1. The free energy change, ∆G
a. Is equal to –RT in keq
b. Is equal to zero at equilibrium
c. Is directly proportional to the standard free
energy change, ∆G
d. Can only be calculated when the reactants
and products are present at 1mol/1
Correct Answer: b
.
2. Biological oxidation-reduction reactions always involve
a. direct participation of oxygen
b. formation of water
c. transfer of hydrogens
d. transfer of electron(s).
Correct Answer: d
.
3. If the ΔG΄º of the reaction A–> B is -40 kJ/mol, under standard conditions the reaction
a. Will proceed spontaneously from left to right
b. Is at equilibrium
c. Will never reach equilibrium
d. Will proceed spontaneously from right to left
Correct Answer: a
.
4. Which one of the following compounds does not have a large negative free energy of hydrolysis?
a. ADP
b. 1,3-bis phosphoglycerate
c. Thioesters (e.g. acetyl-CoA)
d. 3-phosphoglycerate
Correct Answer: d
.
5. The structure of NAD+ does not include
a. a pyrophosphate bond
b. an adenine nucleotide
c. two ribose residues
d. a flavin nucleotide
Correct Answer: d
.
6. Gluconeogenesis is decreased by
a. Epinephrine
b. Glucocorticoids
c. Insulin
d. Glucagon
Correct Answer: c
.
7. Pyruvate carboxylase is regulated by
a. Induction
b. Repression
c. Allosteric regulation
d. All of these
Correct Answer: d
.
8. Fructose-2, 6-biphosphate is formed by the action of
a. Fructose-1, 6-biphosphatase
b. Phosphofructokinase-2
c. Phosphofructokinase-1
d. Fructose biphosphate isomerase
Correct Answer: b
.
9. An amphibolic pathway among the following is
a. Glycolysis
b. Gluconeogenesis
c. Citirc acid cycle
d. HMP shunt
Correct Answer: c
.
10. Glycogenin is
a. Intermediate in glycogen breakdown
b. Protein primer for glycogen synthesis
c. Uncoupler of oxidative phosphorylation
d. Polymer of glycogen molecules
Correct Answer: b
.
11. During starvation, ketone bodies are used as a fuel by
a. Erythrocytes
b. All of these
c. Brain
d. Liver
Correct Answer: c
.
12. Cyclic AMP is formed from ATP by the enzyme adenylate cyclase which is activated by the hormone
a. Testosterone
b. Progesterone
c. Epinephrine
d. Insulin
Correct Answer: c
.
13. Galactose is phosphorylated by galactokinase to form
a. Galactose-1, 6 diphosphate
b. All of these
c. Galactose-1-phosphate
d. Galactose-6-phosphate
Correct Answer: c
.
14. An aneplerotic reaction which sustains the availability of oxaloacetate is the carboxylation of
a. Pyruvate
b. Glutamate
c. Citrate
d. Succinate
Correct Answer: a
.
15. Two important byproducts of HMP shunt are
a. Pentose sugars and sedoheptulose
b. NADPH and pentose sugars
c. NADH and pentose sugars
d. Pentose sugars and 4 membered sugars
Correct Answer: b
.
16. Pyruvate dehydrogenase complex and α-ketoglutarate dehydrogenase complexrequire the following for their oxidative decarboxylation
a. NAD+ and FAD
b. COASH and Lipoic acid
c. COASH, TPP,NAD+,FAD, Lipoate
d. COASH and TPP
Correct Answer: c
.
17. In humans, gluconeogenesis
a. is activated by the hormone insulin
b. requires the enzyme hexokinas
c. can result in the conversion of protein into blood glucose
d. helps to reduce blood glucose after a carbohydrate-rich meal
Correct Answer: c
.
18. Which of the following substrates cannot contribute to net gluconeogenesis in mammalian liver?
a. Pyruvate
b. palmitate
c. Alanine
d. Glutamate
Correct Answer: b
.
19. All of the following enzymes involved in the flow of carbon from glucose to lactate (glycolysis) are also involved in the reversal of this flow (gluconeogenesis) except
a. Isomerase
b. phosphofructokinase-1
c. Aldolase
d. Enolase
Correct Answer: b
.
20. The steps of glycolysis between glyceraldehyde 3-phosphate and 3-phosphoglycerate involve all of the following except
a. utilization of Pi
b. oxidation of NADH to NAD+
c. ATP synthesis
d. ) catalysis by phosphoglycerate kinase
Correct Answer: b
.
21. Glycogen is converted to monosaccharide units by
a. Glycogen synthase
b. Glucose-6-phosphate
c. Glycogen phosphorylase
d. Glucokinase
Correct Answer: c
.
22. In the alcoholic fermentation of glucose by yeast, thiamine pyrophosphate is a coenzyme required by:
a. Pyruvate decarboxylase
b. aldolase
c. hexokinase
d. transaldolase
Correct Answer: a
.
23. Which of the following statements about the pentose phosphate pathway is incorrect?
a. It generates CO2 from C-1 of glucose
b. It is prominant in lactating mammary gland
c. It involves the conversion of an aldohexose to an aldopentose
d. ) It requires the participation of molecular oxygen
Correct Answer: d
.
24. The immediate precursors of DNA and RNA synthesis in the cell all contain
a. 3′ triphosphates
b. deoxyribose
c. Ribose
d. 5′ triphosphates
Correct Answer: d
.
25. An enzyme used in both glycolysis and gluconeogenesis is
a. Hexokinase
b. PFK-1
c. Pyruvate kinase
d. 3-phosphoglycerate kinase
Correct Answer: d
.
26. Acyl carrier protein is involved in the synthesis of
a. Glycogen
b. Fatty acid in the mitochondria
c. fatty acid outside the mitochondria
d. Protein
Correct Answer: c
.
27. NADPH required for fatty acid synthesis can come from
a. Hexose monophosphate shunt
b. Oxidative decarboxylation of malate
c. Extramitochondrial oxidation of isocitrate
d. All of these
Correct Answer: d
.
28. One functional sub-unit of multi-enzyme complex for de novo synthesis of fatty acids contains
a. Two —SH groups
b. one —SH group
c. Four —SH groups
d. Three —SH groups
Correct Answer: a
.
29. During each cycle of β-oxidation
a. Two carbon atoms are removed from the carboxyl end of the fatty acid
b. One carbon atom is removed from the carboxyl end of the fatty acid
c. One carbon atom is removed from the methyl
end of the fatty acid
d. Two carbon atoms are removed from the
methyl end of the fatty acid
Correct Answer: a
.
30. Net ATP generation on complete oxidation of stearic acid is
a. 129
b. 131
c. 148
d. 146
Correct Answer: d
.
31. Carnitine is required for the transport of
a. Triglycerides out of liver
b. Long chain fatty acids into mitochondria
c. Short chain fatty acids into mitochondria
d. Triglycerides into mitochondria
Correct Answer: b
.
32. Oxidation of fatty acids occurs
a. On inner mitochondrial membrane
b. On the microsomes
c. In the matrix of mitochondria
d. In the cytosol
Correct Answer: c
.
33. Adipose tissue lacks
a. cAMP-dependent protein kinase
b. Glycerol-3-phosphate dehydrogenase
c. Glycerol kinase
d. Hormone-sensitive lipase
Correct Answer: c
.
34. Alcohol dehydrogenase converts ethanol into
a. Acetyl CoA
b. CO2 and H2O
c. Acetate
d. Acetaldehyde
Correct Answer: d
.
35. Which of the following is not required in the synthesis of fatty acids?
a. HCO3 – (CO2)
b. NADH
c. Acetyl-CoA
d. Biotin
Correct Answer: b
.
36. Enzymes that catalyze the synthesis of long chain fatty acids in vertebrate cells
a. are encoded in mitochondrial genes
b. are localized in the mitochondrial matrix
c. are part of a single polypeptide chain
d. act as seven separate proteins
Correct Answer: c
.
37. Which of these can be synthesized by plants but not by humans?
a. Stearate
b. Linoleate
c. Palmitate
d. Pyruvate
Correct Answer: b
.
38. The enzyme system for adding double bonds to saturated fatty acids requires all of the following except
a. Molecular oxygen
b. NADPH
c. ATP
d. Oxidase
Correct Answer: c
.
39. The synthesis of both glycerophospholipids and triacylglycerols involves
a. phosphatidate phosphatase
b. Phosphatidic acid
c. CDP-choline
d. CDP-diacylglycerol
Correct Answer: b
.
40. Cholesterol is synthesized from
a. Choline
b. Lipoic acid
c. Malate
d. Acetyl-CoA
Correct Answer: d
.
41. Branched chain amino acids are
a. Valine, Leucine and Isoleucine
b. Cysteine and cystine
c. Tyrosine and Tryptophan
d. Glycine and Serine
Correct Answer: a
.
42. Ammonia is transported from muscles to liver mainly in the form of
a. Free ammonia
b. Glutamine
c. Asparagine
d. Alanine
Correct Answer: d
.
43. All of the following are required for synthesis of glutamine except
a. ATP
b. Pyridoxal phosphate
c. Glutamate
d. Ammonia
Correct Answer: b
.
44. Most of the ammonia released from amino acids reflects the coupled action of transaminase and
a. Amino acid oxidase
b. Serine dehydratase
c. Glutamate dehydrogenase
d. Glutamate
Correct Answer: c
.
45. The number of ATP required for urea synthesis is
a. 2
b. 1
c. 0
d. 3
Correct Answer: d
.
46. Which of these is not a protease that acts in the small intestine?
a. Secretin
b. Enteropeptidase
c. Chymotrypsin
d. Trypsin
Correct Answer: a
.
47. The coenzyme involved in a transaminase reaction is
a. pyridoxal phosphate (PLP)
b. thiamine pyrophosphate (TPP)
c. Biotin
d. lipoic acid
Correct Answer: a
.
48. Glutamate is metabolically converted to α-ketoglutarate and NH4+ by a process described as
a. Decarboxylation
b. Racemization
c. Deamination
d. Transamination
Correct Answer: c
.
49. Urea synthesis in mammals takes place primarily in tissues of the
a. Intestine
b. Liver
c. Brain
d. Muscle
Correct Answer: b
.
50. Serine or cysteine may enter the citric acid cycle as acetyl-CoA after conversion to
a. Pyruvate
b. oxaloacetate
c. Succinyl-CoA
d. Propionate
Correct Answer: a
.
