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Indicate the answer choice that best completes the statement or answers the question.

1. The product of the reaction catalyzed by fumarase is:

a. fumarate.
b. citrate.
c. L-malate.
d. oxaloacetate.
e. succinate.

2. Cofactor, which is a necessary part of the pyruvate dehydrogenase component (E1), is:
a. lipoamide.
b. FAD.
c. TPP.
d. CoA.
e. NAD+.

3. Which enzyme catalyzes the reaction of the Krebs cycle that yields FADH2?
a. α-ketoglutarate dehydrogenase complex
b. citrate synthase
c. fumarase
d. succinate dehydrogenase
e. succinyl coenzyme A synthetase

4. What is the purpose of the photosynthetic apparatus?

a. to minimize photoinduced charge separation.
b. to maximize an unproductive return of the electron to its ground state.
c. to maximize photoinduced charge separation.
d. to avoid reducing power.
e. to induce oxidizing power.

5. What is the allosteric stimulator of pyruvate kinase?

a. ADP
b. pyruvate
c. fructose 1,6-bisphosphate
d. fructose 2,6-bisphosphate
e. ATP

6. What MUST be regenerated for glycolysis to proceed?

a. pyruvate
b. ATP
c. NAD+
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d. UDP-glucose
e. NADH

7. What organelle is the site of photosynthesis?

a. chloroplast
b. mitochondria
c. vacuole
d. endoplasmic reticulum
e. vesicle

8. The pathway of the electron flow from H2O to NADP+ in photosynthesis is referred to as:
a. cooperative special pairs.
b. photorespiration.
c. the Z scheme of photosynthesis.
d. the Z scheme of photorespiration.
e. photophosphorylation.

9. What reaction is catalyzed by aldolase?

a. isomerization of DHAP to GAP
b. hydrolysis of either GAP or DHAP
c. reversible cleavage of F-1,6-BP to DHAP and GAP
d. cleavage of DHAP to GAP
e. irreversible aldol condensation of DHAP and GAP

10. The source of carbon for the Calvin cycle is:

a. glucose.
b. carbon dioxide.
c. glycogen.
d. glyoxylate.
e. rubisco.

11. In bacterial photosynthesis, what is one way in which the proton gradient is created?
a. Reduction of a quinone that causes an uptake of two protons from the cytoplasm.
b. reduction of NADPH.
c. transfer of protons from NADH across the membrane via a shuttle system.
d. conversion of H2O to H+.
e. flow of electrons from cytochrome bf to plastocyanin.

12. How many molecules of water are necessary to create one molecule of NADPH?
a. 1
b. 2
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c. 3
d. 4
e. 5

13. How many energy-rich molecules are produced in the glyoxylate cycle?
a. 1 molecule of NADH
b. 2 molecules of NADH
c. 1 molecule of NADH and 1 molecule of FADH2
d. 2 molecules of NADH and 1 molecule of FADH2
e. 3 molecules of NADH, 1 molecule of FADH2, and 1 molecule of ATP

14. Which electron carrier has an isoprenoid tail?

a. NADH
b. cytochrome c
c. coenzyme Q
d. FADH2
e. coenzyme A

15. How many high-energy phosphate bonds are expended in gluconeogenesis?

a. three
b. six
c. two
d. four
e. one

16. What is the other name of Complex IV?

a. Q-cytochrome c oxidoreductase
b. cytochrome c
c. succinate-Q reductase
d. NADH-Q oxidoreductase
e. cytochrome c oxidase

17. An enzyme that catalyzes the oxidation of dihydrolipoamide contains prosthetic groups such as:
a. acetyl.
b. FAD.
c. NAD+.
d. CoA.
e. thiamine.

18. What is the net ATP obtained from one cytoplasmic NADH when it is reoxidized by the electron-transport
chain using the glycerol 3-phosphate shuttle?
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a. 2.5
b. 1.5
c. 2.0
d. 1.0
e. 0.5

19. What cycle allows for the net synthesis of glucose from acetyl CoA?
a. Calvin cycle
b. glyoxylate cycle
c. C4 pathway
d. urea cycle
e. ornithine cycle

20. Which bond occur after the second step of the pyruvate dehydrogenase reaction?
a. carbon–carbon bond
b. carbon–carbon double bond
c. disulfide bond
d. hydrogen bond
e. thioester bond

21. The donor of the two-carbon unit in the first reaction linking the pentose phosphate pathway and glycolysis
is:
a. ribulose 5-phosphate.
b. xylulose 5-phosphate.
c. glyceraldehyde 3-phosphate.
d. sedoheptulose 7-phosphate.
e. ribulose 1,5-biphosphate.

22. Choose the molecule that is NOT associated with the L and M subunits of the bacterial reaction center.
a. bacteriochlorophyll b
b. bacteriopheophytin b
c. quinones
d. magnesium ion
e. ferrous ion

23. The amount of which glucose transporter increases in muscle plasma membrane during physical exercise?
a. GLUT 1
b. GLUT 2
c. GLUT 3
d. GLUT 4
e. GLUT 5
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24. Which is NOT an additional function of the pentose phosphate pathway?
a. synthesis of hexose sugars for nucleotide biosynthesis.
b. catabolism of pentose sugars from the diet.
c. synthesis of pentose sugars for nucleotide biosynthesis.
d. catabolism of less common four- and seven-carbon sugars.
e. synthesis of less common four- and seven-carbon sugars.

25. Where does the charge separation take place within each photosystem in chloroplasts?
a. reaction center
b. light-harvesting protein
c. water-oxidizing complex
d. electron-transport chain
e. ATP synthase

26. The inhibitor of photosystem I is:

a. uric acid.
b. ammonium.
c. paraquat.
d. triazine derivatives.
e. diuron.

27. Chlorophyll a:
a. is a cyclic pentapyrrole.
b. doesn't contain reduced pyrrole rings.
c. has an additional five-carbon ring fused to another pyrrole ring.
d. contains a phytol chain connected by an ether linkage.
e. contains a sodium ion in its core.

28. Which fragment of the electron chain is in the photosynthetic bacterial reaction center?
a. P960 QA QB
b. BPh P960 QA QB
c. BPh P960 QH2 QB
d. P960 BPh QH2 QB
e. P960 BPh QA QB

29. What reactions are used to replenish citric acid cycle intermediates after they are depleted by biosynthetic
pathways?
a. anaplerotic
b. amphibolic
c. amphoteric
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d. biosynthetic
e. cataplerosis

30. Which chemicals inhibits ATP-ADP translocase activity?

a. rotenone
b. dicyclohexylcarbodiimide
c. APAF-1
d. amytal
e. atractyloside

31. Dehydrogenation of glucose 6-phosphate at carbon 1 at the first step of the oxidative phase of the pentose
phosphate pathway is catalyzed by:
a. transaldolase.
b. glucose 6-phosphate dehydrogenase.
c. glucose 1-dehydrogenase.
d. fructose 5-dehydrogenase.
e. 6-phosphogluconate dehydrogenase.

32. What is the side product of the light reactions?

a. O2
b. O2–
c. CO
d. CO2
e. H2O

33. What is the name of an ATP-generating process in which organic compounds act both as the donor and as
the acceptor of electrons?
a. reduction
b. oxidation
c. respiration
d. fermentation
e. ATP synthesis

34. Which of the following, when in the correct protein environment, is a very strong oxidant capable of
extracting electrons from water?
a. calcium center
b. copper center
c. manganese center
d. magnesium center
e. iron center
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35. Which statement is FALSE?
a. After the waste of a valuable high-energy electron, the absorbed light energy can be converted into
heat.
b. The cytochrome subunit of the reaction center must regain an electron to complete the cycle.
c. Cytochrome c2 transfers the electrons from QH2 to complex bc1.
d. The proton gradient drives the synthesis of ATP through the action of ATP synthase.
e. Complex bc1 is homologous to Complex III of the respiratory electron-transport chain.

36. What pathway ensures that sufficient amounts of CO2 are available?
a. crassulacean acid metabolism
b. gluconeogenesis
c. C4 pathway
d. sucrose synthesis
e. cellulose synthesis

37. What molecule binds to dihydrolipoyltransacetylase (E2) and inhibits it?

a. acetyl CoA
b. ADP
c. coenzyme A
d. FAD
e. NADH

38. What are the components of glyceraldehyde 3-phosphate dehydrogenase's active site?
a. reactive histidine residue and NADH with cysteine
b. reactive cysteine residue and NADH with histidine
c. reactive histidine residue and NAD+ with cysteine
d. reactive cysteine residue and NAD+ with histidine
e. reactive cysteine residue and ATP with histidine

39. Dihydrolipoyl dehydrogenase (E3) is inhibited by:

a. acetyl CoA.
b. ADP.
c. FADH2.
d. NADH.
e. pyruvate.

40. What interactions provide electron transfer between two distinct proteins, such as cytochrome c and
Complex III?
a. hydrophobic interactions
b. van der Waals
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c. covalent
d. noncovalent
e. disulfide bonds

41. _____ is the group of photosynthetic organisms that uses sunlight energy as its only vital source.
a. heterotrophs
b. chemotrophs
c. saprotrophs
d. autotrophs
e. autoheterotrophs

42. The cause of formation of ATP in both photophosphorylation and oxidative phosphorylation is:
a. proton-motive force.
b. pH gradient.
c. active transport.
d. electron-motive force.
e. diffusion of protons through the membrane.

43. Rubisco:
a. consists of nine large (L) and nine small (S) subunits.
b. catalyzes a deleterious oxygenase reaction.
c. activity does not depend on carbamate.
d. activity depends on iron.
e. catalyzes the second stage in hexose synthesis.

44. The purpose of phosphorylating glucose in the cytosol is to:

a. store more energy.
b. maintain homeostasis.
c. convert it to a more soluble form.
d. slow the transport of glucose into the cell.
e. destabilize glucose.

45. Proton-motive force is composed of:

a. a chemical gradient.
b. a charge gradient.
c. an electro-chemical gradient.
d. the sum of chemical gradient and electro-chemical gradient.
e. the sum of chemical gradient and charge gradient.

46. Overconsumption of which monosaccharide may lead to obesity, fatty liver, and insulin insensitivity?
a. lactose
b. glucose
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c. galactose
d. fructose
e. sucrose

47. What prosthetic group is tightly bound to the enzyme transketolase?

a. biotin
b. tetrahydrofolate
c. FAD
d. pyridoxal phosphate
e. thiamine pyrophosphate

48. What substance does CO2 condense with to produce two molecules of 3-phosphoglycerate at the first step of
the Calvin cycle?
a. ribulose 5-phosphate
b. enediolate intermediate
c. ribulose 1-phosphate
d. 1,3-bisphosphoglycerate
e. ribulose 3-phosphate

49. In what organelle does glycolate transform into glycine during photorespiration?
a. chloroplast
b. peroxisome
c. mitochondria
d. lysosome
e. glyoxysome

50. What member of the electron-transport chain accepts electrons from iron–sulfur protein?
a. coenzyme A
b. coenzyme Q
c. FAD
d. NAD+
e. succinate dehydrogenase

51. Which component of the bacterial reaction center lies on the cytoplasmic side of the cell membrane?
a. L subunit
b. M subunit
c. H subunit
d. C subunit
e. c-type cytochrome

52. Where is succinate dehydrogenase located in mammalian cells?

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a. inner mitochondrial membrane

b. outer mitochondrial membrane
c. mitochondrial matrix
d. intermembrane space
e. cytosol

53. What are the main noncarbohydrate precursors of gluconeogenesis?

a. glucose, amino acids, ATP
b. fatty acids, fructose, pyruvate
c. ATP, steroids, glycerol
d. glycerol, amino acids, lactate
e. glycerol, fatty acids, ATP

54. Which enzyme is the link between the citric acid cycle and ATP formation?
a. citrate synthase
b. isocitrate dehydrogenase
c. malate dehydrogenase
d. succinate dehydrogenase
e. succinatethiokinase

55. What class of enzymes catalyzes the reaction of transferring a phosphoryl group from ATP to acceptor?
a. kinases
b. phosphatases
c. phosphorylases
d. hydrolases
e. amylases

56. Choose the FALSE statement concerning the activation of Calvin cycle enzymes.
a. Reduced ferredoxin activates thioredoxin by ferredoxin–thioredoxin reductase.
b. The reduced form of thioredoxin activates many biosynthetic enzymes, including chloroplast ATP
synthase, by reducing disulfide bridges that control their activity.
c. Reduced thioredoxin activates several degradative enzymes.
d. NADPH is a signal molecule that activates two biosynthetic enzymes, phosphoribulokinase and
glyceraldehyde 3-phosphate dehydrogenase.
e. In the dark, phosphoribulokinase and glyceraldehyde 3-phosphate dehydrogenase are inhibited by
association with a protein called CP12.

57. How many ATP molecules are required by the C4 pathway for each hexose that is produced from CO2?
a. 48
b. 30
c. 24
d. 18
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e. 12

58. In the transaldolase reaction:

a. transaldolase contains thiamine pyrophosphate as a prosthetic group.
b. the first step is the ionization of thiamine pyrophosphate.
c. transaldolase of the oxidative phase is not homologous to fructose 1,6-bisphosphate aldolase in the
glycolytic pathway.
d. the nitrogen atom of the protonated Schiff base plays the same role in transaldolase as the thiazole-
ring nitrogen atom does in transketolase.
e. a Schiff base is formed between the carbonyl group of the aldose substrate and the ε-amino group of
a glycine residue at the active site of the enzyme.

59. What ions does hexokinase need for its activity?

a. Fe3+
b. K+, Na+
c. Fe3+, Na+
d. Mg2+, Mn2+
e. Fe3+, K+

60. What metal ions are contained in cytochrome c oxidase?

a. aluminium
b. copper
c. iron–nitrate cluster
d. cyanide
e. azide

61. Which conditions will activate pyruvate dehydrogenase kinase, which catalyzes the phosphorylation and
inactivation of E1 in the pyruvate dehydrogenase complex?
a. elevated concentrations of coenzyme A
b. elevated concentrations of NAD+ and ADP
c. elevated concentrations of NADH and ATP
d. Ca2+
e. glucagon

62. What enzyme uses ATP to induce structural changes in rubisco and thus coordinates rubisco activity with
the light reactions?
a. rubisco activase
b. ribulose 1,5-bisphosphate activase
c. ribulose 1,5-bisphosphate ATPase
d. carbon activase
e. carbamate activase
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63. In what part of the cell does the Calvin–Benson cycle occur?
a. matrix of mitochondria
b. inner membrane of mitochondria
c. cytoplasm
d. stroma of the chloroplasts
e. peroxisomes

64. What thiol-containing molecule in its reduced state is critical to reducing reactive oxygen species?
a. NADPH
b. folate
c. vitamin E
d. vitamin C
e. glutathione

65. What are the other names of the citric acid cycle? Select all that apply.
a. Krebs cycle
b. Cori cycle
c. tricarboxylic acid cycle
d. pentose phosphate cycle
e. glyoxylate cycle

66. What is the enzyme-bound intermediate in the conversion of citrate to isocitrate?

a. oxalosuccinate
b. α-ketoglutarate
c. cis-aconitate
d. hydroxyethyl-TPP
e. fumarate

67. What cofactor is required by plastocyanin for proper activity?

a. manganese
b. iron
c. copper
d. magnesium
e. zinc

68. What enzyme catalyzes the anaplerotic reaction of oxaloacetate formation from pyruvate?
a. malatedehydrogenase
b. pyruvate carboxylase
c. pyruvate dehydrogenase
d. pyruvate dehydrogenase kinase
e. pyruvate dehydrogenasephosphatase
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69. What photosynthetic microorganisms were the ancestor of chloroplasts as a result of endosymbiotic events?
a. fusobacteria
b. spirochaeta
c. actinobacteria
d. archaebacteria
e. cyanobacteria

70. The energy for ATP synthesis is generated by the movement of protons from the _____ side of the inner
mitochondrial membrane, establishing a(n) _____ gradient.
a. intermembrane; pH
b. intermembrane; electrical potential
c. matrix; sodium ion
d. matrix; pH
e. None of the answers is correct.

71. Which enzyme is a flavoprotein?

a. aconitase
b. isocitrate dehydrogenase
c. malate dehydrogenase
d. succinate dehydrogenase
e. succinyl CoA synthetase

72. Choose the components of the citric acid cycle that can be used to synthesize amino acids.
a. α-ketoglutarate and oxaloacetate
b. citrate and succinyl CoA
c. isocitrate and oxaloacetate
d. succinate and L-malate
e. succinate and fumarate

73. Cytochromes are:

a. lipid-soluble electron carriers.
b. electron-transferring proteins that contain heme as a prosthetic group.
c. proteins that pump ATP and contain iron–sulfur clusters.
d. transmembrane proteins that carry specific ions and charged metabolites across the inner
mitochondrial membrane.
e. proteins that convert hydrogen peroxide into oxygen and water.

74. What is the other name of Complex II?

a. succinate-Q reductase
b. cytochrome c
c. Q-cytochrome c oxidoreductase
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d. cytochrome c oxidase
e. NADH-Q oxidoreductase

75. In what compartment of chloroplasts does the primary event of photosynthesis take place?
a. cristae
b. matrix
c. intermembrane spaces
d. thylakoid membranes
e. stroma

76. What molecule inhibits hexokinase activity?

a. glucose
b. fructose 6-phosphate
c. glucose 6-phosphate
d. fructose 1,6-bisphosphate
e. fructose 2,6-bisphosphate

77. What is the process in which electromagnetic radiation is converted into chemical energy?
a. respiration
b. photorespiration
c. photosynthesis
d. phosphorylation
e. photoinduced charge separation

78. The transporter of electrons from photosystem II to photosystem I is:

a. cytochrome bf.
b. cytochrome bc1 complex.
c. ferredoxin.
d. plastoquinol.
e. ferredoxin-NADPH+ reductase.

79. How many phases are in the pentose phosphate pathway?

a. 2
b. 3
c. 5
d. 8
e. more than 10

80. The Embden–Meyerhof pathway is also known as:

a. the pentose phosphate pathway.
b. glycolysis.
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c. the citric acid cycle.

d. gluconeogenesis.
e. the Cori cycle.

81. What does bacteriopheophytin have in its center?

a. sodium ion
b. potassium ion
c. one proton
d. two protons
e. magnesium ion

82. Which enzyme catalyzes the reduction of oxygen to water?

a. ATP synthase
b. cytochrome c oxidase
c. NADH-Q oxidoreductase
d. Q-cytochrome c oxidoreductase
e. succinate-Q reductase

83. What is the name of the enzyme that is located on the stromal surface of the thylakoid membranes and
catalyzes condensation of CO2 with the enediolate intermediate?
a. rubisco
b. ribulooxidase
c. ribulocarboxidase
d. ribulose 5-bisphosphate carboxylase
e. ribulose 5-bisphosphate oxygenase

84. Choose the CORRECT order of the steps involved in the conversion of pyruvate to acetyl-CoA.
a. decarboxylation → oxidation → transfer to coenzyme A
b. decarboxylation → transfer to coenzyme A → oxidation
c. oxidation → decarboxylation → transfer to coenzyme A
d. oxidation → transfer to coenzyme A → decarboxylation
e. transfer to coenzyme A → oxidation → decarboxylation

85. In what part of the cell does the pentose phosphate pathway occur?
a. matrix of mitochondria
b. inner membrane of mitochondria
c. cytoplasm
d. stroma of the chloroplasts
e. peroxisomes

86. An isozyme form of hexokinase is expressed by tumors because this enzyme:

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a. impairs the activation of CD8+ T and NK cells.

b. stimulates blood vessel growth.
c. prevents tumor hypoxia.
d. influences the pentose phosphate pathway.
e. can access ATP from oxidative phosphorylation.

87. _____ plays a major role in the regeneration of ribulose 1,5-bisphosphate.

a. Phosphopentoseisomerase
b. Phosphoribulokinase
c. Transketolase and phosphopentose epimerase
d. Sedoheptulose 1,7-bisphosphate phosphatase
e. Transketolase and aldolase

88. What force/power drives the synthesis of ATP during photosynthesis?

a. reducing power
b. oxidizing power
c. proton power
d. proton-motive force
e. electron-motive force

89. What enzyme catalyzes the slowest step of oxidative decarboxylation of pyruvate?
a. dihydrolipoyldehydrogenase
b. dihydrolipoyltransacetylase
c. pyruvate carboxylase
d. pyruvate decarboxylase
e. pyruvate dehydrogenase component

90. What transporter provides glucose 6-phosphate to the lumen of endoplasmic reticulum?
a. T1
b. T2
c. T3
d. GLUT 1
e. GLUT 2

91. Which complex is not included in respirasome?

a. Complex I
b. Complex II
c. Complex III
d. Complex IV
e. Complex V
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92. Light absorbed by chlorophyll a causes an electron to move:
a. from the photon to the chlorophyll.
b. from the ground state to an excited state.
c. to a neighboring water molecule.
d. from chlorophyll to ADP.
e. to a molecule of oxygen.

93. What organ controls the level of glucose in blood?

a. liver
b. kidneys
c. muscles
d. adipose tissue
e. nerve system

94. _____ does NOT pump protons.

a. Complex I
b. Complex II
c. Complex III
d. Complex IV
e. Complex V

95. What is the function of a thioester intermediate such as the one formed from GAP?
a. It speeds up the actual reaction so that more product can be made.
b. The thioester shifts the equilibrium of the first stage of the reaction.
c. The thioester allows the two-step reaction to be coupled so phosphorylation can proceed.
d. The thioester intermediate induces a conformational change that alters enzyme specificity.
e. The thioester prevents the formation of metabolically unfavorable side products.

96. What is the reaction of ATP synthase?

a. AMP3– + 2HPO42– + H+ ATP4– + H2O
b. ADP3– + HPO42–+ H+ ATP4– + H2O
c. ADP3– + HPO42– + 2 H+ ATP4– + H2O
d. AMP3– + 2HPO42– + 2 H+ ATP4– + H2O
e. None of the answers is correct.

97. The concentration of which molecule increases when phosphofructokinase is inactive?

a. glucose
b. fructose
c. glucose 6-phosphate
d. fructose 1,6-bisphosphate
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e. fructose 2,6-bisphosphate

98. The Schiff base:

a. has the structure R3C–NR R .

b. has the structure R2C=NR .

c. belongs to the subclass of imines.

d. is typically formed by the condensation of a ketone with a primary amine.
e. is typically formed by the condensation of an aldehyde with a primary amine.

99. What type of gradient is critical to ATP formation during oxidative phosphorylation?
a. sodium ion
b. chloride ion
c. potassium ion
d. proton
e. electron

100. Choose the CORRECT stoichiometry for the light reactions.

a. The absorption of eight photons yields one O2, two NADPH, and three ATP molecules.
b. The absorption of eight photons yields two O2, three NADPH, and three ATP molecules.
c. The absorption of two photons yields one O2, two NADPH, and two ATP molecules.
d. The absorption of two photons yields three O2, three NADPH, and three ATP molecules.
e. The absorption of eight photons yields one O2, two NADPH, and two ATP molecules.

101. The energy-transforming machinery in the thylakoid membranes does NOT contain:
a. light-harvesting proteins.
b. water-oxidizing complexes.
c. electron-transport chains.
d. reaction centers.
e. ATP synthase.

102. The formation of carboxyphosphate is catalyzed by the subunit of the pyruvate carboxylase called:
a. biotin carboxylase domain.
b. biotin carboxyl carrier protein.
c. carboxyl transferase domain.
d. pyruvate carboxylase tetramerization domain.
e. biotin transferase domain.

103. What phosphoryl donor is used in the reaction of converting oxaloacetate to phosphoenolpyruvate?
a. ATP
b. GTP
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c. ADP
d. AMP
e. NADH

104. Which enzymes are found in the glyoxylate cycle but not in the citric acid cycle?
a. malate synthase and isocitrate dehydrogenase
b. glyoxylate synthase and malate synthase
c. isocitrate lyase and malate dehydrogenase
d. malate synthase and isocitrate lyase
e. succinyl CoA synthetase and glyoxylate synthase

105. Two primary raw materials for gluconeogenesis in the human liver are:
a. galactose and sucrose.
b. acetate and oxaloacetate.
c. lactate and alanine.
d. fructose and alanine.
e. lactose and lactate.

106. What is the primary mode of regulation for the pyruvate dehydrogenase complex?
a. feedback inhibition by citrate
b. feed-forward activation by glucose
c. allosteric activation by ATP and NADH
d. allosteric inhibition by ADP and CO2
e. inhibition by phosphorylation

107. What is NOT the name of the pathway that oxidizes glucose to carbon dioxide to generate NADPH?
a. pentose phosphate pathway
b. hexose monophosphate pathway
c. phosphogluconate pathway
d. pentose shunt
e. glucose phosphate pathway

108. Expression of what molecules is stimulated by glucagon?

a. glucose 6-phosphate and pyruvate
b. fructose 2,6-bisphosphate and hexokinase
c. fructose 1,6-bisphosphate and phosphoenolpyruvate carboxykinase
d. fructose 6-phosphate and phosphofructokinase
e. glucose and pyruvate kinase

109. What prosthetic group or enzyme does NOT take part in photorespiratory reactions?
a. glycolate oxidase
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b. catalase
c. transaminase
d. FMN
e. FAD

110. Why is the C4 pathway necessary for tropical plants?

a. Plants keep the stomata of their leaves closed in the heat during the day to prevent water loss.
b. Tropical plants do not have proper day/light cycles to maintain the balance of CO2 necessary for
carbohydrate storage.
c. Carbon dioxide is concentrated in bundle-sheath cells, which are the major sites of photosynthesis.
d. Tropical plants with a C4 pathway do a lot photorespiration because of the high concentration of CO2
in their bundle sheath cells.
e. The C3 pathway requires an extra 12 ATP when compared to the C4 pathway.

111. Inhibitory factor 1:

a. prevents the wasteful hydrolysis of ATP.
b. inhibits apoptosis.
c. takes part in generating heat from ATP synthesis.
d. stops the transfer of electrons in respiration.
e. stops the process of the malate–aspartate shuttle.

112. What is a reason that glucose is a common metabolic fuel used by living organisms?
a. It stores a lot more energy than fats or carbohydrates.
b. In cells it is stored in a free form; thus, there is no need to waste energy on excess stages of
degradation.
c. It is the only sugar used by the brain and kidney as a fuel source.
d. It is a ketose and thus a nonreducing sugar.
e. In its stable ring structure, glucose is unlikely to nonezymatically glycosylate proteins.

113. What cytochrome is the only water-soluble cytochrome of the electron-transport chain?
a. cytochrome P450
b. cytochrome b5
c. cytochrome c
d. cytochrome c oxidase
e. coenzyme Q

114. In the oxidative phase of the pentose phosphate pathway, transformation of 6-phosphoglucono-δ-lactone to
6-phosphogluconate is catalyzed by:
a. 6-phosphogluconate dehydrogenase.
b. lactonase.
c. glucose 6-phosphate dehydrogenase.
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d. ribulose 6-phosphate dehydrogenase.

e. transaldolase.

115. Falciparum malaria, a disease that requires NADPH for growth, is caused by the parasite Plasmodium
falciparum. The deficiency of which enzyme leads to an increase NADPH, and eventually hemolytic anemia?
a. glucose 1-dehydrogenase.
b. glucose 6-phosphate dehydrogenase.
c. glucose 1-phosphate dehydrogenase.
d. transketolase.
e. NADPH:cytochrome P450 oxidoreductase.

116. Which molecules are the special pair in the bacterial reaction center?
a. the pair of BPh molecules.
b. the pair of BChl-b molecules.
c. the pair of BChl-a molecules.
d. one molecule of BPh and one molecule of BChl-b.
e. one molecule of BChl-a and one molecule of BChl-b.

117. What type of enzyme plays a key role in apoptosis?

a. cytochrome P450
b. electron-transport complexes
c. caspase
d. enzymes of the citric acid cycle
e. ATPase

118. The KM of glucose 6-phosphate dehydrogenase for NADP+ is _____ the KM for NAD+.
a. 1000 times greater than
b. 10 times greater than
c. equivalent to
d. 10 times lower than
e. 1000 times lower than

119. In what part of the eukaryotic cell is oxidative phosphorylation carried out?
a. plasmatic membrane
b. cytoplasm
c. outer mitochondrial membrane
d. inner mitochondrial membrane
e. mitochondrial matrix

120. Choose the FALSE statement concerning the regulation of the pentose phosphate pathway.
a. The level of NADP+ is very important in regulation of the pathway.
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b. Low levels of NADP+ inhibit oxidation of glucose 6-phosphate.

c. NADPH competes with NADP+ in the binding active site of glucose 6-phosphate dehydrogenase.
d. The nonoxidative phase of the pathway is primarily controlled by the availability of the substrates.
e. The reaction of dehydrogenation of glucose 6-phosphate does not influence the rate of the whole
pathway.

121. What kind of product is the molecule of O2 in the actions of photosystem II?
a. key product
b. source product
c. side product
d. final product
e. intermediate product

122. What enzyme scavenges superoxide radicals by catalyzing the conversion radicals into hydrogen peroxide
and molecular oxygen?
a. superoxide dismutase
b. catalase
c. glutathione peroxidase
d. glutathione-S-transferase
e. tocopherol

123. Which ions are transferred in the same/opposite direction accompanied by the light-induced transfer of H+
into the thylakoid space?
a. Cl– and PO43–
b. PO43– and K+
c. PO43– and Mg2+
d. Cl– and K+
e. Mg2+ and Cl–

124. The first control site in the Krebs cycle is inhibited by:
a. acetyl CoA.
b. ADP.
c. Mg2+.
d. NAD+.
e. NADH.

125. A readily mobilized sugar that is commonly used to transport carbohydrates through a plant is:
a. glucose.
b. fructose.
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c. sucrose.
d. amylose.
e. amylopectin.

126. The product of the oxidative decarboxylation of α-ketoglutarate in the tricarboxylic acid (TCA) cycle is:
a. citryl coenzyme A.
b. isocitrate.
c. oxaloacetate.
d. oxalosuccinate.
e. succinyl coenzyme A.

127. Choose the wrong statement concerning the binding-change mechanism.

a. It describes proton-driven ATP synthesis.
b. One of the steps is ADP and Pi binding.
c. One of the steps is ATP synthesis.
d. One of the steps is ATP release.
e. One of the steps is ADP release.

128. Which of the citric acid cycle enzymes is also part of an electron-transport complex?
a. isocitrate dehydrogenase
b. α-ketoglutarate dehydrogenase
c. succinate dehydrogenase
d. malate dehydrogenase
e. none of the answers

129. Which enzyme complex in the inner mitochondrial membrane that carries out the
synthesis of ATP does NOT exist?
a. Complex V
b. F1F0 ATPase
c. ATP synthase Complex V
d. mitochondrial ATPase
e. cytoplasmic ATPase

130. High levels of pyruvate:

a. inhibit pyruvate dehydrogenase kinase and therefore increase the activity of the pyruvate
dehydrogenase complex.
b. activate pyruvate dehydrogenase kinase and consequently activate the pyruvate dehydrogenase
complex.
c. inhibit pyruvate dehydrogenase phosphatase and therefore enhance the activity of pyruvate
dehydrogenase complex.
d. activate pyruvate dehydrogenase phosphatase and hence inhibit the activity of pyruvate
dehydrogenase complex.
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e. activate pyruvate dehydrogenase phosphatase and therefore promote phosphorylation of the pyruvate
dehydrogenase complex.

131. What metabolic adaptation is employed by plants living in hot, dry climates to prevent water loss and
decrease photorespiration?
a. crassulacean acid metabolism
b. cellulose synthesis at night
c. C4 pathway
d. increased fructose 2,6-bisphosphatase activity
e. inhibition of glycolate salvage

132. The cellular defense system against oxidative damage contains all of the following molecules EXCEPT:
a. glutathione peroxidase.
b. vitamin E.
c. superoxide dismutase.
d. catalase.
e. vitamin A.

133. How many NADH molecules are formed in the citric acid cycle?
a. 1
b. 2
c. 3
d. 4
e. 5

134. What is the main role of the proton gradient?

a. ATP synthesis
b. ATP release from the synthase
c. coupling of ATP synthesis and respiration
d. Q-cycle occurrance
e. membrane charging

135. What is the other name of Complex I?

a. succinate-Q reductase
b. cytochrome c oxidase
c. Q-cytochrome c oxidoreductase
d. NADH-Q oxidoreductase
e. cytochrome c

136. Which of the following reactions catalyzed by transketolase does NOT coordinate the pentose phosphate
pathway with glycolysis?
a. C5 + C5 C3 + C7
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b. C4 + C5 C3 + C6
c. C3 + C7 C6 + C4
d. C5 + C6 C2 + C9
e. C4 + C5 C3 + C6

137. The inhibitor of the rate-limiting step in the citric acid cycle is:
a. α-ketoglutarate.
b. acetyl CoA.
c. ADP.
d. isocitrate.
e. succinyl CoA.

138. What organ is the site of gluconeogenesis?

a. brain
b. kidneys
c. pancreas
d. muscles
e. spleen

139. What enzyme's isoform can produce GTP from GDF by substrate-level phosphorylation?
a. α-ketoglutarate dehydrogenase complex
b. aconitase
c. citrate synthase
d. malate dehydrogenase
e. succinyl CoA synthetase

140. In the oxidative phase of the pentose phosphate pathway, transformation of glucose 6-phosphate to 6-
phosphoglucono-δ-lactone is catalyzed by:
a. 6-phosphogluconate dehydrogenase.
b. lactonase.
c. glucose 6-phosphate dehydrogenase.
d. ribulose 6-phosphate dehydrogenase.
e. transaldolase.

141. Choose the name of a highly hydrophobic 20-carbon alcohol esterified to an acid side chain of chlorophyll
a.
a. pheophytin
b. hem
c. reaction center
d. polyene
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e. phytol

142. How many molecules of ATP and NADPH are consumed in the incorporation of a single CO2 molecule
into a hexose?
a. 2 ATP, 3 NADPH
b. 3 ATP, 2 NADPH
c. 18 ATP, 12 NADPH
d. 12 ATP, 18 NADPH
e. 12 ATP, 12 NADPH

143. What is an allosteric inhibitor of gluconeogenesis?

a. NADH
b. ATP
c. AMP
d. fructose 6-phosphate
e. phosphoenolpyruvate

144. Which enzyme transfers the phosphoryl group from GTP to ADP to form ATP?
a. citrate synthase
b. isocitrate dehydrogenase
c. nucleoside diphosphokinase
d. succinate dehydrogenase
e. succinate thiokinase

145. Which chemicals does NOT inhibit the electron-transport chain?

a. rotenone
b. antimycin A
c. oligomycin
d. azide
e. amytal

146. What pathway does NOT require extra energy to pump CO2 into the bundle sheath cells and is used by
plants that are not able to grow in hot, dry climates?
a. crassulacean acid metabolism pathway
b. C3 pathway
c. C4 pathway
d. CAM pathway
e. Hatch–Slack pathway

147. What prosthetic group is associated with ferredoxin-NADP+ reductase?

a. manganese center
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b. plastoquinone
c. quinone A1
d. FAD
e. iron–sulfur center

148. What molecule inhibits fructose 1,6-bisphosphatase?

a. glucose
b. fructose 6-phosphate
c. glucose 6-phosphate
d. fructose 1,6-bisphosphate
e. fructose 2,6-bisphosphate

149. Most of the electron-transport chain is organized into a:

a. ribosome.
b. respirasome.
c. apoptosome.
d. spliceosome.
e. synthasome.

150. How many molecules of acetyl CoA enter the glyoxylate cycle per turn?
a. 1
b. 2
c. 3
d. 4
e. 5

151. What activates first in case of O2 absence?

a. VEGF
b. HIF-1
c. GLUT 1
d. GLUT 2
e. ATP production

152. External NAD+ derives from:

a. pyruvate.
b. ATP.
c. niacin.
d. thiamine.
e. lactate.

153. In the oxidative phase of the pentose phosphate pathway, transformation of 6-phosphogluconate to ribulose
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5-phosphate is catalyzed by:
a. 6-phosphogluconate dehydrogenase.
b. lactonase.
c. glucose 6-phosphate dehydrogenase.
d. ribulose 6-phosphate dehydrogenase.
e. transaldolase.

154. In the overall equation for the Calvin cycle, three molecules of _____ and two molecules of _____ are
consumed in incorporating a single CO2 molecule into a hexose.
a. NADPH; ATP
b. ATP; NADPH
c. NADPH; Pi
d. Pi; NADH
e. NADH; ATP

155. Which compounds have networks of conjugated double bonds?

a. polyene
b. phytol
c. reaction center
d. galactolipid
e. hem

156. Which coenzyme is required by glyceraldehyde 3-phosphate dehydrogenase in chloroplasts to convert 3-

phosphoglycerate into glyceraldehyde 3-phosphate?
a. NADH
b. NADPH
c. NAD+
d. NADP+
e. thiamine pyrophosphate

157. Which statements about Complex I is TRUE?

a. The complex is not able to act as a proton pump.
b. The membrane-embedded part of the complex has two proton half-channels.
c. One set of half-channels is exposed to the matrix and the other to the intermembrane space.
d. The flow of two electrons from NADH to coenzyme Q through NADH-Q oxidoreductase leads to the
pumping of two hydrogen ions out of the mitochondrial matrix.
e. QH2 takes up two protons from the matrix for its oxidation.

158. What enzyme of the glyoxylate cycle catalyzes the reaction of the isocitrate cleavage forming succinate
and glyoxylate?
a. aconitase
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b. citrate synthase
c. isocitrate lyase
d. malate synthase
e. malate dehydrogenase

159. What is the function of glucokinase?

a. It supplies fructose 6-phosphate for glycogen synthesis.
b. It catalyzes the reaction of forming glucose from glycogen.
c. It supplies glucose 6-phosphate for glycogen synthesis and formation of fatty acids.
d. It catalyzes the reaction of transformation of glucose 6-phosphate to pyruvate.
e. It supplies glucose for glycogen synthesis and formation of fatty acids.

160. According to the acceptor control mechanism, the rate of respiration depends on the level of what
substance?
a. fructose
b. NADPH
c. glucose
d. ADP
e. ATP

161. In what structure of prokaryotic cells does ATP synthesis occur?

a. mitochondrial matrix
b. outer plasmatic membrane
c. inner membrane
d. nucleolus
e. plasmid

162. What product is formed after oxidative decarboxylation of pyruvate in the mitochondrial matrix?
a. acetyl CoA
b. citrate
c. acetyllipoamide
d. glucose
e. NADH

163. What reaction does glyceraldehyde 3-phosphate dehydrogenase catalyze?

a. conversion of glyceraldehyde 3-phosphate into 1,3-bisphosphoglycerate
b. conversion of glucose 6-phosphate into fructose 6-phosphate
c. conversion of 1,3-bisphosphoglycerate into 3-phosphoglycerate
d. conversion of fructose 6-phosphate into glucose 6-phosphate
e. conversion of 1,3-bisphosphoglycerate into dihydroxyacetone phosphate

164. What is the other name of Complex III?

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a. Q-cytochrome c oxidoreductase
b. succinate-Q reductase
c. NADH-Q oxidoreductase
d. cytochrome c oxidase
e. cytochrome c

165. What is an allosteric inhibitor of phosphofructokinase?

a. NADH
b. ATP
c. AMP
d. fructose 1,6-bisphosphate
e. GTP

166. Which chemical prevents the influx of protons through ATP synthase and also is used as an antifungal
agent?
a. antimycin A
b. oligomycin
c. dicyclohexylcarbodiimide (DCC)
d. 2,4-dinitrophenol (DNP)
e. amytal

167. What term is used to describe an ATP-generating process in which an inorganic substance such as oxygen
serves as the ultimate electron acceptor?
a. electron transport
b. respiration
c. fermentation
d. anaerobic phosphorylation
e. aerobic dephosphorylation

168. Which intermediate is found at the traditional start and finish point of the citric acid cycle?
a. citrate
b. isocitrate
c. α-ketoglutarate
d. succinate
e. oxaloacetate

169. What are the special pairs in the reaction centers of plants?
a. P960+ and BChl-b
b. P960 and P700
c. P700 and P680
d. BChl-b and P960
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e. P960 and P680

170. A lipoyl group of dihydrolipoyl transacetylase (E2) is covalently attached to:

a. lysine residue.
b. histidine residue.
c. phosphohistidine residue.
d. hydroxyethyl group.
e. acetyl group.

171. What organ is the main site of fructose metabolism?

a. pancreas
b. salivary gland
c. liver
d. kidneys
e. adipose tissue

172. Choose the cell compartment where free glucose forms during gluconeogenesis.
a. mitochondrion
b. cytoplasm
c. lumen of endoplasmic reticulum
d. nucleus
e. Golgi apparatus

173. Approximately how many ATP or GTP equivalents will be produced from fuel molecules during one turn
of the citric acid cycle?
a. 6
b. 9
c. 10
d. 12
e. 38

174. What enzymes are tightly associated with FAD or FMN?

a. transferases
b. kinases
c. isomerases
d. flavoproteins
e. lyases

175. Choose the FALSE statement about ATP synthase in chloroplasts.

a. CF0 conducts protons across the thylakoid membrane.
b. CF1 catalyzes the formation of ATP from ADP and Pi.
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c. The subunit composition of CF1 is α3β3γδε.

d. The membrane orientation of CF1–CF0 is the same compared with that of mitochondrial ATP
synthase.
e. ATP and NADPH are released into the stromal space.

176. Which tissue has the least active pentose phosphate pathway?
a. adrenal gland
b. liver
c. adipose tissue
d. ovary
e. skeletal muscle

177. What substance is a member of the hexose monophosphate pool?

a. fructose 1,6-bisphosphate
b. fructose 6-phosphate
c. fructose 1-phosphate
d. 1,3-bisphosphoglycerate
e. 3-phosphoglycerate

178. In which process is ATP generated without the concomitant formation of NADPH?
a. oxidative phosphorylation
b. Krebs cycle
c. active transport
d. cyclic photophosphorylation
e. photoinduced charge separation

179. Blood tests on this enzyme are very important for cataract diagnosis.
a. galactokinase
b. galactose 1-phosphate uridyl transferase
c. phosphoglucomutase
d. UDP-galactose 4-epimerase
e. phosphofructokinase

180. What is the principal photoreceptor in chloroplasts of green plants?

a. β-carotene
b. chlorophyll a
c. chlorophyll b
d. pheophytin
e. phycocyanin

181. What type of protein makes the outer mitochondrial membrane relatively permeable?
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a. proton pump
b. voltage gated transporter
c. ATP-powered pump
d. porin
e. transporters

182. What is the function of glyceraldehyde 3-phosphate dehydrogenase?

a. oxidation of an aldehyde by NAD+ and formation of acyl-phosphate
b. oxidation of an alcohol to an aldehyde by NAD+
c. dehydration and dephosphorylation of GAP
d. hydrolysis of GAP
e. removal of the 3-phosphoryl group from GAP

183. In cyclic phosphorylation:

a. electrons from reduced ferredoxin are transferred to ferredoxin–NADP+ reductase.
b. the flow of electrons through cytochrome bf pumps protons into the stroma.
c. NADPH is not generated.
d. the side product is O2.
e. electrons arise from the reaction center of photosystem II.

184. A mutant isocitrate dehydrogenase produces an oncogenic metabolite such as:

a. α-ketoglutarate.
b. 2-hydroxyglutarate.
c. acetoacetate.
d. isocitrate.
e. oxalosuccinate.

185. The energy-rich molecule without thioester bond is:

a. orthophosphate.
b. oxalosuccinate.
c. succinyl CoA.
d. succinyl phosphate.
e. succinate.

186. Which statement about Q cycle is FALSE?

a. The Q cycle takes place in Complex III.
b. In the first half of the cycle, one of two electrons of a bound QH2 is transferred to cytochrome c and
the other to a bound Q, forming the semiquinone radical anion Q•–.
c. The newly formed Q dissociates and enters the Q pool.
d. In the second half of the cycle, a second QH2 gives up its protons to Complex III, one to a second
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molecule of cytochrome c, and the other to reduce Q•– to QH2.

e. The removal of two protons from the matrix contributes to the formation of the proton gradient.

187. Choose the CORRECT path taken by a pair of electrons as it travels down the electron-transport chain.
a. NADH Complex I CoQ Complex III Cytc Complex IV O2
b. FADH2 Complex I CoQ Complex III Cytc Complex IV O2
c. NADH Complex I Complex II Complex III Cytc Complex IV O2
d. FADH2 Complex III CoQ Complex II Cytc Complex IV O2
e. None of the answers is correct.

188. _____ contains an iron–sulfur cluster.

a. Aconitase
b. Succinyl CoA synthetase
c. Isocitrate dehydrogenase
d. Fumarase
e. Malate dehydrogenase

189. What stimulates protein kinase A, which leads to inactivation of liver pyruvate kinase?
a. fructose
b. insulin
c. glucose
d. glucagon
e. pyruvate

190. In bacterial photosynthesis, how would the light energy be used if the reduced bacteriopheophytin (BPh–)
returned the electron to the P960+ cytochrome?
a. It would follow a separate electron-transport chain.
b. It would be lost as heat.
c. It would stimulate the ejection of a second electron.
d. A proton would be pumped.
e. Energy would be stored for future purposes.

191. What subunits form the structural and functional core of the bacterial photosynthetic reaction center?
a. L and M
b. M and C
c. M and H
d. L and H
e. L and C

192. What molecule activates pyruvate kinase by feed-forward stimulation?

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a. glucose
b. fructose 6-phosphate
c. glucose 6-phosphate
d. fructose 1,6-bisphosphate
e. fructose 2,6-bisphosphate

193. What ion does alcohol dehydrogenase contain in its active site?
a. K+
b. Na+
c. Ca2+
d. Cu2+
e. Zn2+

194. What is the result of the reaction sequence of glycolysis, where glucose undergoes a phosphorylation, an
isomerization, and a second phosphorylation?
a. formation of glucose 6-phosphate
b. formation of fructose 6-phosphate
c. formation of fructose 1,6-bisphosphate
d. isomerization of glucose 6-phosphate to fructose 6-phosphate
e. isomerization of fructose 6-phosphate to glucose 6-phosphate

195. In the transketolase reaction:

a. transketolase does not contain a prosthetic group.
b. the first step is the formation of the Schiff base.
c. the first step is the ionization of thiamine pyrophosphate.
d. the carbanion of thiamine pyrophosphate attacks the aldose substrate.
e. the activated glycoaldehyde intermediate attacks the ketose substrate to form a new ketose product.

196. What enzyme of the glyoxylate cycle catalyzes a condensation of acetyl CoA and glyoxylate?
a. aconitase
b. citratesynthase
c. isocitrate lyase
d. malate synthase
e. malatedehydrogenase

197. What transport protein provides glucose to the liver cells immediately in case of glucose excess in the
blood?
a. GLUT 1
b. GLUT 2
c. GLUT 3
d. GLUT 4
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e. GLUT 5

198. Which enzyme transfers electrons from a membrane-soluble carrier to a water-soluble carrier in the
electron-transport process?
a. ATP synthase
b. cytochrome c oxidase
c. NADH-Q oxidoreductase
d. Q-cytochrome c oxidoreductase
e. succinate-Q reductase

199. What enzymes do NOT take part in the regeneration of ribulose 1,5-bisphosphate?
a. transketolase
b. sedoheptulose 1,7-bisphosphate phosphatase
c. glucose 6-phosphate dehydrogenase
d. phosphopentose epimerase
e. phosphoribulokinase

200. The malate–aspartate shuttle:

a. takes part in the heart and liver and is mediated by four membrane carriers and four enzymes.
b. transfers electrons from NADH to oxaloacetate, forming malate.
c. contains malate dehydrogenase as the only enzyme.
d. doesn't need transamination reaction to form aspartate from oxaloacetate.
e. is restarted in the matrix by deamination of aspartate and oxaloacetate formation.

201. Light absorption induces electron transfer from P680 to:

a. pheophytin.
b. plastoquinone.
c. cytochrome c.
d. chlorophyll a.
e. ferredoxin.

202. What component of the bacterial reaction center forms the proton gradient?
a. cytochrome bc1 complex
b. P960
c. BPh
d. QA – QB
e. cytochrome c2

203. A catalytic cofactor in the pyruvate dehydrogenase reaction is:

a. pyruvate.
b. acetyl CoA.
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c. CoA.
d. FAD.
e. NAD+.

204. In what form does oxaloacetate leave the mitochondrion?

a. in unchanged form
b. phosphoenolpyruvate
c. pyruvate
d. succinate
e. malate

205. What force is created by the unequal distribution of H+ across the inner mitochondrial membrane?
a. proton
b. electron
c. electrical
d. proton-motive
e. hydrophobic

206. What molecule is the ending point of purine's fermentation?

a. acetate
b. propionate
c. lactate dioxide
d. carbon
e. formate

207. What is considered a product of the citric acid cycle?

a. acetate
b. α-ketoglutarate
c. NAD+
d. oxaloacetate
e. carbon dioxide

208. What process is wasteful because of conversion of organic carbon into CO2 without the production of
ATP, NADPH, or another energy-rich metabolite?
a. processes of light reactions of photosynthesis
b. processes of dark reactions of photosynthesis
c. hexose monophosphate pool
d. photorespiration
e. respiration

209. Accessory pigments:

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a. help to absorb photons that cannot pass through the chloroplast.

b. such as chlorophyll a are present in the reaction center in large amounts.
c. increase the space of photon absorption.
d. are situated in the center of the light-harvesting complex.
e. decrease the level of photosynthesis in autumn.

210. Which chemical uncouples electron transport from ATP synthesis?

a. 2,4-dinitrophenol (DNP)
b. dicyclohexylcarbodiimide (DCC)
c. oligomycin
d. carbon monoxide (CO)
e. cyanide CN–

211. What molecule, which is an intermediate in the citric acid cycle, inhibits phosphofructokinase in the liver?
a. isocitrate
b. citrate
c. fructose 6-phosphate
d. glucose 6-phosphate
e. oxaloacetate

212. What nutrient is required for the carboxylation of pyruvate in humans?

a. biotin
b. thiamine
c. riboflavin
d. niacin
e. folic acid

213. What group of organisms cannot synthesize chemical fuels such as glucose from carbon dioxide and water
by using sunlight as their only energy source?
a. heterotrophs
b. chemotrophs
c. saprotrophs
d. autotrophs
e. autoheterotrophs

214. Which statement is TRUE?

a. The inner membrane is quite permeable because it contains mitochondrial porin, or VDAC (voltage-
dependent anion channel).
b. The membrane potential is negative on the cytoplasmic side and positive on the matrix side.
c. In bacteria, ATP-synthesizing complexes are located in the outer plasmatic membrane.
d. The genomes of mitochondria don't range in size across species.
e. Mitochondria are semi-autonomous organelles, because mitochondria depend on the cell, and cells
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that contain mitochondria in turn depend on these organelles for oxidative phosphorylation.

215. Choose the CORRECT statement.

a. ATP and ADP can diffuse freely across the inner mitochondrial membrane.
b. ADP enters the mitochondrial matrix only if ATP exits.
c. Translocase acts as a simporter.
d. ANT compose about 45% of all proteins in the inner mitochondrial membrane.
e. ANT is the only transporter which provides ATP synthase with its substrates.

216. Which form of thioredoxin activates certain Calvin cycle enzymes?

a. reduced
b. oxidized
c. dimeric
d. phosphorylated
e. dephosphorylated

217. What intermediate is needed for the conversion of galactose into glucose by reacting with galactose 1-
phosphate?
a. glucose 1-phosphate
b. fructose 6-phosphate
c. glucose 6-phosphate
d. UDP-galactose
e. UDP-glucose

218. Choose the WRONG statement concerning the structure of ATP synthase.
a. It is a large, complex enzyme resembling a ball (F1 subunit) on a stick (F0 subunit).
b. The F0 subunit is embedded in the inner mitochondrial membrane and contains the proton channel;
otherwise, the F1 subunit protrudes into the mitochondrial matrix.
c. Isolated F1 subunits do not display ATPase activity.
d. The F1 subunit consists of five types of polypeptide chains (α3, β3, γ, δ, and ε).
e. ATP synthases interact with one another to form dimers, which then associate to form large
oligomers of dimers.

219. _____ is involved in both in the Calvin cycle and the pentose phosphate pathway.
a. Glucose 6-phosphate dehydrogenase
b. Gructose 1,6-bisphosphatase
c. 3-Phosphoglycerate kinase
d. Transaldolase
e. Triose phosphate isomerase

220. Complete the following reaction for photosystem I (be sure to balance the reaction with regard to the
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electrons): Pc (Cu+) + Fdox + light

a. Pc (Cu+) + (Cu+) Fdred
b. Pc (Cu2+) + Fdred
c. Pc + Fdred (Cu2+)
d. Pc– (Cu3+) + Fdred
e. Pc (Cu+) + Fdred

221. What ion is found in the center of the tetrapyrrole in chlorophyll a?

a. calcium
b. manganese
c. iron
d. copper
e. magnesium

222. What are the allosteric inhibitors of pyruvate kinase?

a. phosphoenol pyruvate and ADP
b. pyruvate and ATP
c. fructose 1,6-bisphosphate and ADP
d. fructose 1,6-bisphosphate and AMP
e. alanine and ATP

223. What is toxic due to its ability to react with neighboring sulfhydryls of dihydrolipoyl groups, thus blocking
their reoxidation to lipoamide?
a. fluoroacetate
b. carbon monoxide
c. arsenite
d. rotenone
e. cyanide

224. A prosthetic group of the dihydrolipoyl transacetylase (E2) is:

a. acetyllipoamide.
b. acetyl CoA.
c. dihydrolipoamide.
d. hydroxyethyl-TPP.
e. lipoamide.

225. Formation of oxaloacetate from pyruvate in the anaplerotic reaction is activated by:
a. acetyl CoA.
b. acetoacetate.
c. coenzyme A.
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d. ATP.
e. pyruvate.

226. What is the name of the mechanism proposed by Peter Mitchell that explains how ATP synthesis and
electron transport are coupled?
a. chemiosmotic hypothesis
b. oxidative phosphorylation hypothesis
c. electron transport hypothesis
d. proton-motive force hypothesis
e. ATP recycling hypothesis

227. Electron flow down the electron-transport chain leads to:

a. the transport of protons across the inner mitochondrial membrane from inside the matrix to the
intermembrane space.
b. the transport of protons across the inner mitochondrial membrane from the intermembrane space into
the matrix.
c. the coupled synthesis of GTP.
d. a dangerous imbalance of K+ ions across the mitochondrial membrane.
e. None of the answers is correct.

228. Glycolysis is the metabolic pathway during which _____ of glucose.

a. one molecule of pyruvate and two molecules of ATP are formed from one molecule
b. two molecules of pyruvate and two molecules of ATP are formed from one molecule
c. two molecules of pyruvate and one molecule of ATP are formed from two molecules
d. one molecule of pyruvate and one molecule of ATP are formed from two molecules
e. one molecule of pyruvate and two molecules of ATP are formed from two molecules

229. What concentration change does NOT contribute to activation of Calvin cycle enzymes?
a. increase in stromal pH in the light reactions.
b. increase in the H+ concentration in stroma in the light reactions.
c. increase in the concentration of stromal NADPH in the light reactions.
d. increase in the concentration of reduced ferredoxin in stroma in the light reactions.
e. increase in the concentration of Mg2+ in stroma in the light reactions.

230. Which intermediate is formed during the first oxidative decarboxylation reaction of the citric acid cycle?
a. cis-aconitate
b. enol intermediate
c. hydroxyethyl-TPP intermediate
d. oxalosuccinate
e. isocitrate

231. What functions as a "flexible swinging arm" when it transfers the reaction intermediate from one active
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site to the next?
a. FAD
b. NAD+
c. lipoamide
d. thiamine pyrophosphate
e. coenzyme A

232. Which cofactor supplies the reducing power for reduction of glutathione by glutathione reductase?
a. FMN
b. TPP
c. FAD
d. NADPH
e. NADH

233. The inhibitor of photosystem II is:

a. uric acid.
b. ammonium.
c. paraquat.
d. triazine derivatives.
e. reactive oxygen.

234. Choose the CORRECT statement concerning the action of transketolase and transaldolase.
a. Transketolase transfers a three-carbon unit.
b. Transaldolase transfers a three-carbon unit.
c. Transketolase transfers a four-carbon unit.
d. Transaldolase and transketolase transfer a four-carbon unit.
e. Transaldolase and transketolase transfer a three-carbon unit.

235. High-transfer-potential electrons are captured by the pyruvate dehydrogenase complex in the form of:
a. acetyl CoA.
b. acetyllipoamide.
c. ATP.
d. FADH2.
e. NADH.

236. What prosthetic group is present in Complexes I, II, and III of electron transport?
a. semiquinone
b. flavin mononucleotide
c. coenzyme Q
d. heme group
e. iron–sulfur cluster
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237. How is light used in photosynthesis?

a. The light is necessary to make chlorophyll green, so the pigment can transmit electrons.
b. The light is used to generate high-energy electrons with a great reducing potential.
c. The light provides heat energy for the chloroplasts.
d. The light is absorbed by oxygen, which is converted into water.
e. The light is necessary to activate ATP synthase.

238. ADP levels regulate the rate of oxidative phosphorylation via:

a. regulatory control
b. donor control
c. respiratory control
d. ADP level control
e. Warburg effect

239. The core of the water-oxidative complex contains:

a. a calcium ion, four manganese ions, and four water molecules.
b. a calcium ion, two manganese ions, and two water molecules.
c. two calcium ions, four manganese ions, and four water molecules.
d. a calcium ion and four water molecules.
e. a calcium ion, a manganese ion, and a water molecule.

240. Choose the major difference between the bacterial system and photosystem II.
a. The bacterial system contains quinones, unlike photosystem II.
b. Photosystem II, unlike the bacterial system, transfers electrons to bacteriopheophytin.
c. The bacterial system, unlike photosystem II, transfers electrons to pheophytin.
d. The source of electrons.
e. The source of protons.

Indicate one or more answer choices that best complete the statement or answer the question.

241. Select all that apply. The formation of xylulose 5-phosphate from ribose 5-phosphate is catalyzed by:
a. phosphopentose isomerase.
b. hosphopentose epimerase.
c. phosphohexose isomerase.
d. transketolase.
e. transaldolase.

242. Select all that apply. The products of the first reaction linking the pentose phosphate pathway and
glycolysis are:
a. ribulose 5-phosphate.
b. glyceraldehyde 3-phosphate.
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c. sedoheptulose 7-phosphate.
d. xylulose 5-phosphate.
e. erythrose 4-phosphate.

243. What processes allow electrons from cytoplasmic NADH to enter mitochondria? Select all that apply.
a. glycerol 3-phosphate shuttle
b. cytochrome c shuttle
c. malate–aspartate shuttle
d. quinone shuttle
e. succinate shuttle

244. What are the products of the reaction of isocitrate cleavage by isocitrate lyase in the glyoxylate cycle?
Select all that apply.
a. glyoxylate
b. succinate
c. oxaloacetate
d. citrate
e. coenzyme A

245. What enzymes catalyze virtually irreversible reactions of glycolysis? Select all that apply.
a. phosphoglycerate kinase
b. phosphofructokinase
c. aldolase
d. hexokinase
e. pyruvate kinase

246. Which sugar(s) is/are converted into ribulose 5-phosphate by a single enzymatic step? Select all that apply.
a. ribose 5-phosphate
b. xylulose 5-phosphate
c. erythrose 4-phosphate
d. fructose 6-phosphate
e. sedoheptulose 7-phosphate

Enter the appropriate word(s) to complete the statement.

247. The products in the reaction of glyceraldehyde 3-phosphate plus sedoheptulose 7-phosphate are erythrose
4-phosphate and _______.

248. Transformation of glucose into lactate in the presence of oxygen in tumors is called aerobic glycolysis or
_______.

249. In the initial step of Complex I, two high-potential electrons are transferred from NADH to the _______
prosthetic group of this complex.
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250. Photosystem II responds to wavelengths of light shorter than _______ nm.
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Answer Key
1. c

2. c

3. d

4. c

5. c

6. c

7. a

8. c

9. c

10. b

11. a

12. b

13. a

14. c

15. b

16. e

17. b

18. b

19. b

20. e

21. b

22. d

23. d

24. a
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25. a

26. c

27. c

28. e

29. a

30. e

31. b

32. a

33. d

34. c

35. c

36. c

37. a

38. d

39. d

40. a

41. d

42. a

43. b

44. e

45. e

46. d

47. e

48. b

49. b
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50. b

51. c

52. a

53. d

54. d

55. a

56. c

57. b

58. d

59. d

60. b

61. c

62. a

63. d

64. e

65. a

66. c

67. c

68. b

69. e

70. d

71. d

72. a

73. b

74. a
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75. d

76. c

77. c

78. a

79. a

80. b

81. d

82. b

83. a

84. a

85. c

86. e

87. e

88. d

89. e

90. a

91. b

92. b

93. a

94. b

95. c

96. b

97. c

98. a

99. d
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100. a

101. b

102. a

103. b

104. d

105. c

106. e

107. e

108. c

109. e

110. c

111. a

112. e

113. c

114. b

115. b

116. b

117. c

118. e

119. d

120. e

121. c

122. a

123. e

124. e
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125. c

126. e

127. e

128. c

129. e

130. a

131. a

132. e

133. c

134. b

135. d

136. d

137. e

138. b

139. e

140. c

141. e

142. b

143. c

144. c

145. c

146. b

147. d

148. e

149. b
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150. b

151. b

152. c

153. a

154. b

155. a

156. b

157. c

158. c

159. c

160. d

161. c

162. a

163. a

164. a

165. b

166. b

167. b

168. e

169. c

170. a

171. c

172. c

173. c

174. d
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175. d

176. e

177. b

178. d

179. b

180. b

181. d

182. a

183. c

184. b

185. d

186. d

187. a

188. a

189. d

190. b

191. a

192. d

193. e

194. c

195. c

196. d

197. b

198. d

199. c
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200. b

201. a

202. a

203. d

204. e

205. d

206. e

207. e

208. d

209. c

210. a

211. b

212. a

213. a

214. e

215. b

216. a

217. e

218. c

219. d

220. b

221. e

222. e

223. c

224. e
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225. a

226. a

227. a

228. b

229. b

230. d

231. c

232. d

233. d

234. b

235. e

236. e

237. b

238. c

239. a

240. d

241. a, b

242. b, c

243. a, c

244. a, b

245. b, d, e

246. a, b

247. fructose 6-phosphate

248. Warburg effect

249. FMN
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250. 680
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Indicate the answer choice that best completes the statement or answers the question.

1. Choose the INCORRECT statement about the regulation of liver phosphorylase, if glucose is present in the
diet.
a. The default state of liver phosphorylase is the a form.
b. Liver phosphorylase, like muscle phosphorylase, is sensitive to regulation by AMP.
c. The binding of glucose to the active site shifts the a form from the active R state to the less-active T
state.
d. The enzyme reverts to the low-activity T state only when it detects the presence of sufficient glucose.
e. Conversion of phosphorylase b in the R state into phosphorylase a in the R state requires two ATP
molecules.

2. What allosteric effector is NOT responsible for the regulation of phosphorylase?

a. insulin
b. adrenaline
c. glucagon
d. AMP
e. noradrenaline

3. Which molecule is formed in the end of the first elongation cycle of fatty acid synthesis?
a. acetoacetyl ACP
b. acetyl ACP
c. butyryl ACP
d. malonyl ACP
e. propionyl ACP

4. What disease is caused by high levels of urate?

a. severe combined immunodeficiency
b. Lesch–Nyhan syndrome
c. gout
d. spina bifida
e. phenylketonuria

5. What is the main step for the regulation of pyrimidine biosynthesis in bacteria?
a. oxidation of dihydroorotate by NAD+ to form orotate
b. formation of carbamoylaspartate
c. orotate coupling to PRPP
d. phosphorylation of bicarbonate by ATP
e. phosphorylation of carbamic acid

6. What is NOT an advantage of high urate serum levels such as those found in humans? Select all that apply.
a. High levels of urate may prevent cancer development.
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b. Urate is about as effective as ascorbate (vitamin C) as an antioxidant.

c. Urate is a highly effective scavenger of reactive oxygen species.
d. Urate is used in the purine salvage pathway that is remarkably energy saving.
e. High levels of urate may prolong life span in higher primates.

7. Asparaginase catalyzes the reaction of asparagine transformation into:

a. aspartate and NH4+.
b. glutamate and oxaloacetate.
c. pyruvate and NH4+.
d. pyruvate and glutamate.
e. oxaloacetate and aspartate.

8. Which statement about Lesch–Nyhan syndrome is INCORRECT?

a. The cause of Lesch–Nyhan syndrome is the lack of hypoxanthine-guanine phosphoribosyl
transferase.
b. Complex behavioral violations can be caused by the absence of a single enzyme.
c. Its main characteristics are compulsive self-destructive behavior, cognitive disabilities, and
spasticity.
d. Stopping a single metabolic reaction cannot cause complex behavioral consequences.
e. Lesch–Nyhan syndrome demonstrates that the salvage pathway for the synthesis of IMP and GMP is
not of minor importance.

9. What is role of the P clusters that are located in the nitrogenase?

a. nitrogen oxidation
b. electron storage
c. nitrogen reduction
d. nitrogen fixation
e. nitrogen storage

10. What reaction is NOT catalyzed by cobalamin enzymes?

a. intramolecular rearrangements
b. methylations
c. reduction of ribonucleotides to deoxyribonucleotides
d. the conversion of L-methylmalonyl CoA into succinyl CoA
e. the conversion of propionyl CoA into succinyl CoA

11. How is aspartate transcarbamoylase (ATCase) regulated?

a. ATCase is inhibited by CTP and stimulated by ATP.
b. ATCase is inhibited by ATP and stimulated by CTP.
c. ATCase is inhibited by UMP and stimulated by ATP.
d. ATCase is inhibited by ATP and stimulated by UMP.
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e. ATCase is inhibited by CTP and UMP.

12. Key allosteric regulation of glycogen synthase occurs via:

a. glycogen synthase kinase.
b. glycogen synthase a.
c. glycogen synthase b.
d. hormones.
e. mediators.

13. Assembly of a nucleoside from the activated sugar and a preformed base is known as a(n):
a. salvage pathway.
b. synthetic pathway.
c. catabolic pathway.
d. anabolic pathway.
e. de novo pathway.

14. In muscle, the first event in the breakdown of glycogen due to binding of a hormone is:
a. cytoplasmic cAMP levels rise.
b. protein kinase A phosphorylates phosphorylase kinase.
c. adenylate cyclase is activated.
d. protein kinase A is activated.
e. activation of a G protein.

15. Which enzyme does NOT catalyze the substitution of a phosphoryl group for an amino group?
a. aspartate transcarbamoylase
b. carbamoyl phosphate synthetase II
c. carbamoyl phosphate synthetase I
d. uridine monophosphate synthetase
e. cytidine triphosphate synthetase

16. What compound is formed by acetoacetate oxidation with NADH consumption?

a. 3-hydroxy-3-methylglutaryl CoA
b. D-3-hydroxybutyrate
c. acetoacetyl CoA
d. acetone
e. acetyl CoA

17. What coenzyme does UDP-glucose in glycogen synthase correspond to?

a. UDP
b. PLP
c. NAD+
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d. NADPH
e. AMP

18. What are amino acids that must be supplied in the diet called?
a. essential amino acids
b. basic amino acids
c. acidic amino acids
d. nonessential amino acids
e. proteinogenic amino acids

19. Choose the CORRECT statement about the mechanism of glycogen phosphorolysis.
a. Glycogen phosphorylase always cleaves glycogen phosphorolytically.
b. Both the glycogen substrate and the glucose 1-phosphate product have a β configuration at C-1.
c. Glycogen phosphorylase requires the coenzyme pyridoxal phosphate, a derivative of pyridoxine
(vitamin B9).
d. Substrates bind antagonistically, causing water exclusion.
e. The 5 -phosphate group of pyridoxal phosphate acts as a general acid–base catalyst.

20. What is used by ribonucleotide reductase as the direct source of electrons?

a. NADPH
b. FADH2
c. thioredoxin
d. ubiquinol
e. NADH

21. What process precedes the biosynthesis of amino acids?

a. the L isomer of glutamate formation
b. reduction of the protonated Schiff base
c. protonation of the Schiff base
d. Schiff base formation between the ammonium ion and α-ketoglutarate
e. nitrogen fixation

22. Glycine condenses with succinyl CoA in the first step of synthesis of:
a. thiamine.
b. histamine.
c. glutathione.
d. porphyrin.
e. folate.

23. Carbamoyl phosphate synthetase II (CPS II) consists of _____ chain(s).

a. 5
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b. 4
c. 3
d. 2
e. 1

24. What pathway degrades an acyl CoA into acetyl CoA?

a. acyl transferase cycle
b. chylomicron cycle
c. glyoxylate cycle
d. carnitine cycle
e. β-oxidation

25. The ATP-binding region of nitrogen-fixating reductase is a(n) _____ domain.

a. iron–sulfur
b. electron-binding
c. P-loop NTPase family
d. molybdenum-binding
e. molybdenum–sulfur

26. What process is NOT controlled by protein degradation through the ubiquitin-proteasome pathway?
a. gen translation
b. organ formation
c. circadian rhythms
d. cholesterol metabolism
e. tumor suppression

27. Ketogenic amino acids that degrade into acetyl CoA can give rise to:
a. amino acids.
b. fatty acids.
c. nucleic acids.
d. lipids.
e. carbohydrates.

28. Which amino acid is a metabolite in the urea cycle but is not used as a building block of proteins?
a. ornithine
b. aspartate
c. glutamate
d. lysine
e. arginine

29. What common biochemical strategy allows ammonia to be generated for use within the same enzyme?
a. ammonia fixation
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b. glutamine hydrolysis
c. ammonia activation
d. glutamate hydrolysis
e. glutamate activation

30. What inhibits fatty acid synthesis by disaggregating acetyl CoA carboxylase 1 into inactive dimers?
a. linoleoyl CoA
b. linolenoyl CoA
c. malonyl CoA
d. palmitoyl CoA
e. succinyl CoA

31. Which substrate is NOT needed for de novo synthesis of pyrimidines?

a. ribose 5-phosphate
b. aspartate
c. glutamate
d. glutamine
e. bicarbonate

32. What prosthetic group do aminotransferases contain?

a. amino group
b. carboxy group
c. pyridoxal phosphate group
d. phosphoryl group
e. methyl group

33. Glucagon and epinephrine control both glycogen breakdown and glycogen synthesis through:
a. protein kinase A.
b. protein kinase B.
c. cAMP.
d. phosphorylase.
e. glucagon.

34. In the urea cycle, the second nitrogen of urea enters the cycle in the form of which metabolite?
a. alanine
b. glutamine
c. ornithine
d. aspartate
e. arginine

35. What primer catalyzes the formation of α-1,4-glucose polymers?

a. glycogenin
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b. glycogen
c. calmodulin
d. insulin
e. glucose

36. Phosphorylase kinase:

a. is the enzyme that consists of two (αβγδ)4 lobes that are joined by a β4 bridge.
b. contains the δ subunit with the active site, while all of the remaining subunits play regulatory roles.
c. contains the δ subunit that is the target for the Ca2+-binding protein calmodulin.
d. contains targets of protein kinase B such as α and β subunits.
e. is activated when Ca2+ binds to the δ subunit and then acetylation of the β and α subunits occurs.

37. Which amino acids are degraded by muscles?

a. Val, Leu, Ile
b. Val, Met, Leu
c. Met, Leu, Val
d. Ile, Gly, Met
e. Leu, Gly, Met

38. The first step in de novo pyrimidine biosynthesis is the:

a. cleavage of two molecules of ATP.
b. synthesis of carbamoyl phosphate from bicarbonate and ammonia.
c. phosphorylation of carbamic acid by a molecule of ATP.
d. reaction of carbamoyl phosphate with aspartate to form carbamoylaspartate.
e. attachment to ribose phosphate.

39. Glutathione does NOT:

a. protect red blood cells from oxidative damage.
b. serve as a sulfhydryl buffer.
c. serve as an antioxidant.
d. play a key role in detoxification.
e. serve as a chelator.

40. What catalyzes the formation of butyryl ACP from crotonyl ACP in fatty acid synthesis?
a. β-ketoacyl reductase
b. β-ketoacyl synthase
c. 3-hydroxyacyl dehydratase enoyl reductase
d. acetyl transacylase
e. enoyl reductase

41. What is the intermediate in the conversion of inosinate into guanylate?

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a. adenylate
b. hypoxanthine
c. adenylosuccinate
d. orotidylate
e. xanthylate

42. What enzyme forms α-1,6 linkages during glycogen synthesis?

a. branching enzyme
b. glycogen synthase
c. glycosyltransferase
d. pyrophosphorylase
e. glycogen synthase kinase

43. Which enzyme determines fatty acid chain length in fatty acid synthesis?
a. 3-ketothiolase
b. β-ketoacyl reductase
c. fatty acid thiokinase
d. malonyl transacylase
e. thioesterase

44. What cofactor is required by phenylalanine hydroxylase?

a. flavin mononucleotide
b. pyridoxal phosphate
c. dihydrofolate
d. nicotinamide adenine dinucleotide
e. tetrahydrobiopterin

45. An allosteric inhibitor of glutamate dehydrogenase is:

a. GTP.
b. ATP.
c. AMP.
d. ADP.
e. NADH.

46. What hormone signifies the starved state?

a. insulin
b. glucagon
c. epinephrine
d. cortisol
e. None of the answers is correct.

47. What process converts N2 to NH3?

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a. urea cycle
b. glutamine hydrolysis
c. denitrification
d. nitrogen fixation
e. citric acid cycle

48. Tyrosine is a precursor to:

a. melatonin and epinephrine.
b. epinephrine and serotonin.
c. serotonin and melatonin.
d. melanin and epinephrine.
e. melanin and serotonin.

49. Choose the INCORRECT statement about the regulation of muscle phosphorylase.
a. The default state of muscle phosphorylase is the b form.
b. Muscle phosphorylase b is activated by the presence of high concentrations of AMP.
c. AMP stabilizes the conformation of phosphorylase b in the active R state.
d. ATP acts as a positive allosteric effector.
e. Phosphorylase a is fully active, regardless of the concentration of AMP, ATP, or glucose 6-
phosphate.

50. Which reaction establishes stereochemistry at the α-carbon atom in amino acids?
a. dehydration
b. oxidation
c. transamination
d. hydrolysis
e. amination

51. Choose two nonessential amino acids for which glutamate is the precursor.
a. alanine and asparagine
b. aspartate and cysteine
c. proline and arginine
d. tyrosine and serine
e. glycine and glutamine

52. What is the mechanism of ubiquitin binding to the target protein?

a. ε-Amino groups of lysine residue on the targeted protein covalently connect with the C-terminal
glycine residue of ubiquitin.
b. ε-Amino groups of glycine residue on the targeted protein covalently connect with the C-terminal
lysine residue of ubiquitin.
c. ε-Amino groups of lysine residue on the targeted protein covalently connect with the N-terminal
glycine residue of ubiquitin.
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d. ε-Amino groups of glycine residue on the targeted protein covalently connect with the N-terminal
lysine residue of ubiquitin.
e. α-Amino groups of glycine residue on the targeted protein covalently connect with the N-terminal
lysine residue of ubiquitin.

53. _____ is decarboxylated to form uridylate.

a. Adenylate
b. Cytidylate
c. Guanylate
d. Orotidylate
e. Thymidylate

54. What enzyme exposes a single glucose residue joined by an α-1,6-glycosidic linkage?
a. hexokinase
b. transferase
c. phosphoglucomutase
d. glycogen phosphorylase
e. α-1,6-glucosidase

55. What stimulates the breakdown of triacylglycerols by phosphorylation of perilipin and activation of a
hormone-sensitive lipase in adipose tissue?
a. ADP
b. citrate
c. glucagon
d. glyceraldehyde 3-phosphate
e. insulin

56. Choose the amino acids that are synthesized using homocysteine as an intermediate.
a. cysteine and alanine
b. proline and tryptophan
c. methionine and proline
d. glycine and alanine
e. methionine and cysteine

57. What is the intermediate in the conversion of inosinate into adenylate?

a. guanylate
b. hypoxanthine
c. adenylosuccinate
d. orotidylate
e. xanthylate

58. What is the structure of the reductase of the nitrogenase complex?

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a. heterotetramer
b. homodimer
c. heterodimer
d. monomer
e. pentamer

59. What enzyme is the amino-terminal reader?

a. ubiquitin activating enzyme
b. ubiquitin-protein ligase
c. ubiquitin-conjugating enzyme
d. monooxygenase
e. aminotransferase

60. Choose the correct sequence of reactions that lead to the serine synthesis from 3-phosphoglycerate.
a. hydrolysis; dehydration; transamination
b. oxidation; dehydration; hydrogenation
c. oxidation; dehydration; transamination
d. oxidation; transamination; hydrolysis
e. oxidation; transamination; dehydration

61. What do S-Adenosylmethionine and fruit ripening have in common?

a. S-Adenosylmethionine is the precursor of propylene that induces the ripening of fruit.
b. S-Adenosylmethionine is a critical signal molecule in fruit ripening.
c. S-Adenosylmethionine is the precursor of hydrogen sulfide that induces the ripening of fruit.
d. S-Adenosylmethionine causes premature spoiling of fruit.
e. S-Adenosylmethionine is the precursor of ethylene that induces the ripening of fruit.

62. What type of glycosidic bonds is found at the branch points of glycogen?
a. α-1,2
b. α-1,4
c. α-1,6
d. β-1,4
e. β-1,6

63. What amino-terminus amino acids are highly destabilizing and prefer rapid ubiquitination?
a. methionine and leucine
b. valine and serine
c. serine and isoleucine
d. isoleucine and valine
e. arginine and leucine

64. What is a tripeptide that functions as an antioxidant?

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a. glutathione
b. aspartame
c. oxytocin
d. thyrotropin-releasing hormone
e. ferredoxin

65. What enzyme requires a shift of a phosphoryl group to form glucose 6-phosphate?
a. phosphoglucomutase
b. transferase
c. hexokinase
d. glucose 6-phosphatase
e. phosphorylase

66. What is a product of ketogenic amino acids degradation?

a. pyruvate
b. acetoacetate
c. oxaloacetate
d. α-ketoglutarate
e. argininosuccinate

67. What insulin-sensible enzyme of glycogen synthesis takes part in the phosphorylation of glycogen synthase?
a. phosphofructokinase
b. UDP-glucose phosphorylase
c. protein kinase A
d. protein kinase B
e. glycogen synthase kinase

68. Where does fatty acid synthesis take place?

a. in cytoplasm
b. in lysosomes
c. in the mitochondrial matrix
d. in peroxisomes
e. on the outer mitochondrial membrane

69. Which enzyme includes several isozymes having different chain-length specificity?
a. b-ketothiolase
b. L-3-hydroxyacyl CoA dehydrogenase
c. acyl CoA dehydrogenase
d. acyl CoA synthetase
e. enoyl CoA hydratase

70. Which nucleotide is most commonly used as energy currency?

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a. ATP
b. UTP
c. GTP
d. CTP
e. TTP

71. What is the mechanism of action of allopurinol?

a. It allosterically inhibits xanthine oxidase.
b. It blocks release of the reaction products of adenosine deaminase, therefore inactivating the enzyme.
c. It inactivates the enzyme by keeping the molybdenum atom of xanthine oxidase in the +6 oxidation
state.
d. It allosterically inhibits adenosine deaminase.
e. Xanthine oxidase uses it as a substrate, and the product remains tightly bound to the active site.

72. What makes the molecule of S-adenosylmethionine much more reactive than N5-methyltetrahydrofolate?
a. The methyl group of the methionine unit is activated by the negative charge on the adjacent sulfur
atom.
b. The methyl group of the methionine unit is activated by the positive charge on the adjacent sulfur
atom.
c. The ethyl group of the methionine unit is activated by the positive charge on the adjacent sulfur
atom.
d. The methyl group of the adenosine unit is activated by the positive charge on the adjacent sulfur
atom.
e. The propyl group of the methionine unit is activated by the positive charge on the adjacent sulfur
atom.

73. Which is the coenzyme of propionyl CoA carboxylase?

a. biotin
b. cobalamin
c. FAD
d. phosphopantetheine
e. riboflavin

74. What protein is the δ subunit of phosphorylase kinase?

a. protein kinase A
b. phosphorylase
c. adenylate cyclase
d. protein phosphatase 1
e. calmodulin

75. Alimentation and the following degradation of proteins provide cells with:
a. carbohydrates.
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b. fatty acids.
c. amino acids.
d. nucleic acids.
e. lipids.

76. Choose the conditions for the fixation of N2 in an industrial process.

a. a cadmium catalyst, 150°C, pressure of 250 atmospheres
b. a copper catalyst, 600°C, pressure of 400 atmospheres
c. an iron catalyst, 500°C, pressure of 300 atmospheres
d. a molybdenum catalyst, 700°C, pressure of 350 atmospheres
e. an iron catalyst, 800°C, pressure of 100 atmospheres

77. What is the activated form of glucose required for glycogen synthesis?
a. glucose 6-phosphate
b. glucose 1-phosphate
c. ADP-glucose
d. UDP-glucose
e. GDP-glucose

78. Sodium bicarbonate secreted from the pancreas:

a. stimulates synthesis of polypeptide products of pepsin digestion.
b. makes pH in the stomach more acidic.
c. plays a role in the release of pancreatic hormones.
d. neutralizes pH of the food.
e. provides food from the stomach to the intestines.

79. Which statement about glutamine phosphoribosyl amidotransferase is INCORRECT?

a. It catalyzes the committed step in purine synthesis.
b. It is allosterically regulated by the final products of the pathway.
c. It is feedback-inhibited by nucleotides.
d. It is inhibited by AMP, IMP, and GMP.
e. It is activated by hypoxanthine.

80. What amino acid is added to indole in the biosynthesis of tryptophan?

a. glutamine
b. serine
c. tyrosine
d. alanine
e. glycine

81. Why is the biological reduction of N2 to NH3 an eight-electron process?

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a. At least 1 mol of H2 in addition to 2 mol of NH3 for each mol of N2 is generated.

b. At least 2 mol of H2 in addition to 2 mol of NH3 for each mol of N2 are generated.
c. At least 3 mol of H2 in addition to 2 mol of NH3 for each mol of N2 are generated.
d. At least 4 mol of H2 in addition to 3 mol of NH3 for each mol of N2 are generated.
e. At least 1 mol of H2 in addition to 4 mol of NH3 for each mol of N2 is generated.

82. Choose the correct answer. DNA is built from:

a. nucleotides.
b. nucleosides.
c. deoxyribonucleotides.
d. ribonucleotides.
e. deoxyribonucleosides.

83. What catalyzes the formation of malonyl CoA in fatty acid synthesis?
a. β-ketoacyl synthase
b. β-ketoacyl reductase
c. acetyl CoA carboxylase
d. acetyl transacylase
e. malonyl transacylase

84. Which amino acids can be directly deaminated to produce NH4+?

a. serine and threonine
b. serine, asparagine, and threonine
c. proline and threonine
d. proline and valine
e. proline and serine

85. Which reaction is NOT carried out by carbamoyl phosphate synthetase II?
a. glutamine hydrolysis
b. phosphorylation of bicarbonate
c. formation of carbon–nitrogen bonds through acylphosphate intermediates
d. phosphorylation of carbamic acid
e. ammonia incorporation into urea

86. The half-life of a cytosolic protein is primarily determined by the:

a. length of the protein chain.
b. amino terminal residue.
c. sequence at the carboxyl terminus.
d. presence of repeated sequences.
e. three-dimensional structure.
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87. What enzyme is NOT used in purine catabolism?

a. adenosine deaminase
b. xanthine oxidase
c. nucleoside phosphorylase
d. ribonucleotide reductase
e. inosine monophosphate cyclohydrolyase

88. Which statement about adenosine deaminase deficiency is INCORRECT?

a. It has been successfully treated by gene therapy.
b. It has not been successfully treated yet.
c. It is associated with severe combined immunodeficiency.
d. It results in an increase of the normal level of dATP, which inhibits DNA synthesis.
e. Persons suffering from this disease have acute recurring infections.

89. What is the primary glycosidic bond found in glycogen?

a. α-1,3
b. α-1,4
c. α-1,6
d. β-1,4
e. β-1,6

90. Which nucleotide is most commonly used as a second messenger in signal-transduction pathways?
a. TTP
b. ADP
c. AMP
d. CMP
e. GTP

91. The readily mobilized storage form of glucose in humans, a very large branched polymer, is:
a. glycogen.
b. starch.
c. insulin.
d. inulin.
e. sucrose.

92. Where does nitrogen for amino acids, purines, and pyrimidines ultimately come from?
a. nitric acid
b. nitrogen dioxide
c. hydrazine
d. atmospheric nitrogen
e. hydroxylamine
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93. What enzyme is inhibited by glucagon and insulin stimulated acetylation?

a. protein phosphatase 1
b. glycogen phosphorylase
c. nucleotide diphosphokinase
d. phosphorylase b
e. phosphofructokinase

94. Choose the CORRECT order of the activation of the regulatory cascade for glycogen breakdown.
a. glucagon protein kinase A adenylate cyclase ATP phosphorylase kinase
phosphorylase a
b. glucagon 7TM receptor adenylate cyclase phosphorylase kinase Protein kinase A
Phosphorylase a
c. glucagon adenylate cyclase cAMP phosphorylase a protein kinase A phosphorylase
kinase
d. epinephrine 7TM receptor adenylate cyclase cAMP protein kinase A phosphorylase
kinase phosphorylase a
e. epinephrine adenylate cyclase 7TM receptor ATP protein kinase B phosphorylase
kinase phosphorylase a

95. What catalyzes the formation of D-3-hydroxybutyryl ACP from acetoacetyl ACP in fatty acid synthesis?
a. β-ketoacyl reductase
b. β-ketoacyl synthase
c. L-3-hydroxyacyl CoA dehydrogenase
d. 3-hydroxyacyl dehydratase
e. 3-hydroxyacyl CoA hydrolyase

96. What statement about the functions of tetrahydrofolate and its derivatives is NOT correct?
a. Tetrahydrofolate serves as a donor of one-carbon units in degradative reactions.
b. The methyl group of thymine comes from N5,N10-methylenetetrahydrofolate.
c. The tetrahydrofolate derivative can donate a one-carbon unit in an alternative synthesis of glycine.
d. Tetrahydrofolate derivatives serve as donors of one-carbon units.
e. Tetrahydrofolate serves as an acceptor of one-carbon units in degradative reactions.

97. How might feedback inhibition processes have evolved?

a. duplicating genes encoding catalytic domains
b. evolution of homologous subunits in the enzyme catalyzing the committed step
c. linking specific regulatory domains to catalytic domains
d. linking multiple regulatory domains to one another
e. linking multiple regulatory domains to multiple catalytic domains
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98. How many energy-rich molecules are formed after b-oxidation of butyryl CoA (C3H7CO~SKoA)?
a. FADH2 + NADH + acetyl CoA
b. 2 FADH2 + 2 NADH + 2 acetyl CoA
c. 2 FADH2 + NADH + acetyl CoA
d. FADH2 + 2 NADH + acetyl CoA
e. FADH2 + NADH + 2 acetyl CoA

99. The committed step in fatty acid synthesis is the formation of:
a. acetoacetyl ACP.
b. butyryl ACP.
c. crotonyl ACP.
d. malonyl ACP.
e. malonyl CoA.

100. What side product is produced by xanthine oxidase?

a. •O2–
b. H2O2
c. •OH
d. O2
e. H2O

101. How many molecules of ATP does glucose 6-phosphate yield after complete oxidation?
a. 1
b. 2
c. 16
d. 31
e. 32

102. Which enzyme catalyzes the cleavage of 3-ketoacyl CoA in fatty acid oxidation?
a. 3-hydroxyacyl CoA hydrolyase
b. L-3-hydroxyacyl CoA dehydrogenase
c. acyl CoA dehydrogenase
d. fatty acid thiokinase
e. β-ketothiolase

103. Why does O2 bind to leghemoglobin?

a. The nitrogenase complex can be activated by leghemoglobin.
b. The nitrogenase complex can be activated by O2.
c. The nitrogenase complex can be inactivated by leghemoglobin when paired with O2.
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d. The nitrogenase complex can be inactivated by leghemoglobin.

e. The nitrogenase complex can be inactivated by O2.

104. Aspartate aminotransferase belongs to:

a. monooxygenases.
b. pyridoxal-dependent transaminases.
c. reductases.
d. transaminases.
e. decarboxylases.

105. What is the major product of the fatty acid synthase in animals?
a. arachidonate
b. laurate
c. myristate
d. palmitate
e. stearate

106. Which statement about ribonucleotide reductases is INCORRECT?

a. For all ribonucleotide reductases, the mechanism of action is based on the exceptional reactivity of
cysteine radicals.
b. A stable tyrosyl radical is employed in the active site of E. coli ribonucleotide reductase.
c. Ribonucleotide reductases that do not contain tyrosyl radicals have been found.
d. A stable tyrosyl radical is generated by the reaction of oxygen at a nearby site containing a
manganese atom.
e. The ribonucleotide reductase of E. coli consists of two subunits: R1 and R2. They are dimers.

107. Which nucleotide within its derivative participates in the formation of glycogen?
a. UDP
b. ADP
c. AMP
d. CMP
e. GTP

108. What is a product of transamination of aspartate and α-ketoglutarate?

a. glutamine
b. asparagine
c. pyruvate
d. oxaloacetate
e. glucose

109. Which enzyme needs NADPH in β-oxidation of unsaturated fatty acids?

a. cis-Δ3-enoyl CoA isomerase
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b. 2,4-dienoyl CoA reductase

c. acyl CoA dehydrogenase
d. propionyl CoA carboxylase
e. methylmalonyl CoA mutase

110. Which ketone body is formed from acetyl CoA in three reactions catalyzed sequentially by 3-ketothiolase,
hydroxymethylglutaryl CoA synthase, and hydroxymethylglutaryl CoA cleavage enzyme?
a. 3-hydroxy-3-methylglutaryl CoA
b. D-3-hydroxybutyrate
c. acetoacetate
d. acetoacetyl CoA
e. acetone

111. How is phosphorylase b converted into phosphorylase a?

a. addition of a phosphate to a serine residue
b. dimerization, which forms the active site pocket
c. cleavage of 10 amino acids from the N-terminal end of the protein
d. binding of glucose, an allosteric modifier
e. isomerization of phosphorylase b

112. What term describes a specific sequence of amino acids that indicates that a particular protein should be
degraded?
a. consensus sequence
b. proteasome recognition sequence
c. degron
d. ubiquitin binding domain
e. intron

113. What occurs after a carbohydrate-rich meal?

a. Blood-glucose levels increase, leading to glycogen storage in the liver.
b. Blood-glucose levels increase, leading to glycogen storage in the muscle.
c. Glucose uptake from the blood increases as a result of the action of insulin.
d. Glucagon is absent.
e. All of the answers are correct.

114. Which are enzymes that digest triacylglycerols into free fatty acids and monoacylglycerol?
a. dehydrogenases
b. lipases
c. lyases
d. synthetases
e. transferases
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115. What type of enzyme plays a key role in glycogen breakdown?
a. phosphorylase
b. phosphatase
c. transferase
d. phosphoglucomutase
e. hexokinase

116. What catalyzes the formation of acetyl ACP in fatty acid synthesis?
a. β-ketoacyl reductase
b. β-ketoacyl synthase
c. acetyl CoA carboxylase
d. acetyl transacylase
e. enoyl reductase

117. What source of fuel energy is used by the brain instead of glucose under starvation conditions?
a. acetoacetate
b. alanine
c. glycogen
d. lactate
e. proteins

118. How many equivalent molecules of ATP should be consumed to synthesize one urea molecule?
a. 1
b. 2
c. 3
d. 4
e. 5

119. What is the committed step in purine nucleotide biosynthesis?

a. the conversion of PRPP to phosphoribosylamine
b. the cyclization of 5-formaminoimidazole-4-carboxamide ribonucleotide to form inosinate
c. the attachment of a glycine residue to 5-phosphoribosyl-1-amine
d. the oxidation of inosinate to xanthylate
e. the elimination of fumarate

120. The regulator N-acetylglutamate is required for the regulation of:

a. aminotransferases activity.
b. monooxygenase activity.
c. dihydropteridine reductase activity.
d. carbamoyl phosphate synthetase activity.
e. ornithine decarboxylase activity.
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121. The conversion of ribonucleotides to deoxyribonucleotides is catalyzed by:
a. nucleoside phosphorylase.
b. ribonucleotide reductase.
c. nucleoside diphosphate kinase.
d. dihydrofolate reductase.
e. catalase.

122. What is the function of liver glycogen degradation?

a. to export glucose to other tissues when glucose levels are low
b. to maintain glucose levels after a large meal
c. to provide for the large energy needs of the liver
d. to allow for synthesis of lipids
e. None of the answers is correct.

123. Which reaction product is formed after hydration of trans-Δ2-enoyl CoA by crotonase?
a. 3-ketoacyl CoA
b. D-3-hydroxyacyl CoA
c. L-3-hydroxyacyl CoA
d. acetyl CoA
e. HS-CoA

124. A high level of what amino acid is correlated with the damage of cells lining the blood vessels?
a. serine
b. cysteine
c. S-adenosylmethionine
d. citrulline
e. homocysteine

125. Which reaction product is formed from acetoacetate in reactions catalyzed by a specific CoA transferase
and thiolase during utilization of acetoacetate as a fuel?
a. 3-hydroxy-3-methylglutaryl CoA
b. D-3-hydroxybutyrate
c. acetoacetyl CoA
d. acetyl CoA
e. succinyl CoA

126. What inhibits acetyl CoA carboxylase 1 and subsequently inhibits fatty acid synthesis?
a. AMP-activated protein kinase
b. citrate
c. insulin
d. protein kinase B
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e. protein phosphatase

127. Choose the reaction that takes place in the mitochondrial matrix during biosynthesis of porphyrins in
mammals.
a. condensation of four molecules of porphobilinogen to form a linear tetrapyrrole
b. cyclization of linear tetrapyrrole to form uroporphyrinogen III
c. decarboxylation of the acetate side chains of uroporphyrinogen III to form coproporphyrinogen III
d. condensation of two molecules of δ-aminolevulinate to form porphobilinogen
e. condensation of glycine and succinyl CoA to form δ-aminolevulinate

128. Where do the sulfur atom and the carbon skeleton of cysteine come from?
a. The sulfur atom and the carbon skeleton both come from serine.
b. The sulfur atom and the carbon skeleton both come from homocysteine.
c. The sulfur atom comes from homocysteine and the carbon skeleton comes from serine.
d. The sulfur atom comes from homocysteine and the carbon skeleton comes from adenine.
e. The sulfur atom comes from homocysteine and the carbon skeleton comes from tyrosine.

129. Choose the CORRECT statement concerning the roles of glycogen metabolism.
a. In muscles, glycogen metabolism is regulated to maintain the blood-glucose concentration.
b. In muscles, glycogen metabolism is regulated to meet the needs of the organism as a whole.
c. In the liver, glycogen metabolism is regulated to meet the energy needs of the muscle itself.
d. In the liver, glycogen metabolism is regulated to maintain the blood-glucose concentration.
e. In the liver, glycogen metabolism is regulated to meet the energy needs of the nervous system.

130. The ultimate reductant in the synthesis of deoxyribonucleotides is:

a. FADH2.
b. NADH.
c. NADPH.
d. quinone.
e. riboflavin.

131. How many carbon atoms are there in the fatty acid chain shortened in one round of fatty acid oxidation?
a. 1
b. 2
c. 3
d. 4
e. 5

132. What enzyme catalyzes the transition of glutamate to glutamine?

a. glutaminase
b. glutamyl peptidase
c. gamma-glutamyltransferase
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d. glutamine synthetase
e. glutamate dehydrogenase

133. Urea is synthesized in the:

a. intestines.
b. kidneys.
c. pancreas.
d. spleen.
e. liver.

134. Which enzyme has no ATP-grasp domain?

a. formylglycinamidine synthase
b. succinylaminoimidazole carboxamide ribonucleotide synthetase
c. adenylosuccinate synthetase
d. glycinamide ribonucleotide (GAR) synthetase
e. aminoimidazole ribonucleotide synthetase

135. What molecule is required for the movement of long-chain fatty acyl groups from the cytosol into the
mitochondrial matrix?
a. creatine
b. carnitine
c. creatinine
d. cholesterol
e. cyanocobalamin

136. Why is glycogen branching important?

a. Branching significantly alters the melting point.
b. Branching decreases the solubility of glycogen.
c. Branching increases the rates of glycogen synthesis and degradation by increasing the potential sites
of action.
d. Branching allows glycogen to be transported to other areas of the cell.
e. None of the answers is correct.

137. An example of a reaction controlled by enzyme multiplicity is phosphorylation of:

a. asparagine by aspartokinases.
b. aspartate by aspartokinases.
c. glutamine by glutamine synthetase.
d. glutamate by aspartokinases.
e. glutamine by aspartokinases.

138. The degradative pathways of Ile and Val are common to:
a. glycine.
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b. leucine.
c. lysine.
d. glutamine.
e. serine.

139. In liver, arginine hydrolyzes to:

a. glutamate and urea.
b. aspartate and fumarate.
c. fumarate and succinate.
d. citrulline and ornithine.
e. ornithine and urea.

140. What is the MOST significant functional group in the pyridoxal phosphate group?
a. ketone
b. amino group
c. aldehyde
d. methyl group
e. carboxyl group

141. What is the approximate energy yield from the complete oxidation of fatty acids?
a. 3 kcal g–1
b. 4 kcal g–1
c. 6 kcal g–1
d. 9 kcal g–1
e. 11 kcal g–1

142. What enzyme of glycogen breakdown prepares a free glucose molecule to be processed by the pentose
phosphate pathway?
a. glycogen phosphorylase
b. hexokinase
c. α-1,6-glucosidase
d. transferase
e. phosphoglucomutase

143. The overexpression of ubiquitin-protein ligase leads to:

a. Angelman syndrome.
b. unusually happy disposition.
c. autism.
d. uncoordinated movement.
e. absence of speech.
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144. Threonine deaminase, the PLP enzyme that catalyzes the formation of α-ketobutyrate, inhibits:
a. serine.
b. alanine.
c. leucine.
d. isoleucine.
e. valine.

145. _____ serves as the glucose "sensor" enzyme in liver cells.

a. Glucose 6-phosphatase
b. Hexokinase
c. Phosphoglucomutase
d. UDP-glucose pyrophosphorylase
e. Phosphorylase a

146. What units CANNOT be carried by tetrahydrofolate?

a. methyl
b. methylene
c. ethyl
d. formyl
e. formimino

147. What is the largest storage site of glycogen in humans?

a. lungs
b. liver
c. skeletal muscle
d. kidneys
e. spleen

148. What amino acid residue is present in the catalytic site of phosphoglucomutase?
a. serine
b. lysine
c. cysteine
d. histidine
e. tyrosine

149. Pyruvate is the entry point in the citric acid cycle for:
a. cysteine, leucine, and proline.
b. valine, leucine, and isoleucine.
c. tyrosine, lysine, and valine.
d. cysteine, alanine, and serine.
e. serine, histidine, and valine.
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150. Glutamine synthetase can cumulatively inhibit:
a. substrates for glutamine metabolism, alanine, and glycine.
b. final products of glutamine metabolism, serine, and glycine.
c. intermediates of glutamine metabolism, glycine, and isoleucine.
d. final products of glutamate metabolism, glycine, and isoleucine.
e. final products of glutamine metabolism, alanine, and glycine.

151. Which amino acid is an important precursor to dopamine?

a. serine
b. tyrosine
c. valine
d. threonine
e. isoleucine

152. What is the main disadvantage of methotrexate as a therapeutic agent?

a. It inhibits dihydrofolate reductase, thus significantly diminishing the quantities of precursors for
DNA synthesis.
b. It causes severe headache.
c. It kills all rapidly growing cells.
d. It kills stem cells, resulting in a loss of immune system protection during therapy.
e. It causes the formation of kidney stones and other symptoms of gout.

153. Molecules of _____ store iron in tissues.

a. ferritin
b. transferrin
c. hemoglobin
d. ferredoxin
e. haptoglobin

154. What molecule is used to transport acetyl groups from the mitochondrial matrix to the cytoplasm?
a. dihydroxyacetone phosphate
b. succinyl CoA
c. oxaloacetate
d. a-ketoglutarate
e. citrate

155. What protein has the longest life in the human organism?
a. ubiquitin
b. ornithine decarboxylase
c. hemoglobin
d. crystallin
e. insulin
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156. Carbon skeletons of amino acids do NOT come from intermediates of:
a. glycolysis.
b. the pentose phosphate pathway.
c. the citric acid cycle.
d. the Krebs cycle.
e. the Calvin cycle.

157. Surplus amino acids are:

a. stored in proteasomes.
b. stored in protein scaffolds.
c. used as the metabolic fuel.
d. stored as albumin.
e. stored as glycogen.

158. Ammoniotelic organisms excrete excess nitrogen as:

a. xanthine.
b. NH4+.
c. urea.
d. uric acid.
e. arginine.

159. How many energy-rich molecules are needed for one elongation cycle of fatty acid synthesis?
a. 1 NADH
b. 2 NADH
c. 1 NADH and 1 FADH2
d. 2 NADH and 1 FADH2
e. 2 NADH and 2 FADH2

160. Why is the conversion of nitrogen and hydrogen to form ammonia difficult kinetically?
a. Concentrations of reagents are low.
b. Activation energy is required to form intermediates.
c. The surface area of reactants is small.
d. Many catalysts are needed.
e. Reactants are in different phases.

161. Choose the pathway of nucleotide synthesis when at the first step the framework for a base is assembled
from simpler molecules and then a sugar is attached.
a. salvage pathway
b. synthetic pathway
c. catabolic pathway
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d. anabolic pathway
e. de novo pathway

162. A pyrimidine base linked to a sugar and phosphorylated at 5' is called a:

a. nucleotide.
b. nucleoside.
c. ribonucleoside.
d. deoxynucleoside.
e. pyrimidinylate.

163. What vitamin supplement is recommended to be taken during the first trimester of pregnancy to prevent
the birth defect spina bifida?
a. ascorbic acid
b. riboflavin
c. nicotinamide
d. folic acid
e. α-tocopherol

164. What enzyme can break only α-1,4-glycosidic bonds on glycogen branches?
a. α-1,6-glucosidase
b. α-4-glucosidase
c. glycogen phosphorylase
d. hexokinase
e. phosphoglucomutase

165. Choose the major metabolic precursor of alanine, leucine, and valine in bacteria and plants.
a. pyruvate
b. ribose 5-phosphate
c. oxaloacetate
d. α-ketoglutarate
e. 3-phosphoglycerate

166. Which statement about acyclovir (acycloguanosine) treatment of herpes simplex infections is
INCORRECT?
a. Viral thymidine kinase converts acyclovir into its monophosphate by adding a phosphate to the
carbonyl group.
b. Acyclovir monophosphate is phosphorylated by cellular enzymes to yield acyclovir triphosphate.
c. Acyclovir triphosphate competes with dGTP for DNA polymerase.
d. Viral thymidine kinase binds acyclovir more than 200 times as tightly as native cellular thymidine
kinase.
e. Viral thymidine kinase differs from the mammalian enzyme and thus provides a therapeutic target.
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167. Which reaction in the β-oxidation pathway yields FADH2?

a. carboxylation of propionyl CoA
b. cleavage of 3-ketoacyl CoA
c. hydration of trans-Δ2-enoyl CoA
d. oxidation of L-3-hydroxyacyl CoA
e. oxidation of acyl CoA

168. The function of the enzyme acyl CoA synthetase is:

a. lipolysis to release free glyceraldehyde.
b. ATP-dependent reduction prior to activation.
c. ATP-dependent activation of fatty acids using CoA.
d. production of acetyl CoA for the TCA cycle.
e. formation of ketone bodies.

169. What is one of the fundamental challenges of incorporating nitrogen into biomolecules?
a. reaction conditions
b. the size of the biomolecules where nitrogen is incorporated
c. the charge of the nitrogen
d. establishing the correct stereochemistry
e. the charge of the biomolecules

170. Where does oxidation of long-chain and branched fatty acids take place?
a. in the cytoplasm
b. in lysosomes
c. in the mitochondrial matrix
d. in peroxisomes
e. on the outer mitochondrial membrane

171. Which amino acids act as nitrogen donors for most amino acids?
a. glycine and glutamate
b. tryptophan and isoleucine
c. glutamine and leucine
d. glycine and tryptophan
e. glutamate and glutamine

172. The methyl donor in the synthesis of TMP from dUMP is:
a. N5-methyltetrahydrofolate.
b. N5, N10-methylenetetrahydrofolate.
c. S-adenosylmethionine.
d. methylcobalamin.
e. methotrexate.
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173. Which reaction in the β-oxidation pathway yields NADH?

a. carboxylation of propionyl CoA
b. cleavage of 3-ketoacyl CoA
c. hydration of trans-Δ2-enoyl CoA
d. oxidation of L-3-hydroxyacyl CoA
e. oxidation of acyl CoA

174. Which amino acid does carbamoyl phosphate synthetase II use as a nitrogen source?
a. valine
b. glutamine
c. alanine
d. arginine
e. lysine

175. Which enzyme catalyzes the formation of 3-ketoacyl CoA in the β-oxidation pathway?
a. 3-hydroxyacyl CoA hydrolyase
b. L-3-hydroxyacyl CoA dehydrogenase
c. acyl CoA dehydrogenase
d. fatty acid thiokinase
e. β-ketothiolase

176. What class of enzymes cleaves most aromatic rings in biological systems?
a. dioxygenases
b. monooxygenases
c. biopterin-linked lyases
d. aromatic oxidases
e. aminotransferases

177. What molecule is an activated form of ribose phosphate and a precursor for histidine?
a. ribose triphosphate
b. PRPP (5-phosphoribosyl-1-pyrophosphate)
c. ATP
d. cyclic AMP
e. ADP

178. Which molecule is NOT part of pyrimidine nucleotides?

a. orotidylate
b. uridylate
c. cytidylate
d. xanthylate
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e. thymidylate

179. What is a coenzyme of methylmalonyl CoA mutase?

a. pyridoxamine
b. niacin
c. riboflavin
d. cobalamin
e. pantothenic acid

180. How many molecules of acetyl CoA are needed for laurate (12:0) synthesis?
a. 4
b. 5
c. 6
d. 7
e. 8

181. What organ contains the hydrolytic enzyme glucose 6-phosphatase?

a. brain
b. lungs
c. muscle
d. liver
e. kidneys

182. What cholesterol derivatives facilitate the digestion of fats by incorporating dietary triacylglycerols into
micelles in the intestine?
a. vitamin D
b. testosterone
c. bile acids
d. aldosterone
e. progesterone

183. What molecule must be excluded from the active site of glycogen phosphorylase?
a. glucose
b. glucose 1-phosphate
c. water
d. phosphate
e. None of the answers is correct.

184. What supplies the reductive power for fatty acid synthesis?
a. ATP
b. FADH2
c. NADPH
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d. NADH
e. succinyl CoA

185. Which statement about the synthesis of PRPP from ribose 5-phosphate by PRPP synthetase is
INCORRECT?
a. It is the committed step in purine synthesis.
b. It is allosterically regulated by nucleotides.
c. It is inhibited by IMP.
d. It is inhibited by AMP.
e. It is inhibited by GMP.

186. Choose the substrate and the type of reaction of histamine synthesis, respectively.
a. histidine; carboxylation
b. histidine; oxidation
c. alanine; decarboxylation
d. histidine; decarboxylation
e. serine; carboxylation

187. What amino acid is essential?

a. serine
b. glycine
c. proline
d. valine
e. asparagine

188. The synthesis of fatty acids with an odd number of carbon atoms starts with:
a. D-3-hydroxybutyryl ACP, which is formed from acetoacetyl ACP.
b. acetyl ACP, which is formed from acetyl CoA.
c. butyryl ACP, which is formed from butyryl CoA.
d. butyryl ACP, which is formed from crotonyl ACP.
e. propionyl ACP, which is formed from propionyl CoA.

189. What aminotransferases are the indicators of liver damage if detected in blood?
a. valine, serine, methionine
b. alanine, serine, valine
c. aspartate, alanine
d. methionine, alanine
e. serine, aspartate

190. Which molecule is NOT the part of purine nucleotides?

a. inosinate
b. orotidylate
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c. adenylosuccinate
d. xanthylate
e. guanylate

191. What type of phosphorylase is stimulated by AMP and contains two cysteine molecules that form a
disulfide bond?
a. brain phosphorylase
b. muscle phosphorylase
c. liver phosphorylase
d. kidney phosphorylase
e. lung phosphorylase

192. Isozymes are enzymes with:

a. different catalytic mechanisms but identical regulatory properties.
b. essentially identical catalytic mechanisms but different regulatory properties.
c. essentially identical catalytic mechanisms and identical regulatory properties.
d. essentially identical domain structure but different regulatory properties.
e. essentially identical domain structure and identical regulatory properties.

193. What is the typical displacing nucleophile in purine synthesis?

a. coenzyme A
b. a metal ion
c. ammonia or an amino group
d. pyridoxamine
e. carbonyl group

194. Choose the reaction in which amino acids could be synthesized from α-ketoacids.
a. hydroxylation reaction
b. acylation reaction
c. phosphorylation reaction
d. transamination reaction
e. transpeptidation reaction

195. What enzyme is inactivated by protein phosphatase 1 via dephosphorylating?

a. phosphorylase a
b. phosphorylase b
c. protein kinase A
d. adenylate cyclase
e. nucleotide diphosphokinase

196. Which ketone body is formed by slow, spontaneous decarboxylation of acetoacetate?

a. D-3-hydroxybutyrate
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b. L-methylmalonyl CoA
c. acetone
d. dihydroxyacetone phosphate
e. pyruvate

197. What amino acids are solely ketogenic?

a. Leu, Val
b. Val, Gly
c. Lys, Leu
d. Gly, Leu
e. Lys, Val

198. Choose the CORRECT statement about allosteric regulation of the E. coli ribonucleotide reductase.
a. Each polypeptide of the R1 subunit contains two allosteric sites: One of the sites controls the overall
activity of the enzyme, and the other regulates substrate specificity.
b. Each polypeptide of the R1 subunit contains three allosteric sites: One of the sites is activated by
specific protein kinase, the second site controls the overall activity of the enzyme, and the third site
regulates substrate specificity.
c. Each polypeptide of the R1 subunit contains two allosteric sites: One of the sites controls the overall
activity of the enzyme, and the other can be activated by specific protein kinase.
d. Allosteric regulation of the enzyme controls its overall activity.
e. The E. coli ribonucleotide reductase contains no allosteric sites.

199. What enzyme is absent or deficient in the case of phenylketonuria?

a. phenylalanine transaminase
b. phenylalanine N-methyltransferase
c. phenylalanine N-acetyltransferase
d. phenylalanine hydroxylase
e. monooxygenase

200. What physiological conditions render phosphorylase b less active?

a. high ATP, AMP, and glucose 6-phosphate levels
b. high ATP and low calcium ion levels
c. high ATP and glucose 6-phosphate levels
d. high AMP and low ATP levels
e. None of the answers is correct.

201. Inborn mistakes of amino acid metabolism of α-aminoadipic semialdehyde dehydrogenase cause:
a. albinism.
b. hyperlysinemia.
c. tyrosinemia.
d. citrullinema.
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e. homocystinuria.

202. What regulatory protein controls the specificity of adenylyl transferase?

a. PII
b. PIII
c. PI
d. PVII
e. PVI

203. What product of the first step of methionine degradation is an important methyl group donor?
a. 5-methyltetrahydrofolate
b. methylcobalamin
c. S-adenosylmethionine
d. S-adenosylhomocysteine
e. propionyl CoA

204. Choose the enzyme that performs without substrate channeling within it.
a. glutamine phosphoribosyl amidotransferase
b. tryptophan synthetase
c. CAD of mammals
d. ribonucleotide reductase
e. carbamoyl phosphate synthetase II

205. How many molecules of ATP are hydrolyzed for each reduced molecule of N2?
a. 19
b. 22
c. 20
d. 16
e. 17

206. The primary proteolytic enzyme of the stomach is:

a. trypsin.
b. chymotrypsin.
c. elastase.
d. carboxypeptidase A.
e. pepsin.

207. What was used in ancient Rome to brighten togas?

a. urea
b. fatty acids
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c. enzymes
d. water
e. soap

208. To stimulate the synthesis of glycogen, by inactivating glycogen synthase kinase, insulin would bind to:
a. 7TM receptor.
b. adenylate cyclase.
c. serine kinase receptor.
d. tyrosine kinase receptor.
e. lysine kinase receptor.

209. Choose the correct sequence of intermediates in amino acid biosynthesis by transamination.
a. pyridoxamine phosphate (PMP); internal aldimine; ketamine; external aldimine
b. internal aldimine; pyridoxamine phosphate (PMP); ketamine; external aldimine
c. ketamine; internal aldimine; pyridoxamine phosphate (PMP); external aldimine
d. external aldimine; pyridoxamine phosphate (PMP); ketamine; internal aldimine
e. internal aldimine; ketamine; pyridoxamine phosphate (PMP); external aldimine

210. Choose the enzyme that catalyzes reactions of the general equation XDP + YTP XTP + YDP.
a. nucleoside phosphorylase
b. nucleoside diphosphate kinase
c. nucleoside triphosphate phosphorylase
d. nucleoside triphosphate synthetase
e. nucleotide reductase

211. What product derived from the breakdown of glycogen has different fates in the organism?
a. glucose 1,6-bisphosphate
b. glucose 1-phosphate
c. glucose 6-phosphate
d. ribose
e. UDP-glucose

212. What is the precursor amino acid for nitric oxide?

a. alanine
b. proline
c. arginine
d. serine
e. leucine

213. What catalyzes the formation of malonyl ACP in fatty acid synthesis?
a. 3-hydroxyacyl dehydratase
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b. acetyl CoA carboxylase

c. acetyl transacylase
d. enoyl reductase
e. malonyl transacylase

214. Why do muscles NOT contain glucose 6-phosphatase?

a. Muscles maintain glucose homeostasis of the organism as a whole.
b. Unlike glucose 6-phosphate, glucose is a major fuel for muscles.
c. Glucose 6-phosphate cannot diffuse or be transported out of the cell.
d. Muscles contain another enzyme, acting in a way similar to glucose 6-phosphatase.
e. Muscles receive everything they need from the liver.

215. What type of enzyme catalyzes the formation of UDP-glucose in glycogen synthesis?
a. hexokinase
b. phosphatase
c. phosphorylase
d. transferase
e. phosphoglucomutase

216. What activates fatty acid synthesis?

a. malonyl CoA
b. glucagon
c. phosphorylation of acetyl CoA carboxylase
d. citrate
e. epinephrine

217. Choose the compound that is NOT designed for cancer therapy targeting ribonucleotide reductase.
a. clofarabine
b. gemcitabine
c. amethopterin
d. cladribine
e. dATP analogs

218. Which amino acid side chain in thymidylate synthase activates the ring of dUMP, making C-5 a good
nucleophile?
a. cysteine
b. aspartate
c. glutamine
d. tyrosine
e. serine

219. How many ATP equivalents are used to synthesize one molecule of CTP from bicarbonate, glutamine, and
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ribose 5-phosphate?
a. 3
b. 5
c. 7
d. 9
e. 11

220. What nucleotide is aminated to produce CTP?

a. TTP
b. ATP
c. UTP
d. GTP
e. OTP

221. Choose the CORRECT statement concerning different fiber types.

a. Type IIb fibers are powered by fatty acid degradation and are rich in mitochondria.
b. The amount of glycogen phosphorylase is high in type I fibers.
c. Type IIb fibers use glycogen as their main fuel.
d. Type IIa fibers are rich in glycogen, glycogen phosphorylase, and glycolytic enzymes.
e. Type IIb fibers have properties intermediate between the other two fiber types.

222. What are the two steps of glutamate synthesis?

a. A Schiff base forms between NH3 and α-ketoglutarate; a protonated Schiff base is reduced by the
transfer of a hydride ion from NAD+ to form glutamate.
b. A Schiff base forms between NH4+ and oxaloacetate; a protonated Schiff base is reduced by the
transfer of a hydride ion from NAD(P)H to form glutamate.
c. A Schiff base forms between NH4+ and α-ketoglutarate; a protonated Schiff base is reduced by the
transfer of a hydride ion from NAD(P)H to form glutamate.
d. A Schiff base forms between NH4+ and α-ketoglutarate; a deprotonated Schiff base is reduced by the
transfer of a hydride ion from NAD(P)H to form glutamate.
e. A Schiff base forms between NH4+ and α-ketoglutarate; a protonated Schiff base is reduced by the
transfer of a hydride ion from FADH2 to form glutamate.

223. A synonym of aminotransferases is:

a. aminopeptidases.
b. monooxygenases.
c. aminotransferases.
d. reductases.
e. transaminases.

224. What is the preferable fuel for heart muscle and the renal cortex?
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a. glucose
b. acetoacetate
c. glycogen
d. fatty acids
e. glycerol

225. Choose the nucleotide whose synthesis is widely exploited in the treatment of cancer.
a. dAMP
b. TTP
c. IMP
d. dGMP
e. dCTP

226. The chirality of the amino acid formed is determined by:

a. the site at which ketamine loses a proton.
b. an amino group that is transferred from glutamate.
c. the formation of the internal aldimine.
d. the reaction of pyridoxamine phosphate with an incoming α-ketoacid.
e. the direction from which a proton is added to the quinonoid form.

227. What inhibits the translocase that transports citrate from mitochondria to the cytoplasm and, accordingly,
blocks the entry of fatty acyl CoAs into the mitochondrial matrix when they are abundant?
a. D-3-hydroxyacyl CoA
b. acetoacetyl CoA
c. malonyl CoA
d. palmitoyl CoA
e. propionyl CoA

228. What amino acids have both ketogenic and glucogenic properties?
a. Tyr, Val, Trp, Asp
b. Trp, Ile, Tyr, Phe
c. Ile, Met, His, Ala
d. Phe, Glu, Asn, Lys
e. Val, Ala, Asn, Tyr

229. Covalent modification of phosphorylase a to phosphorylase b is catalyzed by:

a. insulin.
b. calmodulin.
c. protein kinase A.
d. protein kinase B.
e. phosphorylase kinase.
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230. Which amino acids supply carbons as succinyl CoA for eventual entry into metabolism?
a. Met, Val, Leu
b. Met, Ile, Val
c. Ile, Val, Leu
d. Ile, Leu, Gly
e. Val, Gly, Ile

231. Why is phosphorolysis of glycogen energetically advantageous?

a. Phosphorolysis spends two molecules of ATP to form phosphorylated sugar.
b. The released sugar is already phosphorylated.
c. Formed phosphorylated sugar can easily spread out of the cell into the blood.
d. Unlike sugar that is not phosphorylated, phosphorylated sugar gives more energy.
e. There are a lot of transporters for phosphorylated sugar in muscles.

232. What is the structure of the E. coli enzyme tryptophan synthase?

a. monomer
b. α3β1 tetramer
c. α2 dimer
d. α2β2 tetramer
e. β2 dimer

233. Chorismate is a precursor to the amino acids:

a. tryptophan, tyrosine, and phenylalanine.
b. serine, glycine, and cysteine.
c. isoleucine, leucine, and valine.
d. methionine, threonine, and lysine.
e. serine, threonine, and cysteine.

234. Which enzyme family does argininosuccinase belong to?

a. ligases
b. lyases
c. transferases
d. synthetases
e. kinases

235. What is the reaction product of the condensation of acetyl ACP and malonyl ACP in fatty acid synthesis in
bacteria?
a. D-3-hydroxybutyryl ACP
b. acetoacetyl ACP
c. butyryl ACP
d. crotonyl ACP
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e. propionyl ACP

236. Glucose cannot be stored in a free form because:

a. it forms toxic substances.
b. it disrupts the osmotic balance of the cell.
c. it crystallizes and thus causes cell damage or death.
d. it forms polymers, such as glycogen or starch, spontaneously.
e. degradation to glucose takes too much energy.

237. How many enzymes take part in the binding of ubiquitin to the targeted protein?
a. 1
b. 2
c. 3
d. 4
e. 5

238. How many rounds of b-oxidation would be required for C15H31CO~SKoA to be degraded completely to
acetyl-CoA?
a. 7
b. 8
c. 9
d. 15
e. 16

239. What is the first irreversible reaction in a biosynthetic pathway called?

a. committed step
b. captured step
c. snapped step
d. fixed step
e. locked-in step

240. What inhibits carnitine acyltransferase I and, accordingly, blocks the entry of fatty acyl CoAs into the
mitochondrial matrix when they are abundant?
a. L-methylmalonyl CoA
b. acetoacetyl CoA
c. malonyl CoA
d. palmitoyl CoA
e. succinyl CoA

241. What compounds do fatty acids use as building blocks?

a. carbohydrates and glycolipids
b. cholesterol and sphingolipids
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c. glycolipids and phospholipids

d. carbohydrates and proteins
e. phospholipids and carbohydrates

242. Dihydrofolate reductase is an excellent target for anticancer drugs because it is critical in the synthesis of:
a. adenylate.
b. orotidylate.
c. thymidylate.
d. xanthylate.
e. uridylate.

243. Glucose 6-phosphate derived from glycogen cannot be:

a. used as a fuel for anaerobic metabolism.
b. used as a fuel for aerobic metabolism.
c. converted into free glucose to maintain the blood-glucose concentration.
d. processed to generate NADPH.
e. processed to generate NADH.

244. What is the final degradation product of purine catabolism?

a. xanthine
b. hypoxanthine
c. inosine
d. urate
e. urea

245. Which enzyme has NO catalytic dyad comprising a cysteine and a histidine residue?
a. carbamoyl phosphate synthetase II
b. cysteine protease
c. GMP synthetase
d. ribonucleotide reductase
e. CTP synthetase

Indicate one or more answer choices that best complete the statement or answer the question.

246. Choose the CORRECT substrates for carbamoyl phosphate synthetase. Select all that apply.
a. NH4+
b. NH3
c. HCO3–
d. NADH
e. GTP
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247. What enzymes are required to cleave α-1,6-glycosidic branches in glycogen? Select all that apply.
a. transferase
b. α-1,6-glucosidase
c. glycogen phosphatase
d. hexokinase
e. α-1,4-glucosidase

Enter the appropriate word(s) to complete the statement.

248. Linoleate (18:2 cis-Δ9, Δ12) and linolenate (18:3 cis-Δ9, Δ12, Δ15) are essential fatty acids for mammals
because mammals cannot synthesize fatty acids with double bonds at carbon atoms beyond _______ in the fatty
acid chain.

249. Biopterin is produced in the body, which is why it is NOT a _______.

250. In skeletal muscle, the binding of _______ converts phosphorylase b into the active form.
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Answer Key
1. b

2. e

3. c

4. c

5. b

6. d

7. a

8. d

9. b

10. e

11. a

12. c

13. a

14. e

15. d

16. b

17. b

18. a

19. e

20. c

21. e

22. d

23. d

24. e
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25. c

26. a

27. b

28. a

29. b

30. d

31. c

32. c

33. a

34. d

35. a

36. c

37. a

38. b

39. e

40. e

41. e

42. a

43. e

44. e

45. a

46. b

47. d

48. d

49. d
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50. c

51. c

52. a

53. d

54. b

55. c

56. e

57. c

58. b

59. b

60. d

61. e

62. c

63. e

64. a

65. a

66. b

67. e

68. a

69. c

70. a

71. e

72. b

73. a

74. e
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75. c

76. c

77. d

78. d

79. e

80. b

81. a

82. c

83. c

84. a

85. e

86. b

87. d

88. b

89. b

90. c

91. a

92. d

93. b

94. d

95. a

96. a

97. c

98. e

99. e
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100. b

101. d

102. e

103. e

104. b

105. d

106. d

107. a

108. d

109. b

110. c

111. a

112. c

113. a

114. b

115. a

116. d

117. a

118. d

119. a

120. d

121. b

122. a

123. c

124. e
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125. d

126. a

127. e

128. c

129. d

130. c

131. b

132. d

133. e

134. c

135. b

136. c

137. b

138. b

139. e

140. c

141. d

142. b

143. c

144. d

145. e

146. c

147. c

148. a

149. d
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150. e

151. b

152. c

153. a

154. e

155. d

156. e

157. c

158. b

159. b

160. b

161. e

162. a

163. d

164. c

165. a

166. a

167. e

168. c

169. d

170. d

171. e

172. b

173. d

174. b
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175. b

176. a

177. b

178. d

179. d

180. c

181. d

182. c

183. c

184. c

185. a

186. d

187. d

188. e

189. c

190. b

191. a

192. b

193. c

194. d

195. a

196. c

197. c

198. a

199. d
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200. c

201. b

202. a

203. c

204. d

205. d

206. e

207. a

208. d

209. b

210. b

211. c

212. c

213. e

214. c

215. c

216. d

217. c

218. a

219. c

220. c

221. c

222. c

223. e

224. b
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225. b

226. e

227. d

228. b

229. e

230. b

231. b

232. d

233. a

234. b

235. b

236. b

237. c

238. a

239. a

240. c

241. c

242. c

243. e

244. d

245. d

246. b, c

247. a, b

248. C-9

249. vitamin
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250. AMP