MCQ- Questions on Enzymes

MCQ- Questions on Enzymes

MCQ- Questions on Enzymes

Q.1- Glycogen phosphorylase, which mobilizes glycogen for energy, requires which of the followings as a cofactor?

a)Pyridoxal phosphate

b)Tetra hydro folate

c)Adenosyl Cobalamine

d)Coenzyme A

Q.2-Choose the incorrect statement about Active Site of an enzyme-

a) The active site is a three-dimensional cleft

b) The active site takes up a large part of the total volume of an enzyme

c) Substrates are bound to enzymes by multiple weakattractions

d) The specificity of binding depends on theprecisely defined arrangement of atoms in an active site.

Q.3- Any of the following processes except one are involved at the active site of an enzyme to accelerate the rate of reaction-

a) Catalysis by BondStrain

b) Catalysis byProximity and Orientation

c) Non covalentcatalysis

d) Acid basecatalysis

Q.4-A given substrate may be acted upon by a number of different enzymes, each of which uses the same substrate(s) and produces the same product(s). The individual members of a set of enzymes sharing such characteristics are known as-

a)Group specific enzymes


c)Substrate specific enzymes

d)Allosteric enzymes

Q.5-Which statement out of the followings is incorrect about the effect of increasing temperature on enzyme activity-

a)Raising the temperature increases the kinetic energy of molecules

b) Aten degree Centigrade rise in temperature will increase the activity of mostenzymes by 50 to 100%.

c)Most animal enzymes rapidly become denatured at temperatures above 40oC

d)Storage of enzymes at 5°C or below is generally not suitable.

Q.6-A coal mine worker was brought in an unconscious state to emergency room aftera blast in the mine. His blood Carboxy hemoglobin level was high and he wasdiagnosed with CO poisoning. CO is aknown inhibitor of electron transport chain. Which complex of electrontransport chain is inhibited by CO?

a)Complex I

b)Complex II

c)Complex III

d)Complex IV

Q.7-A 42-year-old obese female presented to theemergency center with complaints of worsening nausea, vomiting, and abdominal pain.Her pain was located in the midepigastric area and right upper quadrant. Blood biochemistry revealed high serum amylase level.What is the probable diagnosis for this patient?

a)Viral hepatitis

b)Acute Pancreatitis

c)Renal colic

d)Acute gastritis

Q.8-A 2 -week –old child was brought to the emergency. The parents were fearful that the child had been given some poisonas they noted black discoloration on the diaper. Adiagnosis of Alkaptonuria was made and the child was given Vitamin C as asupplement. Alkaptonuria occurs due to reduced activity of Homogentisic acid oxidaseenzyme. What is the role played by vitamin C in this defect?

a)Acts as an oxidant

b)Acts as a coenzyme

c)Acts as an inducer

d)Acts as a positive allosteric modifier

Q.9-One out of the following enzymes has absolute specificity for its substrate; choose thecorrect option-
a) Urease
b) Carboxy peptidase
c) Pancreatic lipase


Q.10-Which out of the followings is a substrate-specific enzyme?
a) Hexokinase

c) Lactase


Q.11-Which out of thefollowings is not a substrate-specific enzyme?

c) Hexokinase


Q.12-Group I Co-enzymes participate in which of the followingreactions-

a) Oxidation-reduction
c) Phosphorylation
d) All of the above

Q.13-Which out of thefollowing co enzymes takes part in hydrogen transfer reactions in the electron transport chain-

a) Tetrahydrofolate
b) Methyl Cobalamine

c)Co enzyme Q
d) Biotin

Q.14.The conversion of Pyruvate to oxaloacetate involves the participation of a co-enzyme?

a) NAD+
c) Biotin
d) All of the above

Q.15.The nucleophile in serine proteases is
A. / Serine
B. / water
C. / both (a) and (b)
D. / Asparagine
Q.16.How is the enzyme COX-1 important in human health?
A. / It helps to transport carbon dioxide in the blood
B. / It is critical for the biosynthesis of DNA
C. / It is a chemical derivative of aspirin
D. / It catalyzes the production of hormones that maintain the stomach lining
Q.17.Complex enzymes (consisting of more than one part) are known as:
  1. Apoenzymes
  2. Globular Enzymes
  3. Prosthetic Enzymes
  4. Holoenzymes

Q.18. The protein component of complex enzymes is known as the:

A) Cofactor

B) Holoenzyme

C) Apoenzyme

D) Coenzyme

Q19.What attaches to an enzyme in order to activate it, and then de-attaches to deactivate it?

A) Cofactors

B) Competitive inhibitors

C) Co-enzymes

D) Prosthetic groups

Q.20. As product builds up, enzyme reactions slows down. This is known as:

A)Feedback inhibition

B)Endpoint inhibition

C) Negative allosterism

D) Allosterism