ENZYMES

Question 1

Two constants are always measured whenever an enzyme is characterized. These are:

a. K1 and Km
b. Km and Vmax
c. Q10 and Vo
d. Vmax and Q10
e. Vo and K1

Answer 1

b. Km and Vmax

Question 2

Group of enzymes that catalyze the addition or removal of water, ammonia or carbon dioxide to double bonds:

a. hydrolases
b. isomerases
c. ligases
d. lyases
e. oxidoreductases

Answer 2

d. lyases

Question 3

Nonfunctional serum enzyme that is diagnostic of obstructive liver diseases.
A. acid phosphatase
B. alanine aminotransferase
C. alkaline phosphatase
D. aspartate aminotransferase
E. ceruloplasmin

Answer 3

C. alkaline phosphatase

Question 4

Carbonic anhydrase requires which metal ion as cofactor

a. iron
b. zinc
c. magnesium
d. copper
e. sodium,

Answer 4

b. zinc

Question 5

In the effects of substrate concentration on reaction velocity, when substrate concentration is low

a. the reaction velocity is zero order
b. the reaction velocity is first-order
c. the reaction velocity is second order
d. the reaction velocity is mixed order

Answer 5

b. the reaction velocity is first-order

Question 6

Which of the following is the target enzyme of an anti inflammatory drug, aspirin?

a. xanthine oxidase
b. transpeptidase
c. HMG CoA reductase
d. Cyclooxygenase
e. Monoamine oxidase

Answer 6

d. Cyclooxygenase

Question 7

Effect of uncompetitive inhibitors to the Maximum velocity (Vmax) and Michaelis constant (Km)

a. Vmax - none : Km – increases
b. Vmax – decreases : Km – decreases
c. Vmax – decreases : Km - none
d. Vmax – decreases : Km- increases
e. Vmax – increase : Km – none

Answer 7

b. Vmax – decreases : Km – decreases

Question 8

The quantitative value of the Michaelis constant or Km, is a measure of

a. the optimum condition present in the cell
b. relative affinity between the substrate and enzyme
c. the velocity of the biochemical reaction
d. the concentration of the enzyme present

Answer 8

b. relative affinity between the substrate and enzyme

Question 9

This enzyme is valuable in the diagnosis of metastatic carcinoma of the prostate gland.

a. ceruloplasmin
b. alkaline phosphatase
c. lactate dehydogenase
d. acid phosphatase
e. aspartate aminotransferase

Answer 9

d. acid phosphatase

Question 10

A group of enzymes that join two molecules along with breakdown of a pyrophosphate (P-P) bond

a. ligase
b. isomerase
c. lyase
d. transferase

Answer 10

a. ligase