit which metabolic pathway?

A. dihydrofolic acid synthesis pathway* B. Embden-Meyerhof pathway C. Entner–Doudoroff pathway D. pentose-phosphate pathway Difficulty: Moderate ASM Standard: 7, 14 21. Metronidazole and pentamidine are used to treat which type of infection?

A. bacterial B. fungal C. helminth D. protozoan* Difficulty: Difficult ASM Standard: 7, 14, 23 22. Benzimidazoles and avermectins are used to treat which type of infection?

A. bacterial B. fungal C. helminth* D. protozoan Difficulty: Difficult ASM Standard: 7, 14, 23 23. Reverse transcriptase inhibitors, such as AZT, can be used to target which virus?

A. herpes B. HIV* C. influenza D. rabies Difficulty: Easy ASM Standard: 7, 10, 14, 23 24. Which of the following antiviral drugs is not a nucleoside analog?

A. acyclovir B. etravirine* C. sofosbuvir D. vidarabine

Difficulty: Moderate ASM Standard: 7, 14 25. What mechanism of resistance is used by both MRSA and VRSA? A. blocked/reduced penetration B. efflux pump C. inactivation of enzyme D. target modification* Difficulty: Moderate ASM Standard: 3, 7, 14, 22 26. Which of the following contributes to the development of antibiotic resistance?

A. blocked/reduced penetration B. efflux pump C. inactivation of enzyme D. target modification* Difficulty: Easy ASM Standard: 2, 3, 7, 14, 22 27. Examine the results of the disk diffusion assay shown below. Which antimicrobial agent is the most effective?

A. A* B. B C. C D. D Difficulty: Moderate ASM Standard: 14, 28b, 38

28. A macrobroth dilution assay to determine the MIC of amoxicillin on E. coli is shownbelow.

What is the MIC?

(credit: modification of work by Brian Forster)

A. 0.01 µg/mL B. 0.05 µg/mL* C. 0.10 µg/mL D. 5.00 µg/mL Difficulty: Moderate ASM Standard: 14, 28b, 38 29. Using the Etest shown below, determine the approximate MIC of this antibiotic against the bacterium plated.

(credit: Nathan Reading)

A. 0.12 µg/mL B. 0.5 µg/mL* C. 8 µg/mL D. 256 µg/mL Difficulty: Moderate

ASM Standard: 14, 28b, 38 30. Which of the following describes an antibiogram?

A. a compilation of all known antibiotic resistant bacteria found in the United States B. a compilation of local antibiotic susceptibility data broken down by bacterial pathogen* C. a sterile disk infused with antibiotic and used in a Kirby-Bauer disk diffusion assay D. a synthetic antibiotic Difficulty: Easy ASM Standard: 14 True/False 31. Antimicrobial agents may be the metabolites of microorganisms or synthetically made.

Answer: True Difficulty: Easy ASM Standard: 14, 26 32. If antibiotic treatment is needed for immunocompromised individuals who develop infections, the medications should be bactericidal rather than bacteriostatic.

Answer: True Difficulty: Easy ASM Standard: 14, 26 33. Both vancomycin and penicillin target the bacterial cell wall and have the same mode of action.

Answer: False Difficulty: Moderate ASM Standard: 7, 14 34. Chloramphenicol should be used sparingly because it also inhibits the large subunit of mitochondrial ribosomes.

Answer: True Difficulty: Moderate ASM Standard: 7, 26 35. Continued use of quinolones can lead to hallucinations, cardiac complications, and, potentially, anemia.

Answer: True Difficulty: Easy ASM Standard: 14

36. Tamiflu is a hemagglutinin inhibitor commonly used against influenza virus.

Answer: False Difficulty: Easy ASM Standard: 14 37. Isoniazid is an antimetabolite that can be used to treat mycobacterial infections.

Answer: True Difficulty: Moderate ASM Standard: 14 38. Individuals cannot have MRSA as part of their normal flora ormicrobiota.

Answer: False Difficulty: Moderate ASM Standard: 14, 23 39. The Kirby-Bauer disk diffusion assay can distinguish between bacteriostatic and bactericidal agents.

Answer: False Difficulty: Easy ASM Standard: 36 40. The Etest combines both the Kirby-Bauer disk diffusion assay and the minimum inhibitory concentration dilution assay to determine the effectiveness of an antimicrobial compound.

Answer: True Difficulty: Easy ASM Standard: 36 41. Due to concern of antimicrobial resistance, the number of antimicrobial drugs approved by the FDA has increased since the 1980s.

Answer: False Difficulty: Easy ASM Standard: 3, 14, 26 Matching 42. Match the antimicrobial agent to its mode of action.

A. chloramphenicol i. inhibits nucleic acid synthesis B. fluoroquinolone ii. inhibits the 30S ribosomal subunit C. penicillin iii. inhibits cell wall synthesis

D. tetracycline E. trimethoprim Answers: A. v., B. i., C. iii., D. ii., E. iv.

iv. acts as an antimetabolite v. inhibits the 50S ribosomal subunit

Difficulty: Easy ASM Standard: 7, 14 43. Match the antimicrobial agent to its mode of action.

A. bacitracin i. inhibits cell wall synthesis B. diarylquinoline ii. inhibits nucleic acid synthesis C. isonicotinic acid hydrazide iii. disrupts cell membranes D. polymyxin iv. inhibits ATP synthase E. rifampin v. acts as an antimetabolite Answers: A. i., B. iv., C. v., D. iii., E. ii.

Difficulty: Moderate ASM Standard: 7, 14 44. Match the antimicrobial agent to its mode of action.

A. artemisinin i. competes with coenzyme Q for electrons B. atovaquone ii. interferes with heme detoxification C. imidazole iii. produces reactive oxygen species D. pentamidine iv. inhibits ergosterol synthesis E. quinoline v. affects DNA and RNA, and, therefore, protein production Answers: A. iii., B. i., C. iv., D. v., E. ii.

Difficulty: Moderate ASM Standard: 14 45. Match the antiviral to the virus it is used to treat.

A. acyclovir i. hepatitis C B. etravirine ii. HIV C. sofosbuvir iii. influenza D. zanamivir iv. herpes Answers: A. iv., B. ii., C. i., D. iii.

Difficulty: Moderate ASM Standard: 14 Fill in the Blank 46. The microbial environment that has been investigated most thoroughly for the production of antimicrobial compounds is ?

Answer: soil Difficulty: difficult

ASM Standard: 7, 14, 22 47. At the hospital, the fist antimicrobial drug given, especially when the pathogen is not yet known, is often a -spectrum drug.

Answer: broad Difficulty: Easy ASM Standard: 14, 26 48. Ampicillin and amoxicillin are Answer: semisynthetic

penicillins.

Difficulty: Easy ASM Standard: 14, 26 49. Penicillin inhibits the reaction of cell wall synthesis.

Answer: transpeptidation (also accept cross-linking) Difficulty: Difficult ASM Standard: 7, 14 50. Most antifungal agents target Answer: ergosterol

, which is found in the fungal cell membrane.

Difficulty: Easy ASM Standard: 7, 14 51. Artemisinin and quinolines are antimicrobials used against Answer: malaria

.

Difficulty: Easy ASM Standard: 14 52. Carbapenem-resistant gram-negative bacteria are common in Answer: health-care settings (also accept nosocomial infections)

.

Difficulty: Moderate ASM Standard: 3, 14, 23 53. The is the lowest concentration of a drug that inhibits visible growth in culture.

Answer: minimum inhibitory concentration (MIC) Difficulty: Easy ASM Standard: 36

54. The is the lowest concentration of a drug that kills at least 99.9% of the starting inoculum.

Answer: minimum bactericidal concentration (MBC) Difficulty: Easy ASM Standard: 36 55. A group of pathogens called demonstrate cross-resistance.

Answer: ESKAPE

pathogens are multidrug resistant microbes that

Difficulty: Moderate ASM Standard: 3, 14, 22, 23 Short Answer 56. Examine the two growth curves shown below. Identify which drug is the bactericidal agent and which is the bacteriostatic agent. Briefly state how you arrived at your answer.

Sample Answer: Agent A is bacteriostatic. These agents inhibit but do not kill. When the agent is removed, growth resumes. Agent B is bactericidal. These agents kill the target bacteria, as seen in the graph.

Difficulty: Moderate ASM Standard: 14 57. What is the definition of dosage?

Sample Answer: Dosage is the amount of a drug given during a certain time period.

Difficulty: Easy ASM Standard: 26 58. What should be considered when determining dosage?

Sample Answer: Answers can include the following: what the pathogen is, for how long the infection or disease has occurred, the age and body mass of the patient, the half-life of the drug, potential adverse effects resulting from prolonged use, the concentrations at which the drug becomes toxic to the patient.

Difficulty: Easy ASM Standard: 26, 27 59. What should be considered when determining a route of administration?

Sample Answer: Health-care providers should first consider whether the drug needs to go inside of the body to treat the infection. If the patient has a skin infection, then a topical medication could be prescribed. If patient has colitis, rectal therapy (i.e., suppositories) could be used. If the drug can be taken orally, will the drug still be effective after exposure to the acidity of the stomach? Can the drug be absorbed by the gastrointestinal tract to enter the bloodstream? If not, intravenous or intramuscular injection could be given.

Difficulty: Easy ASM Standard: 26 60. Give an example of an antagonistic drug interaction.

Sample Answer: Antacids will increase the pH of the stomach and may negatively impact the absorption of an antimicrobial.

Difficulty: Easy ASM Standard: 26 61. A culture of E. coli is currently in the exponential phase. It is exposed to penicillin. Whatwill happen to the bacteria as they continue to grow and divide in the presence of this antibiotic?

Briefly explain your answer.

Sample Answer: Penicillin inhibits peptidoglycan cross-linking (transpeptidation reaction).

As a result, the bacteria will elongate and then pop, like overfilled balloons, because the integrity of the cell wall is compromised. A video of this can be seen at: https://www.youtube.com/watch?v=UjLmf-cVcMw Difficulty: Moderate ASM Standard: 7, 14 62. What are the three antibiotics typically found in Neosporin?

Sample Answer: bacitracin, neomycin, polymyxin B Difficulty: Easy ASM Standard: 14 63. Why is chloramphenicol rarely used on humans?

Sample Answer: It can result in serious complications such as lethal gray baby syndrome, the suppression of bone marrow production, and anemia.

Difficulty: Easy ASM Standard: 26 64. Why are helmiths, fungi, and protozoan pathogens difficult to treat with antimicrobial agents?

Sample Answer: They have eukaryotic cells, like their hosts. Drugs that inhibit eukaryotic cell processes could have a negative impact on the host cells as well. Thus, it is difficult to develop antimicrobial agents that are selectively toxic for these types of microbes Difficulty: Moderate ASM Standard: 14 65. Some bacteria have a very low level of resistance to antibiotics, while others have a high level of resistance. (a) In terms of natural selection, explain why scientists believe antibiotics should be given only when necessary. (b) What can be done to prevent the further spread of antibiotic resistance?

Sample Answer: (a) As we continue to use antibiotics, we are selecting for microorganisms that are more resistant to our antimicrobial drugs. As a result, drug-resistant microorganisms will be more prevalent and will be harder to target. (b) Doctors should only prescribe antibiotics to treat bacterial infections when needed. Patients should also finish their medication (even if they feel better after only a few days into treatment) to kill off all of the pathogen.

Difficulty: Moderate ASM Standard: 3, 14, 26 66. What is the resistance mechanism for MRSA? Sample Answer: MRSA strains produce a penicillin-binding protein that has a low affinity for β-lactam antibiotics (an example of target modification).

Difficulty: Moderate ASM Standard: 3, 14 67. How do VISA and VRSAdiffer?

Sample Answer: VISA and VRSA strains of Staphylococcus aureus differ in their levels of resistance to vancomycin and in their mechanisms of resistance. VISA has intermediate resistance to vancomycin. Its resistance mechanism involves increasing vancomycin targets (peptidoglycan subunits, D-Ala–D-Ala peptide off NAM). VRSA is resistant to vancomycin and its resistance mechanism is to change the target (peptidoglycan subunits, changing the DAla–D-ala peptide to D-Ala–D-Lac or remove one of the D-Ala amino acids). See image below.

Difficulty: Difficult ASM Standard: 3, 14 68. How could bacteria develop resistance to sulfa drugs (sulfonamide)? Be sure to state a possible resistance mechanism.

Sample Answer: Bacteria can become resistant to antimicrobial agents through spontaneous mutations, transposons, or horizontal gene transfer. There are various answers for the second part of the question. Examples can include target modification of the metabolic enzyme to which sulfa drugs bind, target overproduction of this enzyme, and enzymatic bypass to produce dihydrofolic acid using an alternate pathway.

Difficulty: Difficult ASM Standard: 2, 3, 14 69. What is the difference between MIC and MBC? Sample Answer: The MIC is the lowest concentration of a drug that inhibits visible growth in culture, whereas the MBC is the lowest concentration of a drug that kills at least 99.9% of the starting inoculum.

Difficulty: Easy ASM Standard: 36 70. An MIC assay is shown below. Tube A contains vancomycin at a concentration of 25 mg/mL. The serial dilutions performed are shown. Then Staphylococcus aureus was inoculated into each tube. The tubes were then incubated for 24 hours. After 24 hours, growth was observed only in tubes E and F. From this experiment, identify which tube contains the MIC and calculate the MIC of vancomycin for S. aureus.

Sample Answer: The MIC would be tube D because it contains the lowest concentration that inhibited growth. Tube D has a 10–4 dilution, so the concentration is 25 mg/mL × 10-4 = 2.5 µg/mL. Difficulty: Difficult ASM Standard: 28b, 29a, 36 Brief Essay Essay Question Rubric RATING Failing Criteria for evaluati on

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is poor and contains numerous grammatical mistakes and misspellings.

Below Average Answer fails to provide examples to support an argument.

Writing is poor and grammatical errors are common.

Answer is somewhat incoherent.

Competent

Advanced

Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

0 1 2 3 POINT VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

71. (a) State the five general targets of antibacterial compounds and give an example of an antibiotic that acts on each target. (b) Why are viruses not affected by antibacterial compounds?

Answer: Student answers will vary but should include the following.

(a) The five targets and examples of each are shown below.

(b) Viruses do not have these targets. They do not have a cell wall, a plasma membrane, ribosomes, metabolism, or enzymes for DNA replication. Although some will have enzymes for RNA replication, antibiotics are ineffective against them.

Difficulty: Easy ASM Standard: 7, 14, 26 72. (a) State any four mechanisms of antibiotic resistance that bacteria use. (b) For each multidrug-resistant microbe listed below, state specifically the mechanism it uses to resist the action of the antibiotic.

• MRSA • VISA • VRSA • carbapenem resistance in Pseudomonas aeruginosa Sample Answer: Student answers will vary but should include the following. (a) The four mechanisms are efflux pumps, drug inactivation, decreased/blocked penetration, and target modification. (b) Mechanisms used by each antibiotic-resistant bacterium: • MRSA strains produce a penicillin-binding protein that has a low affinity forβlactam antibiotics (an example of target modification).

• VISA’s resistance mechanism is to increase vancomycin targets (peptidoglycan subunits, D-Ala–D-Ala peptide off NAM; an example of target modification)

• •

VRSA is resistant to vancomycin because of the modification of the peptide component of peptiglycan subunits such that they can no longer bind to vancomycin, an example of target modification.

Carbapenem resistance in P. aeruginosa is due to a decrease in the amount of porins on its outer membrane (because it is gram negative), thus reducing the amount of carbapenem that enters the cell (decreased penetration).

Difficulty: Moderate ASM Standard: 3, 7, 14, 22, 26 73. Explain the treatment of HIV, answering the following four questions: What class of virus is HIV? Briefly describe the life cycle of HIV. In terms of the viral life cycle, why is it difficult to treat HIV? In terms of the viral life cycle, what type of inhibitor drugs could be used to treat HIV? Sample Answer: Student answers will vary but should include the following. HIV is a retrovirus. It is an enveloped virus that contains spike proteins (gp120 and gp41) that recognize and bind to CD4-positive T cells. The virus binds to the CD4 receptor. After entry, the viral RNA is reverse transcribed into DNA, using reverse transcriptase. The DNA is then integrated into the chromosome. The viral DNA is then transcribed into viral RNA and synthesis of the HIV capsid occurs. The capsid proteins come to the cell surface where HIV assembles and buds off the host cell. It is difficult to treat HIV for several reasons. A drug cannot target the host cell because CD4 T cells are necessary for our immune system. A drug cannot be used to target the DNA because the DNA integrates into the host cell genome.

HIV's reverse transcriptase introduces mutations, so drug resistance is common with HIV. Protease inhibitors could be used as long as they target only the viral protein. The use of proteases could damage the host cell and the host. Inhibitors that could be used to disrupt the life cycle of HIV can include fusion inhibitors to prevent initial binding of HIV to the cell.

AZT, a reverse transcriptase, or an integrase inhibitor can prevent viral DNA from integrating into the chromosome.

Difficulty: Moderate ASM Standard: 3, 7, 10, 14, 18 74. Lori has a very bad sore throat. She goes to the doctor and is told that it is not a bacterial infection. (a) The doctor then prescribes an antibiotic for her to take. Should the doctor have given Lori this prescription? Why would the doctor give such a treatment? (b) Lori gets well! A week goes by and then the sore throat comes back. This time the doctor suspects strep throat. A culture is taken and sent to the lab to confirm, using blood agar, that she has strep throat. The lab then performs a Kirby-Bauer disk diffusion assay using antibiotics A through D. The results are shownbelow:

(i) (ii)

Based on the results shown above, which antibiotic worked best?

Circle any antibiotic-resistant colonies. If there are any antibioticresistant bacteria, how could they have arisen? (c) Lori takes the antibiotic as prescribed and a week later returns to the doctor.

Apparently the concentration being used is not working. Should the doctor just give a higher concentration of antibiotic? What problems may arise from this action?

Sample Answer: Student answers will vary but should include the following. (a) Antibiotics target bacteria. In that sense, the doctor shouldn’t have prescribed an antibiotic. The doctor may prescribe an antibiotic not to cure but to help prevent a bacterial infection that may result because of the lowered immunity of the sick person. This should not be done because it can lead to an increase in antibiotic resistance. Heath- care providers often feel pressured to prescribe antibiotics, so he or she may have felt that way. (b) (i) D worked best. (ii) Several colonies were resistant to A (see diagram below).

They could have arisen from spontaneous mutations, transposons, or the mechanisms of horizontal gene transfer (i.e., transformation, transduction, conjugation).

(c) Exposure to antibiotics provides selective pressure, which makes the surviving bacteria more likely to be resistant. Giving higher concentrations provides more selective pressure, potentially resulting in more resistant bacteria and higher MIC concentrations required to eradicate the infection.

Difficulty: Difficult ASM Standard: 2, 3, 14, 22, 26, 28b, 36 This file is copyright 2017, Rice University. All rights reserved.

Chapter 15: Microbial Mechanisms of Pathogenicity * = Correct answer Multiple Choice 1. Which of the following would be considered a symptom?

A. blood pressure reading of 150/90 mm Hg B. body ache and chills* C. fever of 39 C D. heart rate of 120 bpm Difficulty: Easy ASM Standard: N/A 2. Which of the following would be considered a sign?

A. blurry vision B. body ache and chills C. burning sensation during urination D. gross hematuria (visible presence of blood in urine)* Difficulty: Easy ASM Standard: N/A 3. Which of the following is an example of a nosocomial disease?

A. acquiring Giardia while drinking from a stream during a camping trip B. acquiring Listeria after eating at a public restaurant C. acquiring MRSA after touching a locker door handle after an already infected individual did so D. obtaining a Pseudomonas respiratory infection during a recent visit to the hospital* Difficulty: Easy ASM Standard: 23 4. Sickle cell anemia can be classified as which type of disease?

A. idiopathic B. infectious, communicable C. infectious, noncommunicable D. noninfectious* Difficulty: Easy ASM Standard: N/A 5. Which of the following is not a zoonotic disease?

A. rabies B. Rocky Mountain spotted fever

C. typhoid* D. yellow fever Difficulty: Easy ASM Standard: 23 6. What period of disease describes when the patient begins to feel general signs and symptoms?

A. incubation period B. period of convalescence C. period of illness D. prodromal period* Difficulty: Easy ASM Standard: 23 7. During which period of disease is a patient most susceptible to developing a secondary infection?

A. incubation period B. period of convalescence C. period of decline* D. prodromal period Difficulty: Moderate ASM Standard: 23 Examine the graph shown below and then answer questions 8 and 9.

8. Examine the graph and determine the approximate ID 50 of the virus.

A. 10 particles B. 5000 particles C. 13,000 particles* D. cannot be determined from the data collected Difficulty: Moderate ASM Standard: 10, 23, 28b, 29, 36

9. Examine the graph and determine the LD50 of the virus.

A. 10 particles B. 5000 particles C. 13,000 particles D. cannot be determined from the data collected* Difficulty: Moderate ASM Standard: 23, 28b, 29, 36 10. Identify which pathogen is the least virulent on the basis of ID 50 .

A. pathogen A with an ID 50 of 1000 cells* B. pathogen B with an ID50 of 50 cells C. pathogen C with an ID50 of 1 cell D. pathogenicity cannot be determined from ID 50 values Difficulty: Moderate ASM Standard: 23 11. Which of the following is the definition of pathogenicity?

A. the ability of a microbial agent to cause disease* B. the ability of a microbial agent to cause infection C. the ability of a microbial agent to prevent disease D. the ability of a microbial agent to produce an antimicrobial compound Difficulty: Easy ASM Standard: 23 12. Which pathogen cannot pass the blood–placenta barrier and infect a fetus?

A. Herpes simplex virus 1 B. Listeria monocytogenes C. Salmonella typhi* D. Toxoplasma gondii Difficulty: Moderate ASM Standard: 23 13. Which of the following is a common secondary fungal disease?

A. giardiasis B. histoplasmosis C. oral thrush* D. syphilis Difficulty: Moderate ASM Standard: 23 14. Which statement properly describes how Salmonella typhi enters host cells?

A. S. typhi binds to receptors on host cells that cause endocytosis.

B. S. typhi is not an intracellular pathogen.

C. S. typhi secretes effector proteins that cause membrane ruffling.* D. S. typhi specifically invades phagocytic host cells.

Difficulty: Difficult ASM Standard: 8, 13, 22, 23 15. Why are Pseudomonas aeruginosa infections difficult to treat?

A. Because they are gram-positive bacteria, which are harder to treat.

B. Because they form biofilms, which are difficult for antibiotics to penetrate.* C. Because they have a special endotoxin that degrades many antibiotics.

D. Because we do not have any antibiotics that target P. aeruginosa.

Difficulty: Easy ASM Standard: 13, 21, 22, 23 16. Which describes the condition in which blood contains actively dividing bacteria?

A. bacteremia B. septicemia* C. toxemia D. viremia Difficulty: Easy ASM Standard: 13, 23 17. Molecular Koch’s postulates are used to identify which characteristic of pathogens?

A. an effective treatment B. the ID 50 C. the LD 50 D. virulence factor genes* Difficulty: Moderate ASM Standard: 8, 23, 36 18. Hyaluronidase is which type of exoenzyme?

A. glycohydrolase* B. nuclease C. phospholipase D. protease Difficulty: Easy ASM Standard: 22, 23 19. Intracellular pathogens, like Listeria and Rickettsia, produce which type of exoenzyme to aid in escaping the phagosome?

A. glycohydrolases B. nucleases C. phospholipases* D. proteases Difficulty: Moderate ASM Standard: 13, 22, 23 20. Which virulence factor, produced by Staphylococcus aureus, allows the bacterium tobe coated in fibrin that protects it from phagocytes?

A. catalase B. coagulase* C. collagenase D. oxidase Difficulty: Moderate ASM Standard: 13, 22, 23 21. What is the toxic component of endotoxin?

A. lipid A* B. the core oligosaccharide C. the O-antigen D. the peptidoglycan subunits Difficulty: Easy ASM Standard: 8 22. You are working in a hospital and have been asked to perform the LAL test (Limulus amebocyte lysate). After adding the amebocytes from the horseshoe crab to theserum, coagulation is not observed. What conclusion can you draw from this?

A. The patient’s serum contains endotoxin.* B. The patient’s serum contains exotoxin.

C. The patient’s serum does not contain endotoxin.

D. No conclusion can be reached because the LAL test is not used for detection of toxins.

Difficulty: Difficult ASM Standard: 28b, 36, 38 23. In the A-B toxin, which subunit is necessary for making the initial attachment to thehost cell?

A. the A subunit B. the B subunit* C. Depending on the toxin, it could be either the A or B subunit.

D. Neither, because A-B toxins do not function this way.

Difficulty: Easy

ASM Standard: 23 24. An enterotoxin targets which type of cell?

A. cardiac cells B. hepatic cells C. intestinal cells* D. respiratory cells Difficulty: Easy ASM Standard: 23 25. Which toxin inhibits the release of glycine and GABA at the neuromuscular junction, thus preventing the relaxation of muscles?

A. anthrax B. botulinum C. diphtheria D. tetanus* Difficulty: Moderate ASM Standard: 23 26. Which is the target for the diphtheria toxin?

A. charged tRNA molecules B. elongation factor 2* C. mRNA molecules D. the eukaryotic ribosome Difficulty: Difficult ASM Standard: 23 27. Which are the attachment sites for hemagglutinin spike proteins of influenza virus?

A. CD4 receptors B. CD8 receptors C. heparan sulfate D. sialic acid* Difficulty: Easy ASM Standard: 10, 23 28. Which is the name of the toxin produced by species of Aspergillus that can cause liver cancer?

A. aflatoxin* B. citrinin C. ochratoxin D. patulin

Difficulty: Moderate ASM Standard: 9, 23 29. The Panton-Valentine leukocidin from Staphylococcus aureus targets which cell type?

A. intestinal epithelial cells B. neurons C. red blood cells D. white blood cells* Difficulty: Easy ASM Standard: 13, 22, 23 30. Which surface molecules do helminths commonly express that protect them from the host immune system?

A. fibrins B. glycans* C. hemagglutinins D. proteases Difficulty: Easy ASM Standard: 9, 13, 23 True/False 31. The prodromal period is when the maximum number of pathogen particles or organisms are present in an infected host.

Answer: False Difficulty: Easy ASM Standard: 23 32. All pathogens satisfy Koch’s postulates.

Answer: False Difficulty: Moderate ASM Standard: 23 33. Facultative intracellular pathogens can reproduce both inside and outside host cells.

Answer: True Difficulty: Easy ASM Standard: 13, 22, 23 34. The severity of disease depends only on the activity of the pathogen.

Answer: False

Difficulty: Easy ASM Standard: 23 35. The normal flora and microbiota of an individual can cause disease.

Answer: True Difficulty: Moderate ASM Standard: 23 36. All contacts with a pathogen will result in infection.

Answer: False Difficulty: Difficult ASM Standard: 22, 23 37. Extracellular DNA from lysed host cells can function as a means of preventing the spreadof a pathogen in a host.

Answer: True Difficulty: Moderate ASM Standard: N/A 38. Endotoxin is produced only by gram-negative bacteria.

Answer: True Difficulty: Easy ASM Standard: 8 39. Giardia lamblia invades the intestinal mucosa, causing them to shrink and limitingtheir absorption of nutrients.

Answer: False Difficulty: Moderate ASM Standard: 9, 23 40. Bacteria, fungi, and protozoa often use similar virulence factors and mechanisms of pathogenicity.

Answer: True Difficulty: Moderate ASM Standard: 8, 9, 23 Matching 41. Match the disease nomenclature to its meaning.

A. –derma i. cell destruction

B. –emia ii. thickened skin C. –itis iii. tumor formation D. –lysis iv. inflammation E. –oma v. blood Answers: A. ii., B. v., C. iv., D. i., E. iii.

Difficulty: Easy ASM Standard: N/A 42. Match the type of infection to its proper description.

A. focal i. The pathogen goes from one location to a second location.

B. local ii. Asecond infection emerges due to killing of protective flora during antibiotic treatment.

C. secondary iii. The pathogen spreads throughout the host.

D. superinfection iv. The pathogen remains in one location.

E. systemic v. Another disease-causing pathogen emerges after an initial infection.

Answers: A. i., B. iv., C. v., D. ii., E. iii.

Difficulty: Easy ASM Standard: 23 43. Match the bacterial toxin to its mechanism of action.

A. botulinum i. inhibits host cell protein synthesis B. cholera ii. activates adenylate cyclase, resulting in higher levels of cAMP and loss of electrolytes leading to diarrhea C. diphtheria iii. inhibits glycine release to inhibit muscle relaxation D. tetanus iv. inhibits release of acetylcholine to inhibit muscle contraction.

Answers: A. iv., B. ii., C. i., D. iii.

Difficulty: Moderate ASM Standard: 23 44. Match the bacterial toxin to its mechanism of action.

A. Clostridium perfringens α toxin i. inhibits host cell protein synthesis B. pneumolysin ii. overactivates immune system, leading to inflammation and toxic shock syndrome C. Shiga toxin iii. assembles into membrane pores, resulting in cell rupturing D. Streptococcus pyogenes mitogenic iv. degrades membrane phospholipids exotoxin Answers: A. iv., B. iii., C. i., D. ii.

Difficulty: Difficult ASM Standard: 23 Fill in the Blank

45.

pathogens always cause disease.

Answer: Primary (alternative answers: True, Frank) Difficulty: Easy ASM Standard: 23

46.

pathogens can cause disease when the host is immunocompromised.

Answer: Opportunistic Difficulty: Easy ASM Standard: 23

47.

permit pathogens to cause disease.

Answer: Virulence factors Difficulty: Easy ASM Standard: 8, 22, 23

48.

are molecules, receptors, or surface structures necessary for attachment to a host cell.

Answer: Adhesins Difficulty: Moderate ASM Standard: 8, 23

49.

are anatomic locations where pathogens can pass into host tissue.

Answer: Portals of entry Difficulty: Easy ASM Standard: 23

50. A(n) is a biological poison produced by certain pathogens.

Answer: toxin Difficulty: Easy ASM Standard: 23 51.

are exotoxins that can trigger a cytokine storm.

Answer: Superantigens Difficulty: Easy ASM Standard: 23

52.

is a yellowing of the skin and eyes due to the lysis of erythrocytes resulting from infection with either hepatitis B virus or Plasmodium falciparum.

Answer: Jaundice Difficulty: Easy ASM Standard: 23 53.

are extracellular structures in bacteria that are involved in conjugation and can be used as adhesins.

Answer: Pili Difficulty: Easy ASM Standard: 8, 23

54. A(n) is when an influenza virus acquires a new hemagglutinin neuraminidase spike protein from another influenza virus coinfecting the same host cell.

Answer: antigenic shift Difficulty: Moderate ASM Standard: 10, 18, 23 Short Answer 55. Explain the similarity and difference between iatrogenic and nosocomial diseases.

Sample Answer: Both could occur in the hospital setting. However, iatrogenic diseases are the direct result of a medical procedure, whereas nosocomial diseases are simply acquired in a hospital setting.

Difficulty: Easy ASM Standard: 23 56. Why are not all communicable diseases contagious?

Sample Answer: Communicable diseases can be transmitted from person to person. How contagious it is depends upon how the pathogen is transmitted. For example, a sexually transmitted disease is contagious only between sexually active individuals. However, someone who is not sexually active would most likely not acquire the disease.

Difficulty: Moderate ASM Standard: 23 57. Name three different types or classes of noninfectious diseases.

Sample Answer: Any of the following are noninfectious diseases: inherited, congenital, degenerative, nutritional deficiency, endocrine, neoplastic, and idiopathic.

Difficulty: Moderate ASM Standard: 23

58. On the axes below, sketch and identify the five periods of disease progression, and show the severity of symptoms at each stage.

Sample Answer: See below:

Difficulty: Moderate ASM Standard: 23 59. (a) Which part of the body does Helicobacter pylori colonize? (b) What is the virulence factor produced by H. pylori that allows it to survive in that location?

Sample Answer: H. pylori persists in the stomach by producing urease, which raises the pH of the stomach.

Difficulty: Moderate ASM Standard: 13, 22, 23 60. Explain the similarity and difference between chronic and latent infections.

Sample Answer: A chronic disease lasts for months or years. Latent diseases last for years, but are distinguished from chronic diseases by a lack of active replication during extended dormant periods.

Difficulty: Moderate ASM Standard: 23 61. What is the parenteral route?

Sample Answer: The parenteral route refers to any way into the body bypassing the skin and mucous membranes. Thus, it refers to routes into the body other than through the respiratory tract, gastrointestinal tract, or genitourinary tract. It typically it refers to entry into the host through breaks in the skin due to wounds, insect bites, animal bites, and needle pricks.

Difficulty: Moderate ASM Standard: 23 62. (a) Explain what a capsule is and how it functions as a virulence factor. (b) Besides bacteria, do any pathogenic eukaryotic microorganisms produce a capsule?

Sample Answer: The capsule is a type of glycocalyx. The glycocalyx is a coating of molecules external to the bacterial cell wall, typically made of sugars and/or proteins. The capsule is a highly organized type of glycocalyx. It acts as a virulence factor because it assists attachment of pathogens to a host and protects the pathogen against phagocytosis.

Fungi and protozoa also produce capsules. Some helminths produce extracellular polysaccharide glycans that allow them to evade the immune system, functioning in that way like the capsules produced by other pathogenic microbes.

Difficulty: Difficult ASM Standard: 8, 9, 13, 23 63. What are the four steps of pathogenesis?

Sample Answer: exposure (contact), adhesion (colonization), invasion, infection Difficulty: Easy ASM Standard: 23 64. Describe two ways bacterial pathogens can initiate endocytosis into a nonphagocytic host cell.

Sample Answer: Pathogens can secrete effector molecules to trigger entry (membrane ruffling1 ). Alternatively, pathogens can exhibit surface molecules that bind to host cell receptors, allowing the pathogens to enter.2 Difficulty: Moderate ASM Standard: 8, 22, 23 65. How do hyaluronidase and collagenase promote invasion?

Sample Answer: Hyaluronan is a sugar polymer found in the epidermis; it connects adjacent cells in connective tissue. Collagen is an important protein found in connective tissue. These two enzymes promote pathogenic invasion of the host by enabling the pathogen to degrade host cell connective tissue, which, in turn, allows the pathogen to penetrate and spread..

Difficulty: Easy ASM Standard: 22, 23 66. In A-B toxins, how does the A subunit separate from the B subunit inside the host cell?

Sample Answer: The A-B toxin binds to a specific receptor on the host cell via the B subunit.

The toxin is then endocytosed. While in the vacuole, the acidity within the vacuole causes the separation of the two subunits, allowing the A subunit (the activity subunit) to enter the host cell cytoplasm and locate its particular target.

Difficulty: Moderate ASM Standard: 23 67. Explain the similarities and differences between the mechanisms of the botulinum and tetanus toxins.

Sample Answer: Both toxins are A-B neurotoxins. The botulinum toxin inhibits release of acetylcholine, thus inhibiting muscle contraction. The tetanus toxin inhibits glycine release, which, in turn, inhibits muscle relaxation.

Difficulty: Moderate ASM Standard: 23 68. Why must the flu vaccine (flu shot) be given every year?

Sample Answer: The rate of antigenic variation, due to antigenic drift or point mutations, and antigenic shift [change in spike proteins due to gene reassortment in a host coinfected with two different influenza viruses]) is high. The immune system may not recognize a new strain of flu from a previous year’s vaccination.

Difficulty: Moderate ASM Standard: 10, 23 69. What are four ways that helminths protect themselves from the host immune system?

1Other references may refer to this as the trigger mechanism.

2 Other references may refer to this as the zipper mechanism.

Sample Answer: For some helminths, their large size alone is enough to protect them from a host immune response. Others produce a tough outer cuticle. Yet others use glycan mimicry, whereby they produce surface glycan molecules that resemble the glycan molecules found on host cells, thereby “disguising” themselves as host cells. Yet others produce proteases that target host cell antibodies. Others suppress the immune system in other ways, including releasing large amounts of material that may either overload the immune system or cause it to act inappropriately.

Difficulty: Moderate ASM Standard: 9, 23 Brief Essay Essay Question Rubric RATING Failing Criteria for evaluati on

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is poor and contains numerous grammatical mistakes and misspellings.

Below Average Answer fails to provide examples to support an argument.

Writing is poor and grammatical errors are common.

Answer is somewhat incoherent.

Competent

Advanced

Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

0 1 2 3 POINT VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Questions 70 and 71 involve the following scenario: You are working in a hospital and have discovered what you believe to be a new bacterial pathogen that infects both humans and mice. The pathogen causes a nosocomial disease of conjunctivitis. You now wish to characterize this pathogen.

70. You take a conjunctival swab of an infected patient and culture it for any bacteria. You isolate a bacterial pathogen and grow it in pure culture. Using microscopy and a negative stain, you observe the following:

(credit: American Society for Microbiology)

(a) What shape do these cells have? (b) What is the structure surrounding these cells? (c) How could you use Koch’s postulates to determine if this bacterium is the causative agent of the conjunctivitis? (d ) How could you use molecular Koch’s postulates to see if the structure surrounding each cell is necessary for the pathogen’s virulence?

Answer: Student responses may vary but should include the following. (a) The cells are rod or bacilli shaped. (b) There is a capsule surrounding each cell, which is resistant to stain and appears as a clear halo in this negative stain. Capsule is a type of glycocalyx. The glycocalyx is a coating of molecules external to the cell wall, typically made of sugars and/or proteins. Capsule is a highly organized type of glycocalyx. (c) To determine if the pathogen is causing the conjunctivitis, first, swabs should be taken from both healthy and diseased individuals. The pathogen should only be present in diseased individuals. Second, the suspected pathogen should be grown in pure culture (which the question states can be done). Third, healthy individuals (or mice) should be infected with the suspected pathogen. The same disease (i.e., conjunctivitis) should occur. Fourth, the suspected pathogen should again be isolated, grown in pure culture, and match the pathogen that was observed in the second step. (d ) To determine if the capsule is a virulence factor, you can use molecular Koch’s postulates.

First, check that the capsule is produced in virulent strains of this bacterium and not in nonpathogenic strains. Generate a mutation in the genome of the pathogen such that it no longer produces a capsule, and then infect a healthy individual (or mouse) to see if the virulence of the pathogen decreases. Finally, restore the capsule production in that mutant and observe if virulence is restored. If it is, then the capsule is a virulence factor.

Difficulty: Moderate ASM Standard: 6, 8, 23, 32, 36, 38 71. You take various amounts of the pathogen and infect a group of mice. After a week, you record the number of mice that are alive and dead. The data are shown below.

Pathogen Concentration (No. of Live Mice Dead Mice Cells)

101 10 0 2 10 7 3 103 4 6 4 10 2 8 5 10 1 9 106 0 10 (a) Prepare a graph of percent mortality versus concentration of pathogen. (b) Using the graph, calculate the LD 50 . (c) You wish to compare the LD 50 of this pathogen to Pseudomonas aeruginosa, another known bacterial pathogen that causes nosocomial diseases. If the LD50 of P. aeruginosa for mice is 104 , would you say that your new pathogen is more or less virulent than P. aeruginosa? Be sure to explain your answer.

Answer: Student responses may vary but should include the following. (a) Graph is shown below.

(a) The LD 50 will be between 102 and 103 cells (5 × 102 cells) (b) The unknown pathogen is more virulent. The lower the LD 50 , the more virulent it is (i.e., less pathogen is necessary to cause death).

Difficulty: Difficult ASM Standard: 23, 28b, 29, 36, 38 72. Compare and contrast endotoxins and exotoxins. Specifically address their source, composition, effect on the host, and heat stability. Also, compare their LD 50 s.

Answer: Student response should include the following answers (taken from the textbook table).

Difficulty: Moderate ASM Standard: 23 73. Answer the following questions regarding the cholera toxin: (a) What organism produces this toxin? Briefly identify the shape and cell envelope of this organism. (b) In which class of toxin is the cholera toxin? (c) What results from ingestion of the cholera toxin? Be sure to describe in detail the mechanism of action.

Answer: Student responses may vary but should include the following. (a) Vibrio cholerae produces the cholera toxin. V. cholerae is a gram-negative bacterium with a curved rod shape. (b) The cholera toxin is an A-B enterotoxin. (c) The B subunit binds to intestinal epithelial cells and the A subunit enters the intestinal cell and binds to G s (a G protein). This results in increased adenylate cyclase activity, converting ATP into cAMP. The increased cAMP activates a chloride ion channel in the cell, resulting in the release of chloride ions into the intestinal lumen. Due to osmotic pressure, water also leaves the cells and enters the lumen, resulting in “rice-water stool,” a watery diarrhea.

Difficulty: Moderate ASM Standard: 12, 13, 22, 23 74. Explain how Candida albicans, a fungus that is part of the normal flora/microbiota, is an opportunistic pathogen and can cause disease. What diseases can it cause?

Answer: Student responses may vary but should include the following.

Candida albicans is part of the microbiota of the skin, mouth, intestine, and vagina.

Normally, its growth is kept in check by other members of the microbiota or by the environmental conditions of the body.

C. albicans is an opportunistic fungal pathogen and can cause disease when overgrowth occurs. Overgrowth can occur due to the following factors: the use of antimicrobials decrease in the efficacy of the immune system (i.e., being immunocompromised) untreated diabetes in which there is a high sugar content in saliva that allows the fungus to grow vaginal pH changes

decreases in estrogen during menstruation or menopause C. albicans is the causative agent of oral thrush, vaginal yeast infections, and cutaneous candidiasis. The virulence factors of candida include surface glycoproteins that act as adhesins, proteases to degrade keratin, and phospholipases to facilitate entry.

Difficulty: Moderate ASM Standard: 12, 13, 22, 23

This file is copyright 2017, Rice University. All rights reserved.

Chapter 16: Disease and Epidemiology * = Correct answer Multiple Choice 1. Which term refers to the study of the geographic distribution of disease and its transmission? A. epidemiology* B. etiology C. morbidology D. pathology Difficulty: Easy ASM Standard: 23 2. Which term refers to the study of the cause of disease?

A. epidemiolo gy B. etiology* C. morbidology D. pathology Difficulty: Easy ASM Standard: 23 3. Tetanus, which is caused by Clostridium tetani, is an example of which type of disease?

A. endemic B. epidemic C. p ande mic D. spora dic* Difficulty: Easy ASM Standard: 23 4. Malarial disease in Brazil is an example of which type of disease? A. endemic*

B. epidemic C. pandemic D. sporadic Difficulty: Easy ASM Standard: 23 5. Examine the map below. The color distribution on the map is best described as which type of disease?

A. endemic B. epidemic C. pandemic* D. sporadic Difficulty: Moderate ASM Standard: 23 6. Robert Koch was the first to conclusively determine the causative agent of which disease?

A. anthrax* B. gonorrhea C. syphilis D. tuberculosis Difficulty: Easy ASM Standard: 23 7. Which of the following most specifically describes a notifiable disease?

A. any disease caused by a prion B. any disease of public health importance* C. any disease that is highly infectious D. any disease with a high ID50 Difficulty: Easy ASM Standard: 23 8. Which of the following is not a notifiable disease?

A. giardiasis B. gonorrhea C. MRSA* D. Zika Difficulty: Moderate ASM Standard: 23 9. John Snow developed a detailed map (the “ghost map”) to investigate the etiology of which disease?

A. anthrax B. botulism C. cholera* D. listeriosis Difficulty: Easy ASM Standard: 23 10. Which of the following is not an example of evidence used by John Snow to determine that cholera was being transmitted by water in London in the 1800s?

A. a high frequency of cholera cases located near a water pump on Broad Street B. beer workers not contracting cholera because they drank beer rather than water C. microscopic examination of water* D. waste and sewage being dumped into the Thames River Difficulty: Hard ASM Standard: 23 11. Which researcher required that surgeons should use a 5% carbolic acid solution to clean surgical tools as a way to prevent the spread of disease?

A. Alexander Fleming B. Robert Koch C. JosephLister* D. John Snow Difficulty: Easy ASM Standard: 14, 23 12. Which type of studies gathers data from past cases to study present-day cases?

A. descriptive B. experimental C. perspective D. retrospective* Difficulty: Easy ASM Standard: 23

13. You are hired as an epidemiologist for the following study. You wish to determine if potato salad, served at a local farmer’s market a month ago, caused an outbreak of a food -borne illness. You specifically interview individuals who had eaten potato salad and developed the illness, as well as individuals who ate the potato salad and did not develop illness.

Based on this description, which type of study was conducted?

A. case-control* B. cohort method C. cross-sectional D. experimental Difficulty: Moderate ASM Standard: 23 14. You wish to determine if a new drug can cure individuals with colds caused by rhinoviruses.

You invite 50 individuals to participate in the study. Using a double-blind approach, 25 individuals get a sugar pill and 25 get the test drug. Based on this description, which type of study was conducted?

A. case-control B. cohort method C. cross-sectional D. experimental* Difficulty: Moderate ASM Standard: 23 15. Florence Nightingale’s 1958 book included graphs showing that many casualties she observed were due to which of the following?

A. helminths contracted on the battlefield B. preventable infectious diseases* C. prions D. wounds sustained in combat action Difficulty: Easy ASM Standard: 23 16. How long does rhinovirus survive outside physiological fluids?

A. Less than a day* B. Up to 48 hours C. Up to 72 hours D. Up to 1 week Difficulty: Easy ASM Standard: 23 17. Mary Mallon, aka Typhoid Mary, was which type of carrier?

A. B. C. D.

asymptomatic* passive transient zoonotic

Difficulty: Easy ASM Standard: 23 18. Who traced the typhoid outbreak of 1900–1915 to Mary Mallon?

A. Edward Jenner B. Robert Koch C. John Snow D. George Soper* Difficulty: Moderate ASM Standard: 23 19. Listeria monocytogenes, the causative agent of listeriosis, can pass through the blood placenta barrier to infect a fetus. This type of transmission to the fetus is known as which of the following?

A. droplet B. horizontal direct contact C. indirect contact D. vertical direct contact* Difficulty: Moderate ASM Standard: 23 20. Sexually transmitted diseases between sexually active partners are most commonly transmitted by which method?

A. fomites B. horizontal direct contact* C. vehicles D. vertical direct contact Difficulty: Easy ASM Standard: 23 21. Which of the following is not a fomite?

A. catheter B. nurse* C. scalpel D. syringe Difficulty: Easy ASM Standard: 23

22. Tuberculosis is typically transmitted via which of the following?

A. air* B. food C. sexual activity D. water Difficulty: Easy ASM Standard: 23 23. A fruit fly lands on cow feces and then flies over to a bowl of watermelon being served ata farm picnic. The fruit fly in this example is which of the following?

A. biological vector B. fomite C. mechanical vector* D. vehicle Difficulty: Easy ASM Standard: 23 24. Infected fleas that have the bacterium Yersinia pestis growing inside them are able to transmit plague. In this case, the infected fleas are best described as which of the following?

A. biological vectors* B. fomites C. mechanical vectors D. vehicles Difficulty: Moderate ASM Standard: 23 25. Which agency monitors notifiable diseases in the United States?

A. Centers for Disease Control and Prevention* B. Environmental Protection Agency C. Food and Drug Administration D. Homeland Security Difficulty: Easy ASM Standard: 23 26. SARS first occurred in , before becoming a(n) correct pair from the following.

A. China, endemic B. China, pandemic* C. Ireland, endemic D. Ireland, pandemic

disease. Choose the

Difficulty: Moderate ASM Standard: 23 27. Which is the transmission mechanism for West Nile Virus?

A. body-fluid contact B. droplets C. fomite D. vector* Difficulty: Easy ASM Standard: 23 28. The tsetse fly transmits which disease?

A. African sleeping sickness* B. leishmaniasis C. malaria D. typhus Difficulty: Moderate ASM Standard: 23 29. Which of the following is true about modern emerging diseases?

A. Malaria is an example of an emerging disease.

B. They are diseases that increase in frequency after a period of decline.

C. They are diseases that the WHO has classified as being poorly understood.

D. They occur in both developing and developed countries.* Difficulty: Moderate ASM Standard: 3, 23 30. Which of the following statements about quarantine is false?

A. Patients may be released from quarantine if preventive treatment can be administered.

B. Public health authorities can quarantine patients for any diseases.* C. Quarantine facilities can be equipped with special air-handling methods such as HEPA filters.

D. Quarantine times depend on the incubation period of the disease.

Difficulty: Hard ASM Standard: 14, 23 True/False 31. The prevalence of HIV is generally higher than its incidence.

Answer: True Difficulty: Moderate

ASM Standard: 23 32. Etiology is the study of the transmission of diseases.

Answer: False Difficulty: Easy ASM Standard: 23 33. All etiologic agents are pathogens.

Answer: False Difficulty: Hard ASM Standard: 23 34. Nosocomial infections can be acquired in hospital settings.

Answer: True Difficulty: Easy ASM Standard: 23 35. In the 1800s, nosocomial diseases were prevalent.

Answer: True Difficulty: Moderate ASM Standard: 23 36. In experimental epidemiological studies, study subjects are manipulated in some manner.

Answer: True Difficulty: Easy ASM Standard: 28 37. Humans can be reservoirs for pathogens.

Answer: True Difficulty: Moderate ASM Standard: 23 38. An individual with human papillomavirus (HPV) who has genital warts can transmit HPV to their partner via kissing on the lips.

Answer: False Difficulty: Easy ASM Standard: 23 39. The WHO only monitors the prevalence of infectious diseases around the world.

Answer: False Difficulty: Easy ASM Standard: 31 40. Lyme disease is more prevalent in the northern hemisphere.

Answer: True Difficulty: Easy ASM Standard: 23 Matching 41. Match the outbreak to its proper description.

A. endemic i. A disease occurs relatively rarely, without a geographic focus.

B. epidemic ii. A disease produces more cases than expected within a short time in a localized area.

C. pandemic iii. A disease occurs at a relatively constant and often low level within a population.

D. sporadic iv. A disease increases in frequency worldwide.

Answers: A. iii., B. ii., C. iv., D. i.

Difficulty: Easy ASM Standard: 23 42. Match the disease to the most appropriate description, choosing the best option for each disease to use each term once.

A. AIDS i. endemic B. Creutzfeldt-Jakob disease ii. pandemic C. influenza during most winters iii. sporadic D. malaria in Brazil iv. epidemic Answers: A. ii., B. iii., C. iv., D. i.

Difficulty: Moderate ASM Standard: 23 43. Match the type of spread to the best description.

A. common-source spread i. transmitted from a single source to all individuals infected B. continuous-source spread ii. transmitted from a common source that operates for longer than the incubation time for a pathogen C. intermittent-source spread iii. occurs through direct or indirect person-to-person contact D. point-source spread iv. transmitted from a common source that operates for less than the incubation time of a pathogen E. propagated spread v. transmitted from a common source that operates sporadically

Answers: A. i., B. ii., C. v., D. iv., E. iii.

Difficulty: Moderate ASM Standard: 23 44. Match the pathogen to the disease it causes.

A. Borrelia burgdorferi i. African sleeping sickness B. Plasmodium falciparum ii. Lyme disease C. Rickettsia rickettsii iii. malaria D. Trypanosoma brucei iv. plague E. Yersinia pestis v. Rocky Mountain spotted fever Answers: A. ii., B. iii., C. v., D. i., E. iv.

Difficulty: Moderate ASM Standard: 23 Fill in the Blank 45. Of 100,000 individuals exposed to a particular bacterial pathogen, 500 develop disease. Of the 500 individuals who develop the disease, 100 die. The morbidity rate is cases per 100,000 people.

Answer: 500 Difficulty: Moderate ASM Standard: 23 46. Of 100,000 individuals exposed to a particular bacterial pathogen, 500 develop disease. Of the 500 individuals who develop the disease, 100 die. The mortality rate is per 100,000 people.

Answer: 100 Difficulty: Moderate ASM Standard: 23 47. John Snow’s work on cholera showed that a water pump on Broad Street served as a for the spread of infectious disease.

Answer: common source Difficulty: Moderate ASM Standard: 23 48. Joseph Lister required surgeons to use when washing hands and cleaning surgical tools as a means of reducing nosocomial infections.

Answer: phenol (carbolic acid) Difficulty: Easy ASM Standard: 14, 23

49.

epidemiological studies are ones in which data are gathered from study participants through measurements.

Answer: Observational Difficulty: Easy ASM Standard: 28, 31

50. A health-care provider who does not have signs or symptoms of disease and is notinfected but transmits a pathogen from one patient to another is said to be a(n) carrier.

Answer: passive Difficulty: Easy ASM Standard: 23 51. During a parasitic pathogen’s lifecycle, it reaches sexual maturity in the Answer: definitive

host.

Difficulty: Moderate ASM Standard: 14, 23 52. Transmission of pathogens via water, food, and/or air is known as Answer: vehicle

transmission.

Difficulty: Easy ASM Standard: 20, 23 53. A is used to isolate infected individuals to prevent further transmission of a particular pathogen.

Answer: quarantine Difficulty: Easy ASM Standard: 14, 23 54. An infectious disease that caused a pandemic in western Africa in 2014–2015 is Answer: Ebola hemorrhagic fever (or Ebola) Difficulty: Easy ASM Standard: 23 Short Answer 55. What does the field of epidemiology cover?

Sample Answer: Epidemiology is the study of infectious disease distribution, timing, and transmission.

.

Difficulty: Easy ASM Standard: 23 56. Morbidity is dependent upon what two aspects of a disease?

Sample Answer: prevalence and incidence Difficulty: Hard ASM Standard: 23 57. What is the difference between morbidity and mortality?

Sample Answer: Morbidity refers to the state of being diseased, whereas mortality refers to death.

Difficulty: Easy ASM Standard: 23 58. What information is reported in the CDC’s MMWR? Sample Answer: MMWR refers to the Morbidity and Mortality Weekly Report. This report contains the latest information on notifiable diseases. Information it presents can include the number of cases reported for the week, the median number of cases over a 52 weeks, and the cumulative number of cases over the year.

Difficulty: Moderate ASM Standard: 31 59. What does it mean to say that a disease is spread from a point source?

Sample Answer: When a disease spreads from a point source, there is a single source for all individuals infected. The source operates for a shorter time than the incubation period of the pathogen.

Difficulty: Easy ASM Standard: 23 60. What is the difference between intermittent common-source spread and propagated spread of disease?

Sample Answer: In intermittent common-source spread, there is a single source for all individuals infected. Infections can occur sporadically. In propagated spread, there is no single source. Transmission can occur either by direct or indirect contact between individuals.

Difficulty: Moderate ASM Standard: 23 61. What is the difference between descriptive and analytical epidemiological studies?

Sample Answer: Descriptive studies gather information about a disease outbreak through interviews and examination of medical records. Analytical studies involve studying a carefully selected group of individuals.

Difficulty: Moderate ASM Standard: 28, 31, 38 62. What is a cross-sectional observational study?

Sample Answer: A cross-sectional study compares individuals affected by a disease or condition at a single point in time with those unaffected at the same point in time.

Difficulty: Easy ASM Standard: 28 63. What is a double-blind study?

Sample Answer: A study in which neither the participants nor the researchers know what treatment (if any) was given.

Difficulty: Easy ASM Standard: 28 64. During which periods of disease progression can an active carrier transmit disease?

Sample Answer: An active carrier can transmit disease during any or all stages of disease progression (i.e., incubation, prodromal, illness, decline, convalescence).

Difficulty: Moderate ASM Standard: 23 65. While aboard a cruise ship, 10 passengers report having muscle pains, chills, and fever. They all drank from a water fountain located at the stern on the second floor of the ship. You immediately suspect they have Legionnaires disease. This disease is most commonly caused

by Legionella pneumophila, which is normally found living within amoebae. From this scenario, identify the reservoir and source of L. pneumophila.

Sample Answer: The reservoir is the amoebae and the source is the water fountain. (Students may say that water or cooling towers are the reservoir, based upon information found elsewhere, because reservoirs may be living or environmental).

Difficulty: Easy ASM Standard: 23 66. Give an example of a way that a disease can be acquired through horizontal direct-contact transmission.

Sample Answer: Answers may vary. Horizontal direct contact means direct contactbetween individuals other than mother to child (which is vertical direct contact). Examples of ways that diseases can be transmitted through horizontal direct-contact transmission include kissing, licking, and biting.

Difficulty: Moderate ASM Standard: 23 67. What is the difference between mechanical and biological vectors?

Sample Answer: A live animal (other than a human) that transmits an infectious agent from one host to another is called a vector. Biological vectors actively participate in a pathogen’s life cycle. Mechanical vectors merely transport the infectious agent without being infected.

Difficulty: Easy ASM Standard: 14, 23 68. How is the overuse of antibiotics contributing to the reemergence of some infectious diseases?

Sample Answer: The overuse of antibiotics leads to the development of antibiotic-resistant bacteria. Diseases that can normally be treated with antibiotics are now becoming difficult to treat.

Difficulty: Moderate ASM Standard: 3, 23 69. What is the definition of a nosocomial disease?

Sample Answer: A nosocomial disease is a disease acquired in a hospital or other clinical setting. This disease must be different from the disease that originally required the patient to enter the clinical setting.

Difficulty: Easy ASM Standard: NA Brief Essay Essay Question Rubric RATING Failing Criteria for evaluati on

Answer does not provide an argument.

Answer contains inaccuracies.

Writing is poor and contains numerous grammatical mistakes and misspellings.

Below Average Answer fails to provide examples to support an argument.

Writing is poor and grammatical errors are common.

Answer is somewhat incoherent.

Competent

Advanced

Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and

mistakes or misspellings.

free of grammatical errors and misspellings.

3

0 1 2 POINT VALUE Assume rating/grading scale for the question ranges from 0 to 3 points

70. John Snow is considered the “father of epidemiology.” (a) Why is he considered to be the father of epidemiology instead of Robert Koch? (b) What etiological agent did John Snow determine? (c) How does this agent cause disease? (d) What was the reservoir and source of the agent?

Sample Answer: Student answers may vary but should include components of the following. (a) Although Koch was the first to develop a method of identifying a pathogen as the causative agent of a disease (i.e., anthrax), the field of epidemiology also covers the geographic distribution and the mechanisms of transmission of disease. These were aspects that Koch did not determine when he developed his postulates. (b) John Snow investigated an outbreak of cholera in London in 1854. (c) Cholera is an enterotoxin produced by the gram-negative bacterium Vibrio cholerae. The toxin binds to intestinal epithelial cells, causing the production of cAMP. cAMP activates a chloride ion channel in the cell, resulting in the release of ions and an increase in the osmotic pressure of the intestinal lumen. Water will flow out of the cells, resulting in watery diarrhea. (d ) Snow determined that the source of the cholera came from contaminated water from the Thames River. A high prevalence of cases was found near a water pump. Contaminated water is the reservoir for V. cholerae and its toxin.

Difficulty: Hard ASM Standard: 23 71. You wish to determine whether a probiotic pill protects individuals against food -borne illnesses. Explain how you would develop a hypothetical, observational prospective cohort study to see if this is true. (You can assume that you already have clearance from your institution for this study involving human subjects.)

Sample Answer: Student answers may vary but should include components of the following.

The study the student is describing must be: - Observational: The epidemiologist cannot manipulate the subjects. Therefore, thestudy cannot be one in which the probiotic pill is given to any individual by the researcher.

- Prospective: The epidemiologist must track individuals while they are taking the pill. Past use of the pill cannot be used in the study.

- Cohort study: Subjects selected for the study must share a particular characteristic.

Sample Study:

You wish to see if the pill is protective against food-borne illnesses in individuals between the ages of 30 and 40 years. You identify 50 people who self-report that they are currently taking the probiotic pill according to the manufacturer’s directions. The other 50 individuals report they do not take the pill. You conduct surveys once per month asking these individuals to report what they ate over the past month, how often they took the probiotic pill (regardless of their original treatment group), and whether they experienced symptoms of food -borne illness (using a checklist).

Difficulty: Moderate ASM Standard: 28 72. Please note this question has two parts, A and B. You are working for the CDC when a report comes in that individuals on a camping trip have acquired Lyme disease. You are told all the patients have fever, chills, headaches, and muscle aches. They all have a rash (see below). The graph below shows the number of cases of Lyme disease occurring over 20 years.

(credit “photo”: modification of work by Centers for Disease Control and Prevention)

A. Based on the information provided, briefly describe Lyme Disease. Your essay should discuss the following: 1.

What is the causative agent of Lyme disease?

2.

How is Lyme disease transmitted (i.e., is it person-to person, contact, vehicle, or vector transmission)?

3.

Identify the sign(s) the patients are presenting for Lyme disease.

4.

Identify the symptom(s) the patients are presenting for Lyme disease.

5.

Is Lyme disease an emerging or re-emerging disease? Be sure to explain why or why not, based on the data presented in the graph.

When you arrive at the hospital where the campers are being cared for, you wish to set up an epidemiological study to determine where the outbreak of Lyme disease is occurring. The campers have been going around to different campsites for the past 2 weeks and they are unsure when they first began to feel unwell.

B. Discuss how you would set up an observational epidemiological study to determine where the campers may have acquired Lyme disease. Be sure to explain what type of observational study you would choose (i.e., retrospective or prospective) and why. What information would you want to collect to answer your question?

Sample answer: Student answers may vary but should include components of the following. Part A: 1. Lyme disease is caused by the bacterium Borrelia burgdorferi.

2. It is transmitted from mammal reservoirs to humans by tick vectors.

3. Signs can be identified by a health-care provider. In this case, they are fever andrash. 4. Symptoms can only be identified by the patient themselves.

Symptoms listed in this scenario are chills, headaches, and muscle aches.

5. The graph suggests that Lyme disease is an emerging disease. The definition of an emerging disease is a disease that is either new to the human population or has shown an increase in prevalence in the previous 20 years. The data show the number of cases increasing in the past 20 years.

Part B: Before beginning the study, you would need a list of the locations the campers have visited. You could then develop a retrospective study in which you identify individuals who have visited the different campsites these patients have visited. You can then collect data on their medical history to see if they developed Lyme disease.

If they did, then you could trace it back to which campsite has the infected ticks.

Alternatively, a prospective study could be designed. You could follow campers visiting each of the campsites and monitor if they acquire Lyme disease during the course of the study. You would need to take a medical history of each camper before they visit the campsite. In both cases, you would want to look for the same signs and symptoms that the original campers had.

Difficulty: Moderate ASM Standard: 28

This file is copyright 2017, Rice University. All rights reserved.

Chapter 17: Innate Nonspecific Host Defenses * = Correct answer Multiple Choice 1. Which type of cells line the inner surface of blood vessels to prevent microbes from gaining access to blood?

A. ciliated epithelial cells B. endothelial cells* C. keratinized squamous epithelial cells D. squamous epithelial cells Difficulty: Easy ASM Standard: 14 2. Which of the following is not a type of cell junction?

A. centromere* B. desmosome C. gap D. tight Difficulty: Easy ASM Standard: N/A 3. Which layer of the skin contains blood and lymph vessels?

A. dermis B. epidermis C. follicles D. hypodermis* Difficulty: Easy ASM Standard: N/A 4. Which cells produce and secrete mucus?

A. ciliated epithelial cells B. goblet cells* C. keratinized squamous epithelial cells D. Peyer’s patches Difficulty: Easy ASM Standard: 14 5. Which fungus causes rose gardener’s disease?

A. Candida albicans B. Cryptococcus neoformans

C. Histoplasma capsulatum D. Sporothrix schenckii* Difficulty: Moderate ASM Standard: 23 6. Which type of cells line the respiratory tract?

A. ciliated epithelial cells* B. endothelial cells C. keratinized squamous epithelial cells D. squamous epithelial cells Difficulty: Easy ASM Standard: 14 7. What is sebum?

A. a watery, salty liquid that inhibits bacterial growth B. an oily substance released from sebaceous glands that contributes to defense* C. proteins that are involved in bacterial cell division D. visible accumulation of leukocytes, cell debris, and bacteria at the site of infection Difficulty: Moderate ASM Standard: 14 8. What is pus?

A. a watery, salty liquid that inhibits bacterial growth B. an oily substance released from sebaceous glands that contributes to defense C. proteins that are involved in bacterial cell division D. visible accumulation of leukocytes, cell debris, and bacteria at the site of infection* Difficulty: Easy ASM Standard: 14, 23 9. Which antimicrobial enzyme is found in saliva?

A. amylase B. haptocorrin C. lactoperoxidase* D. opiorphin Difficulty: Easy ASM Standard: 14 10. Examine the diagram of peptidoglycan. Which bond (A–D) is targeted by lysozyme?

A. A* B. B C. C D. D Difficulty: Hard ASM Standard: N/A 11. Which chemical mediator is produced by lactobacilli in the female reproductive system and limits the growth of Candida?

A. glucagon B. glycogen C. lactate* D. lactoferrin Difficulty: Moderate ASM Standard: 14 12. Which bacterium is able to invade sweat glands of the skin and can use lipase to degrade sebum?

A. Bacteroides B. Propionibacterium* C. Staphylococcus D. Streptococcus Difficulty: Easy ASM Standard: 14, 23 13. Defensins target which process or structure of a microbial cell?

A. cell membrane* B. cell wall C. DNA synthesis D. protein synthesis

Difficulty: Easy ASM Standard: 14 14. Where are acute phase proteins produced?

A. bone marrow B. liver* C. pancreas D. spleen Difficulty: Easy ASM Standard: 14 15. Which is the best term to describe the process that occurs when an immune cell releases cytokines to nearby cells to trigger a response?

A. autocrine B. endocrine C. hormonal D. paracrine* Difficulty: Easy ASM Standard: 14 16. Which cytokine recruits leukocytes to sites of infections?

A. chemokine* B. histamine C. interferons D. interleukins Difficulty: Moderate ASM Standard: 14 17. Which of the following describes the differentiation of stem cells into various blood cells?

A. autopoiesis B. biopoiesis C. galactopoiesis D. hematopoiesis* Difficulty: Easy ASM Standard: N/A 18. Which of the following leukocytes is an agranulocyte?

A. basophil B. eosinophil C. monocyte* D. neutrophil

Difficulty: Easy ASM Standard: 14 19. Which of the following leukocytes is used for protection against protozoa and helminths?

A. basophil B. eosinophil* C. monocyte D. neutrophil Difficulty: Moderate ASM Standard: 14, 23 20. Which of the following leukocytes initiates inflammation?

A. eosinophil B. mast cell* C. monocyte D. neutrophil Difficulty: Easy ASM Standard: 14 21. Mast cells and basophils release which chemical moderator?

A. defensins B. histamine* C. interferon D. leukocidin Difficulty: Easy ASM Standard: 14 22. Where are Kupffer cells found?

A. brain B. liver* C. lung D. peritoneal cavity Difficulty: Hard ASM Standard: 14 23. Toll-like receptors are examples of which of the following?

A. NAMs B. NKCs C. PAMPs D. PRRs* Difficulty: Easy

ASM Standard: 14 24. Which of the following is not recognized by toll-like receptors?

A. bacterial DNA B. exotoxins* C. flagellin D. peptidoglycan Difficulty: Easy ASM Standard: 14 25. Which of the following is the initial compartment a pathogen enters after being engulfed by a macrophage?

A. inclusion B. lysosome C. phagolysosome D. phagosome* Difficulty: Easy ASM Standard: N/A 26. Which of the following lists in the correct order the events of acute inflammation after tissue injury?

A. altered function, edema, pTaiEnS , hTeB atA , eNrK ytS heEmLaLER.COM B. erythema, edema, heat, pain, altered function* C. heat, pain, edema, erythema, altered function D. heat, pain, erythema, altered function, edema, Difficulty: Easy ASM Standard: 14 27. Which statement is true?

A. Chronic inflammation is caused only by pathogens.

B. Granulomas are examples of chronic inflammation.* C. Mycobacterium tuberculosis does not cause granulomas.

D. Inflammation occurs only if a viral pathogen is present.

Difficulty: Moderate ASM Standard: 14, 23 28. Which part of the brain controls body temperature?

A. brain stem B. cerebellum C. hypothalamus* D. thalamus

Difficulty: Easy ASM Standard: N/A 29. Which of the following is not a common component of neutrophil extracellular traps?

A. actin filaments* B. chromatin C. gelatinase D. lactoferrin Difficulty: Hard ASM Standard: 14 30. Which of the following statements about LPS is false?

A. Only gram-negative bacteria have LPS. B. LPS can stimulate fever in the host.

C. LPS is an endogenous pyrogen.* D. The lipid A component of LPS is the toxic component.

Difficulty: Hard ASM Standard: 8, 14, 23 True/False 31. In healthy individuals, the upT peEr S reTspBirAaN t oK ryStE raL ctLaE nR d . luC ngOsMare sterile.

Answer: False Difficulty: Easy ASM Standard: 14, 23 32. Propionibacterium acnes can use sebum as a food source.

Answer: True Difficulty: Easy ASM Standard: 23 33. The normal pH of urine is 7.0.

Answer: False Difficulty: Easy ASM Standard: N/A 34. All cytokines are chemokines.

Answer: False Difficulty: Moderate ASM Standard: N/A

35. Serum is the liquid portion of blood without clotting factors.

Answer: True Difficulty: Easy ASM Standard: N/A 36. Diapedesis occurs in arteries.

Answer: False Difficulty: Moderate ASM Standard: N/A 37. Immediately after injury, during acute inflammation, vasodilation occurs to deliver leukocytes to the site.

Answer: False Difficulty: Hard ASM Standard: N/A 38. Phagocytic cells can clear granulomas caused by pathogens such as Mycobacterium tuberculosis.

Answer: False Difficulty: Easy ASM Standard: 14, 23 39. Angioedema is a disease that affects the complement system.

Answer: True Difficulty: Moderate ASM Standard: N/A 40. In the crisis phase, fever is reduced by the hypothalamus stimulating vasoconstriction.

Answer: False Difficulty: Easy ASM Standard: 14 Matching 41. Determine whether each feature listed below in A–E is a physical, chemical, or cellular aspect of the innate immune system. An answer may be used more than once.

A. lymphocyte i. physical B. lysozyme ii. chemical C. eyelashes iii. cellular

D. chemokines E. flushing of urinary tract Answers: A. iii., B. ii., C. i., D. ii., E. i.

Difficulty: Easy ASM Standard: 14 42. Match the antimicrobial peptide (AMP) to the body location where it is produced.

A. bacteriocin i. skin B. cathelicidin ii. throughout the body C. defensins iii. gastrointestinal D. histatins iv. mouth Answers: A. iii., B. i., C. ii., D. iv.

Difficulty: Moderate ASM Standard: 14 43. Match the mediator to its function.

A. bradykinin i. causes edema B. chemokine ii. directs leukocytes to a particular location C. histamine iii. induces coughing, vomit, and/or diarrhea D. interferon iv. inhibits transcription and translation E. leukotriene v. bronchoconstriction Answers: A. i., B. ii., C. v., DT .E ivS ., T EB . iA ii.N KSELLER.COM Difficulty: Moderate ASM Standard: 14 44. Examine the picture below. Match the leukocyte to its name.

A. basophil B. eosinophil C. lymphocyte D. monocyte E. neutrophil Answers: A. i., B. ii., C. v., D. iv., E. iii.

Difficulty: Moderate ASM Standard: 14 Fill in the Blank 45. The is the mechanism used to keep the lower portion of the respiratory tract sterile.

Answer: mucociliary escalator

Difficulty: Easy ASM Standard: 14 46. The of urine inhibits the growth of many microbes and potential pathogens in the urinary tract.

Answer: acidity (or lower pH) Difficulty: Moderate ASM Standard: 14 47.

is the term for the muscular contractions of the digestive tract.

Answer: Peristalsis Difficulty: Easy ASM Standard: N/A

48.

is an acute-phase protein involved in the formation of blood clots that trap pathogens.

Answer: Fibrinogen Difficulty: Moderate ASM Standard: 1

49.

is when the pathogen is coated to allow it to be phagocytosed by a macrophage.

Answer: Opsonization Difficulty: Moderate ASM Standard: 14

50.

are proteins that remain after phagocytosis of a pathogen and are presented on the surface of phagocytic cells to stimulate the adaptive immune response.

Answer: Antigens Difficulty: Easy ASM Standard: 14

51.

is the migration of leukocytes from blood vessels to tissues where pathogens are located.

Answer: Diapedesis Difficulty: Easy ASM Standard: 14

52.

are walled-off pockets of infected tissue surrounded by leukocytes in the lung tissue.

Answer: Granulomas/tubercles Difficulty: Moderate ASM Standard: 14, 23 53. A(n) pyrogen is a molecule from a pathogen that triggers fever.

Answer: exogenous Difficulty: Easy ASM Standard: 14, 23 54.

is a disease characterized by chronic edema due to blockage of the lymphatic system.

Answer: Elephantiasis (lymphatic filariasis) Difficulty: Hard ASM Standard: 14, 23

Short Answer 55. Explain how skin acts as both a barrier and a portal of entry for pathogens.

Sample Answer: Keratin makes the surface of the skin tough and resistant to bacterial enzymes. Skin dryness and acidity help prevent the growth of many microorganisms. Skin cells are constantly replaced, T prEoS viT diB nA gN neKwSbEaL rrL ieE r sR . .

S kCinOiM s a portal of entry in that pathogens can gain entry to the host through any break in the skin and spread from there into deeper tissues.

Difficulty: Moderate ASM Standard: 14, 23 56. How does the microbiome act as a physical and chemical barrier of the innate immune system?

Sample Answer: The microbiome acts as a physical barrier in competing with potential pathogens for colonization sites and nutrients within the host. The microbiome acts as a chemical barrier in that it can produce antimicrobial peptides (e.g., bacteriocins) against potential pathogens.

Difficulty: Moderate ASM Standard: 12, 14, 23 57. Name the chemical mediators of the digestive system that eliminate pathogens in the locations listed below. saliva mucus secreted by esophagus stomach pancreas

liver intestines Sample Answer: saliva mucus secreted by esophagus stomach pancreas liver intestines

lactoperoxidase lysozyme gastric acid pancreatic enzymes bile cryptins

Difficulty: Easy ASM Standard: 14, 23 58. What is lactoferrin and what is its mode of action?

Sample Answer: Lactoferrin is a chemical mediator of the innate immune system. It inhibits the growth of microbes by sequestering iron, which is needed for growth.

Difficulty: Easy ASM Standard: 14 59. How do interferons function?

Sample Answer: Generally, interferons are produced and released by cells infected with viruses. Interferons cause neaT rbEyScT elB lsAtoNrKeS duEcL e L traEnR sc.riCpO tioMn and translation to inhibit further viral replication. Interferons can also stimulate various immune cells involved in viral clearance to attack virus-infected cells.

Difficulty: Moderate ASM Standard: 14 60. What does it mean to say that the function of a chemical, such as a cytokine, is autocrine, paracrine, or endocrine?

Sample Answer: When the same cell secretes and receives the cytokine signal, it is an autocrine signal. When the cytokine signal has an effect on a nearby cell, it is a paracrine signal. When the cytokine is secreted into the circulatory system and travels throughout the body to have an effect on many tissues that may be far from the cell producing the cytokine, then it is an endocrine signal.

Difficulty: Easy ASM Standard: 14 61. How is plasma different from serum and how is it collected?

Sample Answer: Plasma is the liquid portion of blood and its clotting factors, whereas serum is the liquid portion of blood with clotting factors removed. To collect plasma, an anticoagulant (e.g., EDTA) is added to the blood. The blood is then placed in a centrifuge to

spin down the cells. The liquid portion that remains at the top of the tube (the supernatant) will be the plasma.

Difficulty: Moderate ASM Standard: N/A 62. How is the membrane attack complex (MAC) formed?

Sample Answer: The MAC forms from complement proteins C6, C7, C8, and C9 on gramnegative bacteria as a result of the complement cascade.

Difficulty: Easy ASM Standard: 14, 23 63. Categorize each leukocyte in the list below into the appropriate categories in the table. Note that choices can be placed in more than one category.

• Basophil • Eosinophil • Mast cell • Monocyte • Neutrophil Phagocytic

Nonphagocytic

TESTB

Sample Answer: Phagocytic

Eosinophil Monocytes Neutrophils

Granulocyte

Agranulocyte

Produce s Histamin e

KSELLER.C M

Nonphagocytic

Granulocyte

Agranulocyte

Basophils Mast cell

Basophils Eosinophils Mast cell Neutrophils

Monocytes

Produce s Histamin e Basophil Mast cell

Difficulty: Hard ASM Standard: 14 64. (a) Is a natural killer (NK) cell a granulocyte or agranulocyte? (b) How do NK cells recognize cells for destruction?

Sample Answer: (a) NK cells are agranulocytes. (b) NK cells recognize normal major histocompatibility complex (MHC) markers on the surface of healthy cells, and these MHC

markers serve as an inhibitory signal preventing NK cell activation. When MHC markers are diminished or absent, the NK cell interprets this as an abnormality and then kills the cell.

Difficulty: Moderate ASM Standard: 14 65. What are the similarities and differences between macrophages and dendritic cells?

Sample Answer: They are both monocytes, phagocytic, and can persist in tissue for a long time. Macrophages in specific body tissues develop characteristics suited to the particular tissue. Dendritic cells reside in the skin and mucous membranes.

Difficulty: Moderate ASM Standard: 14 66. Give four examples of a PAMP. Sample Answer: Answers can vary and can include: peptidoglycan, flagellin, lipopolysaccharide (LPS), or nucleic acids such as viral DNA or RNA. Difficulty: Easy ASM Standard: 7, 14, 23 67. How does the phagolysosome kill pathogens?

Sample Answer: A decrease in pH occurs, triggering the formation of reactive oxygen species that are lethal to pathogens. Reactive nitrogen compounds with cytotoxic potential can also form.

Difficulty: Easy ASM Standard: 14 68. What causes lymphatic filariasis (elephantiasis)?

Sample Answer: Nematodes in lymphatic vessels cause a buildup of leukocytes in the system, leading to edema.

Difficulty: Easy ASM Standard: 23 69. Explain two benefits fever provides the body during an infection.

Sample Answer: Fever raises the body temperature above the optimal growth condition for pathogens (35–37 °C). Fever can also stimulate iron-sequestering compounds from the liver, thus preventing pathogens that require iron for growth.

Difficulty: Moderate ASM Standard: 14 Brief Essay Essay Question Rubric RATING Failing

Below Average

Competent

Advanced

Criteria for evaluatio n

Answer does Answer fails to not provide an provide argument. examples to Answer contains support an inaccuracies. argument.

Writing is Writing is poor poor and and grammatical contains errors are numerous common. grammatical Answer is mistakes and somewhat misspellings. incoherent.

Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

POINT 0 1 2 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

3

70. You work in a health-care facility and have been asked to verify whether other workers are washing their hands properly. You set up an experiment in which you ask the workers to wash their hands with soap containing triclosan for 2 minutes total. You swab their hands every 30 seconds as they wash, transferring the swab to nutrient agar plates. The next day, you measure the CFUs from each plate. The data are shown below:

TWEoSrTkeBrA1NK ELLW ERo. rkCeO r M 2 S 0 seconds 30 seconds 60 seconds 90 seconds 120 seconds

Worker 3

40 45

39 60

37 37

60

8

20

10

1

9

0

0

2

(a) Prepare a graph of the average CFU over time. (b) Which layer of skin did you swab? (c) How does triclosan act as an antimicrobial agent? (d) Assuming that the workers properly washed their hands and that you properly conducted this work using aseptic technique, explain the results of this experiment.

Student answers will vary but should include components of the following. (a)

(b) The layer of skin that was swabbed was the epidermis. (c) Triclosan is a phenolic compound added to antimicrobial soaps. Triclosan blocks an enzyme in the bacterial fatty acid-biosynthesis pathway. (d) Bacteria are embedded in the outermost layers of skin. As handwashing occurs, we remove layers of skin, thus exposing the new layers of skin and the bacteria on them.

This may explain why we see an initial increase in the number of bacteria, before it decreases.

Difficulty: Hard ASM Standard: 7, 14, 23, 28b, 29a 71. Answer the following questions: (a) What is colitis? (b) Name a bacterial pathogen that causes colitis. (c) Describe the bacterial pathogen (cell shape, cell envelope, oxygen requirements) that causes colitis. (d) How can colitis be treated using the microbiome?

Student answers will vary but should include components of the following. (a) Colitis is an inflammation of the colon or large intestine due to the overgrowth of nonresident bacteria. (b) One bacterium that can cause colitis is Clostridium difficile. (c) It is a rod-shaped, gramnegative, obligate anaerobe. (d) Fecal transplants can be used to re-introduce the normal microbiota back into the colon. Fecal samples are collected and the microbiota bacteria that are shed in feces are isolated and then implanted directly into the colon. The introduced microbiota can then recolonize the intestine and compete against C. difficile.

Difficulty: Moderate ASM Standard: 14, 23 72. Answer the following questions about the classic complement cascade: (a) What aspect of the cascade is innate? (b) What aspect of the cascade is adaptive?

(c) How is the cascade started? (d) What happens to gram-positive and gram-negative bacteria at the end of the cascade? Student answers will vary but should include components of the following. (a) The classic complement cascade itself is considered innate in that it is not specific to any particular pathogen. It is able to target any pathogen. (b) The classic pathway is initiated by an antibody binding to the pathogen. Because antibodies are specific for antigens/pathogens, they are produced by the adaptive immune system. (c) The cascade begins by the antibody binding to the pathogen. This activates C1. C1 then activates C2 and C4. C2 and C4 then activate C3. The hydrolysis of C3 produces C3a and C3b. C3b attaches to the surface of the pathogen and recruits other complement proteins in a cascade (C5 through C9). (d) After the cascade has initiated, gram-positive bacteria will be opsonized and then phagocytosed by macrophages. Gram-negative bacteria will be lysed due to the cascade’s formation of a membrane attack complex (MAC).

Difficulty: Moderate ASM Standard: 14, 23 73. Describe what the innate immune system does after someone stabs their finger with a thorn contaminated with a bacterial pathogen.

Student answers will vary but should include components of the following.

After a break in the skin, vasoconstriction occurs. Mast cells release histamine.

Histamine increases blood flow to the wT ouEnS d TsiB teA .N I nK crS eaEsL edLvEaR sc.uC laO r M permeability allows fluid, complement proteins, and leukocytes to enter the infected tissue. The leukocytes will squeeze through the endothelial cells of capillary vessels in a process known as diapedesis. The leukocytes will then follow the chemokines and complement proteins to the wound site. Once there, leukocytes will release chemicals or will perform phagocytosis to kill the bacterial pathogen.

Difficulty: Moderate ASM Standard: 14, 23

This file is copyright 2017, Rice University. All rights reserved.

Chapter 18: Adaptive Specific Host Defenses * = Correct answer Multiple Choice 1. Which of the following are the primary cells involved in the adaptive immune system?

A. dendritic cells B. eosinophils C. lymphocytes* D. macrophages Difficulty: Easy ASM Standard: 14 2. Antibodies are made up of which of the following?

A. carbohydrates B. glycoproteins* C. lipids D. nucleic acids Difficulty: Easy ASM Standard: 14 3. Which molecular fragment on an antigen molecule do antibodies recognize and respond to?

A. epitope* B. Fab region C. Fc region D. variable region Difficulty: Easy ASM Standard: N/A 4. A molecule that is too small to be antigen is known as a(n) typically associated with .

A. adjuvant; allergies B. adjuvant; viruses C. hapten; allergies* D. hapten; viruses Difficulty: Moderate ASM Standard: 7

. These molecules are

5. Which class of antibody is the most abundant in serum?

A. IgA B. IgE

C. IgG* D. IgM Difficulty: Moderate ASM Standard: N/A 6. Which class of antibody provides protection against parasitic pathogens?

A. IgA B. IgE* C. IgG D. IgM Difficulty: Moderate ASM Standard: N/A 7. On an antibody, where do phagocytic cells bind during antibody-mediated opsonization?

A. disulfide bond B. Fab region C. Fc region* D. variable region Difficulty: Easy ASM Standard: 14 8. Which MHC class is mostly likely found on macrophages?

A. class I B. class II* C. both class I and class II D. neither class I nor class II Difficulty: Easy ASM Standard: N/A 9. Which cells do not express MHCs? A. erythrocytes* B. hepatocytes C. intestinal epithelial cells D. leukocytes Difficulty: Hard ASM Standard: N/A 10. Which process describes the cross-linking of pathogens by antibodies so the kidney and

spleen can filter them from the blood?

A. agglutination* B. complementation

C. neutralization D. transformation Difficulty: Moderate ASM Standard: 14 12. Which complement cascade begins with antibodies binding to a pathogen?

A. alternative only B. classical only* C. lectin only D. all three pathways (alternative, classic, and lectin) Difficulty: Hard ASM Standard: 14 13. T cells mature in which location?

A. bone marrow B. testes C. thymus* D. thyroid Difficulty: Easy ASM Standard: 14 14. A cell that has been infected with an intracellular pathogen will be targeted for destruction by which type of lymphocyte?

A. B cell B. CD4+ regulatory T cell C. CD8+ cytotoxic T cell* D. plasma cell Difficulty: Moderate ASM Standard: 14, 23 15. Helper T cells are activated by which of the following?

A. MHC class I B. MHC class II* C. either MHC class I or class II D. both MHC class I and class II presenting the same antigen Difficulty: Easy ASM Standard: 14

16. Cytotoxic T cells are activated by which of the following?

A. MHC class I* B. MHC class II

C. either MHC class I or class II D. both MHC class I and class II presenting the same antigen Difficulty: Easy ASM Standard: 14 17. Which bacterial pathogen species can produce superantigen to trigger toxic shock syndrome?

A. Escherichia B. Listeria C. Staphylococcus* D. Yersinia Difficulty: Moderate ASM Standard: 7, 14, 23 18. Which of the following is the primary function of B cells?

A. to activate T cells B. to phagocytose pathogens C. to produce antibodies* D. to target and destroy cells infected with an intracellular pathogen Difficulty: Easy ASM Standard: 14 19. After antigen presentation and activation, antibodies are produced and secreted by which cells?

A. CD4 T cells B. memory T cells C. naïve B cells D. plasma cells* Difficulty: Moderate ASM Standard: 14 20. Which of the following is the term for activated B cells producing different antibody monomers with the same epitope specificity?

A. class switching* B. clonal expansion C. cross presentation D. VDJ arrangement Difficulty: Moderate ASM Standard: 14

21. Which of the following statements is true?

A. In the secondary response to an antigen, higher levels of IgM will be detected in an individual’s serum.

B. In the secondary response to an antigen, lower levels of IgM will be detected in an individual’s serum.

C. The lag period following secondary exposure to an antigen is longer than the lag period following primary exposure.

D. The lag period following secondary exposure to an antigen is shorter than the lag period following primary exposure.* Difficulty: Hard ASM Standard: 14 22. B cells mature in which location?

A. bone marrow* B. bulbourethral gland C. thymus D. thyroid Difficulty: Easy ASM Standard: 14 23. Which protein released by CD8+ cytotoxic T cells generates pores in target cells?

A. granzyme B. hyaluronidase C. perforin* D. phospholipase Difficulty: Easy ASM Standard: 14 24. TCRs recognize epitopes made of which type of molecule?

A. carbohydrates B. lipopolysaccharide C. nucleic acid D. protein* Difficulty: Easy ASM Standard: 14 25. Who is credited for the discovery of the concept of a vaccine through his work with cowpox and smallpox?

A. Alexander Fleming B. Edward Jenner*

C. Joseph Lister D. Louis Pasteur

Difficulty: Easy ASM Standard: 14, 23 26. Who is credited for the discovery of the vaccine against cholera?

A. Alexander Fleming B. Edward Jenner C. Joseph Lister D. Louis Pasteur* Difficulty: Moderate ASM Standard: 14 23 27. Why was James Phipps (the boy who was purposely infected with cowpox) protected against smallpox?

A. Cowpox and smallpox are the same virus.

B. Cowpox is antigenically similar to smallpox.* C. He was also inoculated with B cells specific for smallpox when he was infected with cowpox.

D. Individuals need to be given a vaccine against only one type of virus to gain protection against all viruses.

Difficulty: Easy ASM Standard: 14, 23 28. Vaccines are an example of which class of immunity?

A. active artificially acquired* B. active naturally acquired C. passive artificially acquired D. passive naturally acquired Difficulty: Moderate ASM Standard: 14, 23 29. Which vaccine would be most protective against diphtheria?

A. conjugate B. inactivated C. live attenuated D. toxoid* Difficulty: Hard ASM Standard: 14, 23 30. Which vaccine would be most protective against the capsule-forming pathogen Neisseria meningitidis?

A. conjugate*

B. inactivated

C. live attenuated D. toxoid Difficulty: Hard ASM Standard: 14, 23 True/False 31. The secondary immune response to the same antigen will result in less antibody production.

Answer: False Difficulty: Easy ASM Standard: 7, 14 32. An antigen can only have one epitope site.

Answer: False Difficulty: Easy ASM Standard: 7, 14 33. It is possible for two different antibodies to recognize the same antigen.

Answer: True Difficulty: Moderate ASM Standard: 7, 14 34. Antibodies are ineffective against toxins.

Answer: False Difficulty: Moderate ASM Standard: 7, 14 35. All nucleated cells can present antigens to trigger the adaptive immune response.

Answer: True Difficulty: Moderate ASM Standard: 14 36. CD8+ cytotoxic T cells can be activated by either MHC class I or cytokines from TH1 cells.

Answer: True Difficulty: Easy

ASM Standard: 7, 14 37. TCRs are secreted by T cells to target free-floating antigens.

Answer: False

Difficulty: Easy ASM Standard: 7, 14 38. After exposure to a protein antigen, antibodies will be immediately detectable in an individual’s serum.

Answer: False Difficulty: Moderate ASM Standard: 7, 14 39. Subunit vaccines do not provide protection against antigenic variation.

Answer: True Difficulty: Easy ASM Standard: 7, 14, 15 40. IgM immunoglobulin can cross the blood-placental barrier and is important for natural passive immunity.

Answer: False Difficulty: Hard ASM Standard: 7, 14 Matching 41. Match each subgroup to its distinguishing feature.

A. CD4+ T cell i. destroys cells infected with intracellular pathogens B. CD8+ T cell ii. orchestrates humoral and cellular immunity C. helper T cell iii. produces antibodies D. plasma cell iv. involved in peripheral tolerance and prevents autoimmune diseases.

Answers: A. iii., B. iv., C. i., D. ii.

Difficulty: Moderate ASM Standard: 14 42. Match the type of T cell to its proper description.

A. memory i. responsible for the secondary response to a particular antigen ii. stimulates B-cell activation B. TH1 iii. stimulates immunity to chronic mucocutaneous infections C. TH2 iv. stimulates cytotoxic CD8+ T cells D. TH17 Answers: A. i., B. iv., C. ii., D. iii.

Difficulty: Moderate ASM Standard: 14 43. Match the example to the type of immunity being acquired.

A. being ill and recovering from an infection B. blood transfusion from someone previously infected with a pathogen C. breastfeeding D. receiving a vaccine Answers: A. iii, B. ii, C. iv, D. i

i. artificial active ii. artificial passive iii. natural active iv. natural passive

Difficulty: Easy ASM Standard: 14 44. Match the class of vaccine to its proper description.

A. conjugate i. killed or otherwise nonfunctional pathogen B. inactivated ii. inactivated toxin C. live attenuated iii. capsule polysaccharide bound to a protein D. subunit iv. weakened pathogen E. toxoid v. immunogenic antigen of the pathogen Answers: A. iii, B. i, C. iv, D. v, E. ii Difficulty: Easy ASM Standard: 7, 14, 23 Fill in the Blank 45.

involves the bindinTgEoS f aTnB tiA boNdK ieS sE toLeL pitoRp. esCoOnMthe surface of viruses to inhibit attachment to host cells.

Answer: Neutralization Difficulty: Easy ASM Standard: 14

46. Antibodies consist of four protein chains held together by Answer: disulfide

bonds.

Difficulty: Moderate ASM Standard: 14 47.

is the region that an antibody recognizes and binds to on an antigen.

Answer: Epitope Difficulty: Easy ASM Standard: 14

48. The is a collection of molecules expressed on the surface of cells and that present antigens to activate T cells.

Answer: major histocompatibility complex (MHC) Difficulty: Easy

ASM Standard: 7, 14 49.

is when antigens normally presented with MHC II are presented on MHC I for CD8+ cytotoxic T cells.

Answer: Cross-presentation Difficulty: Moderate ASM Standard: 7, 14

50. Granzymes are proteases made by CD8+ cytotoxic T cells that enter pores generated by to induce apoptosis.

Answer: perforin Difficulty: Moderate ASM Standard: 14 51.

are toxins that can induce a cytokine storm and can lead to toxic shock syndrome.

Answer: Superantigens Difficulty: Easy ASM Standard: N/A

52.

is a reduction in disease prevalence brought about when relatively few individuals in a population are susceptiblT e E t oSaT nB inAfeNcK t ioSuE sL agLeE ntR . .COM Answer: Herd immunity Difficulty: Moderate ASM Standard: 14, 31

53. In 10th century China, individuals were deliberately inoculated with infectious material from smallpox pustules. This type of inoculation is known as .

Answer: variolation Difficulty: Hard ASM Standard: 14, 31 54.

is the process of making a pathogen less virulent so it can be used as a vaccine.

Answer: Attenuation Difficulty: Moderate ASM Standard: 7, 14

Short Answer

55. What is the difference between an antigen and a PAMP? Sample Answer: An antigen is unique to a specific pathogen, whereas a PAMP (pathogen- associated molecular pattern) can be found on numerous pathogens.

Difficulty: Easy ASM Standard: 7, 14 56. Briefly discuss the two primary characteristics of the adaptive immune system.

Sample Answer: Specificity and memory are the two primary characteristics of the adaptive immune system. Specificity refers to the immune system’s ability to target specific pathogens and not target host cells (i.e., recognizes and does not target self). Memory refers to its ability to quickly respond to pathogens to which it has previously been exposed.

Difficulty: Easy ASM Standard: 14 57. Examine the figure shown below of a secreted glycoprotein.

(a) What does this figure depict? (b) Identify each of the following on the diagram: a. Fab region b. Fc region c. disulfide bond location d. antigen-binding site e. complement protein-binding site Sample Answer: (a) an antibody

(b)

Difficulty: Easy ASM Standard: 14 58. Name the five functions of antibodies.

Sample Answer: Neutralization of pathogens, opsonization for phagocytosis, agglutination, complement activation, and antibody-dependent cell-mediated cytotoxicity Difficulty: Moderate ASM Standard: 14 59. What is opsonization?

Sample Answer: Opsonization is the process of coating a pathogen with a chemical substance (typically an antibody) that allows phagocytic cells to recognize, engulf, and destroy the pathogen more easily.

Difficulty: Easy ASM Standard: 14 60. What are the similarities and differences between T-cell receptors (TCRs) and antibodies?

Sample Answer: Both have a variable region and a constant region. The variable region provides the antigen-binding site. TCRs are produced by T cells and antibodies are produced by plasma cells. TCRs have two protein chains, whereas antibodies have four protein chains.

TCRs are membrane-bound to the T cell, whereas antibodies are secreted.

Difficulty: Moderate ASM Standard: 14 61. One component of the adaptive immune system is the concept of tolerance. Immune cells should not recognize host (or self) antigens. What mechanisms are available to remove lymphocytes with receptors that do recognize self antigens?

Sample Answer: Negative selection of self-reacting lymphocytes can involve elimination by apoptosis and editing or modification of the receptors so they are no longer self-reactive.

Difficulty: Easy ASM Standard: 14 62. How is it possible for the immune system to produce receptors (i.e., TCRs, BCRs, antibodies) against a wide variety of antigens, especially when the immune system has not yet encountered them?

Sample Answer: The VDJ arrangement allows the immune system to produce receptors against a wide variety of antigens. The variable regions of receptors can recognize different types of epitopes of antigens. The genes that code for the variable regions of

receptors are called variable (V), diversity (D), and joining (J) segments. In T-cell receptors, genetic rearrangement brings together one V segment and one J segment to code for the variable region of the α chain. Similarly, genetic rearrangement brings one V segment, one D segment, and one J segment together to code for the variable region of the β chain. In B-cell

receptors and secreted immunoglobulins (antibodies), the variable region of the light chain is made up of V and J segments. Genetic rearrangement of V, J, and D segments generate the heavy chain.

Difficulty: Hard ASM Standard: 14 63. How is a cytokine storm triggered?

Sample Answer: A cytokine storm is triggered by a superantigen. A macrophage presents the superantigen via MHC class II. The superantigen is not recognized by the TCR of the T cell. However, the superantigen can still bind the MHC II and TCR molecules. This nonspecific, uncontrolled activation of the T cell results in an excessive release of cytokines that activate other T cells and cause excessive inflammation.

Difficulty: Moderate ASM Standard: 7, 14, 23 64. In terms of lymphocyte development, what is meant by clonal expansion?

Sample Answer: A lymphocyte with a specific receptor will become active after binding to a presented antigen. That lymphocyte will undergo mitosis to produce more lymphocytes that all share the same antigen specificity.

Difficulty: Easy ASM Standard: 14 65. On the axes below, sketch the relative concentrations of IgM and IgG in serum after a primary and secondary response to the same antigen.

Sample Answer: See graph below.

Difficulty: Moderate ASM Standard: 14 66. How was the concept of a vaccine discovered and who discovered it?

Sample Answer: Exudates from a cowpox pustule on the hand of a dairymaid (Sarah Nelmes) were inserted into scratches on the arm of an 8-year-old boy (James Phipps) by Edward Jenner. Later, when the boy was purposely infected with smallpox, he did not contract the disease.

Difficulty: Easy ASM Standard: 10, 14, 23 67. Against what type of pathogen should a conjugate vaccine be used?

Sample Answer: Conjugate vaccines should be used against pathogens that can produce capsules.

Difficulty: Hard ASM Standard: 7, 8, 14 68. Explain one advantage and one disadvantage to using live attenuated vaccines.

Sample Answer: Advantages include that the pathogen in the vaccine can trigger both cellular and humoral immunity. A live attenuated vaccine also can provide long-lasting immunity. Disadvantages include the challenge of long-term storage, the potential for a patient to acquire the disease (or a milder form of it), and the risk of the attenuated pathogen reverting to full virulence.

Difficulty: Moderate ASM Standard: 14 69. Explain one advantage and one disadvantage to using subunit vaccines.

Sample Answer: An advantage would be that there is a lower risk of side effects because the entire pathogen is not being used in the vaccine. The disadvantages include that there is limited longevity, multiple doses of the vaccine are needed, and there is no protection against antigenic variation.

Difficulty: Moderate ASM Standard: 14 Brief Essay Essay Question Rubric Failin Below RATING g Average Criteria Answer does Answer fails to not provide an for provide evaluatio argument. examples to n Answer contains support an inaccuracies. argument.

Writing is Writing is poor poor and and contains grammatical numerous errors are grammatical common. mistakes and Answer is misspellings. somewhat incoherent.

Competen t Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

ER.COM

TESTBANKSELL 0 1 2 POINT VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Advance d Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

3

70. Discuss the differences between T and B cells and their receptors.

Answer: Student answers will vary but should include the following. The maturation of T cells occurs in the thymus. T cells function in both the innate and adaptive immune responses. They are responsible for destruction of cells infected with intracellular pathogens. The T-cell receptor (TCR) has a variable region and a constant region. The structure of the TCR is smaller and less complex than the immunoglobulin molecules. It only has two peptide chains. T cells are activated by antigen-presenting cells. TCRs can only interact with antigenic epitopes that are presented within the antigen-binding cleft of MHC class I or MHC class II. TCR can only recognize protein epitopes. B cells mature in the bone marrow and produce antibodies. Antibodies are involved in the body’s defense against pathogens and toxins in the extracellular environment. Antibodies and B-cell receptors (BCRs) have two identical heavy chains and two identical light chains connected by disulfide bonds.

Antibodies are secreted, whereas BCRs remain attached to the B cell (the constant region of the receptor spans the B-cell membrane). B cells can be activated either with or without

T cells. They can interact with epitopes on free antigens or with epitopes displayed on the surface of intact pathogens. Antibodies and BCRs can recognize different molecular classes, not just proteins.

Difficulty: Moderate ASM Standard: 14 71. Describe how an intracellular pathogen infecting a hepatocyte is targeted and eliminated via the adaptive immune system. Be sure to discuss all the lymphocytes involved.

Answer: Student answers will vary but should include the following. After the intracellular pathogen invades the hepatocyte (nonleukocyte), an antigen will be presented on the surface of the cell via MHC class I. CD8+ cytotoxic T cells recognize the foreign epitope and begin to produce cytokines. The cytokines (specifically from TH1 cells) will target clonal expansion of that T cell, with all of them recognizing the same antigen. The proliferation of these cytotoxic T cells is also stimulated by cytokines secreted from TH1 cells, which are also activated by the same antigen. Once activated, cytotoxic T cells serve as the effector cells of cellular immunity, recognizing and killing cells infected with intracellular pathogens through a mechanism similar to that of natural killer cells. TCRs of mature cytotoxic T cells bind to the epitope and release perforin, a protein that creates pores in the target cell.

Granzymes are proteases that enter the pores and induce apoptosis.

Difficulty: Hard ASM Standard: 14, 23 72. Compare and contrast T-dependent and T-independent activation of B cells.

Answer: Student answers will vary but should include the following. Antigens can be classified as T-independent and T-dependent. T-independent antigens have repeating epitopes that can induce B-ceT llE reScT ogBnA itiNoK n S anEdLaL ctE ivRa. t ioCnOwMithout involvement from T cells. These antigens include polysaccharides, lipopolysaccharides, and other nonprotein antigens. A second signal, such as interaction of Toll-like receptors with PAMPs, is also required for activation of the B cell. Once activated, the B cell proliferates and differentiates into antibody-secreting plasma cells. In T-dependent activation of B cells, the B cell recognizes and internalizes an antigen. T-dependent antigens are typically protein antigens. The antigen is presented to a helper T cell that is specific to the same antigen. The helper T cell interacts with the antigen presented by the B cell, which activates the T cell and stimulates the release of cytokines that then activate the B cell. Activation of the B cell triggers proliferation and differentiation into antibody-secreting plasma cells.

Difficulty: Hard ASM Standard: 8, 14 This file copyright 2017, Rice University. All rights reserved.

Chapter 19: Diseases of the Immune System * = Correct answer Multiple Choice 1. An allergy is an example of which of the following?

A. a type I hypersensitivity* B. a type II hypersensitivity C. a type III hypersensitivity D. a type IV hypersensitivity Difficulty: Easy ASM Standard: N/A 2. If someone were accidentally given blood of the wrong type, which of the following is likely to occur?

A. an autoimmune disorder B. anaphylaxis C. a hemolytic transfusion reaction* D. a type I hypersensitivity Difficulty: Easy ASM Standard: N/A 3. Granules in mast cells are released to the extracellular environment through which of the following processes?

A. an Arthus reaction B. anaphylaxis C. degranulation* D. the hemolytic response Difficulty: Easy ASM Standard: N/A 4. The term immune tolerance means which of the following?

A. becoming sensitized with repeated exposures B. developing autoimmune disease after repeated exposures C. having an unusually weak immune response to common antigens D. the ability to recognize self and prevent immune attack on one’s own cell* Difficulty: Easy ASM Standard: N/A 5. Desensitization treatment is also known by which of the following terms?

A. allografting

B. autoimmunity C. hyposensitization therapy* D. serum treatment Difficulty: Easy ASM Standard: N/A 6. A granuloma is which of the following infections?

A. acute systemic infection B. chronic local infection* C. chronic systemic infection D. disseminated infection Difficulty: Easy ASM Standard: N/A 7. Rh factors are which of the following?

A. a type of T cell B. important examples of immune cells C. important RBC antigens* D. unimportant in blood transfusions Difficulty: Easy ASM Standard: N/A 8. Serum sickness is which of the following?

A. systemic type I hypersensitivity B. systemic type II hypersensitivity C. systemic type III hypersensitivity* D. systemic type IV hypersensitivity Difficulty: Easy ASM Standard: N/A 9. Which of the following types of transplants has the lowest risk of rejection?

A. allograft B. autograft* C. isograft D. xenograft Difficulty: Moderate ASM Standard: N/A 10. Which of the following types of infection is most common in an individual with X-linked agammaglobulinemia?

A. infections associated with autoimmune inflammations

B. infections caused by extracellular, pyogenic pathogens* C. infections caused by intracellular pathogens D. viral infections Difficulty: Moderate ASM Standard: N/A 11. In some cases, transplanted tissue (such as bone marrow) can produce cytotoxic T cells that attack the host cells of the recipient. Which of the following describes such an attack?

A. a hemolytic transfusion reaction B. an autograft reaction C. graft versus host disease* D. transplant rejection Difficulty: Moderate ASM Standard: N/A 12. Which of the following is an advantage of using vaccines instead of antibacterial sera, such as the diphtheria antitoxin?

A. Antitoxins are less likely to cause type I hypersensitivity.

B. Antitoxins are more likely to cause the disease they are intended to treat.

C. Vaccines are less likely to cause systemic type III hypersensitivity.* D. Vaccines are less likely to cause type II hypersensitivity.

Difficulty: Moderate ASM Standard: N/A 13. Which of the following is an example of a CD4 Th1-mediated reaction?

A. anaphylactic reaction B. chronic asthma C. delayed type hypersensitivity* D. transplant rejection Difficulty: Moderate ASM Standard: N/A 14. Contact dermatitis is an example of which of the following?

A. CD4 TH1-mediated reaction* B. CD4 TH2-mediated reaction C. type of serum sickness D. underdeveloped immune response Difficulty: Moderate ASM Standard: N/A

15. When serum sickness occurs, the immune complexes are removed by which of the following?

A. antigenic cells B. phagocytic cells* C. the major histocompatibility complex D. transplanted tissues Difficulty: Moderate ASM Standard: N/A 16.

Which of the following describes what happens when someone has a reaction to poison ivy?

A. The antigen circulates in the blood, causing a systemic response, such as serum sickness.

B. The antigen remains on the surface of cells, where it is picked up by macrophages.

C. The individual’s cells absorb the antigen and are then targeted by CTLs, which induce apoptosis.* D. The individual’s cells resist the antigen, which is cleared from the cell surfaces by antibodies.

Difficulty: Moderate ASM Standard: N/A

17. Tissue damage caused by delayed type hypersensitivities is largely the result of which of the following?

A. activated macrophages* B. antibodies C. direct attack by sensitized memory TH1 cells D. reactions involving CD4 TH2 cells Difficulty: Moderate ASM Standard: N/A 18. An individual’s first exposure to an antigen capable of eliciting a type I hypersensitivity initially causes which of the following responses?

A. a response by TH1 cells B. a response by TH2 cells* C. cross-linking of IgE D. the release of leukotrienes Difficulty: Moderate ASM Standard: N/A 19. The regions of IgE antibodies capable of binding to specific mast cell receptors are called which of the following?

A. activated regions B. fragment crystallizable regions* C. histamine regions

D. tumor necrosis factor binding sites Difficulty: Moderate ASM Standard: N/A 20. During degranulation, which of the following occurs?

A. Antigen-binding sites attach to granules in cells.

B. Antigens are released into the plasma.

C. Cytotoxic T cells are released.

D. Mast cells release granules containing histamine and other preformed components.* Difficulty: Moderate ASM Standard: N/A 21. Degranulation results in the release of which of the following?

A. bradykinin only B. bradykinin, histamine, and serotonin only C. bradykinin, histamine, serotonin, leukotrienes, prostaglandins, and cytokines* D. prostaglandins, leukotrienes, cytokines, and IgE Difficulty: Moderate ASM Standard: N/A

SE 22. When people take antihistamiTnE esS , tThB eyAaNreKm osL t L likEeR ly.t C ryO inM g to treat which of the following symptoms?

A. itching, headache, and reduced tear production B. pruritus, sneezing, watery eyes, and runny nose* C. redness and swelling associated with an infection D. vomiting and nausea Difficulty: Moderate ASM Standard: N/A 23. Histamine and serotonin can stimulate which of the following?

A. constipation B. decreased vascular permeability C. vasoconstriction D. vomiting* Difficulty: Moderate ASM Standard: N/A 24. Which of the following are the symptoms of a localized type I hypersensitivity reaction?

A. asthma only B. asthma, hay fever rhinitis, and hives* C. constriction of respiratory passages

D. vasodilation and hypotension Difficulty: Moderate ASM Standard: N/A 25. Which of the following symptoms distinguish anaphylaxis from milder type I hypersensitivity reactions?

A. hypertension, blockage of airways, and risk of death B. hypotension, blockage of airways, shock, and risk of death* C. massive tissue damage from cytotoxic reactions with risk of death D. pruritus and rhinitis Difficulty: Moderate ASM Standard: N/A 26. The A and B antigens on the surface of blood cells are which of the following?

A. carbohydrates* B. glycoproteins C. lipids D. proteins Difficulty: Moderate ASM Standard: N/A 27. Severe bronchiole constriction during an allergic reaction can potentially cause which of the following?

A. cyanosis* B. pruritus C. vasoconstriction D. vasodilation Difficulty: Difficult ASM Standard: N/A 28. Which of the following is one possible adaptive reason for type I hypersensitivities?

A. They may be required for “test runs” of the immune response so that it is prepared to fight pathogens when needed.

B. They may have evolved as a response to helminth infections.* C. They may have evolved to increase the risk of adaptive allergic reactions.

D. They may have so much overlap with other hypersensitivities that adaptive benefits for those other hypersensitivities promote type I hypersensitivities.

Difficulty: Difficult ASM Standard: N/A

29. According to current naming conventions, blood-group antigens are named using which of the following?

A. a systematic approach involving the assignment of a number and classification within a particular group (i.e., a collection, group, or series)* B. a systematic approach involving the history of the discovery of the group C. the name of the person responsible for producing antibodies that target the blood-group antigens D. the name of the person who identified the blood-group antigens Difficulty: Difficult ASM Standard: N/A 30. During a hemolytic transfusion reaction, which of the following occurs?

A. Antibodies from the transfused cells attack the recipient’s cells and cause them to lyse.

B. Antigens on the transfused cells are recognized by IgA and IgE and are destroyed.

C. Antigens on the transfused cells are recognized by IgG and IgM and are destroyed.* D. Antigens on the transfused cells spontaneously trigger lysis when exposed to the recipient’s blood.

Difficulty: Difficult ASM Standard: N/A 31. Individuals who have type AB blood have a genotype with which of the following?

A. one A allele and one B alleTleE*STBANKSELLER.COM B. one AB allele and one O allele C. the dominant AB allele D. two recessive AB alleles Difficulty: Moderate ASM Standard: N/A 32. Individuals with type O blood have which of the following?

A. modified A or B glycoprotein antigens on the surface of their blood cells that are unable to trigger an immune response B. neither A nor B glycoprotein antigens on the surface of their blood cells* C. no glycoprotein antigens on the surface of their blood cells D. the O glycoprotein antigen only on the surface of their blood cells Difficulty: Moderate ASM Standard: N/A 33. The antibodies that respond to blood-group antigens are which of the following?

A. antibodies produced from a combination of sources and called isohemagglutinins B. IgA antibodies called isohemagglutinins C. IgE antibodies called isohemagglutinins D. IgM antibodies called isohemagglutinins*

Difficulty: Difficult ASM Standard: N/A 34. Which of the following happens last during the series of inflammatory events triggered by the accumulation of immune complexes in a type III hypersensitivity reaction?

A. C3a and C5a are produced.

B. Complement activation occurs.

C. IgG binds to antibody receptors.

D. Neutrophil and macrophage recruitment occurs.* Difficulty: Difficult ASM Standard: N/A 35. Hypersensitivity pneumonitis can be either a type III or a type IV hypersensitivity depending upon which of the following?

A. whether an environmental cause is present over the short or long term B. whether an environmental or occupational cause is present C. whether immune complexes develop and mediate the response* D. whether there is a different response with subsequent exposures Difficulty: Difficult ASM Standard: N/A 36. Which of the following hypothetical statements would not be predicted by the hygiene hypothesis?

A. Children in smaller families are more likely to have autoimmune diseases.

B. Children who attend daycare have a lower risk of allergies than those who stay home until they reach school age.

C. Exposure to cleaning chemicals results in greater allergy risk.* D. Living on a farm is associated with reduced risk of hay fever.

Difficulty: Difficult ASM Standard: 23 37. Which of the following describes why it is possible that type I hypersensitivities result from an adaptation against helminth infection?

A. Helminths are unusual parasites because they are targeted by IgE and most parasites are not.* B. Helminths can trigger a type I hypersensitivity, so individuals who have these hypersensitivities are also less susceptible to helminth infections.

C. Repeated exposure to helminths reduces the effectiveness of IgE in responding to other infections.

D. Repeated type I hypersensitivity reactions reduce the risk of helminth infection.

Difficulty: Difficult

ASM Standard: N/A True/False 38. Mechanisms are in place so that hemolytic transfusion reactions no longer occur.

Answer: False Difficulty: Easy ASM Standard: N/A 39. Serum sickness is another term for systemic type III hypersensitivity.

Answer: True Difficulty: Easy ASM Standard: N/A 40. Hypersensitivity pneumonitis can be a type III or type IV hypersensitivity, depending on whether immune complexes accumulate.

Answer: True Difficulty: Moderate ASM Standard: N/A 41. IgE only responds to cell-bouT ndES anTtiB geAnN s.KSELLER.COM Answer: False Difficulty: Moderate ASM Standard: N/A 42. Clonal proliferation in a type I hypersensitivity reaction results from the release of cytokines from TH2 cells.

Answer: True Difficulty: Moderate ASM Standard: N/A 43. Systemic anaphylaxis is a type I hypersensitivity caused by the release of cytokines by TH1 cells.

Answer: False Difficulty: Moderate ASM Standard: N/A 44. IgE molecules have three Fab sites to which allergens can bind.

Answer: False

Difficulty: N/A ASM Standard: Difficult 45. Opsonization of red blood cells occurs after phagocytosis.

Answer: False Difficulty: NA ASM Standard: Difficult 46. The production of IgE-secreting plasma cells can be triggered by interleukin-4.

Answer: True Difficulty: Difficult ASM Standard: N/A 47. Angioedema is caused by vasoconstriction following release of chemical mediators during a type I hypersensitivity reaction.

Answer: False Difficulty: Difficult ASM Standard: N/A Matching 48. Match each chemical mediator with the best description of its effects.

A. heparin i. causes increased mucus and tear formation, increased vascular permeability, and smooth-muscle contraction B. histamine ii. stimulates bradykinin production C. serotonin iii. causes inflammation and cytokine production D. TNF-α iv. causes vasodilation, smooth-muscle contraction, and increased vascular permeability Answers: A. ii, B. i, C. iv, D. iii Difficulty: Moderate ASM Standard: N/A 49. Match each type of transplant with its best definition.

A. allograft i. transplanting tissue from an animal to a human B. autograft ii. transplanting tissue from one individual (not an identical twin) to another of the same species C. isograft iii. transplanting tissue from an individual back to that individual D. xenograft iv. transplanting tissue from one identical twin to another Answers: A. ii B. iii, C. iv, D. i Difficulty: Easy ASM Standard: N/A

50. Match each type of hypersensitivity with its best definition.

A. type I hypersensitivity i. involves IgG, IgM, and IgA B. type II hypersensitivity ii. involves the reaction of IgE with soluble antigen; mastcell degranulation occurs C. type III hypersensitivity iii. involves the reaction of IgG and IgM antibodies with cellular antigens, resulting in cell damage D. type IV hypersensitivity iv. mediated by T cells Answers: A. ii, B. iii, C. i, D. iv Difficulty: Moderate ASM Standard: N/A 51. Match each autoimmune disease with its best description.

A. Addison disease i. causes damage to the adrenal gland; possible symptoms include weakness, hypotension, fatigue, and kidney failure B. multiple sclerosis ii. causes damage to the pancreas; possible symptoms include hyperglycemia, weight loss, excessive urination, and fatigue C. psoriasis iii. causes damage to the myelin sheaths of nerve cells; possible symptoms include muscle weakness, numbness, and problems with memory suEsSTBiA v.NeK pS idE erL mLaE l cRe. ll C t uO rnMover is excessive; itchy and sore D. systemic lupus erythematoT skin patches develop E. type I diabetes mellitus v. associated with the production of autoantibodies against cytoplasmic and nuclear molecules, and with tissue damage and inflammation Answers: A. i, B. iii, C. iv, D. v, E. ii Difficulty: Moderate ASM Standard: N/A 52. Match the primary immunodeficiency with the best description.

A. chronic granulomatous disease i. because bacteria within phagolysosomes are not effectively killed, infections and granulomas develop B. selective IgA deficiency ii. results in lack of IgA, causing increased risk of infections in the lungs and gastrointestinal tract C. severe combined immunodeficiency iii. caused by deficient immune responses (both disease cell mediated and humoral), resulting in susceptibility to severe infections D. X-linked agammaglobulinemia iv. because B cells do not fully mature and differentiate, recurrent, generally pyogenic, infections occur Answers: A. i, B. ii, C. iii, D. iv

Difficulty: Moderate ASM Standard: N/A 53. Match the type IV hypersensitivity with its effector type.

A. chronic asthma i. Cytotoxic T-lymphocyte–mediated reactions occur.

B. contact dermatitis ii. Eosinophils release cytokines and chemicals that promote inflammation.

C. tissue transplant reaction iii. An inflammatory response is caused by macrophages, which also damage tissue.

D. tuberculin reaction iv. can be caused by either an inflammatory response caused by macrophages or by cytotoxic T-lymphocyte– mediated reactions Answers: A. ii, B. iv, C. i, D. iii Difficulty: Difficult ASM Standard: N/A Fill in the Blank 54. In , a systemic allergic reaction causes symptoms such as hypotension, shock, nausea, vomiting, hives, and swelling of the throat.

Answer: anaphylaxis Difficulty: Easy ASM Standard: N/A 55. When a self-antigen causes a type II hypersensitivity reaction, the reaction can be described as a(n) disorder.

Answer: autoimmune Difficulty: Easy ASM Standard: N/A 56. When a prick puncture skin test or intradermal test is performed to test for allergies, a positive response is indicated by a(n) reaction.

Answer: wheal-flare Difficulty: Moderate ASM Standard: N/A 57. Although they may be measured during diagnosis, measurement of serum _ not sufficient to confirm allergic disease.

Answer: IgE Difficulty: Moderate ASM Standard: N/A

levels is

58. A common treatment for insect venom allergies is Answer: desensitization

therapy.

Difficulty: Moderate ASM Standard: N/A 59. When individuals are treated using allergy shots (i.e., injections of allergen), IgG antibodies are produced that can act as .

Answer: blocking antibodies Difficulty: Moderate ASM Standard: N/A 60. The first treatment for life-threatening anaphylaxis is an injection of Answer: epinephrine

.

Difficulty: Moderate ASM Standard: N/A 61. Rh− mothers who carry Rh+ fetuses and who then become pregnant with another Rh + fetus are given injections of during the 28th week of pregnancy and after delivery.

Answer: RhoGAM [or human Rho(D) immune globulin] Difficulty: Moderate ASM Standard: N/A 62. TSH-receptor antibody (thyroid-stimulating immunoglobulin) is produced by individuals with .

Answer: Graves disease Difficulty: Difficult ASM Standard: N/A 63. The production of antibodies that target acetylcholine receptors causes muscle weakness that can be severe and life threatening.

Answer: myasthenia gravis Difficulty: Difficult ASM Standard: N/A Short Answer 64. Which type of hypersensitivity is systemic lupus erythematosus?

Sample Answer: SLE is a type III hypersensitivity.

Difficulty: Easy

, resulting in

ASM Standard: N/A 65. Why would someone use a Mantoux test?

Sample Answer: The Mantoux test is a screening test for tuberculosis.

Difficulty: Easy ASM Standard: N/A 66. What triggers allergy-induced asthma?

Sample Answer: Allergy-induced asthma occurs when someone is exposed to inhaled allergens.

Difficulty: Easy ASM Standard: N/A 67. Which hypothesis suggests that normal exposure to antigens is important in developing a healthy immune response and reducing the risk of allergies?

Sample Answer: The hygiene hypothesis suggests that normal antigen exposure reduces the risk of developing immune disease.

Difficulty: Easy ASM Standard: N/A 68. What do immunohematologisT tsEsS tuT dB y?ANKSELLER.COM Sample Answer: Immunohematologists study the relationship between the immune response, the blood, and blood-forming tissues.

Difficulty: Moderate ASM Standard: N/A 69. How does the ABO blood group system show codominance?

Sample Answer: Individuals who have one A allele and one B allele fully express both alleles, which is an example of codominance.

Difficulty: Moderate ASM Standard: N/A 70. What types of symptoms occur if someone is accidentally given a transfusion with the wrong blood type?

Sample Answer: A transfusion with an incompatible blood type causes hypotension, pruritus, fever, chills, urticaria, dyspnea, and hemoglobinuria. If the reaction is sufficiently severe, blood pressure can lower drastically, shock can occur, and the patient may die.

Difficulty: Moderate ASM Standard: N/A

71. Hospitals have systems in place to prevent incompatible blood transfusions. What are these systems called?

Sample Answer: Systems to prevent incompatible blood transfusions are called hemovigilance systems.

Difficulty: Moderate ASM Standard: N/A 72. Which type of reaction occurs when someone is exposed to poison ivy?

Sample Answer: Poison ivy causes contact dermatitis. This is a type IV hypersensitivity reaction.

Difficulty: Moderate ASM Standard: N/A 73. What type(s) of hypersensitivity cause cheese handler’s disease?

Sample Answer: Cheese handler’s disease is a type of hypersensitivity pneumonitis. It can be caused by type III or type IV hypersensitivities.

Difficulty: Moderate ASM Standard: N/A 74. Which type of cells are involved in type IV hypersensitivities?

Sample Answer: T cells are inTvE olSvT edBiA nN tyKpS eE I VLL hyEpR er. seCnO siM t ivities.

Difficulty: Moderate ASM Standard: N/A 75. Which types of treatments are common for mild type I hypersensitivities?

Sample Answer: A variety of medications are available to treat type I hypersensitivities, including over-the-counter treatments. These include antihistamines, antileukotrienes, antiprostaglandins, and anti-inflammatory medications.

Difficulty: Moderate ASM Standard: N/A 76. The detection of which antibodies can help in the diagnosis of celiac disease?

Sample Answer: Diagnosis of celiac disease can involve the detection of IgA antibodies to gluten. Testing also involves the detection of autoantibodies to endomysium, among other components.

Difficulty: Difficult ASM Standard: N/A 77. Why does SLE affect so many different organ systems?

Sample Answer: Autoantibodies are produced, especially antinuclear antibodies. They can target many types of tissues, which can lead to a wide range of possible symptoms.

Difficulty: Difficult ASM Standard: N/A 78. Why is a positive ANA test insufficient to make a lupus diagnosis?

Sample Answer: Although elevated ANA is found in greater than 95% of patients with SLE, elevated ANA does not necessarily mean that an individual has SLE. Instead, at least four of 11 symptoms must be identified, in addition to the detection of autoantibodies, to make the diagnosis.

Difficulty: Difficult ASM Standard: N/A Brief Essay Essay Question Rubric Failin Below Competen RATING g Average t Criteria Answer does Answer fails to Answer provides for not provide an provide an argument evaluatio argument. examples to with one or two n Answer contains support an examples that inaccuracies. argument.

Lsupport TESTBANKSE ER.COMit. Writing is Writing is Writing is poor poor and and grammatical acceptable for the college level contains L errors are but may contain numerous common. one or two grammatical Answer is grammatical mistakes and somewhat mistakes or misspellings. incoherent. misspellings.

POINT 0 1 2 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Advance d Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

3

79. Explain how an individual’s first and subsequent exposures to an allergen differ by describing how the immune system responds to exposure.

Answer: Student answers will vary but should include components of the following. There is a strong Th2-cell response after the first exposure to an allergen. These cells produce IL-4 and IL-13, activating B cells. Clonal proliferation occurs, followed by differentiation of the clones that differentiate into plasma cells. There is a switch from IgM to IgE antibody production. The IgE antibodies bind to mast-cell receptors throughout the body. At this point, the individual is sensitized and capable of an allergic reaction to the allergen. On subsequent exposure to an allergen, the IgE antibodies already present bind to the allergen and this results in the formation of cross-links between IgE molecules on mast cells. This causes degranulation, releasing histamine and other chemicals that cause the allergic response.

Difficulty: Moderate ASM Standard: N/A 80. How is an antinuclear antibody test helpful in the diagnosis of systemic lupus erythematosus?

Why is this test insufficient for the diagnosis?

Answer: Student answers will vary but should include components of the following.

Individuals with lupus have type III hypersensitivity reactions that involve the production of autoantibodies that target the nucleus and cytoplasmic proteins. In most cases, the individual’s antibodies attack the nucleus, and 95% of patients with SLE have antinuclear antibodies (ANAs). Although a positive ANA test is helpful in diagnosis, patients must have at least four of 11 specified symptoms, as well as a positive autoantibody test.

Difficulty: Moderate ASM Standard: N/A 81. Why does IgA deficiency result in increased risk of lung and gastrointestinal infections? In your answer, include a discussion of the normal role of IgA. Answer: Student answers will vary but should include components of the following. IgA is important in the gastrointestinal and respiratory tracts because it is found in secretions (such as mucus). It helps stop pathogens from penetrating epithelial tissues, helping those tissues form effective barriers. Without sufficient IgA in the secretions, pathogens can more easily attach to the linings of the gastrointestinal and respiratory tracts. This increases the risk that they can cause infections.

Difficulty: Difficult ASM Standard: N/A 82. Explain how normal exposures to microbes relate to the “hygiene hypothesis.” Provide examples of evidence. Make sure to explain how people are exposed to microbes in everyday life and through the normal human microbiota.

Answer: Student answers will vary but should include components of the following. The hygiene hypothesis suggests that normal exposure to microbes throughout life reduces the risk of immune disorders. The textbook describes the comparison of immune disorders in less developed countries and industrialized countries, and suggests that the reduced exposure to microbes and antigens in the latter is associated with greater incidence of immune disorders.

Additionally, families with more children have lower rates of hay fever than those with fewer children. This relationship may reflect rates of infection or differences in antigen exposure that may correlate with average family size. The role of the normal microbiota in this process is not explicitly discussed in this chapter, so students need to use their prior knowledge to speculate about its effects and may have answers such as the following. Humans have a normal microbiota that interacts with potential pathogens. For example, the normal microbiota may outcompete other microbes and can produce chemicals (such as bacteriocins) that inhibit their growth. Exposure to the normal microbiota, and its effects on exposure to other microbes, also could affect immune system function.

Difficulty: Difficult ASM Standard: 7 This file is copyright 2017, Rice University. All rights reserved.

TESTBANKSELLER.COM OpenStax Microbiology Test Bank ChCahpateprt2e0r: 2L0a:b oLraatbooryraAton arlyysAisnoafly thseisIm ofmtuhneeIRmesmpounnsee Response

* = Correct answer Multiple Choice 1. Most antigens have how many epitopes?

A. none B. one C. two D. more than two* Difficulty: Easy ASM Standard: N/A 2.

Which best describes monoclonal antibodies?

A. They are produced in living animals only.

B. They are produced in tissue cultures, using B cells extracted from living animals.* C. They are rarely used, so polyclonal antibodies are preferred.

D. They can be produced in either living animals or tissue cultures.

Difficulty: Easy ASM Standard: N/A 3. A hybridoma is which of the following?

A. a cancerous cell B. a fusion of a B cell and a T cell C. a fusion of a normal B cell and a myeloma cell* D. a hybrid of two cancerous cells Difficulty: Easy ASM Standard: N/A 4. Which is the correct term for a visible antigen-antibody complex?

A. epitope B. heavy chain complex C. hybridoma D. precipitin* Difficulty: Easy ASM Standard: N/A 5. Monoclonal antibodies bind to which of the following?

PageA1.3a9soifngle epitope* B. a single hybridoma

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C. multiple epitopes

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D. variable numbers of epitopes Difficulty: Easy ASM Standard: N/A 6. Double immunodiffusion is also known as which of the following?

A. flocculation assay B. Ouchterlony assay* C. precipitin ring test D. radial immunodiffusion assay Difficulty: Moderate ASM Standard: N/A 7. Which technique is used to help view tissues, using microscopy?

A. electrophoresis B. immunostaining* C. lateral flow assays D. western blotting Difficulty: Easy ASM Standard: 32 8. Which technique could be useTdEtoST raB piA dlNyKdS iaE gnLoLseEsRtr.eC p O t hM roat or mycoplas m a pneumonia by labeling bacteria with fluorescent monoclonal antibodies?

A. brightfield microscopy and ELISA techniques B. fluorescence microscopy and direct fluorescent antibody techniques* C. immunohistochemistry and immunostaining techniques in varying combinations D. western blotting with chromogens or fluorogens Difficulty: Easy ASM Standard: 32 9. Which of the following describes antiserum?

A. a type of vaccine produced in the laboratory B. antibodies obtained by exposing blood to an antigen in the lab C. monoclonal antibodies obtained from the blood of an animal injected with an antigen D. whole serum containing antibodies obtained from an animal exposed to an antigen* Difficulty: Moderate ASM Standard: N/A Page 141 of

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10. When does an antibody test result in a false positive?

A. An individual tests as though she does not have the antigen even though she does.

B. An individual tests as though she has the antigen even though she does not.* C. Antibodies bind to the antigen too strongly, causing an error in the testing protocol.

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D. Variations in antibodies cause them to fail to bind to an antigen that is present.

Difficulty: Moderate ASM Standard: N/A 11. Test sensitivity is defined as which of the following?

A. the probability that an individual will have a false-positive test result B. the probability that an individual with an infection will test positive* C. the probability that an individual with an infection will test negative D. the probability that a test will detect multiple antigens simultaneously Difficulty: Moderate ASM Standard: N/A 12. Which of the following most commonly results from exposure to a single antigen?

A. A single antibody is produced that can respond to multiple antigens.

B. A single antibody is produced that is specific to that antigen.

C. Multiple antibodies are produced because antigens usually have multiple epitopes.

D. Multiple antibodies are produced to respond to a single epitope.* Difficulty: Moderate ASM Standard: N/A 13. When a particular test rarely pTrE odSuT ceBsAfaNlsKeSnE egLaL tiE veR s,.itChOaM s which of the following?

A. high sensitivity* B. high specificity C. low sensitivity D. low utility Difficulty: Moderate ASM Standard: N/A 14. Compared with the production of polyclonal antibodies, the production of monoclonal antibodies is which of the following?

A. completed without hybridomas B. easier and faster C. less expensive D. more expensive* Difficulty: Moderate ASM Standard: N/A Page 143 of

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15. Which type of antibody is preferable for western blot tests and why?

A. monoclonal antibodies, because they are more sensitive and produce a clearer signal B. monoclonal antibodies, because they are more specific and less expensive

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C. polyclonal antibodies, because they are able to bind to specific epitopes even though they are more expensive D. polyclonal antibodies, because they can bind to multiple epitopes, generally produce a stronger signal, and are less expensive* Difficulty: Moderate ASM Standard: N/A 16. What problem makes it difficult to use humanized monoclonal antibody cocktails to treat pathogens?

A. It is less expensive to use monoclonal antibody cocktails rather than purified monoclonal antibodies.

B. It is too technically difficult to separate out the different monoclonal antibodies.

C. Monoclonal antibodies are not sufficiently strong to target pathogens without being used in high concentrations.

D. Monoclonal antibodies are so specific that they may not target all serovars of a pathogen.* Difficulty: Moderate ASM Standard: N/A 17. Which technique has been proposed to make less-expensive monoclonal antibodies?

A. They can be humanized so that they are easier to use in humans.

B. They can be produced in complex mixtures rather than in purified versions.

C. They can be produced in gT enEeS t icTaB llA yN enKgS inE eeLreLdEpRla.nC tsOaM s plantibodies.* D. They can be produced using RT-PCR techniques.

Difficulty: Moderate ASM Standard: N/A 18. ZMapp is an experimental drug that appeared to be a promising treatment during the 2014– 2015 Ebola outbreak. Which is a major limitation to using this type of medication?

A. ZMapp consisted of polyclonal antibodies, so it was not sufficiently specific to work effectively.

B. ZMapp consisted of three monoclonal antibodies to treat multiple Ebola strains, making it prohibitively expensive even if available in sufficient quantities.* C. ZMapp was produced by genetically engineered plants and the virus used to introduce it into plants could cause a problematic immune response in humans.

D. ZMapp was produced in tissue cultures, which is a slow and laborious process that can’t be used to make medications in bulk quantities.

Difficulty: Moderate ASM Standard: N/A Page 145 of

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19. Which of the following correctly describes the effect of a particular factor of a precipitin reaction on the amount of precipitin formed?

A. A 1:1 ratio of antibody to antigen yields the maximum amount of precipitate.

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B. Monoclonal antibodies generally bind more and, therefore, produce more precipitate than polyclonal antibodies.

C. The greater the affinity of the antibody for the antigen, the greater the amount of precipitate.* D. The lack of a lattice increases precipitation compared with the presence of a lattice.

Difficulty: Moderate ASM Standard: N/A 20. The precipitin ring test is used to do which of the following?

A. qualitatively identify the presence of a particular antibody in an antiserum B. quantify the relative amount of a specific antibody present in an antiserum only* C. quantify the relative amount of a specific antigen present in an antiserum only D. quantify the relative amounts of a specific antibody and the antigen to which it binds present in an antiserum Difficulty: Moderate ASM Standard: N/A 21. Which is the formal definition of an antibody titer?

A. It is a fractional expression of the highest dilution of serially diluted antibody that results in visible precipitation.

B. It is a whole-number expression of the reciprocal of the highest dilution of serially diluted antibody that results in visibleTpErS ecTipBitA atN ioKnS .*ELLER.COM C. It represents the highest dilution in a serial dilution test that shows a positive result, rounded to a whole number.

D. It represents the total number of dilutions needed to get a positive result.

Difficulty: Moderate ASM Standard: N/A 22. What is a major difference between the precipitin reaction test and flocculation assays?

A. Only flocculation involves a visible lattice of antibody and antigen.

B. Only flocculation involves the observation of lipids foaming in a positive result.* C. Only flocculation involves the observation of precipitate in a positive result.

D. Only flocculation involves the use of a serial dilution technique.

Difficulty: Moderate ASM Standard: N/A 23. A plaque reduction assay is used to quantify which of the following?

A. antibodies produced by a patient during a bacterial infection B. antibodies produced by a patient during a viral infection* Page 147 of

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C. antigens produced by a bacterium during a bacterial infection D. antigens produced by a virus during viral infection

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Difficulty: Moderate ASM Standard: N/A 24. Which test would be most helpful in further examining abnormal patterns of protein abundance previously identified using a PAGE assay?

A. a neutralization assay B. a precipitin ring test C. an indirect ELISA test D. immunoelectrophoresis* Difficulty: Moderate ASM Standard: N/A 25. Glycerol is used during the precipitin ring test to do which of the following?

A. form a seal to prevent evaporation of the antiserum and antigen B. fully dissolve the antiserum and antigen into a homogenous solution C. prevent the antiserum and antigen solutions from mixing at all D. prevent the antiserum and antigen solutions from mixing except at their interface* Difficulty: Difficult ASM Standard: N/A 26. Why is cross-matching needed before a blood transfusion?

A. Cross-matching is a final cThE ecSkTbB efA orNeKtrS anEsL fuLsiEoR n. thC atOiM nvolves mixing the patient’s blood with a small sample of the blood to be transfused as an additional check.* B. Cross-matching is the first attempt to make sure the blood is compatible before more thorough testing.

C. Cross-matching refers to checking the needed blood type and the blood type of the patient before ordering blood for transfusion.

D. Cross-matching would be needed for planned surgery but is a quality control measure not necessary in an emergency situation.

Difficulty: Difficult ASM Standard: N/A 27. What causes jaundice and how would the presence of maternal antibodies affect newborn jaundice?

A. Jaundice is caused by excessive breakdown of blood cells; the maternal antibodies activate complement and begin this process.* B. Jaundice is caused by excessive quantities of red blood cells, so having maternal antibodies to the newborn’s cells would reduce the risk of jaundice.

C. Jaundice is caused by the breakdown of blood cells; maternal antibodies inhibit complement production and the newborn’s blood cells, therefore, are vulnerable to Page 149 of

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destruction.

D. Jaundice is caused by the breakdown of blood cells; maternal antibodies inhibit this process and reduce the risk of jaundice.

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Difficulty: Difficult ASM Standard: N/A 28. Why is a direct hemagglutination assay helpful in detecting the influenza virus?

A. A human cell infected by the influenza virus produces a protein called neuraminidase on its surface that can cross-link red blood cells.

B. The influenza virus has a protein called hemagglutinin on its capsid that can cross-link red blood cells.* C. The influenza virus has a protein called neuraminidase on its surface that can cross-link red blood cells.

D. The influenza virus has multiple proteins on its capsids (hemagglutinin and neuraminidase) that can cross-link red blood cells.

Difficulty: Difficult ASM Standard: N/A 29. Which test can be used to determine titers of antiviral antibodies in a patient’s serum?

A. the Coombs’ test B. the cross-matching test C. the direct hemagglutination assay D. the viral hemagglutination inhibition assay* Difficulty: Difficult ASM Standard: N/A 30. Which of the following is not used as a mechanism to detect the presence of antigen in a sample in EIA protocols?

A. When the antigen binds to the antibody, antibody with a bound enzyme will cleave a colorless fluorogen that fluoresces.

B. When the antigen binds to the antibody, antibody with bound alkaline phosphatase will cleave a colorless substrate, releasing a colored product.

C. When the antigen binds to the antibody, antibody with bound horseradish peroxidase will cleave a colorless substrate, leaving a colored product.

D. When the antigen binds to the antibody, the antigen-antibody complex will precipitate, forming an easily observable line at the interface.* Difficulty: Difficult ASM Standard: 32 31. If you performed a direct ELISA but failed to add the chromogen, which of the following would happen?

A. The antibody would be less visible in the wells if present.

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B. The antibody would be unable to bind to the antigen.

C. The antibody would detach from the enzyme.

D. The antibody would not be visible even if present.*

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Difficulty: Difficult ASM Standard: N/A 32. Why would a spectrophotometer be helpful in interpreting the results of a sandwich ELISA? A. It would allow for visualization of the antibody-antigen complex.

B. It would allow one to use a single test to differentiate previous exposure from acute infection.

C. It would be faster, although less sensitive.

D. It would provide more information because the absorbance measured would be proportional to the amount of antigen in the wells.* Difficulty: Difficult ASM Standard: N/A True/False 33. The production time for monoclonal antibodies is much faster than the production time for polyclonal antibodies.

Answer: False Difficulty: Easy ASM Standard: N/A 34. Lateral flow tests are inexpensive and easy to perform, which has enabled the development of a wide range of diagnostic tests for home use based upon this technology.

Answer: True Difficulty: Easy ASM Standard: N/A 35. In direct ELISA testing, a patient’s sample is added to a well with immobilized antibodies already present in its base.

Answer: False Difficulty: Moderate ASM Standard: N/A 36. A positive indirect ELISA test is sufficient to make an HIV diagnosis.

Answer: False Difficulty: Moderate ASM Page 153 of

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Standard: N/A 37. CD8 cells can be detected in host tissue by using immunostaining.

Answer: True

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Difficulty: Moderate ASM Standard: N/A 38. A typical home pregnancy test is a lateral flow test that detects human chorionic gonadotrophin in urine.

Answer: True Difficulty: Moderate ASM Standard: N/A 39. Seroconversion occurs relatively quickly once someone is exposed to HIV, so detection of antibodies against HIV is recommended using ELISA within a week after exposure.

Answer: False Difficulty: Difficult ASM Standard: N/A 40. One test involved in diagnosing systemic lupus erythematosus involves detecting antinuclear antibodies by using indirect fluorescent antibody detection.

Answer: True Difficulty: Difficult ASM Standard: N/A Matching 41. Match each type of assay with an important application of its use.

A. direct agglutination i. diagnosis of influenza B. direct hemagglutination ii. testing patients for rheumatoid factor C. indirect agglutination iii. pretransfusion blood testing D. indirect hemagglutination iv. serotyping bacteria Answers: A. iv., B. i., C. ii., D. iii.

Difficulty: Moderate ASM Standard: N/A 42. Match each type of immunoblot or enzyme immunoassay with the best description.

A. enzyme-linked immunosorbent assay i. Proteins are transferred to a membrane and then identified using enzyme-antibody conjugates.

B. immunoblots ii. Specific molecules are stained using Page 155 of

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C. immunochromatographic assays

enzyme-antibody conjugates. iii. Target molecules are quantified using enzyme-antibody conjugates that bind to them.

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D. immunostaining

iv. Varied techniques that use fixed antibody to capture flowing, labeled antigen-antibody complexes.

Answers: A. iii., B. i., C. iv., D. ii.

Difficulty: Moderate ASM Standard: N/A 43. Match each type of assay with a specific procedure that exemplifies it.

A. enzyme-linked immunosorbent assay i. direct or indirect ELISA B. immunoblots ii. immunohistochemistry C. immunochromatographic assays iii. sandwich ELISA D. immunostaining iv. western blotting Answers: A. i., B. iv., C. iii., D. ii.

Difficulty: Easy ASM Standard: N/A 44. Match each fluorescent antibody technique with its best description.

A. direct fluorescent antibody i. used to detect antibodies for a particular disease from a patient’s serum sample BC. flow cytometry ii. used to label pathogens from patients’ samples with fluorogen-antibody conjugates for detection CD. fluorescence-activated cTeE ll S soTrB t eA r NK iiiS .E usL edLE t oRs. epCaO raM t e cells into subpopulations via a device that adds charges to fluid droplets DB. indirect fluorescent antibody iv. used to count cells that have been labeled with fluorogen-antibody conjugate markers, using a laser Answers: A. ii., B. iv., C. iii. D. i.

Difficulty: Difficult ASM Standard: N/A Fill in the Blank 45. PAGE is the abbreviation for .

Answer: polyacrylamide gel electrophoresis Difficulty: Easy ASM Standard: N/A 46. Often used to identify a molecule of interest, a(n) to fluoresce.

Answer: fluorochrome

is a molecule that can be made

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Difficulty: Easy ASM Standard: N/A

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47. The product of the fusion of a cancerous B cell (a myeloma cell) with a normal B cell is called a(n) .

Answer: hybridoma Difficulty: Moderate ASM Standard: N/A 48. Manufactured antibodies designed to bind to a single epitope are called Answer: monoclonal antibodies

.

Difficulty: Moderate ASM Standard: N/A 49. The test used to identify proteins after protein gel electrophoresis is called the Answer: western blot

_ test.

Difficulty: Moderate ASM Standard: N/A 50. After , the antibody levels in a patient’s serum are high enough for detection, enabling diagnosis.

Answer: seroconversion Difficulty: Moderate ASM Standard: N/A 51. Lattice formation is detected using the Answer: precipitin

ring test.

Difficulty: Moderate ASM Standard: N/A 52. Flocculants are formed by Answer: insoluble

antigens in a suspension.

Difficulty: Moderate ASM Standard: 53. Plates that allow multiple reactions to be run side by side in a small area, such as those used in ELISA testing, are called plates.

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Answer: microtiter Difficulty: Moderate ASM Standard: N/A

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54. Because antibodies can cause bacterial serovars to clump, characteristic can be used to identify the serovars.

Answer: agglutination

assays based on this

Difficulty: Difficult ASM Standard: N/A 55. Herceptin is an example of a(n) that can be used to treat cancer.

Answer: monoclonal antibody (or humanized monoclonal antibody) Difficulty: Difficult ASM Standard: N/A Short Answer 56. Why is a chromogen used in ELISA testing?

Sample Answer: A colorless chromogen reacts with the enzymes in the reaction so positive samples can be recognized by their color.

Difficulty: Easy ASM Standard: N/A 57. If you do a neutralization assay and find there are antibodies to a virus, does that mean the LLhyER patient has a current infectionTwEiS t hTthBaA tN viK ruSs?EW o r.wChOyMnot?

Sample Answer: No, the patient may have had a previous exposure. It is necessary to do a second assay to monitor changes in antibody level to determine whether an infection is current.

Difficulty: Easy ASM Standard: N/A 58. What is flocculation?

Sample Answer: Flocculation is the foaming that occurs during the flocculation assay from the reaction of antibodies and antigens.

Difficulty: Easy ASM Standard: N/A 59. What does ELISA stand for?

Sample Answer: ELISA is the acronym for enzyme-linked immunosorbent assay.

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ASM Standard: N/A 60. Why is a chromogenic substrate sometimes used in western blotting?

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Sample Answer: An antibody can be bound to an enzyme that can react with the chromogenic substrate. When an enzyme reacts with this substrate, a visible color is produced. The color provides an indication that the enzyme, and, therefore, the antibody, is present.

Difficulty: Easy ASM Standard: N/A 61. How do direct and indirect ELISA differ?

Sample Answer: In direct ELISA, immobilized antigens in microtiter plates are exposed to an antibody-enzyme conjugate that binds if the antigens are present. A chromogen enables bound antibody-antigen complexes to be identified, allowing the researcher to know whether the antigen is present. In indirect ELISA, known antigen is attached and then a sample from a patient is added so that any antibodies in the sample will bind to the antigen.

A secondary antibody with a conjugated enzyme is added to identify whether antibodies were present in the patient sample. The figure below illustrates the process.

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Difficulty: Moderate ASM Standard: N/A 62. What is a disadvantage of using monoclonal antibodies to detect bacterial serovars?

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Sample Answer: Monoclonal antibodies are so specific that they may not detect all serovars of a bacterium.

Difficulty: Moderate ASM Standard: N/A 63. You want to test whether a patient has a current viral infection. You conduct a first neutralization assay and then conduct a second assay after 2 weeks. You find that a onefourth dilution is the greatest dilution that produces a 50% plaque reduction for the first assay. For the second assay, you find that a 1/32 dilution is the greatest dilution that produces a 50% plaque reduction. What were the patient’s titers for the first and second tests? Does the patient have a current infection?

Sample Answer: The patient’s titers were four for the first test and 32 for the second test, so the patient does have a current infection.

Difficulty: Moderate ASM Standard: N/A 64. How is IEP useful in diagnosing multiple myeloma?

Sample Answer: IEP (immunoelectrophoresis) is useful in diagnosing multiple myeloma because patients with this type of cancer cannot produce normal antibodies; instead, they produce abnormal antibodies that show up in a distinctive pattern on an electrophoresis gel.

Difficulty: Moderate ASM Standard: N/A 65. How does southwestern blotting differ from western blotting?

Sample Answer: Western blotting involves the identification of proteins blotted from a polyacrylamide gel subjected to electrophoresis to separate the proteins. In southwestern blotting, SDS-PAGE is used and then the blotted proteins are exposed to a labeled DNA probe. This enables identification of DNA-protein interactions. Southern blotting is used to examine DNA, whereas western blotting is used to examine proteins. Thus, southwestern blotting gets its name because it looks for interactions between DNA and proteins.

Difficulty: Moderate ASM Standard: N/A 66. What is the purpose of the complement fixation test?

Sample Answer: It is used to detect the presence of a pathogen by detecting the presence of antibodies directed toward some component of the pathogen.

Difficulty: Moderate ASM Standard: N/A 67. Why are red blood cells especially useful for evaluating complement-mediated cytolysis and for the complement-fixation test?

Sample Answer: When red blood cells lyse, they release hemoglobin and cause the solution to become pink to red. (Complement can cause cell lysis. In the complement-fixation test, a sample of patient serum is used. Pathogen antigen is added. If the patient has been exposed to the pathogen and has antibodies, the antibodies will bind to the antigen and the available complement will be fixed. The addition of red blood cells and antibodies to red blood cells will not cause a color change, because there is no complement left to lyse the red blood cells. If antibodies to the pathogen are not present, then the presence of complement allows lysis of the red blood cells and the solution will become pink from the release of hemoglobin.)

Difficulty: Difficult ASM Standard: N/A 68. During the complement fixation test, why is it necessary to heat patients’ samples?

Sample Answer: Heating destroys complement that is already present, allowing the researcher to control the amount of complement.

Difficulty: Difficult ASM Standard: N/A 69. Give an example of a clinical test that uses flocculation.

Sample Answer: There are multiple possible answers, but the book mentions the VDRL test for syphilis.

Difficulty: Difficult ASM Standard: N/A 70. How would your results be affected if you did an indirect ELISA test and did not sufficiently rinse the patient serum from the plates before adding the secondary antibody-enzyme complex? Why would this occur?

Sample Answer: This could cause false-positive results due to cross-reactivity with other components of the serum.

Difficulty: Difficult ASM Standard: N/A Brief Essay Essay Question Rubric RATING Failing

Below Average

Competent

Advanced

Criteria for evaluatio n

Answer does Answer fails to not provide an provide argument. examples to Answer contains support an inaccuracies. argument.

Writing is Writing is poor poor and and contains grammatical numerous errors are grammatical common. mistakes and Answer is misspellings. somewhat incoherent.

Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

POINT 0 1 2 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Answer clearly provides an argument with two or more excellent examples that support it. Student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

3

71. Explain the process used to produce polyclonal antibodies.

Answer: Student answers will vary but should include components of the stages shown in Figure 20.3. These include injection of an antigen into an animal (which is usually done twice), the activation of B cells in response to antigen exposure, the production of polyclonal antibodies by plasma B cells, and the extraction of antiserum from the animal to obtain the antibodies. In many cases, the antiserum must be purified to remove antibodies other than those of interest.

Difficulty: Moderate ASM Standard: N/A 72. Why would it be a problem to inject monoclonal antibodies from mouse cells directly into humans? How is this problem addressed?

Answer: Student answers will vary but should include the following. Humans would develop an immune response to the mouse antibodies and neutralize them, so the antibodies have to be “humanized.” This is accomplished by using genetic engineering to produce a gene for a human antibody with only the antigen-binding site from the mouse antibody. The antigen- binding site is the critical component to recognize and bind to the desired antigen.

Difficulty: Moderate ASM Standard: N/A 73. Explain the trade-offs involved in evaluating sensitivity and specificity in choosing a test for the detection of HIV. In your answer, reference the types of HIV tests currently used.

Answer: Student answers will vary but should include the following. Students may choose to discuss the use of the western blot test (immunoblotting) as an example of a test currently

used for HIV detection. Other possible tests mentioned in the chapter for HIV detection include agglutination, ELISA, nucleic acid antigen, and RT-PCR tests. Students should address the potential harm from someone being told they are infected when they are not (as is more likely with a test that lacks specificity) or of being told they are not infected when they are (as is more likely with a test that lacks sensitivity). Ideally, students should discuss the way initial testing (such as indirect ELISA) must be confirmed with additional testing (such as RT-PCR or immunoblotting).

Difficulty: Difficult ASM Standard: 31a 74. New testing approaches will make it easier for people to test for diseases such as HIV at home, as with a home pregnancy test. Discuss the pros and cons of the increased use of direct-to-consumer sales of tests for such serious illnesses. Include an overview of some of the types of tests that are facilitating this trend.

Answer: Student answers will vary but should include the following. The types of tests that are easy to use at home include lateral flow tests (used in home pregnancy tests) and lab-on- a-chip technology. Students may discuss the convenience, reduced expense, and increased testing access associated with over-the-counter testing. However, they should also discuss the ethical concerns such as receiving a devastating diagnosis without the presence of a health- care professional for immediate advice and support.

Difficulty: Difficult ASM Standard: 31

KlSl rEigLhLtsErR This file is copyright 2017, Rice T UE niS veTrsBitAyN . A es. erCvO edM.

Chapter 21: Skin and Eye Infections * = Correct answer Multiple Choice 1. The top part of the skin, which is exposed to the environment, is called: A. adipose tissue B. the dermis C. the epidermis* D. the hypodermis Difficulty: Easy ASM Standard: N/A 2. Which bacterial genus is commonly associated with acne?

A. Candida B. Clostridium C. Propionibacterium* D. Salmonella Difficulty: Easy ASM Standard: 23 3. Papillomas are also known as: A. comedones B. pustules C. urticaria D. warts* Difficulty: Easy ASM Standard: N/A 4. Tinea corporis is also known as: A. conjunctivitis B. ringworm* C. viral keratitis D. warts Difficulty: Easy ASM Standard: 23 5. The conjunctiva is the: A. boundary of the lens of the eye B. layer of mucus covering the eye C. layer of tissue surrounding the entire eye

D. mucous membranes of the eye* Difficulty: Easy ASM Standard: N/A 6. A deep lesion that develops from multiple boils is called a: A. carbuncle* B. furuncle C. macule D. pustule Difficulty: Easy ASM Standard: 23 7. Systemic symptoms are most likely to develop with a: A. carbuncle* B. comedo C. cyst D. pustule Difficulty: Easy ASM Standard: 23 8. Which of the following descrT ibE esSiT mB peAtiNgK o?SELLER.COM A. a highly contagious infection caused by Staphylococcus aureus and Streptococcus pyogenes that causes vesicles, pustules, and bullae* B. a mild and self-limiting viral infection that can be caused by a wide range of infectious agents C. a noncontagious rash (not caused by an infectious agent) that spreads rapidly across the skin D. a systemic fungal infection caused by Candida spp. and other species that is difficult to treat Difficulty: Easy ASM Standard: 23 9. Which of the following is true of the normal skin microbiota?

A. It does not change over time.

B. It is always identical in all parts of the body.

C. It varies between moist and dry areas only, but is consistent in areas of similar moisture content.

D. It varies depending on microenvironment and is an important part of the nonspecific immune system.* Difficulty: Moderate ASM Standard: 23, 24

10. One reason that the skin is inhospitable to microbes is that: A. It is moist and hypersaline, which prevents growth by most species of microbes.

B. It is relatively lacking in salt and is hypotonic to bacteria.

C. It is relatively moist and this inhibits their growth.

D. The normal microbiota outcompetes other microbes and inhibits their growth.* Difficulty: Moderate ASM Standard: 23, 24 11. An important difference between sebaceous glands and sweat glands is that: A. Sebaceous glands are not typically associated with hair follicles, whereas sweat glands typically are associated with hair follicles.

B. Sebaceous glands are tubular and sweat glands are coiled.

C. Sweat glands are found fully within the dermis, whereas sebaceous glands are found fully within the epidermis.

D. Sweat glands produce a watery fluid, whereas sebaceous glands produce lipid -rich sebum.* Difficulty: Moderate ASM Standard: N/A 12. How does sebum affect microbial growth on the skin?

A. It dries out the skin, reducTinEgSthTeBaA biNliK tySoEf L mLicEroRb. esCtO oM grow where it is present.

B. It may aid growth by providing nutrients but also has components that inhibit microbial growth.* C. It only aids microbial growth, providing a source of nutrition without generally having any harmful effects on microbes.

D. It repels microbes and they cannot grow where it is present, making it an important part of the nonspecific immune response.

Difficulty: Moderate ASM Standard: 23, 24 13. Sebum-rich areas of the skin, such as the back, generally harbor which of the following?

A. highly mixed microbial populations, including a range of bacteria and fungi B. less diverse microbial populations than other regions* C. more diverse microbial populations than other regions D. varied microbial diversity that is difficult to predict compared with other skin regions Difficulty: Moderate ASM Standard: 23, 24 14. The normal skin microbiota primarily includes: A. bacteria and fungi only B. bacteria, fungi, and viruses*

C. bacteria only D. fungi only Difficulty: Moderate ASM Standard: 23, 24 15. The vitreous humor: A. has a microbiota similar to that of the conjunctiva B. has a rich bacterial microbiota, but no fungi C. has a variable and diverse microbial population D. has no normal microbiota* Difficulty: Moderate ASM Standard: 23, 24 16. What is one way you can distinguish between a Streptococcus and a Staphylococcus infection?

A. Staphylococcus bacteria are gram negative, whereas Streptococcus bacteria are gram positive.

B. Streptococcus bacteria are catalase positive, whereas Staphylococcus bacteria are catalase negative.

C. Streptococcus bacteria grow on mannitol salt agar, whereas Staphylococcus bacteria do not.

D. Under the microscope, StaTpEhS ylT ocBoA ccNuK sS baEcL t eL riaEfRo. rmCO clM usters and Streptococcus bacteria do not.* Difficulty: Moderate ASM Standard: 23 17. Individuals who wear contact lenses are at particular risk of developing which of the following?

A. acute bacterial conjunctivitis B. blepharitis C. herpes simplex virus 1 lesions D. keratitis* Difficulty: Moderate ASM Standard: 23 18. Neonatal conjunctivitis is commonly treated with which of the following?

A. chloramphenicol B. erythromycin* C. fluoroquinolones D. penicillin Difficulty: Moderate

ASM Standard: 14, 23 19. What does it mean to say that HSV-1 is often latent?

A. It is always present in infected individuals, but lesions may be small or hidden.

B. It is normally difficult to detect even when causing an active infection, unless appropriate screening tests are conducted.

C. It undergoes cycles of rapid growth and slower growth, affecting the symptoms that can be observed.

D. It undergoes periods of inactivity when it resides in trigeminal nerve ganglia and does not cause symptoms.* Difficulty: Moderate ASM Standard: 10, 23 20. To reduce transmission risk and symptoms, HSV-1 is often treated with which of the following?

A. azithromycin B. fluoroquinolones C. itraconazole D. valacyclovir* Difficulty: Moderate ASM Standard: 14, 23 21. The relatively mild viral disease usually caused by human herpesvirus-6, or sometimes human herpesvirus-7, is better known as: A. chicken pox B. fifth disease C. measles D. roseola* Difficulty: Moderate ASM Standard: 23 22. Fifth disease is normally: A. allowed to resolve without treatment* B. prevented through vaccination C. treated intensively with intravenous antibiotics D. treated with topical antibiotic ointments Difficulty: Moderate ASM Standard: 14, 23 23. Tineas are commonly caused by which of the following?

A. bacteria such as Staphylococcus and Streptococcus B. human papillomaviruses, especially strains 16 and 18

C. parasites such as helminths D. Trichophyton, Epidermophyton, and Microsporum fungi* Difficulty: Moderate ASM Standard: 23 24. Acanthamoeba keratitis is generally treated with which of the following?

A. cephalosporins and fluoroquinolones B. chlorhexidine, azoles, and polyhexmamethylene biguanide* C. intravenous vancomycin administered in a hospital D. penicillins and related antibiotics Difficulty: Moderate ASM Standard: 23 25. Deerflies spread which of the following?

A. Acanthamoeba B. the loa loa worm* C. the varicella-zoster virus D. staphylococcal bacteria Difficulty: Moderate ASM Standard: 23 26. Albendazole is a medication that affects the ability of organisms to use tubulin to synthesize microtubules. Although it has other uses, from this information, what can you tell about the type of infection it is used for?

A. It is probably used to treat bacterial infections because bacteria use tubulin within their cell walls.

B. It is probably used to treat many varied infections because tubulin is present in all cells.

C. It is probably used to treat parasitic infections such as those caused by helminths because they are eukaryotes.* D. It is probably used to treat viral infections because viruses require tubulin to replicate.

Difficulty: Difficult ASM Standard: 9, 14, 23 27. The skin is an effective barrier against many pathogens. All the following describe ways that pathogens penetrate the skin except for which one?

A. Bacteria on the surface of the skin often gradually consume the epidermis and dermis, creating a pathway to deeper parts of the body.* B. Helminths may burrow into the skin, creating their own paths to deeper tissues.

C. Microbes may enter the body through skin that has been damaged, allowing them to reach deeper tissues.

D. The loa loa worm enters the bloodstream through the bite of the deerflies that carry it.

Difficulty: Difficult ASM Standard: 23 28. The most common subcutaneous mycosis in temperate regions, sporotrichosis, is usually treated with: A. azithromycin B. itraconazole* C. penicillin D. tetracycline Difficulty: Difficult ASM Standard: 14, 23 29. Candidiasis is common and often mild. Of the patients below, which would most likely be an appropriate candidate for preventive or long-term treatment for candidiasis?

A. a patient undergoing treatment for cancer who has a history of candidiasis* B. a patient who has been in remission from cancer for 2 years C. a patient with a history of repeated cases of mild cutaneous candidiasis D. a patient with newly diagnosed cutaneous candidiasis who has not previously been diagnosed with this infection Difficulty: Difficult ASM Standard: 14, 23 30. Why is a wet mount of a KOH preparation often used to diagnose tineas?

A. KOH dissolves the fungal cells, allowing their internal structures to be viewed.

B. KOH helps dissolve the keratin in the tissues, which better reveals the fungal structures.* C. KOH is necessary to fully spread the sample on the slide.

D. KOH stains the tissue, making fungi more visible.

Difficulty: Difficult ASM Standard: 23 31. Which of the following is not true of biofilms?

A. Biofilms often form in wounds and are associated with medical devices such as prosthetic joints and catheters.

B. Cells in biofilms are generally more resistant to antibiotic treatment.

C. Nutrients are equally distributed throughout a biofilm, so all the cells are healthy and resistant.* D. The biofilm matrix helps attach cells to a surface.

Difficulty: Difficult ASM Standard: 14, 23 32. Biofilms are commonly considered bacterial structures. Are biofilms always bacterial?

A. No, biofilms may occasionally consist of viruses instead of bacteria.

B. No, fungi (including medically important fungi) may also form biofilms.* C. Yes, each biofilm consists of a monoculture of one species of bacterium.

D. Yes, each biofilm consists of one or more bacterial species with no other species.

Difficulty: Difficult ASM Standard: 9, 21, 23 33. Blackheads differ from whiteheads because whiteheads are covered by skin, whereas blackheads are open to the air. What causes the dark coloration?

A. Lipids within the sebum react with air, resulting in chemical oxidation and the formation of the black color.* B. Sebum is always a dark color, but it is more concentrated in blackheads and is visible because there is no skin covering it.

C. The dead cells turn black as they die.

D. The sebum, dead cells, and lipids within the pore are naturally dark.

Difficulty: Difficult ASM Standard: N/A True/False 34. Biofilms make the treatment of skin infections more difficult.

Answer: True Difficulty: Easy ASM Standard: 21, 23 35. Herpes simplex virus 1 only causes lesions on and around the mouth.

Answer: False Difficulty: Easy ASM Standard: 23 36. Keratitis is always caused by Acanthamoeba.

Answer: False Difficulty: Moderate ASM Standard: 23 37. The immune system is often able to clear warts without medical treatment.

Answer: True Difficulty: Moderate ASM Standard: 23

38. Herpes simplex virus 1 is relatively uncommon; it is estimated that about 3% of individuals in the United States have been infected.

Answer: False Difficulty: Moderate ASM Standard: 23 39. Blackhead pimples are comedones that are covered by skin.

Answer: False Difficulty: Moderate ASM Standard: 23 40. Isotretinoin is used to treat acne, but only in severe cases because of potentially severe side effects.

Answer: True Difficulty: Difficult ASM Standard: 14 41. Bacillus anthracis uses a capsule to help evade the immune response.

Answer: True Difficulty: Difficult ASM Standard: 8, 23 Matching 42. Match each type of lesion with the best illustration.

TESTBANKS ELLER.COM (Credit “iii”: modification of work by Bruce Blaus)

Answers: A. iii., B. ii., C. iv., D. i.

Difficulty: Easy ASM Standard: N/A 43. Match each eye infection with the causative agent.

A. acute hemorrhagic i. viral (e.g., adenovirus) or caused by environmental conjunctivitis irritants B. acute ulcerative blepharitis ii. viral (Picornaviridae) C. follicular conjunctivitis iii. viral (e.g., herpes simplex or varicella zoster) or bacterial (e.g., Staphylococcus) D. papillary conjunctivitis iv. environmental irritants and allergens Answers: A. ii., B. iii., C. i., D. iv.

Difficulty: Moderate ASM Standard: 23 44. Match each infection with the most likely causative agent.

A. acne i. Pseudomonas aeruginosa B. cellulitis ii. Propionibacterium acnes C. otitis externa iii. Streptococcus pyogenes

D. tinea corporis iv. Trichophyton, Epidermophyton, or Microsporum Answers: A. ii., B. iii., C. i., D. iv.

Difficulty: Moderate ASM Standard: 23 45. Match each infection with the most likely treatment.

A. acne (moderate) i. erythromycin, clindamycin, and others B. erysipelas ii. intravenous antibiotics, debridement, and sometimes amputation C. necrotizing fasciitis iii. antibiotics, especially penicillin D. Pseudomonas aeruginosa iv. polymyxin B, fluoroquinolones, gentamicin, and wound infections others Answers: A. i., B. iii., C. ii., D. iv.

Difficulty: Moderate ASM Standard: 9, 14, 23 46.

Match the fungal infection with its location.

A. tinea capitis i. the body B. tinea corporis ii. the genital region C. tinea cruris iii. nails D. tinea unguium iv. the head Answers: A. iv., B. i., C. ii., DT.EiiS i.TBANKSELLER.COM Difficulty: Moderate ASM Standard: 23

47. Match the infection with a common treatment.

A. Acanthamoeba keratitis i. terbinafine, miconazole, clotrimazole, oral griseofulvin B. loiasis ii. itraconazole C. sporotrichosis iii. diethylcarbamazine, albendazole D. tinea capitis iv. polyhexamethylene biguanide, chlorhexidine, azoles Answers: A. iv., B. iii., C. ii., D. i.

Difficulty: Difficult ASM Standard: 14, 23 Fill in the Blank 48.

is the term for inflammation of the cornea of the eye.

Answer: Keratitis Difficulty: Easy ASM Standard: 23

49.

conjunctivitis is caused by bacteria.

Answer: Acute purulent Difficulty: Easy ASM Standard: 23 50. Tears travel from the lacrimal sac to the inner nose via the Answer: nasolacrimal duct

.

Difficulty: Moderate ASM Standard: 51. Microbes found on the skin may be part of the long-term normal microbiota or they may be microbes.

Answer: transient Difficulty: Moderate ASM Standard: 23, 24 52. When the nasolacrimal duct becomes blocked, the lacrimal sac may become inflamed in a condition called _.

Answer: dacryocystitis Difficulty: Moderate ASM Standard: 23 53. A microbe that is part of the normal human skin microbiota, less virulent than Staphlococcus aureus, and a major cause of nosocomial infections and infections associated with medical devices is .

Answer: Staphylococcus epidermidis Difficulty: Moderate ASM Standard: 23, 24 54.

is a streptococcal cell wall protein that is an important virulence factor.

Answer: M protein Difficulty: Moderate ASM Standard: 8, 23

55. Individuals infected with the loa loa parasite may develop allergic inflammation.

Answer: Calabar swellings Difficulty: Moderate ASM Standard: 23

_, which are areas of

56. Aspergillosis can cause formation of distinctive structures called Answer: eschars

.

Difficulty: Difficult ASM Standard: 23 57. Intertrigo and oral thrush can be caused by Answer: Candida spp.

_.

Difficulty: Difficult ASM Standard: 23 Short Answer 58. Why are individuals with contact lenses at greater risk of developing Acanthamoeba keratitis infection?

Sample Answer: The area between the contact lens and the cornea of the eye is suitable for Acanthamoeba to grow.

Difficulty: Easy ASM Standard: 23 59. Which regions of skin have the least most microbial diversity and why?

NoKuSntEsLoL Sample Answer: Regions wit T hE hiS ghTeB rA am f E seR bu.mCaOrM e associated with lower diversity because chemicals in sebum inhibit growth. [Students may also answer that microbes are most abundant and diverse in moist regions of the skin because other areas are too dry for extensive microbial growth, but this is not specifically addressed in the chapter].

Difficulty: Easy ASM Standard: 23, 24 60. What general groups of microbes are found on the skin, making up the normal microbiota?

Sample Answer: Bacteria, fungi, and viruses are most commonly found in the normal microbiota.

Difficulty: Easy ASM Standard: 23, 24 61. How could someone reduce their risk of developing Acanthamoeba keratitis?

Sample Answer: To reduce the risk of Acanthamoeba keratitis, someone could either avoid using contact lenses or practice careful contact lens hygiene.

Difficulty: Easy ASM Standard: 14, 23 62. What are some factors that make the skin an effective barrier?

Sample Answer: The skin is relatively dry and salty, with secretions that inhibit microbial growth. Additionally, the normal microbiota competes with other microbes and makes it more difficult for them to become established. The normal microbiota also produces substances that inhibit the growth of other microbes.

Difficulty: Moderate ASM Standard: 23, 24 63. What are some ways that a person can reduce their risk of developing ringworm?

Sample Answer: The fungi that cause ringworm thrive in dark, moist environments; therefore, it is important to practice good hygiene in places such as locker rooms and public showers. Wearing appropriate shoes and keeping skin and clothes dry are helpful. Good overall health also helps prevent infection.

Difficulty: Moderate ASM Standard: 14, 23 64. What are some eye conditions that can be caused by environmental irritants?

Sample Answer: Some examples of eye conditions that can be caused by environmental irritants are follicular conjunctivitis, keratitis, nonulcerative blepharitis, and papillary conjunctivitis.

Difficulty: Moderate ASM Standard: N/A 65. What is the usual treatment for someone with a suspected staphylococcal infection of the skin?

Sample Answer: Because MRSA has become so common, it is often assumed that the pathogen is resistant even before testing for antibiotic susceptibility. Ideally, antibiotic susceptibility testing would be used to select the best antibiotic in each case. However, treatment is normally started with TMP/SMZ, a tetracycline, clindamycin, or a linezolid, because MRSA is generally susceptible to those.

Difficulty: Moderate ASM Standard: 14, 23 66. What is a common way that Staphylococcus aureus and S. epidermidis are distinguished by culture methods?

Sample Answer: Because S. aureus is coagulase positive and S. epidermidis is coagulase negative, they can be distinguished using passive agglutination testing (although this does not definitively identify the species). They can also be cultured on mannitol salt agar, which distinguishes coagulase-positive species that ferment mannitol from coagulase-negative species that do not.

Difficulty: Moderate ASM Standard: 23, 34, 36

67. How do tinea corporis, tinea capitis, tinea pedis, tinea barbae, tinea cruris, and tinea unguium differ?

Sample Answer: They are caused by the same species of fungi and distinguished by their location on the body. Tinea corporis is found on the body, tinea capitis is found on the head (primarily the scalp), tinea pedis is found on the feet, tinea barbae is found in beards, tinea cruris is found in the genital region (groin), and tinea unguium is found in nails.

Difficulty: Moderate ASM Standard: 23 68. What is another term for onychomycosis?

Sample Answer: Onychomycosis is also known as tinea unguium.

Difficulty: Moderate ASM Standard: 23 69. What symptoms commonly characterize a Candida infection of a fingernail?

Sample Answer: The nail may become unusually hard and develop a yellow coloration.

Difficulty: Moderate ASM Standard: 23

SE EeRn. 70. What medications can be usedTE f oS r T loB ngA-N t eK rm treLaL tm t oCfOCM andida infections in immunocompromised patients?

Sample Answer: Ketoconazole and itraconazole are most commonly used for long-term treatment of Candida infections.

Difficulty: Difficult ASM Standard: 14, 23 71. Why is it common to leave some viral infections, such as roseola, fifth disease, and viral conjunctivitis, untreated?

Sample Answer: Some viral infections can become serious and require treatment. However, many viral infections are sufficiently mild that treatment is not necessary. Treatment may sometimes be used, even if the condition cannot be cured, to reduce the risk of transmission and severity of symptoms. Immunocompromised individuals may benefit from treatment not necessary for those with healthy immune systems.

Difficulty: Difficult ASM Standard: 14, 23 72. What are the best ways to reduce the risk of viral infections of the eyes and skin?

Sample Answer: Most viral infections of the eyes and skin are primarily spread by contact with infected individuals or their secretions (e.g., respiratory discharge). Good hygiene and avoidance of close contact with infected individuals reduces the risk of transmission.

Individuals with long-term viral skin infections, such as herpes simplex virus infections, can take antiviral medications to reduce the risk of transmitting the virus.

Difficulty: Difficult ASM Standard: 14, 23 Brief Essay Essay Question Rubric RATING Failin Below Average Competent g Criteria Answer does Answer fails to Answer provides for not provide an provide an argument evaluatio argument. examples to with one or two Answer contains support an n examples that inaccuracies. argument. support it.

Writing is Writing is poor Writing is poor and and grammatical acceptable for contains errors are the college level numerous common. but may contain grammatical Answer is one or two mistakes and somewhat grammatical misspellings. incoherent. mistakes or misspellings.

1 2 POINT 0 TESTBANKSEL LER.COM VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Advance d Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

3

73. Staphylococcus epidermidis is a common resident on human skin, contributing to the normal microbiota. Explain why it is still an important concern as a source of infection.

Answer: Student answers will vary but should include components of the following.

Staphylococcus epidermidis on the skin is normally harmless. However, it is an opportunistic pathogen and can cause serious infections when it enters the body. It is a particular problem associated with medical procedures, during which it may be accidentally introduced deeper into the body. It may also be introduced into the body on medical devices.

Difficulty: Moderate ASM Standard: 23, 24 74. A patient in the hospital develops a serious infection after surgery. How could you distinguish between an infection caused by a Staphylococcus species and one caused by a Streptococcus species? If the infection is caused by a Staphylococcus species, then how could you determine whether it was caused by S. aureus or S. epidermidis?

Answer: Student answers will vary but should include components of the following. Species of Staphylococcus and Streptococcus can most easily be distinguished under the microscope because of differences in their morphologies. Staphylococcus forms distinctive grape-like clusters, whereas Streptococcus forms chains. The bacteria can also be cultured;

Staphylococcus has a distinctive opaque white to cream coloration when grown on blood

agar. A catalase test can be used because Staphylococcus is catalase positive, whereas Streptococcus is catalase negative. To distinguish between S. aureus and S. epidermidis, passive agglutination testing can be used, although this does not definitively identify the species): S. aureus is coagulase positive and S. epidermidis is coagulase negative. These bacteria can also be cultured on mannitol salt agar, which distinguishes coagulase-positive species that ferment mannitol from coagulase-negative species that do not. Because species in both genera are gram-positive cocci, Gram staining is not sufficient to distinguish them.

Difficulty: Moderate ASM Standard: 6, 23, 32, 34, 36 75. Explain the pros and cons of screening hospital patients and workers for MRSA to reduce its spread in hospitals. How could these programs be improved?

Answer: Student answers will vary but should include the following. Screening identifies individuals with MRSA, but many people are asymptomatic and may not want treatment.

Additionally, decolonization procedures could increase the risk of resistance to treatment.

The data on the efficacy of these programs are mixed and the protocols used vary greatly.

Students should discuss the roles of individual preferences in screening and treatment, as well as possible options to strengthen these programs, such as studying standardized protocols. Students may also mention other approaches to reduce the risk of crosscontamination, such as checklists to improve compliance with handwashing and other hygiene protocols. This topic is discussed in detail in the Eye on Ethics box on page 917.

Difficulty: Difficult ASM Standard: 14, 23, 31 76. There is a vaccination available for anthrax, but it is only approved for use in those who are at high risk. Why do you think the vaccine is not more widely available? What are the pros and cons of this approach? Could improvements be made?

Answer: Student answers will vary but should include components of the following. The anthrax vaccine requires an initial series of five intramuscular injections over the course of 18 months, then annual booster vaccinations. It is difficult to encourage people to have regular vaccinations, especially on such a frequent schedule, so having widespread vaccination with a relatively difficult vaccine may not be realistic. Additionally, the risk of exposure is so low for most people that it would be an unnecessary effort. The book mentions that postexposure vaccination could potentially be offered to people. If there were a sufficiently increased risk of anthrax exposure, then increased research into postexposure treatment would probably more effective than attempting a widespread vaccination program.

Difficulty: Difficult ASM Standard: 14, 23, 31

This file is copyright 2017, Rice University. All rights reserved.

Chapter 22: Respiratory System Infections * = Correct answer Multiple Choice 1. Which passageway connects the nasopharynx to the middle ear?

A. eustachian tube* B. nasal cavity C. oropharynx D. sinus cavity Difficulty: Easy ASM Standard: N/A 2. Which described the palatine tonsils?

A. connective and muscular tissue within the nasopharynx B. connective and muscular tissue within the oropharynx C. lymphoid tissue within the nasopharynx D. lymphoid tissue within the oropharynx* Difficulty: Easy ASM Standard: N/A 3. Within the respiratory tract, where are oxygen and carbon dioxide exchanged?

A. alveoli* B. bronchi C. bronchioles D. trachea Difficulty: Easy ASM Standard: N/A 4. Rhinitis is an inflammation of which component of the respiratory system?

A. nasal passages* B. oropharynx C. sinuses D. tonsils Difficulty: Easy ASM Standard: N/A 5. Symptoms of the common cold do not include which one of the following?

A. coughing B. headache C. high fever*

D. runny nose Difficulty: Easy ASM Standard: 23 6. Antigenic shift caused a severe influenza pandemic, the “Spanish flu,” during which years?

A. 1908–1909 B. 1918–1919* C. 1955–1956 D. 2006–2007 Difficulty: Easy ASM Standard: 23 7. Which is the most effective way to reduce the risk of influenza transmission?

A. amantadine B. annual vaccination* C. oseltamivir D. tetracycline Difficulty: Easy ASM Standard: 14, 23

TiE 8. FluMist is which of the follow ngS?TBANKSELLER.COM A. inactivated flu treatment B. inactivated flu vaccine C. live attenuated flu treatment D. live attenuated flu vaccine* Difficulty: Easy ASM Standard: N/A 9. Which of the following groups of viruses is not known to be a frequent cause of the common cold?

A. adenoviruses B. coronaviruses C. parainfluenza viruses* D. rhinoviruses Difficulty: Easy ASM Standard: 23 10. The mucociliary escalator effect helps to do which of the following?

A. localize microbes in specific parts of the respiratory tract, enhancing the immune response against them and reducing the risk that they will be exhaled B. move air through the respiratory tract

C. move pathogens deeper into the respiratory tract, where macrophages can engulf them D. remove pathogens from the respiratory tract, eliminating microbes from the lower respiratory tract, and inhibiting pathogen attachment* Difficulty: Moderate ASM Standard: N/A 11. Which of the following is not part of the immune defense of the upper respiratory system?

A. alveolar macrophages* B. defensins C. lysozyme D. secreted IgA antibodies in mucus Difficulty: Moderate ASM Standard: 14 12. When the alveoli become fluid filled in pneumonia, the affected areas are called which of the following?

A. a pneumonitis B. a pneumothorax C. consolidations* D. inflammations Difficulty: Moderate ASM Standard: 23 13. Which microbe causes streptococcal pharyngitis (strep throat)?

A. S. aureus B. S. epidermidis C. S. pyogenes* D. S. typhimurium Difficulty: Easy ASM Standard: 23 14. Streptokinase is a protein that is responsible for which of the following?

A. dissolving blood clots* B. forming blood clots C. forming erythrogenic toxin D. inhibiting the spread of streptococcal bacteria Difficulty: Moderate ASM Standard: 23 15. Which of the following is an example of one of the sequelae of strep throat?

A. acute glomerulonephritis*

B. high fever C. red tonsils D. scarlet fever Difficulty: Moderate ASM Standard: 23 16. Based on the carbohydrate antigens in its cell wall, Streptococcus pyogenes is classified within which Lancefield group?

A. A (the group A strep)* B. B (the group B strep) C. C (the group C strep) D. D (the group D strep) Difficulty: Moderate ASM Standard: 7, 8, 23 17. Otitis media with effusion is distinguished from other forms of otitis media by the presence of which of the following?

A. a high fever B. an inflamed tympanic membrane C. fluid within the middle ear* D. pharyngeal abscesses Difficulty: Moderate ASM Standard: 23 18. Against which lower respiratory infection does vaccination with PCV13 protect?

A. diphtheria B. mycoplasma pneumonia C. pneumococcal pneumonia* D. tuberculosis Difficulty: Moderate ASM Standard: 14, 23 19. Common cold viruses can often be differentiated from influenza by which of the following?

A. absence of a high fever* B. absence of aches and pains C. absence of lower respiratory symptoms D. occurrence of headaches Difficulty: Moderate ASM Standard: 23

20. Which of the following groups of viruses is not known to be a frequent cause of the common cold?

A. adenoviruses B. coronaviruses C. parainfluenza viruses* D. rhinoviruses Difficulty: Easy ASM Standard: 23 21. Which of the following is not a fungus?

A. Blastomyces dermatitidis B. Mucor spp.

C. Mycoplasma pneumoniae* D. Rhizopus arrhizus Difficulty: Moderate ASM Standard: 23 22. Which virus is teratogenic, meaning that pregnant women must be especially cautious in avoiding this virus?

A. measles B. mumps C. rubella* D. varicella Difficulty: Moderate ASM Standard: 23 23. Measles causes primarily which of the following?

A. a skin rash and associated symptoms* B. muscle paralysis and weakness C. swelling of the parotid glands, giving a swollen appearance D. teratogenic effects Difficulty: Moderate ASM Standard: 23 24. Which is an important sign used to diagnose measles?

A. a butterfly rash B. a scratchy, inflamed throat C. Koplik’s spots* D. pus-filled lesions in the pharynx Difficulty: Moderate ASM Standard: 23

25. Which of the following describes how rubella is transmitted?

A. primarily through aerosols produced by infected individuals* B. primarily through contact with fomites touched by infected individuals C. only through contaminated body fluids, such as blood D. only through direct contact with infected individuals Difficulty: Moderate ASM Standard: 23 26. German measles is another name for which disease?

A. mumps B. rubella* C. rubeola D. shingles Difficulty: Moderate ASM Standard: 23 27. Which virus becomes dormant in dorsal ganglia after infection?

A. the common cold virus B. the influenza virus C. the rubella virus D. the varicella-zoster virus* Difficulty: Moderate ASM Standard: 23 28. Influenza transmission between adults is most effectively prevented by which of the following?

A. a complete influenza vaccination series in childhood B. annual vaccination of adults* C. use of prophylactic antiviral medications D. use of prophylactic supportive treatment Difficulty: Moderate ASM Standard: 14, 23 29. Why is Cryptococcus neoformans especially capable of avoiding destruction by the immune system?

A. Their cells have a protective capsule.* B. Their cells have an unusual cell membrane structure that resists attack.

C. Their cells thrive within alveolar macrophages.

D. They produce chemicals that neutralize antibodies.

Difficulty: Moderate

ASM Standard: 7, 8, 23 30. Which of the following is true about the risk of measles transmission?

A. As health-care providers see fewer cases of measles, they are more likely to misdiagnose infected individuals, increasing the risk of transmission.* B. Lower vaccination rates decrease herd immunity and make transmission to susceptible individuals less likely.

C. Measles is not highly contagious, so transmission requires extended contact with an infected individual.

D. Travel patterns have not increased the risk of measles transmission around the world over the last century.

Difficulty: Difficult ASM Standard: 23 31.

Which is not a benefit of using acyclovir treatment for shingles?

A. It is used to reduce the duration of the symptoms of shingles.

B. It is used to reduce the risk of developing shingles after a chicken pox infection.* C. It is used to reduce the risk of postherpetic neuralgia, a painful condition that can develop after shingles.

D. It is used to reduce the severity of shingles symptoms.

Difficulty: Difficult ASM Standard: 14, 23

32. Which of the following is true about histoplasmosis?

A. Histoplasmosis is transmitted directly from one infected person to another person.

B. Histoplasmosis normally produces severe symptoms.

C. Histoplasmosis results in the development of Ghon complexes.

D. Histoplasmosis spores reproduce within alveolar macrophages.* Difficulty: Difficult ASM Standard: 23 33. Which of the following patients would require the most aggressive treatment for coccidiomycosis?

A. an individual known to have been exposed to spores but who had not yet developed symptoms B. an individual who had previously had coccidiomycosis C. an individual who had previously received a liver transplant and who had a disseminated infection* D. a teenager with symptoms but no evidence of disseminated infection Difficulty: Difficult ASM Standard: 14, 23

34. Which of the following microbes requires the greatest precautions when cultured in the laboratory?

A. Blastomyces dermatitidis B. Coccidiodes immitis* C. Histoplasma capsulatum D. Rhizopus arrhizus Difficulty: Difficult ASM Standard: 23, 36 35. An individual with HIV develops a fungal infection and has shortness of breath, fever, and cough. Which microbe is the most likely causative agent?

A. Aspergillus fumigatus B. Blastomyces dermatitidis C. Coccidiodes immitis D. Pneumocystis jirovecii* Difficulty: Difficult ASM Standard: 23 36. Which medication would be the best choice for treating a patient unfortunate enough to have both aspergillosis and histoplasmosis?

A. amphotericin B B. fluconazole C. itraconazole* D. trimethoprim-sulfamethoxazole Difficulty: Difficult ASM Standard: 14, 23 37. Which of the following diseases is a zoonosis?

A. histoplasmosis B. Q fever* C. rubella D. tuberculosis Difficulty: Difficult ASM Standard: 23 38. What would be the most effective method of reducing the risk of Legionnaire’s disease transmission?

A. avoiding contact with any infected individuals B. avoiding the inhalation of soil and dust with possible spores C. cleaning and maintaining air conditioning systems well* D. using careful food preparation techniques

Difficulty: Difficult ASM Standard: 14, 23 39. Which of the following is true for individuals with an egg allergy?

A. They can receive a bivalent influenza vaccination.

B. They can receive a trivalent influenza vaccination.* C. They can receive a vaccination against influenza A strains only.

D. They cannot receive an influenza vaccination.

Difficulty: Difficult ASM Standard: 14, 23 40. The influenza vaccine is designed to contain which of the following: A. one influenza A strain and one influenza B strain, based on a review of the most dominant influenza strains in October B. two influenza A strains and one to two influenza B strains, based on a review of the most dominant influenza strains in February and September* C. two influenza A strains and two influenza B strains, based on a review of the most dominant influenza strains in February D. two influenza A strains and four influenza B strains, based on a review of the most dominant influenza strains in March and October Difficulty: Difficult ASM Standard: 14, 23 True/False 41. Microbes are abundant in the lower respiratory tract.

Answer: False Difficulty: Easy ASM Standard: 20, 23 42. In the elderly, pneumonia is a significant cause of mortality.

Answer: True Difficulty: Easy ASM Standard: 23 43. Although it is a potential pathogen, Staphylococcus aureus is commonly carried in the nostrils of asymptomatic individuals.

Answer: True Difficulty: Moderate ASM Standard: 20, 23

44. The second leading cause of pediatrician visits by young children (under age 5 years) in the United States is acute otitis media.

Answer: True Difficulty: Moderate ASM Standard: 23 45. The common cold is actually caused by more than 200 different viruses.

Answer: True Difficulty: Moderate ASM Standard: 23 46. Respiratory syncytial virus can be life-threatening in infants.

Answer: True Difficulty: Moderate ASM Standard: 23 47. Rickettsial infections are safe to culture in the laboratory, so these approaches are preferred to molecular techniques for diagnosis.

Answer: False Difficulty: Difficult ASM Standard: 23, 34, 36 48. Acute otitis media is less common in individuals who have been vaccinated against influenza, because it can be caused by the same microbes.

Answer: False Difficulty: Difficult ASM Standard: 23 Matching 49. Match each illness with the most appropriate definition.

A. Epiglottitis i. inflammation of the ear B. Laryngitis ii. inflammation of the nasal cavities C. Otitis iii. inflammation of the sinuses D. Rhinitis iv. inflammation of the larynx E. Sinusitis v. inflammation of the epiglottis Answers: A. v., B. iv., C. i., D. ii., E. iii.

Difficulty: Easy ASM Standard: 23 50. Match each illness with its common causative agent.

A. K. pneumoniae and others

i. health-care–associated pneumonias by opportunistic pathogens B. M. pneumoniae ii. atypical (walking) pneumonia C. P. aeruginosa and others iii. acute otitis media D. S. pneumoniae and others iv. streptococcal sore throat E. S. pyogenes v. bacterial pneumonia associated with cystic fibrosis Answers: A. iv., B. i., C. v., D. ii., E. iii.

Difficulty: Easy ASM Standard: 23 51. Match each type of illness with the appropriate vaccine for its prevention.

A. Chicken pox i. BCG B. Diphtheria ii. DtaP, TdaP, DT, Td, or DTP C. Epiglottitis iii. Hib D. Rubella iv. varicella E. Tuberculosis v. MMR vaccine Answers: A. iv, B. ii, C. iii, D. v, E. i Difficulty: Moderate ASM Standard: 14 52. Match each illness with the most appropriate treatment.

A. Diphtheria roN adK-S spEecLt L r uE mRa.nC t ibOioMtics such as penicillin and TESTi.BbA erythromycin, sometimes with antitoxin B. Mycoplasma pneumonia ii. β-lactam antibiotics, macrolides, or fluoroquinolones; susceptibility testing may be needed because of frequent antibiotic resistance.

C. Pneumococcal pneumonia iii. doxycycline, hydroxychloroquine D. Q fever iv. macrolide antibiotics, if not self-limiting Answers: A. i, B. iv, C. ii, D. iii Difficulty: Moderate ASM Standard: 14, 23 53. Match each bacterial disease with its distinguishing characteristics.

A. Acute otitis media i. very common in young children; may occur with or without fluid buildup B. Diphtheria ii. can be associated with serious sequelae, such as acute glomerulonephritis and rheumatic fever C. Pertussis iii. associated with the production of an exotoxin that causes the formation of a pseudomembrane that impairs breathing D. Streptococcal pharyngitis iv. causes severe coughing that can last for months; especially dangerous for infants; can be effectively prevented through vaccination E. Tuberculosis v. associated with severe cough and small, round lesions

in the lungs; antibiotic resistance is a serious problem Answers: A. i, B. iii, C. iv, D. ii, E. v Difficulty: Moderate ASM Standard: 23 54. Match each fungal disease with its distinguishing characteristics.

A. Aspergillosis i. causes respiratory symptoms such as cough and shortness of breath; pneumonia and pulmonary or cerebral hemorrhages may occur B. Blastomycosis ii. causes lesions to develop on the face that may spread and cause meningitis; also known as Valley fever C. Coccidiomycosis iii. rare in healthy individuals; may cause upper or lower respiratory tract symptoms, including headache, fever, congestion, cough, shortness of breath, black oral lesions D. Histoplasmosis iv. causes aches, fever, chills, cough, and chest pain in immunocompromised individuals; causes crusted lesions that may lead to scarring when disseminated E. Murmycosis v. may cause lung lesions resembling Ghon complexes, weakness, and chest pain Answers: A. i, B. iv, C. ii, D. v, E. iii Difficulty: Moderate ASM Standard: 23 55. Match each type of pneumonia with its distinguishing characteristics.

A. Chlamydial pneumonia i. intracellular pathogens; three causative species, with one type causing psittacosis B. Haemophilus pneumonia ii. caused by unencapsulated strains; treatmentis complicated by antibiotic resistance; most commonly causes disease in the elderly, but commonly found in asymptomatic children C. Mycoplasma pneumonia iii. especially problematic in those with cystic fibrosis or exposed to contaminated ventilators in hospitals D. Pseudomonas pneumonia iv. spread in crowded environments; usuallyrelatively mild; called “walking pneumonia” Answers: A. i, B. ii, C. iv, D. iii Difficulty: Difficult ASM Standard: 23 Fill in the Blank 56. MALT stands for .

Answer: mucosa-associated lymphoid tissue Difficulty: Easy

ASM Standard: N/A 57. In DTaP, the “P” stands for .

Answer: pertussis (or B. pertussis components) Difficulty: Easy ASM Standard: 14 58. The round lesions that form in the alveoli of patients with tuberculosis are called Answer: tubercles Difficulty: Easy ASM Standard: 23

.

59. The microbe that causes whooping cough is Answer: Bordetella pertussis

_.

Difficulty: Easy ASM Standard: 23 60. Most bacterial pneumonia is caused by Haemophilus influenzae, Mycoplasma pneumoniae, and pneumoniae.

Answer: Streptococcus Difficulty: Moderate ASM Standard: 23 61. Walking pneumonia is formally called Answer: Mycoplasma

pneumonia.

Difficulty: Moderate ASM Standard: 23 62.

is a rare respiratory infection caused by a strain of Chlamydia that is sometimes transmitted to humans from domestic birds.

Answer: Psittacosis Difficulty: Moderate ASM Standard: 23

63. A type of pneumonia that is a particular problem for individuals with cystic fibrosis is pneumonia.

Answer: Pseudomonas Difficulty: Moderate ASM Standard: 23

64. Ghon complexes are associated with the disease called Answer: tuberculosis

.

Difficulty: Moderate ASM Standard: 23 65. Serious pneumonia in patients with cystic fibrosis is often caused by Answer: Pseudomonas aeruginosa

.

Difficulty: Moderate ASM Standard: 23 66. Bordetella pertussis specimens must be cultured rapidly because viability decreases after hours.

Answer: 24 Difficulty: Difficult ASM Standard: 23, 34 67. In DTaP, the “a” stands for Answer: acellular

.

Difficulty: Difficult ASM Standard: 14 Short Answer 68. Why are patients with cystic fibrosis at particular risk of respiratory infections?

Sample Answer: Cystic fibrosis causes excess mucus to buildup and makes it more difficult for these patients to expel pathogens. The normal immune defenses of the respiratory tract, including the mucociliary escalator, are impaired.

Difficulty: Difficult ASM Standard: 23 69. Compare the diversity and amount of microbiota of the upper and lower respiratory tracts.

Sample Answer: The microbiota of the upper respiratory tract is diverse and numerous. In contrast, the healthy lower respiratory tract eliminates microbes and does not normally have a microbiota.

Difficulty: Easy ASM Standard: 23 70. Describe the pathway traveled by an inhaled microbe that reaches an alveolus.

Sample Answer: The microbe travels through the nasal cavity, then the nasopharynx, and passes through the larynx to the trachea. It then passes through the left or right bronchus, into a bronchiole, and then into an alveolus.

Difficulty: Easy ASM Standard: N/A 71. What is the mucociliary escalator effect?

Sample Answer: The cells lining the respiratory tract produce mucus. Ciliated cells move this mucus and any entrapped pathogens upward, out of the respiratory tract.

Difficulty: Easy ASM Standard: 23 72. What are some examples of virulence factors used by opportunistic pathogens from the normal respiratory tract microbiota?

Sample Answer: Two examples of virulence factors include capsules and adhesins.

Difficulty: Easy ASM Standard: 23 73. Why are β-lactam antibiotics ineffective against M. pneumoniae?

Sample Answer: β-lactam antibiotics target the bacterial cell wall. Because M. pneumoniae lacks a cell wall, these antibioTtiE csSaTreBnAoN t K efS feE ctL ivLeEaR ga.inCsO t iM t.

Difficulty: Moderate ASM Standard: 23 74. What would be a good reason for using Sabouraud’s agar for a culture?

Sample Answer: Sabouraud’s agar is a culture medium that is selective for fungi. You could use it to culture a species such as Histoplasma capsulatum.

Difficulty: Moderate ASM Standard: 23, 33 75. What could cause someone to develop reactivation tuberculosis?

Sample Answer: After someone recovers from tuberculosis, bacteria remain within the Ghon complexes in the lungs. These can later cause disease if an individual becomes immunocompromised.

Difficulty: Moderate ASM Standard: 23 76. How does pertussis cause a buildup of mucus in the lungs?

Sample Answer: A toxin produced by B. pertussis damages the ciliated cells that normally move mucus as part of the mucociliary escalator.

Difficulty: Moderate ASM Standard: 23 77. Why is understanding amoeba important in understanding Legionnaire’s disease?

Sample Answer: Legionnaire’s disease is caused by a bacterium that lives within amoeba, so understanding amoebic life cycles and requirements is important in controlling the disease.

Difficulty: Moderate ASM Standard: 14, 23 78. Why might a health-care professional choose itraconazole rather than amphotericin B or ketoconazole to treat disseminated histoplasmosis?

Sample Answer: Itraconazole is generally used when a patient is immunocompromised.

Difficulty: Moderate ASM Standard: 14, 23 79. People frequently encounter the fungi that can cause histoplasmosis, coccidiomycosis, and other fungal illnesses. Why do most people who encounter these fungi either not develop symptoms or develop only mild symptoms?

Sample Answer: Most people have sufficiently strong immune systems to prevent these fungi from establishing a serious infection.

Difficulty: Moderate ASM Standard: 14, 23 80. Why is antigenic shift associated with influenza pandemics?

Sample Answer: Antigenic shift can cause sufficient change in the antigens of the influenza virus. The immune systems of people who have previously been exposed to other influenza viruses do not recognize the changed influenza virus antigens. This increases the risk of infection to an individual and facilitates the spread of the virus.

Difficulty: Moderate ASM Standard: 23 81. What are the causative agents most commonly responsible for viral pneumonia?

Sample Answer: Common causative agents of viral pneumonia include adenoviruses, influenza viruses, parainfluenza viruses, and respiratory syncytial viruses.

Difficulty: Moderate ASM Standard: 23 82. Why are normally benign species such as S. aureus and K. pneumoniae problematic in a hospital setting?

Sample Answer: These species are opportunistic pathogens that can cause infections, such as health-care–associated pneumonia, in a hospital setting. They are a greater risk in hospitals because patients may be immunocompromised. Patients may also have had invasive treatments or implanted devices through which microbes may be easily transmitted or moved from one bodily location to another.

Difficulty: Difficult ASM Standard: 23 83. How is pertussis diagnosed within 2 weeks of infection? How does the method of diagnosis change if diagnosis is needed 2 to 4 weeks into the infection, compared with after a month?

Sample Answer: During early infection, within about 2 weeks, culturing is effective for diagnosis. PCR can be used within the first month, then ELISA is used for diagnosis.

Difficulty: Difficult ASM Standard: 23, 34, 36 84. Once pathogens start to establish a respiratory infection, how do they make it easier for microbes (either of the same or other species) to establish and spread?

Sample Answer: Because an infection can damage the mucociliary escalator, it can reduce the ability of the respiratory tract to trap and expel pathogens. This makes it easier for the infection to worsen and for other microbes to become established.

Difficulty: Difficult ASM Standard: 14, 23 Brief Essay Essay Question Rubric RATING Failin Below g Average Criteria Answer does Answer fails to for not provide an provide evaluatio argument. examples to n Answer contains support an inaccuracies. argument.

Writing is Writing is poor poor and and grammatical contains errors are numerous common. grammatical Answer is mistakes and somewhat misspellings. incoherent.

Competen t Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

POINT 0 1 2 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Advance d Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

3

85. There was a devastating influenza pandemic in 1918–1919. What factors leading up to this pandemic contributed to its severity?

Answer: Student answers will vary but should include components of the following. It is possible that antigenic shift occurred, producing a new H1N1 strain with components of avian and human viruses. Additionally, wartime conditions contributed to the spread of the virus. These conditions included crowding, insufficient sanitation, and the large-scale movement of people for purposes associated with World War I. Difficulty: Moderate ASM Standard: 23, 31 86. For many respiratory illnesses discussed in the chapter, antibiotic resistance is an increasing concern. Give some specific examples from the chapter and discuss how this problem can be addressed.

Answer: Student answers will vary but should include at least one example and ways to address the problem. Diseases that are particularly relevant include tuberculosis, Haemophilus pneumonia, and pneumococcal pneumonia. Students may choose to discuss appropriate use of antibiotics (including prescribing only when necessary, encouraging patients to take the full dose, using susceptibility testing, and following the most recent guidelines) and/or the use of vaccination to reduce antibiotic use. Students may also choose to discuss initiatives to encourage health-care professionals to prescribe antibiotics when appropriate (i.e., not for viral infections) and recommendations suggesting when it may be appropriate to wait before prescribing.

Difficulty: Moderate ASM Standard: 14, 23, 31 87. Consider the pros and cons of maintaining samples of dangerous diseases such as smallpox after they have been eradicated from humans. What are the arguments for and against maintaining these samples? What do you personally think is the best course of action? Justify your answer with evidence from this chapter.

Answer: Student answers will vary but should include a discussion of issues raised in the Eye on Ethics “Smallpox Stockpiles” feature box in this chapter (https://cnx.org/contents/5CvTdmJL@4.4:Hl39exzu@3/Viral-Infections-of-the-Respir).

Advantages include having the samples available for study and to use in developing vaccines or treatments if the virus re-emerges. Disadvantages include concerns about accidental releases of the pathogens or their intentional use as biological weapons.

Difficulty: Difficult ASM Standard: 23, 31 88. Concerns about vaccination have led to drops in vaccination rates despite a lack of evidence to back up these concerns. Discuss the implications of falling vaccination rates for respiratory illnesses and your thoughts on how this problem may be addressed.

Answer: Student answers will vary but should include the following. When vaccination rates drop too low, herd immunity is less effective and susceptible individuals (such as immunocompromised individuals or those who cannot be vaccinated) are at greater risk

for infection. Illnesses that are spread through the respiratory route can be very contagious and easily spread in public places such as schools and libraries.

Additionally, health-care providers may be less likely to suspect these illnesses in their patients and, thus, may misdiagnose them. Students may discuss different approaches to better identify these illnesses in patients as well as encourage appropriate vaccination out of concern for their patients.

Difficulty: Difficult ASM Standard: 14, 23, 31 89. Why is the influenza vaccine each year based on a review of dominant influenza strains in February and October, not just at the start of influenza season? What is the length of time between the peak of influenza season and the decision about strains to include and why? Answer: Student answers will vary but should include the following. The prevalence and incidence of influenza increase in winter so it is important to prepare a virus before this increase. The vaccine is planned in February in the northern hemisphere and in October in the southern hemisphere. The vaccine must be planned well in advance of the start of influenza season during winter because it takes time to produce and distribute the vaccine.

Difficulty: Difficult ASM Standard: 14, 23, 31 This file is copyright 2017, Rice University. All rights reserved.

Chapter 23: Urogenital System Infections * = Correct answer Multiple Choice 1. What is a glomerulus?

A. a capillary bed that contacts a nephron* B. a connecting duct in the urinary system C. a part of the urinary bladder D. the part of the nephron that drains into the ureter Difficulty: Easy ASM Standard: N/A 2. Urine leaves the urinary bladder through which structure?

A. collecting duct B. meatus C. ureter D. urethra* Difficulty: Easy ASM Standard: N/A 3. What tube(s) in the male reproductive system transfer(s) sperm to the vas deferens?

A. the epididymis* B. the prostate C. the seminal tubules D. the seminal vesicles Difficulty: Easy ASM Standard: N/A 4. Which of the following refers to inflammation of the bladder?

A. cystitis* B. glomerulonephritis C. orchitis D. pyelonephritis Difficulty: Easy ASM Standard: N/A 5. Which of the following is typically true of the kidneys?

A. They are colonized by Candida spp.

B. They are colonized by lactobacilli.

C. They are colonized by staphylococci.

D. They are colonized by no normal microbiota.*

Difficulty: Easy ASM Standard: 23, 24 6. Which refers to dysuria?

A. bladder pain B. painful urination* C. production of urine that contains blood D. production of urine that contains pus Difficulty: Easy ASM Standard: N/A 7. In the United States, which sexually transmitted infection is especially common in individuals between the ages of 15 and 24 years?

A. chlamydia B. gonorrhea* C. HIV/AIDs D. syphilis Difficulty: Easy ASM Standard: 23

AaNlKvS EiRcr.oCbiOotMa is unbalanced but there is no 8. Which condition occurs whenTtE heSnToB rm agE inLaL l m inflammation?

A. bacterial vaginitis B. bacterial vaginosis* C. chancroid D. pelvic inflammatory disease Difficulty: Easy ASM Standard: 22 23, 24 9. Which of the following STIs is caused by a protozoan?

A. chlamydia B. genital warts C. herpes D. trichomoniasis* Difficulty: Easy ASM Standard: 23 10. Which of the following is not a function of the urinary system?

A. excreting wastes B. filtering blood

C. producing urea*

D. regulating the balance of salt and water in the body Difficulty: Moderate ASM Standard: 23, 24 11. In most women, which is the most common acid-producing bacterial genus in the vagina?

A. Lactobacillus* B. Megasphaera C. Pseudomonas D. Staphylococcus Difficulty: Moderate ASM Standard: 23, 24 12. Which of the following does not contribute to nonspecific immune defense against vaginal infections?

A. The normal microbiota decreases estrogen levels that enhance microbial growth.* B. The normal microbiota outcompetes other microbes for binding sites and nutrients.

C. The normal microbiota produces an acidic environment that inhibits microbial growth.

D. The normal microbiota produces hydrogen peroxide and bacteriocins.

Difficulty: Moderate ASM Standard: 22 23, 24 13. What are the two most common causative agents of pelvic inflammatory disease?

A. Escherichia coli and Proteus vulgaris B. Group B Streptococcus and Neisseria gonorrhoeae C. Lactobacillus spp. and Escherichia coli D. Neisseria gonorrhoeae and Chlamydia trachomatis* Difficulty: Moderate ASM Standard: 23 14. If a urinary dipstick shows the presence of nitrite, which bacteria would most likely be present because of their ability to convert nitrate to nitrite?

A. Escherichia coli or Klebsiella pneumoniae* B. Klebsiella pneumoniae or Staphylococcus saprophyticus C. Neisseria gonorrhoeae or Streptococcus agalactiae D. Streptococcus pyogenes or Chlamydia trachomatis Difficulty: Moderate ASM Standard: N/A

15. Half of all cases of leptospirosis in the United States are found in which state?

A. Alaska B. Florida

C. Hawaii* D. Texas Difficulty: Moderate ASM Standard: N/A 16. Which of the following is not a major cause of nongonococcal urethritis?

A. Chlamydia trachomatis B. Mycoplasma genitalium C. Treponema pallidum* D. Ureaplasma urealyticum Difficulty: Moderate ASM Standard: 23 17. The most common treatment for nongonococcal urethritis involves which of the following?

A. azithromycin and penicillins B. azithromycin and tetracyclines, unless resistance is present* C. cephalosporins and tetracyclines, unless resistance is present D. fluoroquinolones and trimethoprim/sulfamethoxazole Difficulty: Moderate ASM Standard: 14, 23 18. Vaginolysin, a toxin that damages red blood cells and vaginal epithelial cells, is produced by which pathogen?

A. Bacteroides sp.

B. Fusobacterium sp.

C. Gardnerella vaginalis* D. Lactobacillus sp.

Difficulty: Moderate ASM Standard: 23 19. Which of the following describes clue cells?

A. epithelial cells with attached bacterial cells; associated with bacterial vaginosis* B. epithelial cells with damaged cell membranes; associated with nongonococcal urethritis C. lysed epithelial cells; associated with nongonococcal urethritis D. lysed epithelial cells found within the urinary tract during urinary tract infections Difficulty: Moderate ASM Standard: 23

20. Which symptom is not commonly associated with chronic gonorrhea in women?

A. amenorrhea (lack of menstruation)* B. increased menstrual flow

C. pelvic pain D. vaginal discharge Difficulty: Moderate ASM Standard: N/A 21. Due to antibiotic resistance, which of the following is the preferred first treatment for gonorrhea?

A. cephalosporins* B. fluoroquinolones C. penicillins D. tetracyclines Difficulty: Moderate ASM Standard: 7, 14 22. Which of the following is not associated with chlamydial infections?

A. cystitis* B. increased risk of cervical cancer C. orchitis D. salpingitis Difficulty: Moderate ASM Standard: N/A 23. For which infection is routine screening recommended for women younger than age 25 years, beginning prenatal care, or considered to be at high risk?

A. bacterial vaginosis B. chancroid C. chlamydia* D. syphilis Difficulty: Moderate ASM Standard: 23 24. Haemophilus ducreyi causes which condition?

A. chancroid* B. chlamydia C. syphilis D. urethritis Difficulty: Easy ASM Standard:

23 25. Systemic herpes infections are best detected using which method?

A. cultures

B. examination for cytopathic effects C. immunostaining D. PCR techniques* Difficulty: Moderate ASM Standard: N/A 26. What are condylomata acuminata?

A. abundant lesions caused by HSV-2 B. fleshy pink growths caused by HPV infection* C. rounded, sometimes purulent, lesions caused by Treponema pallidum D. viruses that cause warts to develop Difficulty: Difficult ASM Standard: 23 27. What test is commonly used to combine HPV and Pap testing, in addition to methods that may be used separately to detect HPV? A. ELISA B. LBC* C. NAAT D. PCR Difficulty: Difficult ASM Standard: N/A 28. Trichomonas vaginalis is found as which of the following?

A. a cyst only B. a trophozoite only* C. a trophozoite or as a cyst D. an intracellular parasite only Difficulty: Difficult ASM Standard: 23 29. Trichomonas vaginalis consumes other microbes. What effect does this have?

A. By consuming other pathogens, it reduces the overall microbial load.

B. By consuming other pathogens, it reduces the risk of coinfection.

C. By consuming the normal microbiota, it causes an imbalance that increases the risk of infection.* D. By consuming the normal microbiota, it exhausts its food source and dies.

Difficulty: Difficult

ASM Standard: 23, 24

30. NAAT testing is preferred over evaluation of wet mounts for the diagnosis of trichomoniasis because NAAT is which of the following?

A. less expensive than using wet mounts B. less likely to cause adverse effects to the patient than are wet mounts C. more convenient than using wet mounts D. more sensitive than using wet mounts* Difficulty: Difficult ASM Standard: 34 31. How can primary and secondary syphilis be distinguished?

A. The presence of a hard chancre lesion indicates primary syphilis, whereas lesions of the skin and mucous membranes are found in secondary syphilis.* B. The presence of a localized, soft chancre lesion indicates primary syphilis, whereas secondary syphilis is associated with damage to the nervous system.

C. The presence of localized, soft lesions indicates primary syphilis, whereas systemic disease with lesions throughout the body is associated with secondary syphilis.

D. The presence of more severe, more painful symptoms indicates primary syphilis, whereas secondary syphilis is less noticeable until tertiary syphilis develops.

Difficulty: Difficult ASM Standard: 23 32. Tinidazole is a recommendedTtrEeS atT mB enAt N foKrS wEhL icL hE diR se.aC seO ?M A. human papillomavirus B. syphilis C. trichomoniasis* D. vaginosis Difficulty: Difficult ASM Standard: 14 33. HPV is extremely common and can be associated with genital warts, vaginal cancer, vulvar cancer, penile cancer, and anal cancer. How can it be so common with many infected people not realizing they have been infected?

A. Infections are often asymptomatic although they generally persist throughout life.

B. Infections are often asymptomatic and clear without treatment.* C. Infections generally cause mild symptoms although they generally persist throughout life.

D. Infections generally produce variable symptoms and are difficult to diagnose, even when suspected.

Difficulty: Difficult ASM Standard: N/A

True/False

34. In treating urethritis, it is important to consider that N. gonorrhoeae and C. trachomatis are often both present and must both be treated.

Answer: True Difficulty: Easy ASM Standard: 14, 23 35. Mycoplasma hominis, M. genitalium, and Ureaplasma urealyticum are rarely present in the microbiota of individuals without symptoms of urethritis.

Answer: False Difficulty: Easy ASM Standard: N/A 36. Lack of a cell wall means penicillins are ineffective against Mycoplasma genitalium.

Answer: True Difficulty: Moderate ASM Standard: 7, 14 37. Chlamydia often does not cause symptoms.

Answer: True Difficulty: Moderate ASM Standard: N/A 38. Herpes can be passed from mother to fetus, causing neonatal herpes.

Answer: True Difficulty: Moderate ASM Standard: 23 39. Lesions must be present in the birth canal for a mother to transmit herpes to a neonate.

Answer: False Difficulty: Moderate ASM Standard: 14, 23 40. All HPV strains are associated with both genital warts and cervical cancer.

Answer: False Difficulty:

Moderate ASM Standard: 23 41. HPV vaccination protects against all strains of HPV that can cause cervical cancer.

Answer: False

Difficulty: Difficult ASM Standard: 14, 23 42. There is no way to conclusively determine whether an individual has candidiasis because Candida is found in the normal microbiota. Answer: False Difficulty: Moderate ASM Standard: 23, 24 Matching 43. Match each type of inflammation with the affected structure.

A. cystitis i. inflammation of the urethra B. orchiditis ii. inflammation of the bladder C. pyelonephritis iii. inflammation of the fallopian tubes D. salpingitis iv. inflammation of the testicle E. urethritis v. inflammation of the kidney Answers: A. ii., B. iv., C. v., D. iii., E. i.

Difficulty: Easy ASM Standard: 23 44. Match each pathogen with the best description (bacterial, fungal, protozoal, or viral).

A. Candida albicans i. bacterial B. Chlamydia trachomatis ii. fungal C. HSV-2 iii. protozoal D. Trichomonas vaginalis iv. viral Answers: A. ii., B. i., C. iv., D. iii.

Difficulty: Moderate ASM Standard: 23 45. Match each disease with the common causative agent.

A. bacterial vaginosis i. Haemophilus ducreyi B. cervical cancer ii. Gardnerella vaginalis C. chancroid iii. HPV D. syphilis iv. Treponema pallidum E. yeast infection v. Candida albicans Answers: A. ii., B. iii., C. i., D. iv., E. v.

Difficulty: Moderate ASM

Standard: 23 46. Match each disease with the best treatment.

A. bacterial vaginosis i. azithromycin, ceftriaxone, erythromycin, ciprofloxacin

B. chancroid

ii. azithromycin and ceftriaxone but not erythromycin or ciprofloxacin C. chlamydia iii. penicillin G, tetracycline, doxycycline D. gonorrhea iv. clindamycin, metronidazole, tinidazole E. syphilis v. azithromycin, doxycycline, erythromycin, ofloxacin, levofloxaci n Answers: A. iv., B. i., C. v., D. ii., E. iii.

Difficulty: Difficult ASM Standard: 7, 14, 23 47. Match each disease with the best diagnostic approach.

A. bacterial vaginosis i. testing from a sample obtained during a Pap smear with LBC B. herpes ii. vaginal smear with DNA probe, sialidase assay, and Gram staining; use of Amsel’s diagnostic criteria C. human papillomavirus iii. wet mounts, NAATs, Affirm VPII Microbial Identification Test, and OSOM Rapid Test D. trichomoniasis iv. culture from lesions, immunostaining of cultures, PCR, or ELISA; PCR is especially valuable for systemic infections Answers: A. ii., B. iv., C. i., D. iii.

Difficulty: Difficult ASM Standard: 23 Fill in the Blank 48. Another word for vesicles is Answer: blisters

.

Difficulty: Easy ASM Standard: N/A 49. Bacterial vaginosis is associated with a(n) Answer: increase

in vaginal pH.

Difficulty: Easy ASM Standard: 22, 23 50. The two main categories of bacterial urethritis are Answer: gonococcal, nongonococcal Difficulty: Moderate ASM

and

.

Standard: N/A 51. A gonorrhea infection may enter the bloodstream. This results in bacterial infection of the blood.

, which is a

Answer: bacteremia Difficulty: Moderate ASM Standard: 23 52. The pathogen that is the major protozoan cause of urinary tract infections is Answer: Trichomonas vaginalis

.

Difficulty: Easy ASM Standard: 23 53. Exposure to contaminated water can lead to a bacterial kidney infection called Answer: leptospirosis

_.

Difficulty: Moderate ASM Standard: 23 54. Nervous system damage can occur in Answer: tertiary

syphilis.

Difficulty: Moderate ASM Standard: 23 55. Soft chancres are a symptom T ofESTBANK, S anEiL nL f eE ctR io. nC oO f tM he reproductive tract.

Answer: chancroid Difficulty: Moderate ASM Standard: 23 56. Candida is a dimorphic fungus, so the formation of tubes after cultivation can be used for diagnosis.

Answer: chlamydospores

and pseudohyphae from germ

Difficulty: Difficult ASM Standard: 23 57.

may be chronic or acute and can develop after S. pyogenes infection.

Answer: Glomerulonephritis Difficulty: Moderate ASM

Standard: 23 Short Answer 58. Why are the urinary and reproductive systems generally more prone to infections than are other body systems?

Sample Answer: The urinary and reproductive tracts are open to the external environment, increasing the risk of infection.

Difficulty: Easy ASM Standard: 23, 24 59. Describe the pathway urine takes from the kidney until it leaves the body.

Sample Answer: Urine is produced in the nephrons of the kidneys and drains from the kidney through the ureter. It travels through the ureter to the urinary bladder, then through the urethra to leave the body.

Difficulty: Easy ASM Standard: N/A 60. What is the difference between vaginitis and vaginosis?

Sample Answer: Vaginitis is a general term used to refer to any vaginal inflammation, whereas vaginosis refers to an imbalance in the normal vaginal microbiota without inflammation.

Difficulty: Moderate ASM Standard: 23 61. What is intermenstrual bleeding?

Sample Answer: IntermenstruTaE l bSleTeB diAnN gK isSbE leL edLinEgRt. haCt O ocMcurs between normal periods of menstruation; this suggests a possible infection.

Difficulty: Easy ASM Standard: 23, 24 62. Why is it better to diagnose bacterial vaginosis using examination of vaginal secretions instead of bacterial culture?

Sample Answer: Because the most common causative agent, Gardnerella vaginalis, is commonly found in healthy women, its presence in culture is not diagnostic of bacterial vaginosis.

Difficulty: Moderate ASM Standard: 23, 24 63. How does disruption of the normal microbiota lead to bacterial vaginosis?

Sample Answer: When the normal lactobacilli are disrupted through factors such as hormonal changes, the pH of the vagina increases, along with the risk of bacterial vaginosis.

Difficulty: Moderate

ASM Standard: 22, 23 64. What types of systemic effects can STIs have?

Sample Answer: In addition to affecting the urogenital system, STIs can cause a wide range of systemic effects. For example, tertiary syphilis affects the nervous system, gonorrhea can cause bacteremia, and HPV can lead to the development of cancer.

Difficulty: Moderate ASM Standard: 23 65. What are some symptoms of cystitis?

Sample Answer: Cystitis is associated with dysuria, bladder pain, hematuria, and pyuria.

Difficulty: Moderate ASM Standard: N/A 66. It is often important to obtain a “clean catch” of urine to test for infection. How is a clean catch obtained?

Sample Answer: The penis of male patients and both the urethral opening and labia of female patients are washed before sample collection and the first part of the urine flow is discarded.

Difficulty: Moderate ASM Standard: 23, 24 67. What complications can develop in elderly patients who develop cystitis?

Sample Answer: Elderly patients often develop potentially serious complications, including kidney infections and sepsis.

Difficulty: Moderate ASM Standard: N/A 68. What culture medium is used to culture a urine specimen?

Sample Answer: MacConkey agar and blood agar are generally used to culture urine specimens.

Difficulty: Moderate ASM Standard: 23 69. Why is it important to do blood cultures when evaluating patients with pyelonephritis?

Sample Answer: The pathogens may spread through the blood, requiring immediate treatment.

Difficulty: Moderate ASM Standard: 14,

23 70. How can Streptococcus pyogenes infection potentially cause glomerulonephritis?

Sample Answer: When S. pyogenes antigens are in the blood, immune complexes form between these and antibodies. These immune complexes become lodged in the glomeruli and the resulting immune response causes damage to the kidneys.

Difficulty: Difficult ASM Standard: 23 71. How is leptospirosis generally diagnosed?

Sample Answer: The fastest methods for diagnosis involve using PCR, ELISA, indirect immunofluorescence, and slide agglutination.

Difficulty: Moderate ASM Standard: 23 72. What virulence factors does C. trachomatis have?

Sample Answer: C. trachomatis has a range of virulence factors. These include stress response proteins, polymorphic outer-membrane autotransporter proteins, and type III secretion effectors.

Difficulty: Moderate ASM Standard: 23 Brief Essay Essay Question Rubric RATING Failin Below Competen g Average t Criteria Answer does TAnswer ESTBANKSEL fails to EAnswer R.COM provides for not provide an provide examples an argument evaluatio argument.

L to support an with one or two n Answer contains argument. examples that support it. inaccuracies.

Writing is poor Writing is and grammatical Writing is acceptable for poor and errors are the college level contains common. but may contain numerous Answer is one or two grammatical somewhat grammatical mistakes and incoherent. mistakes or misspellings. misspellings.

0 1 2 POINT VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Advance d Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

3

73. Explain how bacterial vaginosis can be diagnosed, including Amsel’s diagnostic criteria.

Answer: Student answers will vary but should include the following. Culturing is not effective because the causative agents are common in the normal microbiota. Instead, vaginal

secretions should be examined using a DNA probe, a sialidase assay, or microscopic examination. Clue cells are an important potential diagnostic feature. Amsel’s diagnostic criteria include at least three of the four following criteria: white to yellow discharge, a fishy odor (especially if 10% KOH is added), a pH higher than 4.5, and the presence of clue cells.

Difficulty: Moderate ASM Standard: 23 74. Why is N. gonorrhoeae urethritis sometimes difficult to treat?

Answer: Student answers will vary but should include the following. There are two major considerations. The first is that antibiotic resistance has been a problem with this species, leading to a shift to cephalosporins for treatment. The second is that N. gonorrhoeae often occurs along with C. trachomatis and treatment must effectively address both. The current recommendation is to use ceftriaxone and azithromycin.

Difficulty: Moderate ASM Standard: 14, 23, 31 75. Explain how the virulence factors of Ureaplasma urealyticum increase its ability to cause disease.

Answer: Student answers will vary but should include the following.

Ureaplasma urealyticum produces phospholipases that damage target cell plasma membranes, immunoglobulin α proteases that protect against host antibodies, and other substances.

Immunoglobulin α also produces hydrogen peroxide that can damage target cell membranes.

Other possible virulence factors include multiple banded antigen and urease.

Difficulty: Moderate ASM Standard: 23 76. Discuss how antibiotic resistance affects treatment recommendations and what can be done to deal with resistance.

Answer: Student answers will vary but should include the following. Students should provide examples of how antibiotic recommendations have changed for some pathogens because of resistance. Additionally, students should mention the general concepts of the following recommendations for antibiotic use: completing courses of antibiotics and using multiple antibiotic agents when needed. One potential example would be the common co-occurrence of N. gonorrhoeae and C. trachomatis, meaning that both should be treated simultaneously. Another example is the increasing U. urealyticum resistance to tetracyclines, meaning that fluoroquinolones are increasingly used instead.

Difficulty: Difficult ASM Standard: 14, 23, 31

This file is copyright 2017, Rice University. All rights reserved.

Chapter 24: Digestive System Infections * = Correct answer Multiple Choice 1. What is the pharynx?

A. an accessory digestive organ B. part of the gastrointestinal tract* C. part of the mouth D. the exit of the gastrointestinal tract Difficulty: Easy ASM Standard: N/A 2. What type of digestion occurs in the mouth?

A. chemical breakdown of food only B. physical breakdown of food only C. chemical and physical breakdown of food* D. neither chemical nor physical breakdown of food Difficulty: Easy ASM Standard: N/A 3. What types of microbes are found in the mouth?

A. archaea only B. bacteria only C. archaea and bacteria* D. neither archaea nor bacteria Difficulty: Easy ASM Standard: 23, 24 4. The environment in the stomach is which of the following?

A. acidic* B. alkaline C. neutral D. variable Difficulty: Easy ASM Standard: N/A 5. Oral thrush is caused by which pathogen?

A. Candida spp., including C. albicans* B. Herpes simplex virus 1 C. Prevotella intermedia

D. Streptococcus mutans

Difficulty: Easy ASM Standard: 23, 24 6. Shigellosis is also known as which of the following?

A. amoebic dysentery B. bacillary dysentery* C. salmonellosis D. typhoid fever Difficulty: Easy ASM Standard: 23 7. Typhoid fever is caused by which pathogen?

A. Salmonella paratyphi only B. Salmonella typhi only C. Salmonella paratyphi or S. typhi* D. Shigella dysenteriae Difficulty: Easy ASM Standard: 23 8. Cholera is best controlled by which of the following?

A. eradicating mosquito popuT laEtiS onTsBaA ndNuKsS inE gLinLseEcR t . reC peOllM ant B. increasing stomach acidity by avoiding the use of antacids and proton pump inhibitors C. using good sanitation and hygiene practices to the greatest extent possible* D. using prophylactic antibiotics for those visiting areas where cholera is endemic Difficulty: Easy ASM Standard: 14, 23 9. Plaque on teeth is an example of which of the following?

A. a biofilm* B. a cavity C. an infection D. dental caries Difficulty: Moderate ASM Standard: 21, 23, 24 10. How does Staphylococcus aureus cause gastrointestinal symptoms?

A. by producing enterotoxins when growing in food* B. by producing neurotoxins that are released into the food C. by reproducing in the intestines, causing enteritis

D. by reproducing in the stomach, causing gastritis and ulcers

Difficulty: Moderate ASM Standard: 23 11. What is the scientific name of the unusual bacterium that can survive in the acidic environment of the stomach and is associated with peptic ulcers, as well as with increased risk of stomach cancer?

A. Escherichia coli O157:H7 B. Heliobacter pylori* C. Salmonella typhi D. Vibrio cholerae Difficulty: Easy ASM Standard: 23, 24 12. What is the minimum safe holding temperature for cooked food?

A. 4 °C B. 40 °C C. 60 °C* D. 80 °C Difficulty: Moderate ASM Standard: 14, 23 13. Which group contains the moT stEdS anTgB erAoN usKES.EcoLlL i sEtrR ai. nC s fOoM r causing gastrointestinal illness?

A. EHEC* B. EIEC C. EPEC D. ETEC Difficulty: Moderate ASM Standard: 23 14. Hemolytic uremic syndrome is a serious condition that may lead to all but which of the following?

A. hypersecretion of fluids* B. kidney failure C. postinfection irritable bowel syndrome D. reactive arthritis Difficulty: Moderate ASM Standard: 23 15. Which is true about the treatment for ETEC?

A. Antibiotic treatment should be avoided because it increases the risk of HUS, although supportive therapy may be helpful.

B. Antibiotics are not recommended, although supportive therapy may be helpful.

C. Fluoroquinolones, ceftriaxone, and azithromycin are recommended in most cases.

D. It is usually self-limiting, although medications such as fluoroquinolones, doxycycline, TMP/SMZ, and rifamixin can be used.* Difficulty: Moderate ASM Standard: 14, 23 16. Which of the following aids identification of Vibrio cholerae, the causative agent for cholera, through culturing?

A. It produces green colonies on MacConkey agar.

B. It produces red colonies on MacConkey agar.

C. It produces white/colorless colonies on MacConkey agar.* D. It will not grow on MacConkey agar.

Difficulty: Moderate ASM Standard: 23 17. Which of the following is a disease that is often transmitted by undercooked, contaminated poultry?

A. Campylobacter jejuni gastroenteritis* B. Cholera C. Helicobacter pylori-related ulcers D. Vibrio parahemolyticus gastroenteritis Difficulty: Moderate ASM Standard: 23 18. Which of the following is not true about Clostridium difficile?

A. It can cause the development of pseudomembranous colitis.

B. It is a serious cause of nosocomial infections and can develop in association with antibiotic or proton pump inhibitor use.

C. It is common in normal human gastrointestinal microbiota.

D. It is not capable of forming endospores.* Difficulty: Moderate ASM Standard: 8, 23 19. Why is fecal transplant a promising treatment for Clostridium difficile infections?

A. It disrupts the pseudomembrane.

B. It provides a way to introduce medicine into the colon.

C. It replenishes the healthy microbiota.* D. It stimulates the expulsion of contaminated stool.

Difficulty: Moderate ASM Standard: 14, 23, 24

20. Yersinia entercolitica and Y. pseudotuberculosis commonly cause which of the following?

A. constipation due to bowel inflammation B. intoxications C. severe sepsis D. stomach ulcers Difficulty: Moderate ASM Standard: 23 21. A breath test can be used to detect which of the following pathogens?

A. E. coli O157:H7 B. H. pylori* C. S. typhimurium D. V. cholerae Difficulty: Moderate ASM Standard: 23 22. Which of the following is the most important mode of transmission for rotaviruses?

A. direct contact with infected individuals B. the consumption of undercooked fish C. the fecal-oral route* D. the inhalation of air droplets Difficulty: Easy ASM Standard: 23 23. Vaccination is routinely recommended for which type of virus?

A. adenovirus B. astrovirus C. norovirus D. rotavirus* Difficulty: Moderate ASM Standard: 14, 23 24. Jaundice is an important symptom of which disease?

A. hepatitis* B. norovirus gastroenteritis C. rotavirus gastroenteritis D. salmonellosis Difficulty: Easy

ASM Standard: 23 25. Which of the following is true regarding the diagnosis of amoebic dysentery?

A. A stool O&P exam is not usually diagnostic.

B. Enzyme immunoassay is especially useful because it allows the clinician to distinguish a current infection from prior exposure.

C. Examining a stool specimen on a single day is usually sufficient to catch almost all cases.

D. Magnetic resonance imaging may show the presence of liver abscesses.* Difficulty: Moderate ASM Standard: 23 26. Which of the following refers to neurocysticercosis?

A. Taenia asiatica adults form cysts in peripheral nervous tissue.

B. Taenia asiatica larvae become established in the intestines.

C. Taenia solium larvae form cysts in the brain/central nervous tissue.* D. Taenia solium proglottids lodge in nervous tissue.

Difficulty: Moderate ASM Standard: 23 27. In a clinical setting, rotavirus is most commonly diagnosed using which of the following?

A. culturing B. enzyme immunoassay* C. microscopy D. NAAT Difficulty: Difficult ASM Standard: 23 28. Which hepatitis virus can only infect an individual who has already been infected by hepatitis B virus?

A. HAV B. HCV C. HDV* D. HEC Difficulty: Moderate ASM Standard: 23 29. Which pathogen that can be transmitted via water is especially resistant to chlorination treatment?

A. Cryptosporidium parvum B. Cyclospora cayetanensis C. Entamoeba histolytica D. Giardia lamblia*

Difficulty: Difficult ASM Standard: 14, 23

30. A distinctive blue halo, visible upon examination using ultraviolet fluorescence microscopy, indicates the presence of which of the following?

A. Cryptosporidium hominis, as opposed to Cryptosporidium parvum, which does not fluoresce B. Cyclospora cayetanensis oocysts that are autofluorescing* C. Giardia lamblia cysts that have been exposed to chlorine D. the presence of Entamoeba histolytica cysts stained with blue fluorescent dye Difficulty: Difficult ASM Standard: 6, 23 31. Metronidazole would be an effective treatment for which condition?

A. cryptosporidiosis B. cyclosporiasis C. giardiasis* D. HCV Difficulty: Difficult ASM Standard: 14, 23 32. Which statement is not true about a way that Ascaris travels within the body?

A. It burrows through the skin of the feet and travel to the gastrointestinal tract through the circulatory system.

B. It can enter the respiratory tract from the circulatory system.

C. It can migrate from the lungs to the gastrointestinal tract.

D. It produces proteases that allow it to travel from the gastrointestinal tract through tissues to the circulatory system.* Difficulty: Difficult ASM Standard: 23 33. The movement of Ancylostoma braziliense through the skin causes the condition known as cutaneous larva migrans. Which of the following is a distinctive symptom of this condition?

A. Their tracks are visible and cause itching.* B. They cause small, localized patches of painless bumps.

C. They extend a breathing tube through the skin to breathe.

D. They produce painless nodules that are visible on the skin.

Difficulty: Difficult ASM Standard: 23

34. Hookworms penetrate the skin. They considered with gastrointestinal pathogens for which of the following reasons?

A. They more commonly cause infection after ingestion in undercooked food.

B. They penetrate the skin and then burrow directly to the gastrointestinal tract.

C. They penetrate the skin and then migrate through the circulatory system directly to the gastrointestinal tract.

D. They migrate through the circulatory system to the lungs, then are coughed up and swallowed to reach the gastrointestinal tract.* Difficulty: Difficult ASM Standard: 23 True/False 36. Pancreatic juice helps neutralize acidic, partially digested food in the small intestine.

Answer: True Difficulty: Easy ASM Standard: N/A 37. The small intestine contains the most diverse and numerous microbiota of the gastrointestinal tract.

Answer: False Difficulty: Easy ASM Standard: 23, 24 38. It safe to consume food from T aE reS frTigBerAaN toKr S seE t L t oLmEaR in.taCinOaMtemperature of 10 °C. Answer: False Difficulty: Moderate ASM Standard: 14, 23 39. Herpes simplex virus 1 can cause a mouth infection called herpetic gingivostomatitis.

Answer: True Difficulty: Moderate ASM Standard: 23, 24 40. Oral thrush occurs when a pathogen not normally part of the oral microbiota colonizes the oral cavity.

Answer: False Difficulty: Moderate ASM Standard: 23, 24

41. Mumps causes swelling of the parotid glands and can have serious complications, such as encephalitis and meningitis.

Answer: True

Difficulty: Moderate ASM Standard: 23, 24 42. The large intestine contains Clostridium spp. and archaeans, among many other microbial species.

Answer: True Difficulty: Moderate ASM Standard: 23, 24 43. Corticosteroids can cause strongyloidiasis to become more severe, because they stimulate an excessive immune response.

Answer: False Difficulty: Difficult ASM Standard: 14, 23, 24 Matching 44. Match each type of hypersensitivity with the best definition.

A. colitis i. inflammation of the stomach B. enteritis ii. inflammation of the colon C. gastritis iii. inflammation of the gums D. gastroenteritis iv. iT nfE laS mTmBaA t ioNnKoSf E thLeLliE veRr.COM E. gingivitis v. inflammation of the intestinal mucosa F. hepatitis vi. inflammation of both the stomach and intestinal mucosa Answers: A. ii., B. v., C. i., D. vi., E. iii., F. iv.

Difficulty: Easy ASM Standard: N/A 45. Match each hepatitis virus with the best description.

A. hepatitis virus A i. can only cause infection in patients infected with HBV; usually self-limiting B. hepatitis virus B ii. transmitted via body fluids; often asymptomatic but can cause cirrhosis and liver cancer; no vaccine exists C. hepatitis virus C iii. transmitted via the fecal-oral route, especially in undercooked food or contaminated water; can also be transmitted person to person or as a zoonosis, depending on genotype; most common in developing countries; vaccine available in China.

D. hepatitis virus D iv. transmitted via contaminated food and water, as well as through direct contact; usually relatively mild and self-limiting; vaccine exists

E. hepatitis virus E

v. transmitted via body fluids; can cause cirrhosis and liver cancer; vaccine exists Answers: A. iv., B. v., C. ii., D. i., E. iii.

Difficulty: Moderate ASM Standard: 14, 23 46. Match each type of infection with the recommended treatment.

A. EPEC i. ivermectin, albendazole B. giardiasis ii. clotrimazole, nystatin, fluconazole, itraconazole; amphotericin B for severe cases C. oral thrush iii. fluoroquinolones, doxycycline, rifamixin, TMP/SMZ if necessary D. shigellosis iv. metronidazole, tinidazole E. strongyloidiasis v. ciprofloxacin, azithromycin Answers: A. iii., B. iv., C. ii., D. v., E. i.

Difficulty: Difficult ASM Standard:14 47. Match each pathogen with its classification.

A. Clostridium perfringens B. Cryptosporidium parvum C. HBV D. Trichinella spiralis Answers: A. ii., B. iii., C. i., D. iv.

i. virus ii. bacterium iii. protist iv. helminth

Difficulty: Moderate ASM Standard: 23 48. Match each disease with the most common diagnostic method used for it.

A. Campylobacter jejuni gastroenteritis i. culture on selective medium with elevated temperature and low oxygen concentration B. giardiasis ii. microscopic examination of oral samples C. oral candidiasis D. norovirus E. taeniasis Answers: A. i., B. iii., C. ii., D. v., E. iv.

Difficulty: Difficult ASM Standard: 23 Fill in the Blank

iii. O&P exam, sometimes ELISA and direct fluorescence antibody assays iv. microscopic examination of stool for segments and eggs from three separate days v. rapid enzyme immunoassay confirmed with RT-qPCR

49.

can develop from chronic, severe gingivitis.

Answer: Periodontitis

Difficulty: Easy ASM Standard: N/A 50. Cholera is caused by the pathogen Answer: Vibrio cholerae

.

Difficulty: Easy ASM Standard: 23 51.

can have serious complications, such as encephalitis and deafness.

Answer: Mumps Difficulty: Moderate ASM Standard: 23

52. Acute necrotizing ulcerative gingivitis is also known as Answer: trench mouth or Vincent’s disease

.

Difficulty: Moderate ASM Standard: 23 53. Shigella dysenteriae type 1 produces a toxin that affects protein synthesis in endothelial cells called .

Answer: Shiga toxin Difficulty: Moderate ASM Standard: 23 54. Many virulence factors of Salmonella typhi are found on Answer: Salmonella pathogenicity islands

.

Difficulty: Moderate ASM Standard: 23 55. The E. coli pathogenic group that causes traveler’s diarrhea is Answer: ETEC (enterotoxigenic E. coli) Difficulty: Moderate ASM Standard: 23

_.

56. The fibrin layer of dead epithelial cells and leukocytes that can develop during Clostridium difficile infection is called a .

Answer: pseudomembrane Difficulty: Moderate ASM Standard: 23

57. The locus of enterocyte effacement (LEE) pathogenicity island is found in Answer: enteropathogenic E. coli (EPEC)

.

Difficulty: Difficult ASM Standard: 23 58. The activity of the A-B toxin of Vibrio cholerae is through Answer: adenylate cyclase

.

Difficulty: Moderate ASM Standard: 23 Short Answer 59. How does the acidic environment in the stomach affect its microbiota?

Sample Answer: Most microbes are killed by the acidic environment, which is part of the nonspecific immune response. Heliobacter pylori is unusual because it thrives in the stomach and is associated with stomach ulcers.

Difficulty: Easy ASM Standard: 23, 24

BhAiN 60. Foodborne illness can be causTeE dS byTw chKBSaEcillL usEsRp. ecCieOs M that produces a toxin that causes vomiting and one that causes diarrhea?

Sample Answer: Bacillus cereus can cause gastroenteritis.

Difficulty: Easy ASM Standard: 23 61. What are symptoms of cholera?

Sample Answer: Cholera causes severe diarrhea (rice-water stool), which can lead to severe dehydration. Dehydration, in turn, can lead to shock, renal failure, and even death, if good medical care is not available.

Difficulty: Easy ASM Standard: 23 62. Why do noroviruses often cause large-scale illness in dense accommodations, such as cruise ships?

Sample Answer: Noroviruses are highly contagious and not killed by standard disinfectant regimens for killing bacteria, so they can spread rapidly when people are in close contact.

Difficulty: Easy ASM Standard: 14, 23

63. If you kill Staphylococcus aureus in food products and then consume them, it is still possible to become sick. How is this possible?

Sample Answer: Staphylococcus aureus produces enterotoxins and enterotoxin-like toxins that are heat stable. These may be present in food even if the food has been cooked to sufficiently high temperatures that the bacteria are killed, because these enterotoxins are not destroyed by standard cooking temperatures or boiling at 100 °C. Difficulty: Moderate ASM Standard: 14, 23 64. What conditions can increase the risk of Clostridium difficile infection?

Sample Answer: Clostridium difficile infections often occur after long-term antibiotic or proton pump inhibitor use. Individuals who are immunocompromised are at increased risk.

Difficulty: Moderate ASM Standard: 23 65. What toxins are produced by Clostridium difficile?

Sample Answer: Clostridium difficile produces C. difficile toxin A (TcdA) and C. difficile toxin B (TcdB).

Difficulty: Moderate ASM Standard: 23 66. How can astroviruses be diagnosed?

Sample Answer: To diagnose astroviruses, stool samples are examined and then tested using enzyme immunoassays and electron microscopy.

Difficulty: Moderate ASM Standard: 23 67. What are the best approaches to controlling rotoviruses, noroviruses, and astroviruses?

Sample Answer: Good hygiene and sanitation, including good hand -washing techniques, are very helpful. Changing disinfectant procedures may be necessary because standard procedures may not be sufficient. Sick individuals should stay away from healthy individuals to reduce the risk of transmission.

Difficulty: Moderate ASM Standard: 14, 23 68. How do hepatitis viruses cause jaundice?

Sample Answer: Hepatitis viruses affect the liver (“hepatitis” means inflammation of the liver). As the viruses replicate in liver cells, they interfere with the ability of the liver to

break down hemoglobin. This leads to a buildup in the blood of bilirubin, a breakdown product of hemoglobin. Because the normal metabolism and breakdown of bilirubin is disrupted, the color of the excessive bilirubin produces the yellowish skin color associated

with jaundice. The same color can be seen as one of the colors of a bruise, appearing during the breakdown of hemoglobin.

Difficulty: Moderate ASM Standard: 23 69. Why is the HBV vaccine recommended for health-care workers?

Sample Answer: HBV can be transmitted through body fluids. Health-care workers are at increased risk of exposure due to possible needle sticks or other exposure to body fluids.

Difficulty: Moderate ASM Standard: 23 70. How does the HBV vaccine protect against HDV? Sample Answer: Individuals can only develop an HDV infection if they are already infected with HBV. HDV requires the HBV virus to replicate. If someone has been vaccinated against HBV, they can’t become infected with HDV. Difficulty: Moderate ASM Standard: 23 71. Why is an enzyme immunoassay insufficient to determine whether someone has amoebic dysentery at the time of the exam versus at some time in the past?

TuEnSoaTsBsaAyN Sample Answer: Enzyme imm s dKeS teEctLaLnE t ibRo. dC ieO s.M Someone who has been previously exposed to Entamoeba histolytica would have antibodies for it even if not currently infected.

Difficulty: Difficult ASM Standard: 23 72. Why should you generally discontinue any existing antibiotic treatment for a patient with a Clostridium difficile infection? Should you discontinue all treatment?

Sample Answer: Clostridium difficile can develop after antibiotic use because the normal flora is disrupted, allowing for C. difficile overgrowth. It’s important to discontinue the current antibiotic because it may have played a role in the development of the infection. Other treatments, including supportive treatments, fecal transplants, metronidazole, and vancomycin, may also be used.

Difficulty: Difficult ASM Standard: 14, 23

73. How can Giardia transmission through public water supplies be prevented?

Sample Answer: Giardia forms cysts that are resistant to chlorine and cold temperatures.

Public-water suppliers can use filters to trap the cysts to reduce the risk of infection. It is also important to reduce sources of contamination through which Giardia could get into the water.

Difficulty: Difficult ASM Standard: 14, 23 Brief Essay Essay Question Rubric Failin Below RATING g Average Criteria Answer does Answer fails to for not provide an provide evaluatio argument. examples to n Answer contains support an inaccuracies. argument.

Writing is Writing is poor poor and and grammatical contains errors are numerous common. grammatical Answer is mistakes and somewhat misspellings. incoherent.

Competen t Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

POINT 0 1 2 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Advance d Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

3

74. Describe how you would treat an individual with Giardia, including what could happen if the infection fails to clear. The latter part of the question is not directly answered in the chapter; therefore, you should speculate about what you could do.

Answer: Student answers will vary but should include the following. The recommended treatment for Giardia is metronidazole, with tinidazole as a second option. If the infection does not clear during treatment, it can be chronic. Chronic Giardia infections can become resistant and difficult to treat. There are some other medications that have been used to treat Giardia, some experimental treatments have been tried, and nonstandard doses can be used.

At that point, a health-care professional would need to consult the most recent guidelines and recommendations, and consider nonstandard treatments.

Difficulty: Moderate ASM Standard: 14, 23 75. How could you recognize an Ascaris infection from clinical symptoms and laboratory testing?

Answer: Student answers will vary but should include the following. Symptoms of Ascaris infection may be mild to nonexistent, or patients may have shortness of breath, cough, abdominal pain, nausea, bloody stool, weight loss, and fatigue. Intestinal blockage

occasionally occurs and worms may be visible to the naked eye in stool. Examination of the stool can be used to identify worms and/or eggs. Worms may also be coughed up.

Imaging (including radiographs, MRIs, and ultrasounds) can be used to look for large numbers of worms, as could occur in a blockage.

Difficulty: Moderate ASM Standard: 23 76. Explain the relationship between immunosuppression and Strongyloides infections.

Answer: Student answers will vary but should include the following. Strongyloides infections are often asymptomatic and the immune system keeps the infection under control.

Immunosuppression affects the infection in several ways. It increases the rate of autoinfection, in which the worms re-enter the body after excretion. It also increases the ability of larvae to migrate throughout the body. As a result, someone who was previously asymptomatic could develop severe symptoms after treatment with immunosuppressive medication or due to factors (such as illness) that cause immunosuppression.

Difficulty: Difficult ASM Standard: 23 77. You suspect that an individual has a helminthic infection. How can you narrow down the cause to choose the best treatment?

Answer: Student answers will vary but should include the following. Symptoms of different helminthic infections vary and should help reduce the list of best testing protocols.

Additionally, many helminthic parasites can be detected through microscopic examination of the stool. By doing this test fiT rsE t,S itTcB ouAldNK beSpEoL ssL ibEleRt. o C idO enMtify the organism if the symptoms alone were not sufficient to decide on a diagnostic protocol.

Depending on the symptoms, imaging may be helpful if there is evidence of a localized problem (e.g., an abscess or neurological symptoms). Muscle biopsies, serological testing, and immunological testing, among other options, are also available but most useful if a particular organism is suspected.

Difficulty: Difficult ASM Standard: 14, 23

This file is copyright 2017, Rice University. All rights reserved.

TESTBANKSELLER.COM OpenStax MicrobiolC o ghyaTpetsetrB2a5n:k Circulatory and Lymphatic System Infections Chapter 25: Circulatory and Lymphatic System Infections

* = Correct answer Multiple Choice 1. Where does oxygenated blood enter the heart?

A. the left atrium* B. the left ventricle C. the right atrium D. the right ventricle Difficulty: Easy ASM Standard: N/A 2. Which artery carries deoxygenated blood?

A. aorta B. femoral C. pulmonary* D. subclavian Difficulty: Easy ASM Standard: N/A 3. Which of the following is an infection of the inner lining of the heart?

A. endocarditis* B. myocarditis C. pericarditis D. vasculitis Difficulty: Easy ASM Standard: 23 4. Which pathogen causes toxic shock syndrome?

A. Enterococcus faecalis B. Pseudomonas aeruginosa C. Staphylococcus aureus* D. Vibrio cholerae Difficulty: Easy ASM Standard: 23 5. Which pathogen causes gas gangrene?

A. Bacillus spp.

Page B 11. 5Colof stridium spp.* C. Staphylococcus spp.

D. Streptococcus spp.

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Difficulty: Easy ASM Standard: 23 6. What is another name for tularemia?

A. brucellosis B. rabbit fever* C. toxic shock syndrome D. Valley fever Difficulty: Easy ASM Standard: 23 7. The gram-negative bacterium Yersinia pestis causes which disease(s)?

A. bubonic plague only B. bubonic and septicemic plague only C. pneumonic and septicemic plague only D. bubonic, pneumonia, and septicemic plague* Difficulty: Easy ASM Standard: 23 8. Which of the following infections is transmitted by ticks?

A. brucellosis B. ehrlichiosis* C. plague D. rat bite fever Difficulty: Easy ASM Standard: N/A 9. Which organ of the human body removes damaged red blood cells?

A. heart B. kidneys C. liver* D. pancreas Difficulty: Moderate ASM Standard: N/A 10. Which of the following is true of lymphatic fluid?

A. It contains erythrocytes.

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B. It is sterile.

C. It travels at slower speeds than blood.* D. Its fluid composition is very different from plasma.

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Difficulty: Moderate ASM Standard: N/A 11. Which of the following is a type of primary lymphoid tissue?

A. bone marrow* B. diffuse lymphoid tissue C. lymph nodes D. the spleen Difficulty: Moderate ASM Standard: N/A 12. What is a dangerous drop in blood pressure associated with infection called?

A. bacteremia B. hypotensive shock C. sepsis D. septic shock* Difficulty: Moderate ASM Standard: 23 13. Which of the following is true of staphylococcal toxic shock syndrome?

A. Most infected individuals have negative serological tests even if infected.

B. Most infected individuals T haE vS eT neBgA atN ivK eS skEinLL anE d Rb. loC odOM cultures.* C. Most infected individuals test negative, so clinical symptoms are used for diagnosis.

D. Most infected individuals test positive in both serological tests and cultures.

Difficulty: Moderate ASM Standard: 23 14. Instead of basing diagnosis solely on clinical symptoms and patient history, what common approach is used to confirm a tularemia infection?

A. culturing techniques B. direct fluorescent antibody microscopic examination* C. light microscopy and Gram staining.

D. phase-contrast microscopy Difficulty: Moderate ASM Standard: 6, 23 15. Which of the following individuals would be most likely to receive antibiotics for cat scratch disease?

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A. an individual likely to be repeatedly exposed to infected cats B. an individual undergoing cancer treatment simultaneously* C. an individual who exhibits a fever D. an individual who develops pus nodules at the site of the scratch

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Difficulty: Moderate ASM Standard: 14, 23 16. What are buboes?

A. abscesses within blood vessels B. abscesses within lungs C. infected swellings involving follicles D. inflamed, swollen lymph nodes* Difficulty: Moderate ASM Standard: 23 17. Which of the following describes undulant fever?

A. It is associated with seizures.

B. It is associated with an especially high temperature.

C. It is chronic.

D. It is variable; it comes and goes.* Difficulty: Moderate ASM Standard: 23 18. Rocky Mountain spotted fever is most common in which region of the United States?

EiL A. the Midwestern United StaTteEs,SiT ncBluAdN inKgSM n nLeE soRta., C IoOwMa, North Dakota, South Dakota, and Wisconsin B. the northeastern United States, including New York and Connecticut C. the southeastern United States, including Oklahoma, Arkansas, Tennessee, Missouri, and North Carolina* D. the western United States, including the Rocky Mountains of Colorado and Wyoming Difficulty: Moderate ASM Standard: 23 19. Which of the following best describes Borrelia burgdorferi?

A. a bacillus that causes plague B. a coccus that causes cat scratch disease C. a spirillum that causes Rocky Mountain spotted fever D. a spirochete that causes Lyme disease* Difficulty: Moderate ASM Standard: 23 Page 120 of

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20. How should a tick be removed?

A. It should be covered with petroleum jelly until it releases its hold and can be easily removed.

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B. It should be grasped gently with blunt tweezers on the head, near its site of attachment, and pulled very carefully until it releases its grip.* C. It should be grasped gently with tweezers on the tick’s abdomen, then twisted until it comes off.

D. It should be touched with a hot match until it releases its grip, then gently removed, taking care to extract all parts.

Difficulty: Moderate ASM Standard: 14, 23 21. A radiograph is used to diagnose which condition?

A. anaplasmosis B. infectious arthritis C. Lyme disease D. osteomyelitis* Difficulty: Moderate ASM Standard: 23 22. Which of the following conditions is caused by the Epstein-Barr virus?

A. erhlichiosis B. infectious mononucleosis* C. Rocky Mountain spotted fever D. yellow fever Difficulty: Moderate ASM Standard: 23 23. What is the standard protocol for HIV diagnosis?

A. ELISA testing, repeated after 6 months for confirmation and followed by NATs B. serological testing followed by Western blot or PCR testing for confirmation or NATs* C. serological testing only, with no additional testing needed D. viral culturing followed by appropriate serological testing for confirmation Difficulty: Moderate ASM Standard: 23 24. Malaria is an important cause of mortality worldwide, making it a significant public health concern. What is the classic presentation of malaria?

A. abrupt development of a dangerously high fever B. abrupt development of malaise with cycles of chills and high fever, among other symptoms* C. slowly escalating headache, nausea, and vomiting, without fever and with variable other Page 122 of

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symptoms D. slowly escalating temperature that reaches dangerously high levels after several days to a week

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Difficulty: Moderate ASM Standard: 23 25. Which type of pathogen causes babesiosis?

A. a bacterium B. a fungus C. a protist* D. a virus Difficulty: Moderate ASM Standard: 23 26. What is the best approach to treating toxic shock syndrome, a potentially deadly condition?

A. decontamination and debridement without the use of antibiotics, because of the risk of toxin release by dying bacteria B. decontamination, debridement, vasopressors, and a combination antibiotic therapy such as clindamycin with vancomycin* C. decontamination, debridement, vasoconstrictors, and a combination antibiotic therapy such as clindamycin with daptomycin D. decontamination, vasopressors, and treatment with a single antibiotic Difficulty: Difficult ASM Standard: 14, 23 27. Bartonella henselae is generally transmitted to humans by what means?

A. bites by vectors such as mosquitoes B. cat scratches and bites* C. consumption of undercooked meat D. consumption of contaminated water Difficulty: Moderate ASM Standard: 23 28. Of the 15 known virulence factors for Yersinia pestis, which of the following indicates how many are factors that facilitate attachment to host cells?

A. about one-fourth B. about one-third C. only one or two D. more than half* Difficulty: Difficult ASM Page 124 of

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Standard: 23 29. Which of the following would a urease-deficient strain of Brucella be unable to do?

A. attach to host cells effectively

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B. penetrate host cells effectively C. spread rapidly through the circulatory system D. survive in the acidic environment of the stomach* Difficulty: Difficult ASM Standard: 13, 23 30. Pamela spends a day hiking in the woods then finds a tick on her skin that evening. Could the tick have transmitted Lyme disease?

A. Yes, because any contact with an infected tick is sufficient to transmit Lyme disease.

B. Yes, because the tick was probably attached for more than 4 hours.

C. No, because Lyme disease is not transmitted by ticks.

D. No, because the tick was not attached for at least 24 hours.* Difficulty: Difficult ASM Standard: 23 31. Which of the following is not a type of medication used to treat HIV? A. medications that block RNA-dependent DNA polymerases B. medications that block HIV replication enzymes C. medications that denature the virus* D. medications that prevent the virus from entering cells Difficulty: Difficult ASM Standard: 10, 14, 23 32. An individual is suspected of having malaria on the basis of clinical symptoms. Which steps should a medical professional take to confirm and treat a malaria diagnosis?

A. microscopic analysis of a blood smear and staining, followed by treatment with azithromycin, doxycycline, or tetracycline.

B. microscopic analysis of a blood smear and/or enzyme immunoassay followed by treatment with chloroquine, artemether, atovaquone, or lumefantrine* C. PCR followed by treatment with nifurtimox or benznidazole D. serological tests followed by treatment with stibogluconate or amphotericin B Difficulty: Difficult ASM Standard: 14, 23 33. Which form of Schistosoma penetrates the skin?

A. cercariae* B. cysts C. miracidia D. spores Page 126 of

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Difficulty: Difficult ASM Standard: 23

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True/False 34. Pericarditis is an inflammation of the heart muscle.

Answer: False Difficulty: Easy ASM Standard: N/A 35. Infectious arthritis is a bacterial infection that can be acute or chronic.

Answer: True Difficulty: Easy ASM Standard: 23 36. Septicemic plague has a high mortality rate, approaching 100% in untreated individuals and approximately 50% even if antibiotics are given.

Answer: True Difficulty: Moderate ASM Standard: 14, 23 37. Lyme disease always causes a bull’s eye rash.

Answer: False Difficulty: Moderate ASM Standard: 23 38. Malaria is caused by a protozoan parasite, most commonly Plasmodium falciparum.

Answer: True Difficulty: Moderate ASM Standard: 23 39. Staphylococcus aureus is the most common cause of osteomyelitis.

Answer: True Difficulty: Moderate ASM Standard: 23 40. Prophylactic antibiotic treatment is sometimes used for those at high risk of developing Page 128 of

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recurrent rheumatic fever.

Answer: True Difficulty: Difficult ASM Standard: 23

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41. Doxycycline is rarely used to treat infections caused by EBV. Answer: False Difficulty: Difficult ASM Standard: 14, 23 Matching 42. Match each type of blood condition with the best definition.

A. bacteremia i. bacteria are reproducing in the blood B. septicemia ii. bacteria are present in the blood C. toxemia iii. viruses are present in the blood D. viremia iv. toxins are present in the blood Answers: A. ii., B. i., C. iv., D. iii.

Difficulty: Easy ASM Standard: 23 43. Match each bacterial disease with its causative agent.

A. plague i. Rickettsia rickettsii B. rabbit fever ii. Yersinia pestis C. relapsing fever iii. Francisella tularensis v.EBRa. rtC onOeM lla quintana D. rheumatic fever TESTBANKSELiL E. Rocky Mountain spotted fever v. Borrelia sp.

F. trench fever vi. Streptococcus pyogenes Answers: A. ii., B. iii., C. v., D. vi., E. i., F. iv.

Difficulty: Moderate ASM Standard: 23 44. Match each viral disease with its characteristic symptoms.

A. Burkitt lymphoma i. flu-like symptoms that develop into pulmonary edema, hypotension, pneumonia, and shock B. Chikungunya fever ii. blisters, high fever, rash, and joint pain that may last for months C. Ebola virus disease iii. headache, fever, vomiting, diarrhea, and hemorrhage that may lead to severe bleeding, shock, and organ failure D. hantavirus pulmonary syndrome iv. flu-like symptoms followed by a latent period without symptoms, then wasting, and increased susceptibility to opportunistic infections E. HIV infection/AIDS v. malignant B-cell tumors and oral hairy leukoplakia Answers: A. v., B. ii., C. iii., D. i., E. iv.

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45. Match each disease with the antimicrobial therapy most frequently used for its treatment.

A. babesiosis i. stibogluconate or amphotericin B B. Chagas disease ii. nifurtimox or benznidazole C. leishmaniasis iii. atovaquone and azithromycin or clindamycin and quinine D. malaria iv. praziquantel E. schistosomiasis v. chloroquine, atovaquone, artemether, or lumefantrine F. toxoplasmosis vi. sulfadiazine, pyrimethamine, or spiramycin Answers: A. iii., B. ii., C. i., D. v., E. iv., F. vi.

Difficulty: Moderate ASM Standard: 14, 23 46. Match the disease with the mode of transmission.

A. babesiosis i. direct contact with body fluids from an infected individual B. hantavirus pulmonary syndrome ii. exposure to pathogens that enter the bloodstream through injury or trauma, sometimes followed by dissemination C. infectious mononucleosis iii. inhalation of contaminated rodent feces or urine D. osteomyelitis iv. bite by an infected tick E. tularemia v. ingestion of infected meat or handling of infected animals Answers: A. iv., B. iii., C. i., T DE .

KSELLER.COM iS i.,TEB.A v.N Difficulty: Difficult ASM Standard: 23 Fill in the Blank 47. Epstein-Barr virus causes Burkitt lymphoma and Answer: infectious mononucleosis

.

Difficulty: Easy ASM Standard: 23 48.

are a class of viruses that are transmitted by arthropod vectors.

Answer: Arboviruses Difficulty: Easy ASM Standard: 23

49.

plague is easier to treat than the other two forms.

Answer: Bubonic Difficulty: Moderate ASM Standard: 14, 23

50. Ebolavirus is classified as a type of virus called a Answer: filovirus

.

Difficulty: Moderate ASM Standard: 23 51. Hantavirus pulmonary syndrome is treated using _ Answer: supportive

_ care.

Difficulty: Moderate ASM Standard: 14, 23 52. After initial acute infection with HIV, patients experience a period of Answer: latency

_.

Difficulty: Moderate ASM Standard: 23 53. One opportunistic infection associated with AIDS is Answer: Pneumocystis

pneumonia.

Difficulty: Moderate ASM Standard: 23 54. Toxoplasmosis can be contracted by handling contaminated Answer: cat

feces.

Difficulty: Moderate ASM Standard: 23 55. The symptoms of malaria occur when parasites called stage, are released simultaneously.

Answer: merozoites

, based on their life cycle

Difficulty: Difficult ASM Standard: 23 56. During the first trimester of pregnancy, women with toxoplasmosis may be treated with to reduce the risk of birth defects.

Answer: spiramycin

Difficulty: Difficult ASM Standard: 14, 23 Short Answer

57. What is another name for cytomegalovirus?

Sample Answer: Cytomegalovirus is also known as human herpesvirus 5.

Difficulty: Easy ASM Standard: 23 58. What is ART? Sample Answer: ART is antiretroviral therapy, like that used to treat HIV. Students may also mention that it usually involves the use of multiple drugs to help prevent resistance.

Difficulty: Easy ASM Standard: 14, 23 59. What other disease can be caused by hantavirus besides hantavirus pulmonary syndrome?

Sample Answer: Hemorrhagic fever with renal syndrome (HFRS) can also be caused by hantavirus. Students may also mention that HFRS has not been reported in the United States.

Difficulty: Easy ASM Standard: 23 60. What is an example of a helminthic disease that affects the circulatory and lymphatic systems? .C Sample Answer: Schistosom iT a sEisS(T b iB lhAarNzK i aS ) E is L anLE exR am plO e M of a helminthic disease that affects the circulatory and lymphatic systems.

Difficulty: Easy ASM Standard: 23 61. What is the difference between the pericardium, myocardium, and endocardium?

Sample Answer: The pericardium is the sac surrounding the heart, the myocardium is the heart muscle, and the endocardium is the inner lining of the heart.

Difficulty: Moderate ASM Standard: N/A 62. How can someone reduce their risk of contracting toxoplasmosis?

Sample Answer: They should use good food hygiene, including washing vegetables and preparing food appropriately by cooking it thoroughly, and use good hygiene and hand washing when in contact with cat litter.

Difficulty: Moderate ASM Standard: 14, 23

63. How can the risk of malaria infection be reduced without the use of medication?

Sample Answer: Malaria is transmitted by mosquitoes, so people can avoid areas with mosquitoes, wear protective clothing, use insect repellent, and use insect netting to protect beds.

Difficulty: Moderate ASM Standard: 14, 23 64. Why is yellow fever no longer a significant threat in the United States, when it used to be common?

Sample Answer: Yellow fever is transmitted by mosquitoes and efforts to control mosquitoes have made it less common. Students may also mention that vaccination has reduced rates of yellow fever infection, but vector control has been most critical in the United States.

Difficulty: Moderate ASM Standard: 14, 23 65. What are the potential consequences if a woman contracts cytomegalovirus during pregnancy?

Sample Answer: If cytomegalovirus is transmitted to the fetus, it can sometimes (in approximately 20% of cases) result in birth defects such as deafness.

Difficulty: Moderate ASM Standard: 23 66. What does it mean to say that HIV is a retrovirus?

Sample Answer: Retroviruses are RNA viruses that have a DNA stage in their life cycle. They use the enzyme reverse transcriptase to copy their RNA into cDNA. Difficulty: Moderate ASM Standard: 10, 23 67. How is leishmaniasis transmitted?

Sample Answer: Leishmaniasis is transmitted by sand flies.

Difficulty: Moderate ASM Standard: 23 68. How do snails play a role in the life cycle of Schistosoma?

Sample Answer: After Schistosoma hatch as miracidia, they infect freshwater snails. They develop into cercariae within the snails before returning to the water, with the ability to infect humans.

Difficulty: Moderate ASM Standard: 69. How does Leishmania survive within phagolysosomes?

Sample Answer: Leishmania has virulence factors that are able to inhibit enzymes that would normally digest pathogens within the phagolysosome. Students may also provide more information regarding these virulence factors.

Difficulty: Difficult ASM Standard: 23 70. Which patients with Epstein-Barr virus are at risk of developing Burkitt lymphoma?

Sample Answer: Burkitt lymphoma can develop in immunocompromised patients, such as those with HIV or malaria.

Difficulty: Difficult ASM Standard: 23 71. A patient has developed symptoms a week after removing a tick, but did not keep the tick.

The patient did not notice a bull’s eye rash and the symptoms are unclear. While waiting for diagnostic testing, what antibiotic is most likely to be useful and why?

Sample Answer: Although not effective against all tick diseases, doxycycline is frequently useful for these illnesses. It is effective in treating Lyme disease, ehrlichosis, and Rocky Mountain spotted fever. However, it is not effective for other tick-borne illnesses, such as babesiosis. The decision would be affected by the prevalence of specific tick-borne diseases in the area.

Difficulty: Difficult ASM Standard: 23 Brief Essay Essay Question Rubric RATING Failin Below g Average Criteria Answer does Answer fails to not provide an for provide evaluatio argument. examples to n Answer contains support an inaccuracies. argument.

Writing is Writing is poor poor and and contains grammatical numerous errors are grammatical common. mistakes and Answer is misspellings. somewhat incoherent.

Competen t Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

Advance d Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

0 1 2 POINT VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

3

72. Explain how a bacterial infection can lead to life-threatening septic shock, including a description of what causes blood pressure changes.

Answer: Student answers will vary but should include the following. A bacterial infection causes an immune response. Large quantities of interleukin-1 and TNF-α released into the blood cause vasodilation accompanied by leakage from blood vessels due to reduced tight junctions in their epithelia. As fluid leaks from the circulatory system and causes edema, and blood vessels widen, the reduced blood volume can cause blood pressure to fall. Shock is the condition in which blood pressure is too low for the body to function normally.

Kidney and respiratory functions may fail. In addition, the huge cytokine release into the blood as part of the inflammatory response may also lead to the formation of blood clots.

Overall, this may lead to organ failure and death.

Difficulty: Moderate ASM Standard: 23 73. Why is it so difficult to find a way to remove the HIV virus from the body once an infection is established? Why does the immune system fail to eliminate it?

Answer: Student answers will vary but should include the following. The HIV virus integrates into the host cell chromosome as a provirus, making it difficult to target.

Additionally, it mutates rapidly because it uses reverse transcriptase to transcribe its RNA genome to cDNA. Reverse transcriptase is not able to proofread, so viruses that use it mutate relatively rapidly. This means the virus changes too quickly for the body to produce specific antibodies that reliably target it. Additionally, the virus infects CD4 T cells and KmSuEnLocLoEmRp. these eventually decrease in numbeT r,EcS auTsiBnA g N im roC mOisMe. Difficulty: Moderate ASM Standard: 14, 23 74. Cytomegalovirus is a relatively common virus that can cause serious consequences for some individuals. Describe its prevalence and reasons why particular populations are at higher risk of serious complications.

Answer: Student answers will vary but should include the following. Cytomegalovirus is so common that about half of individuals have experienced infection before adulthood. In most cases, individuals are asymptomatic or the symptoms are mild. However, cytomegalovirus can cause infectious mononucleosis and symptoms such as fatigue and fever. The virus is of particular concern for pregnant women, transplant recipients, and immunocompromised individuals (e.g., transplant recipients and individuals with AIDS). The virus can cause serious birth defects if contracted during pregnancy. Immunocompromised individuals experience more serious symptoms. Transplant recipients can be exposed to the virus through transplanted tissues, but they are also immunosuppressed and can experience reactivation of old CMV infections. For this reason, approximately 20% of transplant recipients develop symptomatic CMV. Difficulty: Difficult ASM

Standard: 23 75. Malaria is a major public health concern worldwide. Compare malaria with yellow fever, focusing on infection prevention, and speculate on what public health efforts may be most effective in combating malaria.

Answer: Student answers will vary but should include the following. Malaria is caused by a protozoan parasite (Plasmodium spp.) and yellow fever is caused by a flavivirus.

However, both are transmitted by mosquitoes. Both malaria and yellow fever are rare in the United States, but this could change if the vectors became more common. Both diseases are found in Africa, but Yellow Fever is also found in South America. Because both diseases are transmitted by mosquitoes, control of the mosquito species that serve as vectors is important in controlling infections. Improved mosquito control has been sufficient to reduce rates of both diseases, which was important in allowing the construction of the Panama Canal. A vaccination is available for yellow fever, so a combination of vector control and vaccination has been helpful in reducing outbreaks.

The World Health Organization Yellow Fever Initiative has worked to reduce yellow fever prevalence since 2006. Malaria continues to be an important public health concern. Individuals traveling to areas with malaria can take prophylactic medications such as chloroquine, artemether, atovaquone, and lumefantrine.

There is no vaccine available at present. Additionally, any measures that improve mosquito control can help control malaria. These include the use of insecticides and insect repellents, mosquito-repellant bed nets, and reduction of mosquito breeding sites.

Difficulty: Difficult ASM Standard: 23 This file is copyright 2017, Rice University. All rights reserved.

Chapter 26: Nervous System Infections * = Correct answer Multiple Choice 1. Which of the following is the innermost membrane surrounding the brain?

A. arachnoid mater B. dura mater C. pia mater* D. ventricle mater Difficulty: Easy ASM Standard: N/A 2. Which term describes tingling or numbness in peripheral nerves?

A. neuralgia B. neurological deficit C. neuropathy* D. neurotaxis Difficulty: Easy ASM Standard: N/A 3. Which part of a neuron releases neurotransmitters?

A. the dendrites B. the myelin sheath C. the synapse D. the synaptic terminals* Difficulty: Easy ASM Standard: N/A 4. Which of the following terms describes inflammation of the membranes surrounding the brain?

A. cephalic tetanus B. encephalitis C. meningitis* D. neuritis Difficulty: Easy ASM Standard: N/A 5. Before enrolling in college, students are encouraged to undergo vaccination for which of the following diseases?

A. botulism B. candidiasis

C. listeriosis D. meningococcal meningitis* Difficulty: Easy ASM Standard: 23 6. Hansen’s disease is more commonly known as which of the following?

A. leprosy* B. pneumococcal meningitis C. poliomyelitis D. tetanus Difficulty: Easy ASM Standard: 23 7. Which of the following is an example of a transmissible spongiform encephalopathy?

A. chronic wasting disease* B. St. Louis encephalitis C. tetanus D. Zika virus Difficulty: Easy ASM Standard: N/A 8. Which term describes a nervous system infection caused by a fungus?

A. bacillary infection B. dermatomycosis C. neuromycosis* D. transmissible spongiform encephalopathy Difficulty: Easy ASM Standard: 23 9. Human African trypanosomiasis is transmitted by which of the following?

A. contaminated water B. mosquitoes C. ticks D. tsetse flies* Difficulty: Easy ASM Standard: 23 10. Schwann cells serve a function similar to that of oligodendrites, but, unlike oligodendrites,

they are located in which part of the nervous system?

A. brain B. central nervous system

C. peripheral nervous system* D. spinal cord Difficulty: Moderate ASM Standard: N/A 11. Which of the following describes the difference between a glial cell and a neuron?

A. Neurons are white matter and glial cells are gray matter.

B. Neurons conduct impulses and glial cells have supportive roles.* C. Only neurons are technically nervous tissue.

D. Only neurons can contribute to myelination.

Difficulty: Moderate ASM Standard: N/A 12. A lumbar puncture (spinal tap) reveals the presence of leukocytes in the cerebrospinal fluid.

This finding most likely indicates which of the following?

A. an adverse medication reaction B. head trauma C. infectious meningitis or encephalitis* D. leukemia Difficulty: Moderate ASM Standard: 23 13. Which of the following is not a common cause of bacterial meningitis?

A. Haemophilus influenzae B. Neisseria meningitidis C. Staphylococcus aureus* D. Streptococcus pneumoniae Difficulty: Moderate ASM Standard: 23 14. Which fungal pathogen causes brain abscesses, rather than meningitis?

A. Aspergillus fumigatus B. Candida albicans C. Coccidioides immitis D. Rhizopus arrhizus* Difficulty: Moderate ASM Standard: 23

15. Which of the following is the most common outcome of Cryptococcus neoformans infection?

A. granuloma formation B. meningitis

C. pneumonia D. subclinical respiratory infection* Difficulty: Moderate ASM Standard: 23 16. Which of the following describes the role of the thick capsule of Cryptococcus neoformans?

A. It facilitates movement across the blood-brain barrier.

B. It inhibits clearance by phagocytosis.* C. It is involved in cell entry.

D. It triggers hypersensitivity reactions.

Difficulty: Moderate ASM Standard: 23 17. Which of the following statements about antifungal medications is false?

A. They are generally used at low doses.

B. They can only be administered short term.* C. They do not easily cross the blood-brain barrier.

D. They often have strong side effects.

Difficulty: Moderate ASM Standard: 14, 23 18. When histoplasmosis causes meningitis, in which way does the pathogen reach the brain?

A. directly from the external environment B. from the external environment via the olfactory nerve C. through dissemination from a respiratory infection* D. through dissemination from a skin infection Difficulty: Moderate ASM Standard: 23 19. Naegleria fowleri is most common in which of the following habitats?

A. cold mountain lakes B. northern rivers C. the ocean D. warm bodies of freshwater* Difficulty: Moderate ASM Standard: 23 20. Which form of Naegleria fowerli causes primary amoebic encephalitis?

A. cyst B. endospore C. merozoite

D. trophozoite* Difficulty: Moderate ASM Standard: 23 21. Amoebic keratitis is caused by: A. Acanthamoeba and Balamuthia* B. Acanthamoeba and Naegleria C. Balamuthia and Entamoeba D. Naegleria and Entamoeba Difficulty: Moderate ASM Standard: 23 22. Which of the following is a sign or symptom of Winterbottom’s?

A. a central nervous system lesion in individuals with rabies B. an indication of meningitis C. lymph node enlargement associated with trypanosomiasis* D. septicemia associated with vector-borne illness Difficulty: Moderate ASM Standard: 23 23. Trypanosomiasis is generallyTdE iaS gnToB seAdNuK siS ngEL wL hiE chRo.fCthOeMfollowing?

A. clinical signs and symptoms only B. microscopy* C. nucleic acid testing D. serologic testing Difficulty: Moderate ASM Standard: 6, 23 24. Which of the following is one of the most common parasitic causes of brain abscesses in immunocompromised patients?

A. Naegleria fowleri B. Taenia solium C. Toxoplasma gondii* D. Trypanosoma brucei Difficulty: Moderate ASM Standard: 23

25. Which of the following is usually diagnosed via imaging?

A. African trypanosomiasis B. arboviral encephalitis C. neurocysticercosis*

D. rabies Difficulty: Moderate ASM Standard: 23 26. With which of the following is rabies treated upon exposure?

A. rabies immune globulin B. rabies vaccination C. rabies immune globulin and vaccination* D. supportive therapy only Difficulty: Moderate ASM Standard: 14, 23 27. Transmissible spongiform encephalopathies are caused by which agent?

A. acellular particles that resemble viruses B. particles consisting of genetic material with no outer covering C. prions that resemble normal proteins and lack nucleic acid* D. subcellular particles with proteins and DNA Difficulty: Moderate ASM Standard: N/A 28. Meningitis can cause which oT fE t hS eT foBllA oN wiKnS g?ELLER.COM A. abnormal glucose levels in the CSF B. abnormal protein levels in the CSF C. leukocytes in the CSF D. leukocytes and abnormal glucose and protein levels in the CSF* Difficulty: Moderate ASM Standard: 23 29. For how long should cryptococcal infections in non-HIV–infected individuals be treated with amphotericin B and flucytosine?

A. a few days B. about a week C. at least 10 days D. at least 10 weeks* Difficulty: Difficult ASM Standard: 14, 23

30. Which animals are the most common reservoirs for rabies?

A. birds, mice, and goats B. cats, dogs, and horses C. opossums, skunks, and feral cats

D. raccoons, bats, skunks, and foxes* Difficulty: Difficult ASM Standard: 23 31. Which of the following causes the symptoms of rabies?

A. Brain cells are destroyed.

B. Hydrophobia results in dehydration.

C. Neurotransmitter function is disrupted in the brain.* D. Peripheral nerves are killed throughout the body.

Difficulty: Difficult ASM Standard: 23 32. Which of the following is the natural reservoir for West Nile Virus?

A. birds* B. humans C. mosquitoes D. raccoons Difficulty: Moderate ASM Standard: 23 33. Which of the following is notTtrEuS eT ofBHAaN nK seS n’EsLdL isE eaR se.?COM A. It is caused by Mycobacterium leprae.

B. It is highly contagious.* C. It may be transmitted by armadillos.

D. Many humans have natural immunity.

Difficulty: Difficult ASM Standard: 23 34. Demyelination is an important component of infection by which of the following?

A. Clostridium tetani B. Listeria monocytogenes C. Mycobacterium leprae* D. Neisseria meningitidis Difficulty: Difficult ASM Standard: 23 35. Listeria monocytogenes is able to penetrate the intestinal wall and blood-brain barrier

because of which of the following?

A. a capsule B. internalins* C. neurotoxins

D. small size Difficulty: Difficult ASM Standard: 23 True/False 36. Neuropathy is caused solely by pathogens.

Answer: False Difficulty: Easy ASM Standard: 23 37. Rabies cannot be diagnosed in humans before death because diagnosis requires direct examination of central nervous system tissue.

Answer: False Difficulty: Easy ASM Standard: 23 38. Meningitis can be caused by pathogens or by noninfectious means.

Answer: True Difficulty: Moderate ASM Standard: 23 39. Rabies is always fatal once symptoms begin to appear.

Answer: False Difficulty: Moderate ASM Standard: 23 40. If someone is bitten by a wild animal that escapes, it is better to wait to confirm a case of rabies through laboratory testing rather than begin treatment as soon as it is suspected.

Answer: False Difficulty: Moderate ASM Standard: 23 41. Pulsed-field gel electrophoresis is used to distinguish Listeria monocytogenes subtypes.

Answer: True

Difficulty: Moderate ASM Standard: 23 42. Meningococcal meningitis can result in limb amputation.

Answer: True Difficulty: Difficult ASM Standard: 23 43. Botulism is caused by the release of tetanus toxin in spoiled food.

Answer: False Difficulty: Difficult ASM Standard: 23 Matching 44. Match each structure with its best definition.

A. axon i. the main body of a neuron, containing the nucleus and most of the cell’s organelles B. dendrites ii. the long extension of a neuron through which an action potential travels to transmit a signal C. myelin sheath iii. a gap into which neurotransmitters are released to transmit chemical signals from one cell to another D. soma iv. a finely branched extension from a neuron that picks up incoming impulses E. synapse v. an insulated covering produced by oligodendrites or Schwann cells that spT eeE dsStT heBA coN ndKuScE t ioLnLoEf R ne.rC voOuM s impulses Answers: A. ii., B. iv., C. v., D. i., E. iii.

Difficulty: Easy ASM Standard: N/A 45. Match each vaccine with its best description.

A. DTaP i. protects against a type of meningitis B. Hib vaccine ii. a killed virus vaccine that protects against polio C. Sabin vaccine iii. protects against tetanus and two other bacterial infections D. Salk vaccine iv. an attenuated virus vaccine that protects against polio Answers: A. iii., B. i., C. iv., D. ii.

Difficulty: Moderate ASM Standard: 14, 23 46. Match each type of meningitis with its best description.

A. Cryptococcus meningitis i. generally relatively mild compared with other types of meningitis; caused by a variety of pathogens B. Haemophilus influenzae type B meningitis

ii. can cause a petechial rash and C. meningococcal meningitis

is of particular concern for college students iii. the causative agent is gram positive and lancet shaped

D. pneumococcal meningitis E. viral meningitis

iv. caused by a fungus v. treated with doxycycline, fluoroquinolones, cephalosporins, or carbapenems

Answers: A. iv., B. v., C. ii., D. iii., E. i.

Difficulty: Moderate ASM Standard: 23 47. Match each disease with its best description.

A. aspergillosis i. bacterial disease B. kuru ii. viral disease C. leprosy iii. protozoal disease D. PAM iv. fungal disease E. poliomyelitis v. prion disease Answers: A. iv., B. v., C. i., D. iii., E. ii.

Difficulty: Moderate ASM Standard: 23 48. Match each disease with its best diagnostic protocol.

A. Creutzfeldt-Jakob disease i. evaluation of clinical presentation; serologic testing of serum or CSF B. cryptococcosis ii.BeA vaNluKaS tiE onLoLfEclRin.icCaO l M presentation, acid-fast staining, TEST and microscopy of skin biopsy specimens or smears C. eastern equine encephalitis iii. evaluation of clinical symptoms and new specific virus RNA assay, RT-PCR testing, and MAC-ELISA testing D. Hansen’s disease iv. histological examination of brain biopsy specimens E. Zika virus v. lumbar puncture with negative CSF stain and routine culture Answers: A. iv., B. v., C. i., D. ii., E. iii.

Difficulty: Moderate ASM Standard: 23 49. Match each virus with the best description.

A. eastern equine encephalitis i. transmitted by Aedes, Coquillettidia, and Culex mosquitoes; birds are reservoirs B. Japanese encephalitis ii. transmitted by Culex tarsalis mosquitoes; has caused relatively few cases in the United States.

C. St. Louis encephalitis iii. carried by three species of Culex mosquitoes; a serious outbreak occurred in 1975 D. western equine encephalitis iv. transmitted by Culex mosquitoes; birds are a reservoir; became a problem in the United States in 1999

E. West Nile encephalitis

v. worldwide, causes the most cases of vaccinepreventable encephalitis; reservoirs include birds and pigs Answers: A. i., B. v., C. iii., D. ii., E. iv.

Difficulty: Difficult ASM Standard: 23

Fill in the Blank 50. The liquid within the central nervous system is called Answer: cerebrospinal

fluid.

Difficulty: Easy ASM Standard: N/A 51. West Nile virus is transmitted by Answer: mosquitoes

.

Difficulty: Easy ASM Standard: 23 52. When symptoms are caused by the toxin produced by a pathogen, the condition is called a(n) .

Answer: intoxication Difficulty: Easy ASM Standard: 23 53. Proteinaceous infectious particles are also known as Answer: prions

.

Difficulty: Easy ASM Standard: N/A 54. There is a vaccine available for Answer: Japanese Difficulty: Moderate ASM Standard: 14, 23

encephalitis, a type of viral encephalitis.

55. The reservoir for eastern equine encephalitis is Answer: birds Difficulty: Moderate ASM Standard: 23

.

56. Traditionally, rabies diagnosis relied on identifying tissues.

Answer: Negri bodies

_ in central nervous system

Difficulty: Moderate ASM Standard: 23 57. Jonas Salk developed a vaccine for Answer: poliomyelitis

.

Difficulty: Moderate ASM Standard: 14 58.

is a transmissible spongiform encephalopathy found in sheep.

Answer: Scrapie Difficulty: Moderate ASM Standard: N/A

59. Individuals with transmissible spongiform encephalopathies develop plaques.

Answer: neurofibrillary, amyloid

tangles and

Difficulty: Moderate ASM Standard: N/A 60. Patients exposed to rabies can be treated with rabies vaccine and rabies Answer: immune globulin (antibodies)

.

Difficulty: Difficult ASM Standard: 14, 23 61. Naegleria fowleri can be identified in CSF by using a modified trichome or Answer: Giemsa-Wright Difficulty: Difficult ASM Standard: 23 Short Answer 62. What composes the central nervous system?

stain.

Sample Answer: The brain and spinal cord make up the central nervous system.

Difficulty: Easy ASM Standard: N/A

63. What virus is associated with microcephaly in infants?

Sample Answer: The Zika virus is associated with microcephaly in infants.

Difficulty: Easy ASM Standard: 23 64. What symptoms appear soon after someone is exposed to botulinum neurotoxin through ingestion of contaminated food?

Sample Answer: Exposure through the gastrointestinal tract initially causes gastrointestinal symptoms such as dysphagia (difficulty swallowing), nausea, vomiting, cramping, diarrhea, and/or constipation. It also causes blurred vision and drooping eyelids. The symptoms then progress and muscle weakness and flaccid paralysis follow.

Difficulty: Easy ASM Standard: 23 65. What type of meningitis can be prevented by vaccination with the Hib vaccine?

Sample Answer: Haemophilus influenzae type b meningitis can be prevented by vaccination with the Hib vaccine.

Difficulty: Easy ASM Standard: 14, 23 66. What is the blood-brain barrieTr?ESTBANKSELLER.COM Sample Answer: The blood-brain barrier refers to various mechanisms that collectively protect the brain from exposure to potential chemicals, toxins, and infectious agents found within the circulatory system. The materials that can travel from the circulatory system into the brain are restricted by the reduced permeability of brain capillaries, tight junctions in capillary endothelial cells, reduced fenestrate in cranial capillaries, and reduced numbers of pinocytic vesicles in cranial capillaries.

Difficulty: Moderate ASM Standard: N/A 67. How do prions cause disease?

Sample Answer: When abnormal (rogue) prion proteins (PrP Sc) enter nervous tissue, they can cause normal prion proteins (PrP C) to become folded incorrectly. Aggregations of abnormal proteins lead to the formation of fibrils that aggregate and kill cells. They contribute to the development of neurofibrillary tangles and amyloid plaques in the brain.

Difficulty: Moderate ASM Standard: N/A

68. Why is listeriosis a risk even if food is refrigerated?

Sample Answer: This pathogen can grow at relatively low temperatures, including those used for standard refrigeration.

Difficulty: Moderate ASM Standard: 14, 23 69. How is botulism treated?

Sample Answer: An antitoxin can be administered, but it does not reverse existing paralysis. An extended recovery period is needed to regain lost neurological functions.

Difficulty: Moderate ASM Standard: 14, 23 70. What makes botulinum toxin useful in medicine?

Sample Answer: Botulinum toxin causes paralysis, so it can be used to relax muscles. It is commonly used for cosmetic purposes (e.g., to relax facial muscles). It can also be used to reduce excessive sweating and to treat muscle contractions associated with cerebral palsy, multiple sclerosis, and Parkinson’s disease.

Difficulty: Moderate ASM Standard: 23, 26 71. What symptoms are most commonly associated with West Nile virus infection?

Sample Answer: Most patients (about 70% to 80%) do not have symptoms. Although dangerous meningitis or encephalitis can occur, about 99% of patients with symptoms have only mild flu-like symptoms.

Difficulty: Moderate ASM Standard: 23 72. What treatments are used for leprosy?

Sample Answer: Leprosy, or Hansen’s disease, is treated with dapsone, rifampin, and clofazimin. (Students may not have learned that clofazimin is used for patients with multibacillary disease, whereas dapsone and rifampin are generally recommended).

Difficulty: Moderate ASM Standard: 14, 23 73. How is neurocysticercosis diagnosed?

Sample Answer: Imaging tests can be used, including CT and MRI testing. Additionally, EIA and ELISA testing may be used. The presence of an elevated level of eosinophils in blood suggests a parasitic infection, although this is not a specific indicator for neurocysticercosis.

Difficulty: Moderate ASM Standard: 23 74. Why is it difficult to eradicate rabies?

Sample Answer: Even if effective vaccination programs exist for domestic pets, the virus persists in wild animals.

Difficulty: Difficult ASM Standard: 23 75. People are often told to get a tetanus shot if they experience a deep puncture wound such as a bite. Why is there a higher risk of tetanus from a deep puncture wound than from a shallow scrape or abrasion?

Sample Answer: Clostridium tetani, the bacterium that causes tetanus by producing tetanus neurotoxin, is anaerobic and cannot grow in an oxygen-rich environment like that on the surface of the skin.

Difficulty: Moderate ASM Standard: 23 76. What is the difference between tuberculoid and lepramatous leprosy?

Sample Answer: Tuberculoid leprosy occurs if leprosy progresses beyond its mildest form.

The symptoms include three or fewer lesions that may persist but that contain relatively few bacteria. In some cases, if the immune system is no longer able to contain the infection, the lepramatous form may develop. Lepramatous leprosy is associated with nerve damage and has the potential to cause disfiguring lesions.

Difficulty: Difficult ASM Standard: 23 Brief Essay Essay Question Rubric RATING Failin Below g Average Criteria Answer does Answer fails to for not provide an provide evaluatio argument. examples to n Answer contains support an inaccuracies. argument.

Writing is Writing is poor poor and and contains grammatical numerous errors are grammatical common. mistakes and Answer is misspellings. somewhat incoherent.

Competen t Answer provides an argument with one or two examples that support it.

Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings.

POINT 0 1 2 VALUE Assume rating/grading scale for the question ranges from 0 to 3 points.

Advance d Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently.

Answer is well organized and free of grammatical errors and misspellings.

3

77. Describe how pathogens can get from the circulatory system into the brain across the bloodbrain barrier.

Answer: Student answers will vary but should include the following. There are four major ways that pathogens can cross the blood-brain barrier. First, they may have virulence factors that allow them entry between cells (i.e., intercellular mechanisms). Second, they may have virulence factors that let them use vacuole- or receptor-mediated mechanisms (i.e., transcellular mechanisms). Third, they may infect peripheral blood leukocytes and use these to cross the barrier (i.e., leukocyte-facilitated mechanisms). Fourth, they may travel through pathways outside of the circulatory system, such as along cranial nerves (i.e., nonhematogenous mechanisms).

Difficulty: Moderate ASM Standard: 23 78. A college student with possible bacterial meningitis undergoes a lumbar puncture. Describe the test results that would lead to a positive diagnosis and indicate what treatment should be initiated if the results are positive.

Answer: Student answers will vary but should include the following. Bacterial meningitis is diagnosed when an individual has more than 10 polymorphonuclear neutrophils/mm3 , less than 45 mg/dL of glucose, and greater than 45 mg/dL of protein in the CSF. Additional testing is needed to determine the type of bacterial meningitis. Hib meningitis can be treated with doxycycline, fluoroquinolones, second - and third -generation cephalosporins, and carbapenems. Cephalosporins or penicillins are used for

meningococcal and pneumococcal NK meningitis. This would not beTnEeS onTaB taA lm enSinEgL itL is.E R.COM Difficulty: Moderate ASM Standard: 14, 23 79. Explain why plasmapheresis can be helpful in treating patients with Guillain-Barré syndrome; include an explanation of what this syndrome is.

Answer: Student answers will vary but should include the following. Guillain-Barré syndrome results from an autoimmune reaction, usually after bacterial or viral infection, and causes increasing neurological symptoms that can result in complete paralysis. The symptoms are caused by the individual producing antibodies that attack and damage the myelin sheaths that are essential for proper signal conduction. Plasmapheresis involves filtering the blood, meaning that the antibodies that are attacking the myelin can be removed. With appropriate supportive treatment, patients can recover fully.

Difficulty: Difficult ASM Standard: N/A 80. When an individual is exposed to rabies, the treatment usually involves multiple components.

What are these components and why are they all necessary?

Answer: Student answers will vary but should include the following. Rabies is treated using multiple doses of rabies vaccine and often with rabies immune globulin. Rabies has an extended incubation period. The immune globulin has an immediate effect on the viral load, whereas vaccination causes the individual to produce rabies antibodies. By using immune globulin and then a series of vaccinations, the infection is slowed while the individual develops sufficient immune response to eliminate the virus.

Difficulty: Difficult ASM Standard: 14, 23 81. Transmissible spongiform encephalopathies cannot currently be treated, so only supportive care is available. Although new diagnostic techniques are being developed, the primary method of diagnosing these diseases is through histological examination of brain tissue. Why has it been difficult to develop treatments for these diseases? If a patient with one of these diseases has surgery at a hospital, do you think that normal sterilization procedures would be sufficient to decontaminate surgical equipment?

Explain all your answers.

Answer: Student answers will vary but should include the following. It has been difficult to develop treatments because these diseases generally have long incubation periods, thus making it harder to trace their source and prevent others from being infected. Also, TSEs are very different from other pathogens such as bacteria, viruses, and fungi. TSEs do not have cellular structures to target. Additionally, the function of

the normal protein that is affected by the abnormal prion protein is not known, even though possibilities have been proposed and are currently being researched. The chapter does not explicitly address the issue of surgical sterilization, although it mentions that clinicians must handle contaminated samples with care. Students may speculate about the effects of normal decontamination procedures, but the WHO and CDC recommend specific stringent sterilization procedures when a TSE may be present. Students mayTsEpS e cTuB l aA t eNthKaS t pEhLyL siE caR l . reC mO oM val methods could remove some contaminated tissue. Sterilization techniques that kill spores and viruses are not necessarily sufficient to inactivate TSEs, although data are lacking on the effectiveness of different methods. Because this is not addressed directly in the chapter, student answers should be assessed on the basis of thoughtfulness and use of background knowledge regarding sterilization and TSEs separately, rather than on having a particular correct answer. Chapter 13 of the text contains more information about prions and students may refer back to the material in that chapter to elaborate further. “Diehard prions” in chapter 13 and the section on prions in chapter 6 may also be useful.

Difficulty: Difficult ASM Standard: 14

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