Question

15) At 60 "C, it is found that the ction of alcohol dehydrogenase is stopped, this could be explained by the fact that the high temperature a) Changes the pH of the system b) Changes the enzyme solubility c) Neutralizes acids and bases in the system d) Increases the concentration of enzymes e) Denaturants the enzyme 16) Cefoperazone is a non-competitive inhibitor of alcohol dehydrogenase. In non-competitive enzyme inhibition the a) Vmax is increased b) Km is increased c) Km is decreasecd d) Km is not affected e) Vmax is not affected For MCQs from 17 to 19: Before racing many marathon runners wil try to increase their glycogen concentration by loading up with foods with high starch content such as pasta. 17) What is the primer required to initiate glycogen synthesis? a) Glucagon b) Glucose c) Glycogenin d) Synthase e) Tyrosine 18) What activates glycogen synthesis? a) Glucagon b) Adrenalin c) Insulin d) cAMP e) Protein kinase A 19) What is the key regulatory enzyme in glycogen synthesis? a) Aldolase b) Glycogen phosphorylase c) Pyruvate kinase d) Glycogen synthase e) Phosphpfractokinase-1 LAT062 Page 5 of 8 Quality and accreditation unit

Answer 1

15) At 60c, it is found that the action of alcohol dehydrogenase is stopped, this could be explained by the fact that the high temperature

e) denatures the enzyme.

The high temperature affects the action of the enzyme and alters the shape of the cells, thereby denatures the enzyme.

16) Cefoperazone is a non-competitive inhibitor of alcohol dehydrogenase. In non-competitive enzyme inhibition the

d) KM is not affected.

This is because the affinity of the enzyme can be measured only by active enzymes and therefore KM is not affected. Non-competitive enzyme inhibition lowers the Vmax. Only the competitive enzyme raises the Km and uncompetitive enzyme inhibition lowers both Vmax and Km.

17). What is the primer required to initiate glycogen synthesis?

c) Glycogenin.

Glycogenin act as a primer for glycogen synthesis in the muscles and the tissues. It emphasizes the polymerization reaction and all molecules begin with the primer glycogenin.

18) Who activates glycogen synthesis?

c) Insulin.

Insulin activates the glycogen synthesis by activating protein phosphate I which stimulates the glycogen synthesis and inhibit the breakdown of glycogen.

19. What is the key regulatory enzyme in glycogen synthesis?

d) Glycogen synthase

Glycogen synthase is the key regulatory enzyme in glycogen synthesis which converts the glucose into glycogen.