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Structure of 10
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Deoxyribonucleic Acid or DNA................................................
Mechanism of Action of Enzymes
Enzymes.....................................................................................
4: Lipids and Fatty Acids
DNA, RNA, and Nucleotides.......................................
Chapter
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Lipids.........................................................................................
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DNA Chemical Properties .........................................................
Function
Fatty Acids
Lipid Categories
DNA
Nucleotide Structure ..................................................................
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Hydrogenation
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Essential Fatty Acids..................................................................
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Types of RNA Molecules
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Enzyme Cofactors......................................................................
Structure of RNA.......................................................................
6: Enzymes and Enzymology
Types of Fatty Acids..................................................................
Biosynthesis and Degradation of Lipids....................................
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and Oxygenation of Fatty Acids
Proteins associated with DNA
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Fatty Acid Synthesis..................................................................
Nucleotides ................................................................................
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Biological Functions of Lipids...................................................
Digestion and Metabolism of Fatty Acids
Synthesis of RNA
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The audio is focused and high-yield, covering the most important topics you might expect to learn in a typical Medical school Biochemistry course. Included are both capsule and detailed explanations of critical issues and topics you must know to master Medical School Level Biochemistry.
There is a Q&A and a “key takeaways” section following each topic to review questions commonly tested and drive home key points.
Also included is a comprehensive test containing the top 100 most commonly tested questions in Biochemistry with the correct answers.
AudioLearn's Medical School Crash Courses support your studies, help with USMLE preparation and provide a comprehensive audio review of the topic matter for anyone interested in what medical students are taught in a typical medical school Biochemistry course.
Written by experts and authorities in the field and professionally narrated for easy listening, this crash course is a valuable tool both during school and when preparing for the USMLE, or if you’re simply interested in the subject of human Biochemistry.
In this course, we'll cover the following topics:
The material is accurate, up to date and broken down into bitesized sections.
To get the most out of this course, we recommend that you listen to the entire audio once while taking notes, then go back and listen to areas you had difficulties with.
Welcome to Biochemistry, a Medical School Crash Course written by our team of medical content developers and narrated by (your name) Presented by AudioLearn
Human Anatomy
Behavioral
Lipids and Fatty Acids
Embryology
Now, let's get started.
Conclusion:
Glucose Catabolism
Anaerobic Metabolism
Proteins and Amino Acids
Gluconeogenesis and Glycogenesis and Biochemistry in Medicine
Aerobic Metabolism
Carbohydrates and Sugars
Cell Biology and Histology
Psychiatry Genetics
Water and Biochemistry
Microbiology and Immunology Sciences Physiology Medicine
Pharmacology Pathology Human
This concludes our lesson on Biochemistry Now would be a good time to go back and re- visit areas you found challenging. We hope you found this to be a great learning experience and invite you to check out our other titles in this series including:
Nutrition Internal
DNA, RNA and Nucleotides
Citric Aid Cycle
Enzymes and Enzymology
Chapter five of the course will involve a basic focus on nucleotides, which are the building blocks of nucleic acids, such as RNA and DNA. Both long chain biochemical molecules are important to gene expression, transcription, and translation of proteins from genetic material.
Thank you for listening and good luck!
This course is to be intended to involve a basic discussion of biochemical principles, the various molecules involved in biochemistry, and how they work together to create and degrade biochemical molecules. The first chapter focuses primarily on the biochemistry of water, which is the universal solvent because it dissolves most of the molecules in the body.
In the third chapter of the course, simple sugars, disaccharides, and polysaccharides will be the focus of the discussion. Different organisms have storage polysaccharides, including glycogen (in humans), starches, and cellulose (which can’t be metabolized by humans.
Preventive Medicine
This has been Biochemistry, a Medical School Crash Course written by our team of medical content developers and narrated by (your name) Presented by AudioLearn
Pediatrics Obstetrics Gynecology Surgery
Introduction to Biochemistry
Preface
The second chapter presents amino acids, which are the building blocks of proteins. There are some amino acids that are essential, meaning the human body cannot manufacture them but they must be consumed in the diet to be incorporated into proteins
Chapter four of the course will involve a discussion of fatty acids and lipids. Like certain essential amino acids, there are specific omega 3 and omega 6 fatty acids that cannot be made by the body but must be incorporated as part of the diet in order to make longer chain fatty acids and triglycerides.
The tenth chapter of the course will focus mainly on the citric acid or Krebs cycle, which is the way in which glycose metabolites get further oxidized into CO2 and water, with preservation of most of the intermediary products.
The eleventh chapter of the course will be a discussion of gluconeogenesis and glycogenesis. In gluconeogenesis, the main outcome is the creation of glucose from other types of molecules. In some cases, the glucose is then metabolized while, in other cases, the glucose gets stored as glycogen in liver, fat, and muscle cells.
In chapter six of the course, enzymes and enzymology will be discussed. Most enzymes are protein-based and are translated/made in the ribosomes. There are some enzymes, called ribozymes, that are made from RNA that act in the ribosomes of the body to create proteins.
The eighth chapter of the course will mainly focus on anaerobic metabolism, which is the type of metabolism that occurs in anaerobic organisms that don’t utilize oxygen or by muscle cells during intense activity when there isn’t enough oxygen to fuel the muscle cells.
The seventh chapter of the course will focus on most aspects of aerobic metabolism. Aerobic metabolism is the main form of metabolism that occurs in the human body as we have oxygen to drive this form of metabolism.
The last and twelfth chapter of the course will present the ways biochemistry interacts with various aspects of medicine, including normal physiological processes, disease states, food biochemistry, and the pharmacology of drugs as it applies to the biochemistry of medicines and drugs developed and taken by the human body at all times.
Altogether, most aspects of the biochemistry of the human body will be discussed in this course so that students understand the processes that go on in the body’s cells to drive the synthesis and breakdown of molecules using energy in some processes and creating energy in other processes.
In the ninth chapter of the course, the main discussion will be on the topic of glucose catabolism. Glucose gets broken down first in glycolysis into pyruvate, lactic acid, and other products. The breakdown products can stay that way or can go into further oxygen based reactions to further oxidize the sugar.
Water has the molecular formula of H2O, meaning that it contains two hydrogen molecules and one oxygen molecule which together make the entire water molecule. Water makes up about seventy percent of the weight of most living organisms. Polar covalent bonds connect the different ions that make up the molecule. Water is considered the universal solvent because it can dissolve many types of biochemical molecules. There are many unique properties of water that make it an important biochemical molecule.
The partial charges on both the hydrogen ions and oxygen ion allow the water molecule to participate in many biochemical reactions. The oxygen atom is electrically negatively charged, while the hydrogen ions are positively charged. Together, this gives the oxygen an affinity to other water molecules as well as the ability to ionize. The ability of hydrogen ions to covalently bond to other molecules makes the water molecule have strong interactions with other molecules. Water also has a high melting point and they high boiling point. It has a high heat of vaporization and a high surface tension.
Chemical Properties of Water
The water molecule consists of two pairs of electrons around an oxygen molecule. The attachment is via a covalent bond that form a tetrahedral arrangement around the oxygen atom having a predicted bond angle of 109.5° between each electron. Because electron pairs repel one another, the actual bond angle between the hydrogen atoms is slightly closer than that at approximately 104.5° This gives the geometry of a molecule of water as being angular or bent, which gives water its polar trait in biochemical reactions.
Chapter 1: Water and Biochemistry
This course is designed to be a discussion of the basics of biochemistry. All of biochemistry begins with a discussion of water, which is the basis behind many biochemical reactions. Water has many biochemical properties that make it important in almost all biochemical functions of the body. In this first chapter, we will discuss the biochemistry of water and how it is important in biochemical reactions, cellular biochemistry, and in metabolism.
Structure of Water
There is a property of molecules called “a colligative property”. This is the collection of properties of a solution that correlate to how many molecules exist in a given volume of solvent rather than what the actual molecules in the solution are. An example of this a colligative property in relationship to water is the osmotic pressure, the freezing point, and the boiling
The high melting point and the high heat of vaporization are basically caused by the attraction between two molecules of water that are adjacent to one another. Each hydrogen ion inside a water molecule shares an electron pair with the central oxygen atom in the water molecule. The result is that each hydrogen molecule has a slightly positive charge, which is attracted to the electronegative charge of the oxygen molecule. This type of bonding is what allows for the molecular process of water called hydrogen bonding.
The definition of heat of vaporization is the amount of heat needed to change a gram of water in liquid form into its gaseous form. The heat of vaporization of water is high because of the hydrogen binding between the molecules. If you think about it, the world is covered almost entirely in water, giving it a higher ability to retain heat and giving it a more stable climate than other planets, giving it the ability to support life. Evaporative cooling of water happens when the liquid molecules that have the greatest amount of kinetic energy leave the water form to turn into gaseous form, stabilizing the temperature around bodies of water, such as lakes and ponds. It also keeps animals and plants from being overheated when being heated up.
The specific heat of a molecule is the amount of heat required to raise the temperature of one gram of water by one degree Celsius. Water has an extremely high heat capacity, meaning that it changes temperature very slowly after gaining or losing physical energy. After ammonia, water has the highest specific heat capacity of any other molecule. This is because of the hydrogen bonding between the molecules. When heat is absorbed, the hydrogen bonds break, allowing the molecules of water to flow freely. When the temperature drops, the hydrogen bonds re form and energy is released. This resistance to a sudden temperature change makes water a good substrate for organisms to survive in without having to suffer extremes in temperature fluctuation. Because most organisms are made from water, they are able to regulate their internal body temperature.
Compared to other hydride molecules, water or H2O, has a high melting point as well. This is also due to the high hydrogen bonding between the water molecules. When water is solid (as in ice), there are four different hydrogen bonds involved. Two hydrogens are each capable of bonding as a bond donor and one oxygen molecule is able to accept two hydrogen bonds from nearby molecules.
As mentioned, some of the unique properties of water include a high surface tension, a high heat capacity, a high boiling point, and a high melting point. This means that the bonding between water and many other molecules is extremely high.
Water has a higher boiling point than one would expect. The reason for this is the same as is true for the melting point. There is such a strong intermolecular force between the molecules of water that much more force is required to break the molecules apart so they can turn into gaseous form. Water boils at about 100 degrees Celsius or about 212 degrees Fahrenheit.
Density as it Relates to Water
The property of cohesion involves having individual water molecules sticking together secondary to the property of hydrogen bonding that we have already discussed. Hydrogen bonding is very fragile when water is in its liquid form but, because of cohesion, water is better structured as a liquid when compared to other organic liquids. The bonds break and reconnect at a high frequency when water is in its liquid phase, leading to both a strong capillary action and a high surface tension. This cohesive property of water is more important to plants than it is to animals and, without the property of cohesion, plants would be dehydrated and could not undergo the photosynthetic process.
Cohesion results in a high surface tension of water. Water has the highest surface tension of most other liquid substances (other than mercury) because of the hydrogen bonding between the various molecules. This property allows for the ability of water to act like a stretchable film that can support objects that are extremely heavy. Some aquatic organisms have evolved to
The freezing point of water is decreased when it acts as a solvent. This is because the solute doesn’t fit into the watery crystalline structure and less free space is given to other molecules when the water turns into a crystalline state. More enthalpy or energy change is necessary to balance the entropy loss required to freeze the water. Salt is added to snow in winter to melt it faster at a lower freezing temperature. The colligative property of water is determined by the solute added to the solution rather than the amount of solute added to the solution.
Water is a rare substance that is actually less dense as a solid when compared to its liquid form. Once again, it is the hydrogen bonding of water that is the reason behind this. This allows animals, plants, and humans to survive in sub zero temperatures because a lake or pond will freeze from the top down instead of from the bottom up and ice floats on the water surface. As the ambient temperature drops below the freezing point of water, the molecules of water form a lattice with four neighboring water molecules. The hydrogen molecules separate these molecules further apart than they would be in their liquid state, making solid water less dense than liquid water. As the temperature increases, this crystalline structure breaks down and the hydrogen bonds become denser, making liquid water. Water is in its densest state at about four degrees Celsius.
When NaCl is structured like a lattice around water molecules, the structure will often break down because of the strong solute to solution interaction when compared to the solute to solute interaction. This leads to fewer freely floating water molecules in the solution, which causes a decrease in entropy of the system. This means that a higher enthalpy change (energy change) is required to break the forces between the molecules to force them into gaseous form.
point. Water has a collection of colligative properties because it acts as a solution that dissolves solutes, such as sodium chloride in the extravascular tissues of the human body. When sodium chloride is added as a solute to water in solution, the boiling point will increase even further.
Water is amphoteric, meaning it can be an acid or a base. When water is part of a solution, it will change the equilibrium of the solution. When it interacts with a highly acidic solute, it will act as a base and, when it interacts with a highly basic solute, it will act as an acid. Because it has two single hydrogen ions as part of the molecule, it can act as an electron pair donor in biochemical reactions.
Water also has the capability of forming a hydration shell. This is a shell that forms in a waterbased solution when the solute dissolves in the water. The solute can be surrounded by the
There is a chemical term known as the dielectric constant. It refers to the ability of electrons to migrate toward the pole of a positively charged molecule and away from the negatively charged molecules. When this happens, the molecule is called “polarized”. Water has a dipole moment of 6.17 x 10 30 , making it a polarized molecule.
Water is considered a universal solvent because it can dissociate or dissolve most organic compounds. This is because it is a highly polar molecule, with a great deal of electronegativity associated with its oxygen component when compared to its hydrogen component. The positive electric charge of the molecule (the hydrogen side) is attracted to the negative parts of the solute being dissolved, while the positive charge of the molecule (the oxygen side) is attracted to the positive parts of the solute. This makes water able to dissociate and break ionic compounds into separate, dissolvable components.
Because of the polar aspect of water and its ready ability to undergo hydrogen bonding, polar molecules that are uncharged can easily dissolve in it. Water stabilizes these molecules by the effect of its hydrogen binding ability between any polar molecule and the water molecule. Any molecule that has an N H bond, alcohols, aldehydes, and ketones all can form hydrogen bonds, making them soluble in water. All of these molecules are biomolecules found in the human body.
Water as a Universal Solvent
have a large surface area compared to their body weight so they can float without breaking the surface tension of water.
The hydrogen bonds between an uncharged polar molecule and water will be the strongest when the hydrogen atom in the molecule is in a straight line between two different electronegative atoms. Because of this, the property of hydrogen bonding in the water molecule is very directional. Water has the unique ability to recognize and adapt to the different shapes of organic molecules so that it can keep them in solution.
The dielectric constant of a molecule is a measurement of how polarized it is. Water has a high dielectric constant because of its high dipole moment. This gives water the ability to surround ions, blocking the charges of the ions so it can be a good solvent for any type of polar or ionic substance. Therefore, it is called a universal solvent as many types of ions can dissolve in it.
Water is not just the solvent the human body uses as the main thing biomolecules are dissolved in. It plays a significant role in many biochemical reactions inside the body. One specific example is the transformation of adenosine diphosphate (ADP) to adenosine triphosphate (ATP), which is how the human body gets its energy. There is a specific condensation that
When enzymes and other organic molecules are present in solution, sometimes the water molecules form an ordered structure that is separate from the enzymes and the molecules they work on for the interaction to occur. This increases the disorder of the molecules, increasing the entropy and allowing the process that is to occur between the enzyme and its substrate to become more favorable. This forms an enzyme substrate complex that starts the enzymatic process. This is considered an example of “desolvation.”
Non polar substances will not dissolve in water and form an unfavorable interaction with water. The hydrocarbon backbone of many organic molecules must form micelles to be dissolved in water and decrease the entropy of water, which is considered an unfavorable process.
positively charged hydrogen ions that bind to the solute, allowing it to stay in the watery solution.
Water has the ability to be stabilizing to ions like sodium and chloride. It hydrates both ions and decreases the electrostatic interaction between the ions, weakening their tendency to want to go out of solution and form a crystalline lattice. This is also the case with protonated amines, anhydride molecules, carbolic acid, and other biomolecules. Instead of precipitating out as solute solute solids, they form solute solvent interactions, keeping the molecules in solution. In effect, water acts as a screen between the polar aspects of the molecule that would have the solute bind with itself instead of water.
In humans and animals made from cells surrounded by lipids, water needs to be a part of this system. One typical micelle found in nature is the lipid bilayer of the plasma membrane of the cell. There are polar heads on the phospholipids that make up the lipid bilayer that shield the lipid portions of the bilayer. Fat soluble molecules can get inside the membrane but ionic compounds cannot.
Water is an extremely versatile solvent. When a crystal of an ionic compound is placed in water, the ions are broken apart by the water solvent. Hydrogen, being negatively charged, will attract any part of the molecule that is positively charged, while oxygen, being positively charged, will attract any part of the molecule that is negatively charged. It effectively forms a shell around each positively and negatively charged component of an ionic substance so that they don’t bind to each other and precipitate out of solution. The substances can move freely in water is a favorable, energy free occurrence.
Water can interact with hydrophobic molecules as well. It causes that part of a hydrophobic molecule to hide within the hydrophilic components of the molecule, leaving the hydrophobic portion hidden and the hydrophilic part exposed. This is an energetically unfavorable interaction but needs to happen to keep the hydrophobic parts of the molecule away from the water. Organic hydrophobic molecules form a micelle, which involves the hydrophilic parts being exposed to water and shielding the hydrophobic parts.
The bonding that occurs in enzymatic reactions results in a net decrease in the free energy of the environment and an instability of covalent bonds that then can be overcome to break the covalent bond of a substrate, altering the chemical structure of the substrate as part of the enzymatic reaction. The stability of the covalent bond changes exponentially with the binding energy. Large macromolecules, such as RNA, DNA, and proteins have many different sites of potential bonding by the various types of bonds mentioned above that are always acting maximally on the macromolecule. It is these types of bonds that ultimately control the overall three-dimensional structure of the macromolecule.
a. One b. Two c. Three
Water and Hydrogen Bonding
Hydrogen bonding is important to the function of water in biochemical reactions.
1. How many oxygen atoms are in a single molecule of water?
Key Takeaways
Water interacts with hydrophobic molecules because these molecules form micelles that keep the hydrophobic parts of the molecule away from water.
Water is not only an important solvent but it is a part of many biochemical reactions.
Quiz
The hydrogen bonds so important regarding water, along with ionic bonding, hydrophobic bonding, and Van der Waal interactions between molecules are much weaker than any covalent bond in a molecule but, even though they are weak, they are cumulative and have a great effect on what happens inside the human body when it comes to the chemistry of the human body. Any given enzymatic may rely on several of these bonding types, of which hydrogen bonding usually involves the water molecule.
occurs, in which water is produced for ADP to take on its third phosphate group. Water is again necessary for ATP to become hydrated enough to release its energy. Water is rich in electrons, in which the oxygen component serves as a nucleophile. These types of reactions release energy and are favorable in the biochemical environment. The redox reactions that occur in the human body also require water.
Water is the universal solvent found in almost all biochemical systems.
b. Its high boiling point.
c. High boiling point
4. What can be said about the boiling point of water?
5. What aspect of water stabilizes the heat environment of the area around small bodies of water?
2. What property of water allows for its high melting point?
b. High melting point
a. Its high melting point.
c. Water molecules have a high affinity for each other.
c. it is about the same as other molecules of its type at about 212 degrees Fahrenheit.
d. It is higher than it should be at about 120 degrees Celsius.
Answer: c. Water has a high melting point because water molecules have a high affinity for each other.
a. High heat capacity
Answer: a. Each water molecule has just one atom of oxygen, regardless of the charge of the molecule, which is normally neutral because of the two hydrogen ions that have a strong affinity for the oxygen atom.
d. Water has a high covalent bond between the water molecules.
a. The hydrogen and oxygen bonding is extremely tight.
3. Hydrogen bonding in a water molecule allows for what property?
d. All of the above
Answer: d. The hydrogen bonding in a water molecule allows for its high heat capacity, its high melting point, and its high boiling point.
b. It is higher than expected because the forces between the water molecules are greater than other molecules of its type.
d. It depends on its charge
a. It is lower than expected because the forces between the water molecules are weaker than other molecules of its type.
b. Water has a high affinity for ions that do not melt.
Answer: b. The molecules of water have stronger forces than other molecules of its type, giving it a higher than expected boiling point at about 100 degrees Celsius.
7. How does water prevent biomolecules and ionic substances from precipitating out of solution?
Answer: b. Hydrogen molecules in different molecules of water nearby have a bond between one another, called hydrogen bonding, which accounts for an increased affinity of water molecules for one another.
b. It bonds covalently with solutes so they can’t get out of solution.
d. The oxygen part of the molecule binds to the hydrogen of the solutes, preventing their precipitation.
6. There is hydrogen bonding occurring with regard to water that is responsible for much of its properties. Describe what this hydrogen bonding is all about?
d. Its high heat of vaporization.
a. It is highly polar so it promotes the formation of solute-solvent bonds, preventing solute solute bonds.
a. The water molecule is larger than the sodium chloride molecule so it keeps it from precipitating.
b. Hydrogen molecules bind to other hydrogen molecules next to it, causing an increased affinity for each other.
a. Hydrogen molecules bind tightly to the oxygen molecule, preventing its breakup.
c. Hydrogen forces occur between the oxygen molecules on the water molecule, causing an increased affinity between the different water molecules.
d. Hydrogen has an affinity for the oxygen atom on another oxygen molecule, accounting for a high affinity between the molecules of water.
8. What causes the shield that prevents sodium chloride from precipitating?
b. The water molecule surrounds the sodium chloride molecule on all sides so it can’t get near any other sodium chloride molecule.
Answer: d. Water’s high heat of vaporization is what prevents water from turning from its liquid to gaseous form without the need for a high expenditure of energy.
c. Its high specific heat.
c. The hydrogen bonds break in the water molecule and coat the solute, preventing its precipitation.
Answer: a. Water is highly polar, forming solute to solvent bonds, preventing solute to solute bonds that would take the solute and allow it to precipitate out of solution.
c. Water is small so it can surround the sodium chloride molecule on all of its sides, keeping it from precipitating.
c. Hydrophobic bonding
Answer: b. Lipids form a lipid bilayer micelle that hides the hydrophobic parts of the lipid from its more hydrophilic parts (which are exposed to water).
b. The lipids form a bilayer micelle that hides the hydrophobic parts of the lipid.
Answer: d. Water keeps sodium chloride from precipitating because it is polar and its different charges attract the positive and negative charge on sodium chloride molecule, keeping the sodium and chloride from binding to each other in solution.
d. Water is polar and it attracts different charges on the sodium chloride molecule, making it unable to attract the sodium and chloride to one another.
9. How is it that human cells can be surrounded by lipid membranes in a watery matrix?
a. Covalent bonding
d. Hydrogen bonding
a. Lipids are able to dissolve in water because they are polar, too.
d. The lipids don’t have to be attracted to water in order to be present in a watery matrix.
b. Van der Waals bonding
10. What is the main bonding type important in water based reactions?
Answer: d. Hydrogen bonding is the most important aspect of bonding in water based reactions in human biochemistry.
c. There are organic molecules that protect the lipid membrane from water.
