Metabolism of triacylglycerol……………………………………………………….…………..69
Metabolism of ketone bodies. Cholesterol………………………………………………...98
Regulation and pathology of lipid metabolism………………………………………….122
Metabolism of proteins & amino acids. General pathways of amino acids………………………………………………………………………………………………………..139
Ammonia detoxification…………………………………………………………………………..144
Individual pathways of amino acid metabolism……………………………………….166
Metabolism of nucleotides…………………………………………………………………….186
Vitamins. Metabolism and functions of vitamins B1, B2, B3, B5………………….193
Metabolism and functions of vitamins B6, B7, B9, B12, C…………………………….202
Chemical structure, biosynthesis, secretion and metabolism of hormones……………………………………………………………………………………………..212
The mechanism of hormonal action………………………………………………………….226
Hormonal regulation of metabolism…………………………………………………………237
Metabolism of heme. Jaudices………………………………………………………………….253
Blood plasma proteins……………………………………………………………………………..263
AMINO ACIDS
1. How many peptide bonds are present in the peptide shown below:
A. 1
B. 2
C. 3
D. 4
E. 5
2. Calculate the net charge on the tripeptide Gly-Lys-Arg at pH 7,0:
A. +3
B. +2
C. +1
D. 0
E. -1
F. -2
G. -3
3. Name the amino acid that provides the least amount of steric hindrance in proteins:
A. Alanine
B. Tyrosine
C. Phenylalanine
D. Glycine
E. Lysine
4. Name the amino acid that is positively charged at physiological pH:
A. Aspartic acid
B. Valine
C. Histidine
D. Leucine
E. Tryptophan
5. How many peptide bonds are present in the peptide shown below:
A. 1
B. 2
C. 3
D. 4
E. 5
6. Name the aromatic amino acid:
A. Threonine
B. Tyrosine
C. Isoleucine
D. Cysteine
E. Arginine
7. Name the amino acid that influences protein folding by forcing a bend in the chain:
A. Proline
B. Glycine
C. Asparagine
D. Glutamine
E. Alanine
8. Name the two sulfur-containing amino acids:
A. Serine
B. Methionine
C. Threonine
D. Cysteine
E. Valine
9. Which amino acid is able to form a disulfide bridge?
A. Serine
B. Methionine
C. Threonine
D. Cysteine
E. Valine
10. Which of the following statements describe(s) the peptide bond? (More than one answer may be correct)
A. It is the only covalent bond between amino acids in polypeptides.
B. It is a substituted amide linkage.
C. It is formed in a condensation reaction.
D. It is formed in an exergonic reaction.
E. It is unstable under physiological conditions.
11. Name the heterocyclic amino acid:
A. Glutamine
B. Histidine
C. Asparagine
D. Arginine
E. Phenylalanine
12. Which of the following explains why all individual amino acids are soluble in water but not all peptides are soluble?
A. Individual amino acids are zwitterions at physiological pH.
B. All peptides are insoluble in water.
C. The R groups of the amino acid residues in the peptide are charged at physiological pH.
D. All the amino acid residues in the peptide are charged at physiological pH.
E. The R groups on all amino acids can interact noncovalently with water at pH 7,4.
13. Which amino acid(s) can be synthesized in humans?
A. Valine
B. Leucine
C. Lysine
D. Glycine
E. Threonine
14. Which amino acid(s) cannot be synthesized in humans?
A. Serine
B. Alanine
C. Phenylalanine
D. Tyrosine
E. Proline
15. Name the acidic amino acids:
A. Glutamate
B. Glutamine
C. Aspartate
D. Asparagine
E. Arginine
16. Name the neutral amino acid:
A. Tryptophan
B. Arginine
C. Lysine
D. Aspartic acid
E. Glutamic acid
17. Define the charge of histidine at pH=12, if its pI=7,6:
A. +2
B. +1
C. 0
D. -1
E. -2
18. Define the charge of glycine at pH=2, if its pI=6,0:
A. +1
B. 0
C. -1
19. Name the basic amino acid:
A. Lysine
B. Valine
C. Serine
D. Aspartate
E. Glutamine
MATCHING:
20. Optically inactive amino acid A. Proline
21. Aromatic amino acid B. Glycine
22. Heterocyclic amino acid C. Phenylalanine
23. Alicyclic amino acid D. Histidine
24. How many amino acids are encountered in human proteins?
A. 10
B. 15
C. 20
D. 35
E. 50
25. Which amino acid R groups are capable of forming hydrogen bonds?
A. Glycine
B. Proline
C. Isoleucine
D. Methionine
E. Tyrosine
PROTEINS
1. Which of the following statements is/are true concerning peptide bonds?
A. They are the only covalent bond formed between amino acids in polypeptide structures.
B. The angles between the participating C and N atoms are described by the values phi (φ) and psi (ψ).
C. They have partial double-bond character.
D. A and C.
E. All of the above are true.
2. What noncovalent forces stabilize β-sheet structures?
A. Ionic bonds
B. Hydrogen bonds
C. Van der Waals interactions
D. Hydrophobic interactions
3. In the α-helix, the R groups on the amino acid residues:
A. Are found on the outside of the helix spiral.
B. Participate in the hydrogen bonds that stabilize the helix.
C. Allow only right-handed helices to form.
D. A and B are true.
E. A, B, and C are true.
4. Which of the following bonds is/are possible contributors to the stability of the tertiary structure of a globular protein?
A. Covalent disulfide cross-links between 2 cysteine residues.
B. Hydrophobic interactions between phenylalanine and tryptophan R groups.
C. Hydrogen bonds between serine residues and the aqueous surroundings.
D. Ionic bonds between arginine and aspartate R groups.
E. All of the above contribute.
5. Which statements are true of α-helices?
A. Found in the same percentage in all proteins.
B. Stabilized by H bonds between –NH and –CO groups.
C. Found in globular proteins.
D. Affected by amino acid sequence.
E. An extended conformation of the polypeptide chain.
F. Includes all 20 standard amino acids in equal frequencies.
G. Hydrophobic interactions are responsible for the primary structure.
6. Which statements are true of β-helices?
A. Found in the same percentage in all proteins.
B. Stabilized by H bonds between –NH and –CO groups.
C. Found in globular proteins.
D. Affected by amino acid sequence.
E. An extended conformation of the polypeptide chain.
F. Includes all 20 standard amino acids in equal frequencies.
G. Hydrophobic interactions are responsible for the primary structure.
7. Which statements are true of both α-helices and β-sheets?
A. Found in the same percentage in all proteins.
B. Stabilized by H bonds between –NH and –CO groups.
C. Found in globular proteins.
D. Affected by amino acid sequence.
E. An extended conformation of the polypeptide chain.
F. Includes all 20 standard amino acids in equal frequencies.
G. Hydrophobic interactions are responsible for the primary structure.
8. Which statements are true of neither α-helices nor β-sheets?
A. Found in the same percentage in all proteins.
B. Stabilized by H bonds between –NH and –CO groups.
C. Found in globular proteins.
D. Affected by amino acid sequence.
E. An extended conformation of the polypeptide chain.
F. Includes all 20 standard amino acids in equal frequencies.
G. Hydrophobic interactions are responsible for the primary structure.
9. Name the cellular agents that assist in protein folding at elevated temperatures:
A. Vitamins
B. Chaperons
C. Chromosomes
D. DNA
E. RNA
10. Which disease(s) develop(s) as a result of protein misfolding?
A. Lung cancer
B. Alzheimer`s disease
C. Creuzfeld-Jacob disease
D. Mad cow disease
E. All of the above are true
11. Disrupting the hydrophobic interactions of a single-subunit protein would have the greatest effect on the ____structure of that protein:
A. Primary
B. Secondary
C. Tertiary
D. Quaternary
12. Beta pleated sheets are examples of protein's:
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
13. Protein folding is:
A. Automatic, mediated by the protein itself
B. Mediated by other proteins called chaperones
C. Mediated by the ribosomes
D. None of the above
14. Sickle cell disease is due to:
A. A mutation in the beta chain of Hb
B. A mutation in the alpha chain of Hb
C. Infection with a parasite
D. None of the above
15. The four subunits of the hemoglobin (Hb) represent protein's:
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
16. The sequence of different amino acids in the polypeptide chain of a protein is called its:
A. Secondary structure
B. Tertiary structure
C. Primary structure
D. Quaternary structure
17. Infectious self-reproducing agents consisting only of protein, with no nucleic acids (hypothesized in 1982 by Nobel Laureate Stanley
B. Prusiner) are called:
A. Proteins
B. Proteomes
C. Prions
D. Proteinoids
18. Proteins that have a quaternary structure have:
A. A protein and a lipid bonded together
B. Two or more proteins bonded together
C. A protein and a carbohydrate bonded together
D. A protein and a nucleic acid bonded together
19. Which polypeptide could have at least one disulfide bond?
A. Gly-Ile-Trp-Leu-Phe-Gly-Val-Ala-Trp-Leu-Leu-Ile
B. Gly-Pro-Hyp-Gly-Pro-Met-Gly-Pro-Ser-Gly-Pro-Arg
C. Gly-Met-Trp-Glu-Cys-Gly-Glu-Pro-Ala-His-Cys-Leu
20. Which polypeptide would be most likely to be a part of a fibrous protein found in cartilage?
A. Gly-Ile-Trp-Leu-Phe-Gly-Val-Ala-Trp-Leu-Leu-Ile
B. Gly-Pro-Hyp-Gly-Pro-Met-Gly-Pro-Ser-Gly-Pro-Arg
C. Gly-Met-Trp-Glu-Cys-Gly-Glu-Pro-Ala-His-Cys-Leu
ENZYMES
1. Molecule that binds to the active site of an enzyme is called:
A. An activator
B. An inhibitor
C. A substrate
D. A product
2. In some enzymes, components other than amino acid residues are necessary for activity. Such enzymes are called:
A. Simple
B. Complex
C. Allosteric
D. Regulatory
3. Coenzymes are:
A. Types of apoenzymes
B. Proteins
C. Inorganic cofactors
D. Organic cofactors
4. An enzyme is primarily made of:
A. Carbohydrate
B. Protein
C. Nucleic acid
D. Lipid
E. Vitamin
5. A component of enzyme covalently linked to an apoprotein is termed:
A. A coenzyme
B. A cofactor
C. A prosthetic group
6. Which class of enzymes catalyzes the following reaction:
H2N-CO-NH2 + H2O → CO2 + 2NH3
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase
E. Isomerase
F. Ligase
7. Which class of enzymes catalyzes the following reaction:
HOOC-CH2-CH2-COOH + FAD → HOOC-CH=CH-COOH + FAD·H2
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase
E. Isomerase
F. Ligase
8. Which class of enzymes catalyzes the following reaction:
HOOC-CH=CH-COOH + H2O → HOOC-CH(OH)-CH2-COOH
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase
E. Isomerase
F. Ligase
9. Which class of enzymes catalyzes the following reaction:
CH3-CO-COOH → CH3-CHO + CO2
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase
E. Isomerase
F. Ligase
10. Which class of enzymes catalyzes the following reaction:
Galactose + ATP → galactose 1-phosphate + ADP
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase
E. Isomerase
F. Ligase
11. Which class of enzymes catalyzes the following reaction:
CH3-CH2-OH + NAD+ → CH3-CHO + NADH·H+
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase
E. Isomerase
F. Ligase
12. Which class of enzymes catalyzes the following reaction:
Glucose 6-phosphate ↔ fructose 6-phosphate
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase
E. Isomerase
F. Ligase
13. Which vitamin derivatives can be used by oxidoreductases?
A. Pyridoxal phosphate
B. Tetrahydrofolic acid
C. FAD
D. Methylcobalamin
E. NAD+
14. Which vitamin derivatives can be used by transferases?
A. Pyridoxal phosphate
B. Tetrahydrofolic acid
C. FAD
D. Methylcobalamin
E. NAD+
15. Which vitamin derivatives can be used by lyases?
A. Pyridoxal phosphate
B. Tetrahydrofolic acid
C. FAD
D. Methylcobalamin
E. NAD+
Indicate whereas each of the following statements (16-22) about enzymes is true or false:
16. To be effective, they must be present at the same concentration as their substrate:
A. True
B. False
17. They increase the equilibrium constant for the reaction, thus favoring product formation:
A. True
B. False
18. They increase the rate at which substrate is converted to product:
A. True
B. False
19. They ensure that all substrate is converted to product:
A. True
B. False
20. They ensure that the product is more thermodynamically stable than the substrate:
A. True
B. False
21. They lower the activation energy for conversion of substrate to product:
A. True
B. False
22. They are consumed in the reactions that they catalyze:
A. True
B. False
23. Complete enzyme complex including all the protein subunits and prosthetic groups is termed:
A. An apoenzyme
B. A coenzyme
C. A cofactor
D. A holoenzyme
E. A prosthetic group
24. An enzyme without its prosthetic group is called:
A. An apoenzyme
B. A coenzyme
C. A cofactor
D. A holoenzyme
E. A prosthetic group
25. An enzyme facilitates chemical reactions by:
A. Increasing the free-energy difference between reactants and products.
B. Decreasing the free-energy difference between reactants and products.
C. Lowering the activation energy of the reaction.
D. Raising the activation energy of the reaction.
E. None of the above
26. Using site-directed mutagenesis, you have created a mutant form of chymotrypsin that has alanine substituted for the usual arginine at position 195. Which of the following effects do you expect to observe?
A. No effect or a slight increase in affinity for substrate coupled to a complete loss of enzyme activity.
B. A decrease in the affinity for substrate coupled to a decrease in enzyme activity.
C. A complete loss of enzyme activity due to the inability to bind substrate.
27. The top of the energy hill is termed:
A. The ground state
B. The transition state
C. The activation energy
D. The Gibbs free energy
E. The final state
28. The optimum temperature of the human enzymes is:
A. 0°C
B. 25°C
C. 37°C
D. 47°C
E. 100°C
29. The optimum pH of pepsin is:
A. 2
B. 4
C. 6
D. 8
E. 10
30. Which of the following equations represents classical Michaelis-Menten equation?
A. V=Vmax· [S]/Km+ [S]
B. V=Vmax· [S]/Km
C. V=Vmax/Km+ [S]
D. V=Vmax
31. Which of the following equations represents the Michaelis-Menten equation at very low [S]?
A. V=Vmax· [S]/Km+ [S]
B. V=Vmax· [S]/Km
C. V=Vmax/Km+ [S]
D. V=Vmax
32. Which of the following equations represents the Michaelis-Menten equation at very high [S]?
A. V=Vmax· [S]/Km+ [S]
B. V=Vmax· [S]/Km
C. V=Vmax/Km+ [S]
D. V=Vmax
33. Trypsin is to trypsinogen as active enzyme is to:
A. Zymogen
B. Pepsin
C. Pepsinogen
D. Substrate
E. Product
34. An enzyme whose activity is regulated by a modulator other than its substrate is termed:
A. Homotropic
B. Heterotropic
C. Homoheterotropic
35. Allosteric enzyme whose substrate is also a modulator of the activity is termed:
A. Homotropic
B. Heterotropic
C. Homoheterotropic
36. A modulator that increases the overall rate of an enzyme-catalyzed reaction is called:
A. Activator
B. Inhibitor
C. Substrate
D. Product
E. Zymogen
37. An agent that reduces the overall rate of an enzyme-catalyzed reaction is called:
A. Activator
B. Inhibitor
C. Substrate
D. Product
E. Zymogen
38. Class of regulatory enzymes that change their conformation when bound to a modulator is called:
A. Perfect enzymes
B. Allosteric enzymes
C. Complex enzymes
D. Simple enzymes
39. Regulation of enzyme activity by the reversible binding of a phosphate is an example of:
A. Allosteric regulation
B. Covalent modification
C. Zymogen activation
40. Which class of enzymes catalyzes phosphorylation of the regulatory enzymes?
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase
E. Isomerase
F. Ligase
41. Which class of enzymes catalyzes dephosphorylation of the regulatory enzymes?
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase
E. Isomerase
F. Ligase
42. Which amino acid residues can be phosphorylated?
A. Serine
B. Tyrosine
C. Lysine
D. Threonine
E. Cystein
43. Type of regulation in which increasing concentration of a reaction pathway`s product decreases the activity of an allosteric enzyme early in that pathway is called:
A. Positive feed forward
B. Negative feed forward
C. Positive feedback
D. Negative feedback
44. Which of the following is NOT a cellular mechanism for regulatingthe enzyme activity?
A. Partial proteolysis
B. Covalent modification
C. Induced changes in conformation
D. Binding of regulatory peptides via disulfide bonds
45. Type of inhibitor that alters the Km of an enzyme without altering Vmax is:
A. Irreversible
B. Reversible competitive
C. Reversible noncompetitive
46. Which type of inhibition can be overcome by increasing concentration of substrate?
A. Irreversible
B. Reversible competitive
C. Reversible noncompetitive
47. An inhibitor that binds only to ES complex, and therefore cannot bind to the active site is:
A. Irreversible
B. Reversible competitive
C. Reversible noncompetitive
48. An inhibitor that covalently binds to an enzyme is known as:
A. Irreversible
B. Reversible competitive
C. Reversible noncompetitive
49. A specific type of an inhibitor that alters Vmax without affecting Km is termed:
A. Irreversible
B. Reversible competitive
C. Reversible noncompetitive
50. Heavy metal ions are examples of:
A. Irreversible inhibitors
B. Reversible competitive inhibitors
C. Reversible noncompetitive inhibitors
BIOLOGIC OXIDATION
1. Complex I of the electron transport system is called:
A. NADH dehydrogenase
B. QH2 dehydrogenase
C. Succinate dehydrogenase
D. Cytochrome oxidase
E. ATP synthase
2. Complex II of the electron transport system is called:
A. NADH dehydrogenase
B. QH2 dehydrogenase
C. Succinate dehydrogenase
D. Cytochrome oxidase
E. ATP synthase
3. A biological redox reaction always involves:
A. an oxidizing agent
B. a gain of electrons
C. a reducingagent
D. allofthese
4. Coenzyme Q is involved in the electron transport as:
A. a lipid-soluble electron donor
B. a water-soluble electron donor
C. covalentlyattachedcytochromecofactor
D. a lipid-soluble electron carrier
5. Which of the following is not a feature of oxidative phosphorylation?
A. Direct transfer of phosphate from a substrate molecule to ADP
B. An electrochemical gradient across the inner mitochondrial membrane
C. A membrane bound ATP synthase
D. A protonmotiveforce
6. Which of the following is not a significant biological oxidizing agent?
A. FAD
B. Fe3+
C. O2
D. NAD+
7. In the electron transport, electrons ultimately pass to:
A. ADP
B. cytochrome b
C. oxygen
D. Noneofthese
8. During the electron transport, protons are pumped out of the mitochondrion at each of the major sites except for:
A. complex I
B. complex II
C. complex III
D. complex IV
9. Where in the mitochondria does oxidative phosphorylation take place?
A. In the matrix space
B. In the inner membrane
C. In the outer membrane
D. In the intermembrane space
10. What molecules are allowed to freely cross the inner mitochondrial membrane?
A. Water
B. Carbon dioxide
C. Oxygen
D. Carbon monoxide
E. All of these
11. What two molecules are oxidized in the electron transport chain?
A. NADH
B. NADPH·H+
C. FAD·H2
D. FMN·H2
12. What is the name of the enzyme responsible for catalyzing the oxidative phosphorylation reaction that synthesizes ATP?
A. ATP synthase
B. NADH dehydrogenase
C. QH2 dehydrogenase
D. Cytochrome oxidase
13. How many electrons must pass through the electron transport chain in order to synthesize one molecule of ATP?
A. A minimum of 10 electrons
B. A minimum of 8 electrons
C. A minimum of 6 electrons
D. A minimum of 4 electrons
E. A minimum of 2 electrons
14. Cellular respiration refers to:
A. the transferring of oxygen to each cell in the body
B. the breaking down of sugars without oxygen present
C. the splitting of glucose molecules into pyruvate
D. the using of oxygen as a reactant to break down food into bioavailable energy
E. the manufacturing of ATP using ATP synthase
15. In the electron transport chain, oxygen:
A. becomes a reducing agent
B. is the first electron acceptor
C. is the last electron acceptor
D. drives the production of ATP
E. is unnecessary
16. Scientists believe that mitochondria and chloroplasts arose through endosymbiosis. What evidence is true and supports this claim?
A. Both organelles have their own DNA
B. Mitochondria evolved relatively recently compared to chloroplasts
C. Fossil records exist of free-living mitochondria
D. Chloroplasts are where photosynthesis occurs
E. Mitochondria host the electron transport chain
17. The energy used in making ATP from ADP in chemiosmosis is from:
A. The conversion of glucose to pyruvate
B. The stream of protons crossing the inner mitochondrial membrane
C. Potassium pumps
D. The citric acid cycle
E. Acetyl-CoA
18. When FAD·H2 enters the electron transport chain, what happens?
A. It makes more ATP than when NADH donates electrons
B. It makes less ATP than when NADH donates electrons
C. ATP production stops completely
D. The electron transport chain runs in reverse
E. Ethanol is made as a byproduct
19. During the redox reactions of the electron transport chain, where do protons move?
A. Across the inner mitochondrial membrane
B. Across the outer mitochondrial membrane
C. Into the mitochondrial matrix
D. Out of the intermembrane space
E. Into the cytoplasm
20. Oxygen is necessary for cellular respiration because:
A. Combustion cannot take place without oxygen
B. Oxygen runs the ATP synthase motor
C. Glycolysis depletes oxygen, and cellular respiration replenishes it
D. Oxygen accepts electrons at the end of the electron transport chain
E. Pyruvate cannot be made without it
21. Complex III of the electron transport system is called:
A. NADH dehydrogenase
B. QH2 dehydrogenase
C. Succinate dehydrogenase
D. Cytochrome oxidase
E. ATP synthase
22. Complex IV of the electron transport system is called:
A. NADH dehydrogenase
B. QH2 dehydrogenase
C. Succinate dehydrogenase
D. Cytochrome oxidase
E. ATP synthase
23. Complex V is called:
A. NADH dehydrogenase
B. QH2 dehydrogenase
C. Succinate dehydrogenase
D. Cytochrome oxidase
E. ATP synthase
24. Cytochrome a1 is a part of:
A. Complex I
B. Complex II
C. Complex III
D. Complex IV
E. Complex V
25. Cytochrome c1 is a part of:
A. Complex I
B. Complex II
C. Complex III
D. Complex IV
E. Complex V
GLYCOLYSIS
1. Which of the following is the correct sequence of processes in the oxidation of glucose?
A. Krebs cycle - glycolysis - electron transport
B. Glycolysis - Krebs cycle - electron transport
C. Electron transport - Krebs cycle - glycolysis
D. Krebs cycle - electron transport – glycolysis
2. Lactic acid is produced by human muscles during strenuous exercise because of lack of:
A. oxygen
B. NAD+
C. glucose
D. ADP and Pi
3. In aerobic respiration, the compound that enters a mitochondrion is:
A. acetyl CoA
B. pyruvate
C. glyceraldehyde 3-phosphate
D. oxaloacetate
4. Which of the following is NOT a product of energy metabolism?
A. Carbon dioxide
B. Ethanol
C. Lactic acid
D. Water
E. Glucose
5. Which of the following is more likely to be evolved first?
A. Oxidative phosphorylation
B. Photosynthesis
C. Glycolysis
D. Fermentation
E. The electron transport chain
6. What waste product is formed in anaerobic glucose oxidation?
A. Water
B. Lactic acid
C. FADH2
D. NADH
E. ATP
7. What metabolic process is the most widespread among all living organisms?
A. Glycolysis
B. Electron transport chain
C. Oxidative phosphorylation
D. Alcohol fermentation
E. Lactic acid fermentation
8. What molecule accepts the electrons from NADH in fermentation?
A. Ethanol
B. Pyruvate
C. Glucose
D. Carbon dioxide
E. ATP
9. Which of the following is true?
A. All living things use oxygen during respiration
B. Oxygen is used to oxidize glucose
C. Only yeast do anaerobic respiration
D. The bulk of ATP synthesis happens in chemiosmosis
E. Glucose is produced through respiration
10. Fermentation produces:
A. as much ATP as aerobic respiration
B. less ATP than aerobic respiration
C. more ATP than aerobic respiration
D. no ATP
E. variable amounts of ATP depending on the input
11. Why does the glycolytic pathway continue in the direction of glucose catabolism?
A. There are essentially three irreversible reactions that act as the driving force for the pathway
B. High levels of ATP keep the pathway going in a forward direction
C. The enzymes of glycolysis only function in one direction
D. Glycolysis occurs in either direction
12. The released energy obtained by oxidation of glucose is stored as:
A. a concentration gradient across a membrane
B. ADP
C. ATP
D. NAD+
13. A kinase is an enzyme that:
A. removes phosphate groups of substrates
B. uses ATP to add a phosphate group to the substrate
C. uses NADH to change the oxidation state of the substrate
D. removes water from a double bond
14. For every one molecule of sugar glucose which is oxidized __________ molecule of pyruvic acid are produced:
A. 1
B. 2
C. 3
D. 4
15. The enzymes of glycolysis in a eukaryotic cell are located in the:
A. intermembrane space
B. plasma membrane
C. cytosol
D. mitochondrial matrix
16. ATP is one of:
A. Polysaccharides
B. Proteins
C. Nucleotides
D. Amino acids
17. Which of the following regulates glycolysis steps?
A. Phosphofructokinase
B. Hexokinase
C. Pyruvate kinase
D. All of these
18. During glycolysis, the major energy generating step involves:
A. Pyruvate kinase
B. Phosphoglycerate kinase
C. Glyceraldehyde-3 –dehydrogenase
D. Phosphofructokinase
19. Which glycolytic enzyme(s) require(s) an input of energy in the form of ATP?
A. Hexokinase
B. Phosphofructokinase
C. Glyceraldehyde 3-phosphate dehydrogenase
D. Phosphoglycerate kinase
E. Pyruvate kinase
20. Which glycolytic enzyme(s) involve(s) substrate-level phosphorylation?
A. Hexokinase
B. Phosphofructokinase
C. Glyceraldehyde 3-phosphate dehydrogenase
D. Phosphoglycerate kinase
E. Pyruvate kinase
21. Which glycolytic enzyme(s) reduce(s) NAD+?
A. Hexokinase
B. Phosphofructokinase
C. Glyceraldehyde 3-phosphate dehydrogenase
D. Phosphoglycerate kinase
E. Pyruvate kinase
22. Which glycolytic enzyme(s) is/are irreversible under intracellular conditions?
A. Hexokinase
B. Phosphofructokinase
C. Glyceraldehyde 3-phosphate dehydrogenase
D. Phosphoglycerate kinase
E. Pyruvate kinase
23. Which glycolytic enzyme is the committed step?
A. Hexokinase
B. Phosphofructokinase
C. Glyceraldehyde 3-phosphate dehydrogenase
D. Phosphoglycerate kinase
E. Pyruvate kinase
24. Which glycolytic enzyme(s) oxidize(s) NADHH+?
A. Hexokinase
B. Phosphofructokinase
C. Glyceraldehyde 3-phosphate dehydrogenase
D. Lactate dehydrogenase
E. Pyruvate kinase
25. How many ATP is produced in anaerobic glycolysis?
A. 1
B. 2
C. 4
D. 6
E. 8
THE CITRIC ACID CYCLE
1. FAD is reduced to FADH2 during:
A. electron transport phosphorylation
B. lactate fermentation
C. Krebs cycle
D. glycolysis
2. The complete oxidation of glucose yields usable energy in the form of:
A. FAD·H2
B. coenzyme A
C. ATP
D. pyruvicacid
3. The aerobic breakdown of glucose known as respiration involves:
A. electron transport phosphorylation
B. glycolysis
C. Krebs cycle
D. alloftheabove
4. In aerobic respiration, the compound that enters a mitochondrion is:
A. acetyl CoA
B. pyruvate
C. glyceraldehyde 3-phosphate
D. oxaloacetate
5. What reaction of the citric acid cycle produces the FAD·H2 that is oxidized by complex II of the electron transport chain?
A. Citrate → isocitrate
B. Isocitrate → α-ketoglutarate
C. α-ketoglutarate → succinyl-CoA
D. Succinate → fumarate
E. Malate → oxaloacetate
6. What conversion happens during the transition step before the citric acid cycle?
A. Oxygen to water
B. Pyruvate to glucose
C. Glucose to pyruvate
D. Pyruvate to acetyl-CoA
E. Acetyl-CoA to pyruvate
7. The citric acid cycle is called a "cycle" because:
A. what goes around, comes around
B. it was discovered by Mr. Tri Cycle
C. the acetyl-CoA from the beginning is regenerated at the end
D. the oxaloacetate from the beginning is regenerated at the end
E. it makes a circular shape in the mitochondria
8. What compound appears at both the beginning and the end of the citric acid cycle?
A. Lactic acid
B. Ethanol
C. Oxaloacetate
D. Pyruvate
E. Oxygen
9. What occurs in the citric acid cycle?
A. Acetyl-CoA enters the cycle, and ATP, NADH, and FADH2 are produced.
B. Pyruvate enters the cycle, and ATP, NADH, and FADH2 are produced.
C. Acetyl-CoA enters the cycle, and 38 ATP are produced.
D. NADH donates its electrons to a protein.
E. ATP synthase phosphorylates ADP to ATP.
10. The citric acid cycle is so named because:
A. no one could come up with a better name
B. citric acid is reduced in it
C. it produces citric acid as an end product
D. it was first identified in citrus fruits
E. acetyl-CoA joins up with oxaloacetate to make citric acid
11. Name the enzyme catalyzing step 1 of the citric acid cycle:
A. Fumarase
B. Citrate synthase
C. Succinate thiokinase
D. Aconitase
E. Isocitrate dehydrogenase
F. Malate dehydrogenase
G. Succinate dehydrogenase
H. Alpha-ketoglutarate dehydrogenase
12. Name the enzyme catalyzing step 2 of the citric acid cycle:
A. Fumarase
B. Citrate synthase
C. Succinate thiokinase
D. Aconitase
E. Isocitrate dehydrogenase
F. Malate dehydrogenase
G. Succinate dehydrogenase
H. Alpha-ketoglutarate dehydrogenase
13. Name the enzyme catalyzing step 3 of the citric acid cycle:
A. Fumarase
B. Citrate synthase
C. Succinate thiokinase
D. Aconitase
E. Isocitrate dehydrogenase
F. Malate dehydrogenase
G. Succinate dehydrogenase
H. Alpha-ketoglutarate dehydrogenase
14. Name the enzyme catalyzing step 4 of the citric acid cycle:
A. Fumarase
B. Citrate synthase
C. Succinate thiokinase
D. Aconitase
E. Isocitrate dehydrogenase
F. Malate dehydrogenase
G. Succinate dehydrogenase
H. Alpha-ketoglutarate dehydrogenase
15. Name the enzyme catalyzing step 5 of the citric acid cycle:
A. Fumarase
B. Citrate synthase
C. Succinate thiokinase
D. Aconitase
E. Isocitrate dehydrogenase
F. Malate dehydrogenase
G. Succinate dehydrogenase
H. Alpha-ketoglutarate dehydrogenase
16. Name the enzyme catalyzing step 6 of the citric acid cycle:
A. Fumarase
B. Citrate synthase
C. Succinate thiokinase
D. Aconitase
E. Isocitrate dehydrogenase
F. Malate dehydrogenase
G. Succinate dehydrogenase
H. Alpha-ketoglutarate dehydrogenase
17. Name the enzyme catalyzing step 7 of the citric acid cycle:
A. Fumarase
B. Citrate synthase
C. Succinate thiokinase
D. Aconitase
E. Isocitrate dehydrogenase
F. Malate dehydrogenase
G. Succinate dehydrogenase
H. Alpha-ketoglutarate dehydrogenase
18. Name the enzyme catalyzing step 8 of the citric acid cycle:
A. Fumarase
B. Citrate synthase
C. Succinate thiokinase
D. Aconitase
E. Isocitrate dehydrogenase
F. Malate dehydrogenase
G. Succinate dehydrogenase
H. Alpha-ketoglutarate dehydrogenase
19. Which of the following correctly describes the citric acid cycle?
A. Oxygen is required to regenerate electron acceptors
B. Citrate is dehydrated and hydrated by the same enzyme, aconitase
C. 12 ATPs are produced as a result of one round of the cycle
D. The Krebs cycle is located in the mitochondrial matrix
E. All of the above are true
20. Which vitamins are required for the CAC functioning?
A. Thiamine
B. Riboflavin
C. Niacin
D. Pantothenic acid
E. All of the above
21. All of the following enzymes are linked to the reduction of NADH except:
A. Isocitrate dehydrogenase
B. Malate dehydrogenase
C. Lactate dehydrogenase
D. Succinate dehydrogenase
E. Alpha-ketoglutarate dehydrogenase
22. Which enzyme of the Krebs cycle catalyzes the substrate-level phosphorylation of GDP to GTP?
A. Fumarase
B. Citrate synthase
C. Succinate thiokinase
D. Aconitase
E. Isocitrate dehydrogenase
F. Malate dehydrogenase
G. Succinate dehydrogenase
H. Alpha-ketoglutarate dehydrogenase
23. Name the only membrane-bound enzyme in the citric acid cycle:
A. Fumarase
B. Citrate synthase
C. Succinate thiokinase
D. Aconitase
E. Isocitrate dehydrogenase
F. Malate dehydrogenase
G. Succinate dehydrogenase
H. Alpha-ketoglutarate dehydrogenase
24. The committed step in the citric acid cycle is catalyzed by:
A. Fumarase
B. Citrate synthase
C. Succinate thiokinase
D. Aconitase
E. Isocitrate dehydrogenase
F. Malate dehydrogenase
G. Succinate dehydrogenase
H. Alpha-ketoglutarate dehydrogenase
25. How many moles of ATP would you expect to be generated from 1 mole of acetyl-CoA in the presence of a compound that inhibits succinate thiokinase?
A. 2
B. 4
C. 6
D. 8