Biology MCQs with Answer (part 3) by General knowledge Solutions

1. The enzyme of the glycolic pathway, sensitive to inhibiton by fluoride ions is

(A) Hexokinase

(B) Aldolase

(D) Pyruvate kinase

2. In glycolytic pathway, iodacetate inhibits the activity of the enzyme:

(A) Phosphotriose isomerase

(B) Glyceraldehyde-3-phosphate dehydrogenase

(D) Phosphofructokinase

3. In the glycolytic pathway, enolpyruvate is converted to ketopyruvate by

(A) Pyruvate kinase

(B) Phosphoenolpyruvate

(D) Spontaneously

4. In erythrocytes, 2, 3-biphosphoglycerate is derived from the intermediate:

(A) Glyeraldehyde-3-phosphate

(B) 1, 3-Biphosphoglycerate

(D) 2-Phosphoglycerate

5. 2, 3-Biphosphoglycerate in high concentrations, combines with hemoglobin, causes

(A) Displacement of the oxyhemoglobin dissociation curve to the left

(B) Displacement of the oxyhemoglobin dissociation curve to the right

(D) Increased affinity for oxygen

6. Erythrocytes under normal conditions and microorganisms under anaerobic conditions may accumulate

(A) NADPH

(B) Pyruvate

(D) Lactate

7. Enzymes leading to the high energy phosphorylation of substrates during glycolysis include which of the following?

(A) Phosphoglycerate kinase

(B) Enolase

(D) Glyceraldehyde-3-phosphate dehydrogenase

8. Lineweaver – Burk double reciprocal plot is related to

(A) Substrate concentration

(B) Enzyme activity

(D) Both (A) and (B)

9. Phosphofructokinase key enzyme in glycolysis is inhibited by

(A) Citrate and ATP

(B) AMP

(D) TMP

10. One of the enzymes regulating glycolysis is

(A) Phosphofructokinase

(B) Glyceraldehyde-3-phosphate dehydrogenase

(D) Phosphohexose isomerase

11. Hexokinase is inhibited in an allosteric manner by

(A) Glucose-6-Phosphate

(B) Glucose-1-Phosphate

(D) Fructose-1, 6-biphosphate

12. A reaction which may be considered an isomerisation is

(A) Glucose 6-Phosphate fructose 6 phosphate

(B) 3-Phosphoglycerate 2-phosphoglycerate

(D) Pyruvate Lactate

13. The net number of ATP formed per mole of glucose in anaerobic glycolysis is

(A) 1

(B) 2

(D) 8

14. Pyruvate dehydrogenase a multienzyme complex is required for the production of

(A) Acetyl-CoA

(B) Lactate

(D) Enolpyruvate

15. Dietary deficiency of thiamin inhibits the activity of the enzyme:

(A) Pyruvate kinase

(B) Pyruvate dehydrogenase

(D) Enolase

16. Pyruvate dehydrogenase activity is inhibited by

(A) Mercury

(B) Zinc

(D) Sodium

17. In the normal resting state of humans, most of the blood glucose burned as fuel is consumed by

(A) Liver

(B) Adipose tissue

18. All the enzymes of glycolysis pathway are found in

(A) Extramitochondrial soluble fraction of the cell

(B) Mitochondria

(D) Endoplasmic reticulum

19. Most major metabolic pathways are considered mainly either anabolic or catabolic. Which of the following pathway is most correctly considered to be amphibolic?

(A) Citric acid cycle

(B) Gluconeogenesis

(D) Glycolysis

20. The enzymes of the citric acid cycle are located in

(A) Mitochondrial matrix

(B) Extramitochondrial soluble fraction of the cell

21. The initial step of the citric acid cycle is

(A) Conversion of pyruvate to acetyl-CoA

(B) Condensation of acetyl-CoA with oxaloacetate

(D) Formation of α -ketoglutarate catalysed by isocitrate dehydrogenase

22. The substance which may be considered to play a catalytic role in citric acid cycle is

(A) Oxaloacetate

(B) Isocitrate

(D) Fumarate

23. An enzyme of the citric acid cycle also found outside the mitochondria is

(A) Isocitrate dehydrogenase

(B) Citrate synthetase

(D) Malate dehydrogenase

24. The reaction catalysed by α-ketoglutarate dehydrogenase in the citric acid cycle requires

(A) NAD

(B) NADP

(D) ATP

25. If all the enzymes, intermediates and cofactors of the citric acid cycle as well as an excess of the starting substrate acetylCoA are present and functional in an organelle free solution at the appropriate pH, which of the following factors of the citric acid cycle would prove to be rate limiting?

(A) Molecular oxygen

(B) Half life of enzyme

(D) Reduction of cofactors

26. In TCA cycle, oxalosuccinate is converted to α-ketoglutarate by the enzyme:

(A) Fumarase

(B) Isocitrate dehydrogenase

(D) Succinase

27. The enzyme -ketoglutarate dehydrogenase in the citric acid cycle requires

(A) Lipoate

(B) Folate

(D) Inositol

28. The example of generation of a high energy phosphate at the substrate level in the citric acid cycle is the reaction:

(A) Isocitrate α-Ketoglutarate

(B) Succinate α-fumarate

(D) Succinyl CoA α-Succinate

29. Fluoroacetate inhibits the reaction of citric acid cycle:

(A) Isocitrate α-Ketoglutarate

(B) Fumarate α-Malate

(D) Succinate α-fumarate

30. Formation of succinyl-CoA from α-Ketoglutarate is inhibited by

(A) Fluoroacetate

(B) Arsenite

(D) Iodoacetate

31. The number of ATP molecules generated for each turn of the citric acid cycle is

(A) 8

(B) 12

(D) 38

32. Oxidation of one molecule of glucose yields

(A) 12 ATP

(B) 24 ATP

(D) 38 ATP

33. Which of the following intermediates of metabolism can be both a precursor and a product of glucose?

(A) Lactate

(B) Pyruvate

(D) Acetyl-CoA

34. Mitochondrial membrane is freely preamble to

(A) Pyruvate

(B) Malate

(D) Fumarate

35. The reaction of Kreb’s cycle which does not require cofactor of vitamin B group is

(A) Citrate isocitrate

(B) α -Ketoglutarate succinate

(D) Succinate fumarate

36. The coenzyme not involved in the formation of acetyl-CoA from pyruvate is

(A) TPP

(B) Biotin

(D) FAD

37. A carrier molecule in the citric acid cycle is

(A) Acetyl-CoA

(B) Citrate

(D) Malate

38. A specific inhibitor for succinate dehydrogenase is

(A) Arsenine

(B) Arsenite

(D) Fluoride

Answers

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

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Biology MCQs with Answer (part 3) by General knowledge Solutions