Biology MCQs with Answers (part 1) by General knowledge Solutions

1. Enzymes requiring NAD as co-substrate can be assayed by measuring change in absorbance at

(A) 210 nm

(B) 290 nm

(D) 365 nm

2. Different isoenzymes of an enzyme have the same

(A) Amino acid sequence

(B) Michaelis constant

(D) All of these

3. From the pentapeptide, phe-ala-leu-lysarg, phenylalanine residue is split off by

(A) Trypsin

(B) Chymotrypsin

(D) Carboxypeptidase

4. A high-energy phosphate among the following is

(A) Glucose-6-phosphate

(B) Glucose-1-phosphate

(D) All of these

5. The highest energy level is present amongst the following in

(A) 1, 3-Biphosphoglycerate

(B) Creatine phosphate

(D) Phosphoenol pyruvate

6. Daily urinary urobilinogen excretion in adult men is

(A) 0–4 mg

(B) 5–8 mg

(D) 13–20 mg

7. In obstructive jaundice, faecal urobilinogen is

(A) Absent

(B) Decreased

(D) Normal

8. Acetyl-CoA can be formed from

(A) Pyruvate

(B) Fatty acids

(D) All of these

9. Pyruvate is converted into acetyl-CoA by

(A) Decarboxylation

(B) Dehydrogenation

(D) Oxidative deamination

10. Conversion of pyruvate into acetyl CoA is catalysed by

(A) Pyruvate dehydrogenase

(B) Didrolipoyl acetyl transferase

(D) All the 3 acting in concert

11. Pyruvate dehydrogenase complex is located in

(A) Cytosol

(B) Lysosomes

(D) Endoplasmic reticulum

12. A flavoprotein in pyruvate dehydrogenase complex is

(A) Pyruvate dehydrogenase

(B) Didrolipoyl acetyl transferase

(D) None of these

13. Pyruvate dehydrogenase complex is regulated by

(A) Covalent modification

(B) Allosteric regulation

(D) None of these

14. An allosteric inhibitor of pyruvate dehydrogenase is

(A) Acetyl CoA

(B) ATP

(D) Pyruvate

15. Ribozymes:

(A) RNA enzyme

(B) Non-protein enzymes

(D) All of these

16. In citric acid cycle, NAD is reduced in

(A) One reactions

(B) Two reactions

(D) Four reactions

17. Among citric acid cycle enzymes, a flavoprotein is

(A) Malate

(B) Fumarase

(D) Isocitrate dehrogenase

18. In citric acid cycle, GDP is phosphorylated by

(A) Succinate dehydrogenase

(B) Aconitase

(D) Fumarse

19. Malonate is an inhibitor of

(A) Malate dehydrogenase

(B) α-Ketoglutarate dehydrogenase

(D) Isocitrate dehydrogenase

20. Isocitrate dehydrogenase is allosterically inhibited by

(A) Oxalosuccinate

(B) α-Ketoglutarate

(D) NADH

21. All of the following are allosteric enzymes except

(A) Citrate synthetase

(B) a-Ketoglutarate dehdrogenase

(D) Succinate dehydrogenase

22. All of the following are intermediates of citric acid cycle except

(A) Oxalosuccinate

(B) Oxaloacetate

(D) Fumarate

23. All of the following intermediates of citric acid cycle can be formed from amino acids except

(A) α-Ketoglutarate

(B) Fumarate

(D) Oxaloacetate

24. Glycolytic pathway is located in

(A) Mitochondria

(B) Cytosol

(D) Nucleus

25. End product of aerobic glycolysis is

(A) Acetyl CoA

(B) Lactate

(D) CO2 and H2O

26. During fasting, glucose is phosphorylated mainly by

(A) Hexokinase

(B) Glucokinase

(D) None of these

27. Glucokinase is found in

(A) Muscles

(B) Brain

(D) All of these

28. In anaerobic glycolysis, energy yield from each molecule of glucose is

(A) 2 ATP equivalents

(B) 8 ATP equivalents

(D) 38 ATP equivalents

29. Which of the following is an allosteric enzyme?

(A) Phosphohexose isomerase

(B) Phosphotriose isomerase

(D) Phosphofructokinase

30. Glycolysis is anaerobic in

(A) Liver

(B) Brain

(D) Erythrocytes

31. Phosphofructokinase is allosterically inhibited by

(A) Fructose-1, 6-biphosphate

(B) Lactate

(D) Citrate

32. Glucose-6-phosphate is an allosteric inhibitor of

(A) Glucokinase

(B) Hexokinase

(D) None of these

33. ATP is a co-substrate as well as an allosteric inhibitor of

(A) Phosphofructokinase

(B) Hexokinase

(D) None of these

34. Complete oxidation of one molecule of glucose into CO2 and H2O yields

(A) 8 ATP equivalents

(B) 15 ATP equivalents

(D) 38 ATP equivalents

35. A unique by-product of glycolysis in erythrocytes is

(A) Lactate

(B) 1, 3-Biphosphoglycerate

(D) All of these

36. Which of the following enzymes incorporates inorganic phosphate into the substrate?

(A) Phosphoglycerate kinase

(B) Glyceraldehyde-3-phosphate dehydrogenase

(D) Enolase

37. Rapoport-Luebering cycle is located in

(A) Liver

(B) Muscles

(D) Erythrocytes

38. Glycerol can enter glycolytic pathway via

(A) Dihydroxyacetone phosphate

(B) 1, 3-Biphospoglycerate

(D) 2-Phosphoglycerate

39. HMP shunt is present in

(A) Erythrocytes

(B) Liver

(D) All of these

40. Glucose-6-phosphate dehydrogenase is induced by

(A) 6-Phosphogluconolactone

(B) Glucose-6-phosphate

(D) Insulin

41. The decarboxylation reaction in HMP shunt is catalysed by

(A) Gluconolactone hydrolase

(B) 6-Phosphogluconate dehydrogenase

(D) Transaldolase

42. The first pentose formed in HMP shunt is

(A) Ribose-5-phosphate

(B) Ribulose-5-phosphate

(D)Xylulose-5-phosphate

43. The regulatory enzyme in HMP shunt is

(A) Glucose-6-phosphate dehydrogenase

(B) 6-Phosphogluconate dehydrogenase

(D) None of these

44. The rate of HMP shunt reactions is

(A) Increased by Insulin

(B) Increased in diabetes mellitus

(D) Increased in starvation

45. Glycogenesis requires

(A) GTP

(B) CTP

(D) None of these

46. Glycogen synthetase catalyses the formation of

(A) α−1, 4-Glycosidic bonds

(B) α−1, 6-Glycosidic bonds

(D) None of these

47. Glycogenoloysis is increased by

(A) Glucagon

(B) Insulin

(D) cAMP

48. Hepatic glycogenoloysis is increased by

(A) Insulin

(B) Glucagon

(D) Glucocorticoids

Answer

1. C 2. C 3. C 4. C 5. D 6. A 7. A 8. D 9. C 10. D 11. C 12. C 13. C 14. A 15. D 16. C 17. C 18. C 19. C 20. C 21. C 22. C 23. C 24. B 25. C 26. A 27. C 28. A 29. D 30. D 31. D 32. B 33. A 34. D 35. C 36. A 37. D 38. A 39. D 40. D 41. C 42. B 43. C 44. A 45. C 46. A 47. B 48. B

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Biology MCQs with Answers (part 1) by General knowledge Solutions