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

1. The compound which has the lowest density is

(A) Chylomicron

(B) β-Lipoprotein

(D) pre β-Lipoprotein

2. Non steroidal anti inflammatory drugs, such as aspirin act by inhibiting the activity of the enzyme:

(A) Lipoxygenase

(B) Cyclooxygenase

(D) Lipoprotein lipase

3. From arachidonate, synthesis of prostaglandins is catalysed by

(A) Cyclooxygenase

(B) Lipoxygenase

(D) Isomerase

4. A Holoenzyme is

(A) Functional unit

(B) Apo enzyme

(D) All of these

5. Gaucher’s disease is due to the deficiency of the enzyme:

(A) α-Fucosidase (B) β-Galactosidase (C) β-Glucosidase

(D) Sphingomyelinase

6. Neimann-Pick disease is due to the deficiency of the enzyme:

(A) Hexosaminidase A and B

(B) Ceramidase

(D) Sphingomyelinase

7. Krabbe’s disease is due to the deficiency of the enzyme:

(A) Ceramide lactosidase

(B) Ceramidase

(D) GM1 β-Galactosidase

8. Fabry’s disease is due to the deficiency of the enzyme:

(A) Ceramide trihexosidase

(B) Galactocerebrosidase

(D) Sphingomyelinase

9. Farber’s disease is due to the deficiency of the enzyme:

(A) α-Galactosidase

(B) Ceramidase

(D) Arylsulphatase A.

10. A synthetic nucleotide analogue, used in organ transplantation as a suppressor of immunologic rejection of grafts is

(A) Theophylline

(B) Cytarabine

(D) 6-Mercaptopurine

11. Example of an extracellular enzyme is

(A) Lactate dehydrogenase

(B) Cytochrome oxidase

(D) Hexokinase

12. Enzymes, which are produced in inactive form in the living cells, are called

(A) Papain

(B) Lysozymes

(D) Proenzymes

13. An example of ligases is

(A) Succinate thiokinase

(B) Alanine racemase

(D) Aldolase

14 An example of lyases is

(A) Glutamine synthetase

(B) Fumarase

(D) Amylase

15. Activation or inactivation of certain key regulatory enzymes is accomplished by covalent modification of the amino acid:

(A) Tyrosine

(B) Phenylalanine

16. The enzyme which can add water to a carbon-carbon double bond or remove water to create a double bond without breaking the bond is

(A) Hydratase

(B) Hydroxylase

(D) Esterase

17. Fischer’s ‘lock and key’ model of the enzyme action implies that

(A) The active site is complementary in shape to that of substance only after interaction.

(B) The active site is complementary in shape to that of substance

(D) The active site is flexible and adjusts to substrate

18. From the L ineweaver-Burk p lot of Michaelis-Menten equation, Km and Vmax can be determined when V is the reaction velocity at substrate concentration S, the X-axis experimental data are expressed as

(A) 1/V

(B) V

(D) S

19. A sigmoidal plot of substrate concentration ([S]) verses reaction velocity (V) may indicate

(A) Michaelis-Menten kinetics

(B) Co-operative binding

(D) Non-competitive inhibition

20. The Km of the enzyme giving the kinetic data as below is

(A) –0.50

(B) –0.25

(D) +0.33

21. The kinetic effect of purely competitive inhibitor of an enzyme

(A) Increases Km without affecting Vmax

(B) Decreases Km without affecting Vmax

(D) Decreases Vmax without affecting Km

22. If curve X in the graph (below) represents no inhibition for the reaction of the enzyme with its substrates, the curve representing the competitive inhibition, of the same reaction is

(A) A

(B) B

(D) D

23. An inducer is absent in the type of enzyme:

(A) Allosteric enzyme

(B) Constitutive enzyme

(D) Isoenzymic enzyme

24. A demonstrable inducer is absent in

(A) Allosteric enzyme

(B) Constitutive enzyme

(D) Co-operative enzyme

25. In reversible non-competitive enzyme activity inhibition

(A) Vmax is increased

(B) Km is increased

(D) Concentration of active enzyme is reduced

26. In reversible non-competitive enzyme activity inhibition

(A) Inhibitor bears structural resemblance to substrate

(B) Inhibitor lowers the maximum velocity attainable with a given amount of enzyme

(D) Km is decreased

27. In competitive enzyme activity inhibition

(A) The structure of inhibitor generally resembles that of the substrate

(B) Inhibitor decreases apparent Km

(E) Inhibitor decreases Vmax without affecting Km

28. In enzyme kinetics Vmax reflects

(A) The amount of an active enzyme

(B) Substrate concentration

(D) Enzyme substrate complex

29. In enzyme kinetics Km implies

(A) The substrate concentration that gives one half Vmax

(B) The dissocation constant for the enzyme substrate comples

(D) Half of the substrate concentration required to achieve Vmax

30. In competitive enzyme activity inhibition

(A) Apparent Km is decreased

(B) Apparent Km is increased

(D) Vmax is decreased

31. In non competitive enzyme activity inhibition, inhibitor

(A) Increases Km

(B) Decreases Km

(D) Increases Km

32. An enzyme catalyzing oxidoreduction, using oxygen as hydrogen acceptor is

(A) Cytochrome oxidase

(B) Lactate dehydrogenase

(D) Succinate dehydrogenase

33. The enzyme using some other substance, not oxygen as hydrogen acceptor is

(A) Tyrosinase

(B) Succinate dehydrogenase

(D) Cytochrome oxidase

34. An enzyme which uses hydrogen acceptor as substrate is

(A) Xanthine oxidase

(B) Aldehyde oxidase

(D) Tryptophan oxygenase

35. Enzyme involved in joining together two substrates is

(A) Glutamine synthetase

(B) Aldolase

(D) Arginase

36. The pH optima of most of the enzymes is

(A) Between 2 and 4

(B) Between 5 and 9

(D) Above 12

37. Coenzymes are

(A) Heat stable, dialyzable, non protein organic molecules

(B) Soluble, colloidal, protein molecules

(D) Different forms of enzymes

38. An example of hydrogen transferring coenzyme is

(A) CoA

(B) NAD+

(D) TPP

39. An examp le of group transferr ing coenzyme is

(A) NAD+

(B) NADP+

(D) CoA

Answers:

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

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