MCQs on Enzyme for NMDCAT 2021

[MCQ]

Enzymes are the biological polymers accelerating a biochemical reaction. Initially, enzymes react with molecules known as substrates converting it into distinct molecules known as products. They exist in all fluids and tissues of the body. The intracellular enzymes catalyze reactions taking place in metabolic pathways.

The nature of an enzyme is

(a) Lipid
(b) Vitamin
(c) Carbohydrate
(d) Protein

Answer: (d)

[MCQ]

In alcoholism, this enzyme is elevated

(a) acid phosphatase
(b) hepatitis
(c) serum glutamate pyruvate transaminase
(d) glutamyl transpeptidase

Answer: (d)

[MCQ]

With regards to enzyme action, this statement is incorrect

(a) Malonate is a competitive inhibitor of succinic dehydrogenase
(b) the substrate binds with the enzyme at its active site
(c) the non-competitve inhibitor binds the enzyme at a site distinct from that binding the substrate
(d) addition of a lot of succinates does not reverse the inhibition of succinic dehydrogenase by malonate

Answer: (d)

[MCQ]

What is the count of genes that determine the synthesis of one enzyme?

(a) One
(b) Four
(c) Eight
(d) Sixteen

Answer: (a)

[MCQ]

This enzyme was first isolated and purified in the form of crystals

(a) Urease
(b) pepsin
(c) Amylase
(d) Ribonuclease

Answer: (a)

[MCQ]

Macromolecule chitin is

(a) a simple polysaccharide
(b) sulphur containing polysaccharide
(c) phosphorous containing polysaccharide
(d) nitrogen containing polysaccharide

Answer: (d)

[MCQ]

Enzyme-driven metabolic pathways can be made more efficient by

(a) grouping enzymes into multienzyme free-floating complexes
(b) concentrating enzymes with specific cellular compartments
(c) fixing enzymes into membranes so they are adjacent to each other
(d) all of these

Answer: (d)

[MCQ]

Tryptophan synthetase of E.coli, a typical bifunctional oligomeric enzyme consists of

(a) a protein A and one subunit A
(b) a protein designated A
(c) two proteins designated A and B
(d) a protein designated B

Answer: (c)

[MCQ]

This statement about enzymes is true

(a) enzymes accelerate reactions by lowering the activation energy
(b) enzymes are proteins whose three-dimensional form is key to their function
(c) enzymes do not alter the overall change in free energy for a reaction
(d) all of these

Answer: (d)

[MCQ]

The enzyme COX-1 is vital for human health in this way:

(a) it is a chemical derivative of aspirin
(b) catalyzes the hormone-production which maintains the stomach lining
(c) critical for the biosynthesis of DNA
(d) helps in the transportation of carbon dioxide in the blood

Answer: (b)

[Zamzam]

The general mechanism is that an enzyme acts by

A	reducing the energy of activation
B	increasing the energy of activation
C	decreasing the pH
D	increasing the pH

Answer: (a)

[Zamzam]

The coenzyme is

A	often a metal
B	always a protein
C	often a vitamin
D	always an inorganic compound

Answer: (c)

[Zamzam]

An enzyme that joins the ends of two strands of nucleic acid is

A	polymerase
B	ligase
C	synthetase
D	helicase

Answer: (b)

[Zamzam]

Which of the following is produced with the combination of apoenzyme and coenzyme?

A	Holoenzyme
B	Enzyme substrate complex
C	Prosthetic group
D	Enzyme product complex

Answer: (a)

[Zamzam]

An example of competitive inhibition of an enzyme is the inhibition of

A	succinic dehydrogenase by malonic acid
B	cytochrome oxidase by cyanide
C	hexokinase by glucose-6-phosphate
D	carbonic anhydrase by carbon dioxide

Answer: (a)