1. The free energy change, ∆G

a. Can only be calculated when the reactants and products are present at 1mol/1

b. Is equal to –RT in keq

c. Is equal to zero at equilibrium

d. Is directly proportional to the standard free

energy change, ∆G

Correct Answer: c

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. Phosphofructokinase-2

b. Phosphofructokinase-1

c. Fructose biphosphate isomerase

d. Fructose-1, 6-biphosphatase

Correct Answer: a

9. An amphibolic pathway among the following is

a. Gluconeogenesis

b. Citirc acid cycle

c. HMP shunt

d. Glycolysis

Correct Answer: b

10. Glycogenin is

a. Protein primer for glycogen synthesis

b. Uncoupler of oxidative phosphorylation

c. Polymer of glycogen molecules

d. Intermediate in glycogen breakdown

Correct Answer: a

11. During starvation, ketone bodies are used as a fuel by

a. All of these

b. Brain

c. Liver

d. Erythrocytes

Correct Answer: b

12. Cyclic AMP is formed from ATP by the enzyme adenylate cyclase which is activated by the hormone

a. Progesterone

b. Epinephrine

c. Insulin

d. Testosterone

Correct Answer: b

13. Galactose is phosphorylated by galactokinase to form

a. All of these

b. Galactose-1-phosphate

c. Galactose-6-phosphate

d. Galactose-1, 6 diphosphate

Correct Answer: b

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 4 membered sugars

b. Pentose sugars and sedoheptulose

c. NADPH and pentose sugars

d. NADH and pentose sugars

Correct Answer: c

16. Pyruvate dehydrogenase complex and α-ketoglutarate dehydrogenase complexrequire the following for their oxidative decarboxylation

a. COASH and Lipoic acid

b. COASH, TPP,NAD+,FAD, Lipoate

c. COASH and TPP

d. NAD+ and FAD

Correct Answer: b

17. In humans, gluconeogenesis

a. requires the enzyme hexokinas

b. can result in the conversion of protein into blood glucose

c. helps to reduce blood glucose after a carbohydrate-rich meal

d. is activated by the hormone insulin

Correct Answer: b

18. Which of the following substrates cannot contribute to net gluconeogenesis in mammalian liver?

a. Glutamate

b. Pyruvate

c. palmitate

d. Alanine

Correct Answer: c

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. Enolase

b. Isomerase

c. phosphofructokinase-1

d. Aldolase

Correct Answer: c

20. The steps of glycolysis between glyceraldehyde 3-phosphate and 3-phosphoglycerate involve all of the following except

a. ) catalysis by phosphoglycerate kinase

b. utilization of Pi

c. oxidation of NADH to NAD+

d. ATP synthesis

Correct Answer: c

21. Glycogen is converted to monosaccharide units by

a. Glucose-6-phosphate

b. Glycogen phosphorylase

c. Glucokinase

d. Glycogen synthase

Correct Answer: b

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. Fatty acid in the mitochondria

b. fatty acid outside the mitochondria

c. Protein

d. Glycogen

Correct Answer: b

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 into mitochondria

b. Triglycerides out of liver

c. Long chain fatty acids into mitochondria

d. Short chain fatty acids into mitochondria

Correct Answer: c

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. Glycerol-3-phosphate dehydrogenase

b. Glycerol kinase

c. Hormone-sensitive lipase

d. cAMP-dependent protein kinase

Correct Answer: b

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. Biotin

b. HCO3 – (CO2)


d. Acetyl-CoA

Correct Answer: c

36. Enzymes that catalyze the synthesis of long chain fatty acids in vertebrate cells

a. are localized in the mitochondrial matrix

b. are part of a single polypeptide chain

c. act as seven separate proteins

d. are encoded in mitochondrial genes

Correct Answer: b

37. Which of these can be synthesized by plants but not by humans?

a. Pyruvate

b. Stearate

c. Linoleate

d. Palmitate

Correct Answer: c

38. The enzyme system for adding double bonds to saturated fatty acids requires all of the following except


b. ATP

c. Oxidase

d. Molecular oxygen

Correct Answer: b

39. The synthesis of both glycerophospholipids and triacylglycerols involves

a. CDP-diacylglycerol

b. phosphatidate phosphatase

c. Phosphatidic acid

d. CDP-choline

Correct Answer: c

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. Pyridoxal phosphate

b. Glutamate

c. Ammonia

d. ATP

Correct Answer: a

44. Most of the ammonia released from amino acids reflects the coupled action of transaminase and

a. Serine dehydratase

b. Glutamate dehydrogenase

c. Glutamate

d. Amino acid oxidase

Correct Answer: b

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. Racemization

b. Deamination

c. Transamination

d. Decarboxylation

Correct Answer: b

49. Urea synthesis in mammals takes place primarily in tissues of the

a. Muscle

b. Intestine

c. Liver

d. Brain

Correct Answer: c

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