ENZYMES

ENZYMES

1. Who suggested that enzymes are proteins?

a. Northrop b. Buchner c. Kuhne d. Sumner

2. Which determines specificity of enzyme?

a. Protein part b. Coenzyme c. Full Haloenzyme d. Inorganic factor

3. An enzyme acts as catalyst because

a. It accelerates the chemical reaction b. It remain unchanged

c. Enzyme catalysed reactions are reversible d. All correct.

4. An enzyme can accelerate a reaction up to

a. 1010 times b. 101 times c. 10100 times d. 10 times

5. In a metabolic pathway, each step is regulated by

a. an enzyme b. Many enzymes c. a catalyst/ enzyme d. none

6. Adults are intolerant to milk because they are deficient in

a. Lactose b. Protease c. Cellulose d. All of these

7. Lock and Key theory (Template theory) of enzyme action was given by

a. Buchner b. Fischer c. Koshland d. Umberger.

8. Enzymes act by

a. Lowering energy of activation

b. Increasing energy of activation

c. Maintaining energy of activation

d. Without affecting activation energy but increasing reaction time

9. If the prosthetic group/non protein part of an conjugate enzyme (holoenzyme) is removed

then

a. Enzyme becomes inactive b. Activity of enzyme decreases

c. Km constant increases d. Enzyme starts inhibiting the reaction.

10. Mutases and epimerases are

a. Isomerases b. Hydrolases c. Lyases d. ligases.

11. Zymogens are

a. Pro enzymes b. Inactive enzyme precursors c. Both a and b

d. Modulator or hormone.

12. Enzyme kinase requires

a. Mg b. Mn c. K d. Mg + K.

13. Nitrite reeducates forms

a. NH3 b. NO2 c. NO3 d. N2

14. The activity of succinic dehydrogenase is inhibited by

a. Malonate b. Glycolate c. ribosomes d. Fructose 1 - 6 diphosphate

15. Restriction enzymes are

a. To cut DNA at certain places b. To synthesize RNA c. To synthesize RNA

d. To synthesise ATP

16. Poly nucleotide chain can be hydrolyzed by enzymes called

a. Nucleases b.Polymerases c. Proteases d. Ligases

17. Earliest known enzyme was

a. Sucrase b. Zymase c. Diastase d. Urease

18. Sulpha drugs act on the principle of

a. Competitive inhibition b. Allosteric inhibition c. Non-competitive inhibition

d. Feed-back inhibition

19. The protein part of conjugated enzyme is called

a. Holoenzyme b. Conenzyme c. Prosthetic group d. Apoenzyme

20. Enzyme inhibition caused by a product of enzyme catalysed reaction is

a. Competitive inhibition b. Noncompetitive inhibition c. Feed back inhibition

d. Metabolic antagonism

21. Enzymes that catalyse endergonic synthesis coupled with exergonic hydrolysis of ATP are

a. Ligases b. Lyases c. Hydrolases d. Oxidoreductase

22. Which enzyme functions at basic pH of about 9?

a. Pepsin b. Trypsin c. Salivary amylase d. Rennin

23. Substances which bring about changes in allosteric sites are called

a. Activator b. Inhibition c. Promoter d. Modulator

24. The activity of succinate dyhydrogenase is inhibited by

a. Pyruvate b. Glycolate c. Malonate d. Oxaloacetate

25. Enzyme which hydrolysis starch to maltose is

a. Proteose b. Amylase c. Maltase d. Lactase


ANSWERS

1. d 2. a 3. d 4. a 5. a 6. a 7. b 8. a 9. a 10. a

11. c 12. a 13. a 14. a 15. a 16. a 17. c 18. a 19. d 20. c

21. a 22. b 23. d 24. c 25. b