FREE BIOCHEMISTRY MCQs

FREE BIOCHEMISTRY MCQs

1. Which of the following is a substrate for aldolase activity in Glycolytic pathway?
(A) Glyceraldehyde-3-p
(B) Glucose-6-p
(C) Fructose-6-p
(D) Fructose1, 6-bisphosphate

2. The ratio that approximates the number of net molecule of ATP formed per mole of Glucose oxidized in presence of O2 to the net number formed in abscence of O2 is
(A) 4 : 1
(B) 10 : 2
(C) 12 : 1
(D) 18 : 1

3. The “Primaquin sensitivity types of haemolytic anaemia has been found to relate to reduced R.B.C activity of which enzyme?
(A) Pyruvate kinase deficiency
(B) Glucose-6-phosphatase deficiency
(C) Glucose-6-p dehydrogenase deficiency
(D) Hexokinase deficiency

 4. Which of the following hormones is not involved in carbohydrate metabolism?
(A) Cortisol
(B) ACTH
(C) Glucogen
(D) Vasopressin

5. Dehydrogenases involved in HMP shunt are specific for
(A) NADP+
(B) NAD+
(C) FAD
(D) FMN

6. Which of the following enzymes in Glycolytic pathway is inhibited by fluoride?
(A) Glyceraldehyde-3-p dehydrogenase
(B) Phosphoglycerate kinase
(C) Pyruvate kinase
(D) Enolase

7. Out of 24 mols of ATP formed in TCA cycle, 2 molecules of ATP can be formed at “substrate level” by which of the following reaction ?
(A) Citric acid→ Isocitric acid
(B) Isocitrate→ Oxaloacetate
(C) Succinic acid→ Fumarate
(D) Succinylcat→ Succinic acid

8. Which of the following statements regarding T.C.A cycle is true?
(A) It is an anaerobic process
(B) It occurs in cytosol
(C) It contains no intermediates for Gluconeogenesis
(D) It is amphibolic in nature

9. An allosteric enzyme responsible for controlling the rate of T.C.A cycle is
(A) Malate dehydrogenase
(B) Isocitrate dehydrogenase
(C) Fumarase
(D) Aconitase

10. The glycolysis is regulated by
(A) Hexokinase
(B) Phosphofructokinase
(C) Pyruvate kinase
(D) All of these

11. How many ATP molecules will be required for conversion of 2-molecules of Lactic acid to Glucose?
(A) 2
(B) 4
(C) 8
(D) 6

 12. Which of the following enzyme is not involved in HMP shunt?
(A) Glyceraldehyde-3-p dehydrogenase
(B) Glucose-6-p-dehydrogenase
(C) Transketolase
(D) Phosphogluconate dehydrogenase

13. In presence of the following cofactor, pyruvate carboxylase converts pyruvate to oxaloacetate: (A) ATP, Protein and CO2
(B) CO2 and ATP
(C) CO2
(D) Protein

 14. For conversion of oxaloacetate to phosphoenol pyruvate, high energy molecule is required in the form of
(A) GTP only
(B) ITP only
(C) GTP (or) ITP
(D) None of these

15. If the more negative standard reduction potential of a redox pair, the greater the tendency to
(A) To lose electrons
(B) To gain electrons
(C) To lose/gain electrons
(D) To lose and gain electrons

16. Electron transport and phosphorylation can be uncoupled by compounds that increase the permeability of the inner mitochondrial membrane to
(A) Electrons
(B) Protons
(C) Uncouplers
(D) All of these

17. The more positive the E0, the greater the tendency of the oxidant member of that pair to
(A) Lose electrons
(B) Gain electrons
(C) Lose (or) gain electrons
(D) Lose and gain electrons

 18. The standard free energy of hydrolysis of terminal phosphate group of ATP is
 (A) –7,300 cal/mol
 (B) –8,300 cal/mol
 (C) 10,000 cal/mol
 (D) +7,300 cal/mol

 19. The transport of a pair of electrons from NADH to O2 via the electron transport chain produces   (A) –52,580 cal
 (B) –50,580 cal
 (C) 21,900 cal
 (D) +52,580 cal

 20. Sufficient energy required to produce 3 ATP from 3 ADP and 3 pi is
 (A) –21,900 cal
 (B) 29,900 cal
 (C) 31,900 cal
 (D) 39,900 cal

21. The free energy change, AG
(A) Is directly proportional to the standard free energy change, AG
(B) Is equal to zero at equilibrium
(C) Can only be calculated when the reactants and products are present at 1mol/1 concentrations
(D) Is equal to –RT in keq

22. Under standard conditions
(A) The free energy change ∆G°, is equal to 0
(B) The standard free energy change ∆G, is equal to 0
(C) The free energy change, ∆G°, is equal to the standard free energy change, ∆G°
(D) Keq is equal to 1

23. An uncoupler of oxidative phosphorylation such as dinitrophenol
(A) Inhibits electron transport and ATP synthesis
(B) Allow electron transport to proceed without ATP synthesis
(C) Inhibits electron transport without impairment of ATP synthesis
(D) Specially inhibits cytochrome b

24. All of the following statements about the enzymic complex that carries out the synthesis of ATP during oxidative phosphorylation are correct except
 (A) It is located on the matrix side of the inner mitochondrial membrane
 (B) It is inhibited by oligomycin
 (C) It can exhibit ATPase activity
 (D) It can bind molecular O2

 25. Glucokinase
 (A) Is widely distributed and occurs in most mammalian tissues
 (B) Has a high km for glucose and hence is important in the phosphorylation of glucose primarily after ingestion of a carbohydrate rich meal
 (C) Is widely distributed in Prokaryotes
 (D) None of these

 26. The reaction catalysed by phosphofructokinase
 (A) Is activated by high concentrations of ATP and citrate
 (B) Uses fruitose-1-phosphate as substrate
 (C) Is the rate-limiting reaction of the glycolytic pathway
 (D) Is inhibited by fructose 2, 6-bisphosphate

27. Compared to the resting state, vigorously contracting muscle shows
(A) An increased conversion of pyruvate to lactate
(B) Decreased oxidation of pyruvate of CO2 and water
(C) A decreased NADH/NAD+ ratio
(D) Decreased concentration of AMP

28. Which one of the following would be expected in pyruvate kinase deficiency?
(A) Increased levels of lactate in the R.B.C
 (B) Hemolytic anemia
(C) Decreased ratio of ADP to ATP in R.B.C
(D) Increased phosphorylation of Glucose to Glucose-6-phosphate

29. Which one of the following statements concerning glucose metabolism is correct?
(A) The conversion of Glucose to lactate occurs only in the R.B.C
(B) Glucose enters most cells by a mechanism in which Na+ and glucose are co-transported
(C) Pyruvate kinase catalyses an irreversible reaction
(D) An elevated level of insulin leads to a decreased level of fructose 2, 6-bisphosphate in hepatocyte

30. Which one of the following compounds cannot give rise to the net synthesis of Glucose?
 (A) Lactate
 (B) Glycerol
 (C) α-ketoglutarate
 (D) Acetyl CoA

 31. Which of the following reactions is unique to gluconeogenesis?
(A) Lactate Pyruvate
(B) Phosphoenol pyruvate pyruvate
(C) Oxaloacetate phosphoenol pyruvate
(D) Glucose-6-phosphate Fructose-6-phosphate

32. The synthesis of glucose from pyruvate by gluconeogenesis
(A) Requires the participation of biotin
(B) Occurs exclusively in the cytosol
(C) Is inhibited by elevated level of insulin
(D) Requires oxidation/reduction of FAD