Enzymes – Online MCQs Test – Biology MCAT

1. Enzyme is a Greek word which means:

in virus

in fungi

in bacteria

in yeast

2. Enzymes are classified into _________classes:

Five

Three

Six

Four

3. Molecule of ribonucleic acid which function as enzymes are called:

Ribozames

Ribozomes

Ribozymes

Ribosomes

4. Which of the following statements is not correct?

All proteins are enzymes

All enzymes are thermo-labile

All enzymes are biocatalysts

All enzymes are proteins

5. Penicillin blocks the active site of an enzyme that many bacteria use for:

ATP hydrolysis

Synthesis of cell-wall

Cellular respiration

Synthesis of proteins

6. The charge and shape of the active site is formed by:

Amino acids

Cofactor

Allosteric site

Globular shape

7. Regarding nature of enzymes, which one is correct?

Large quantities are required to bring a change in large amount of substrate.

They are specific both in their nature and action.

They are inorganic catalyst.

They are non-specific in their nature but specific in their action.

8. Which one of the following statements regarding enzyme inhibition is correct?

Non-competitive inhibitors often bind to the enzyme irreversibly.

Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein.

Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate

Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme.

9. Magnesium (Mg⁺²) is an inorganic activators for the enzyme:

Esterase

Amylase

Carbonic Anhydrase

Phosphatase

10. Decarboxylases and Dehydratases, are enzymes included in class:

Transferase

Lyases

Ligases

Hydrolases

11. Temperature range for maximum functioning of enzymes is:

30 — 45°C

40-65°C

15—20°C

20—30°C

12. Non-competitive inhibitor is one which:

Competes to the active site of enzyme

Binds close the active site of an enzyme

Binds away from the active site of an enzyme

Normally binds to active site of an enzyme

13. Class hdyrolases includes:

Hydroxylase

Phosphatase

Epimerase

Oxidase

14. Concerning effects of Radiation on enzymes:

generally activated by UV-rays and inactivated by X-rays

generally inactivated by both, UV-rays and X-rays

generally activated by exposure to UV-rays & X-rays

generally inactivated by UV-rays and activated by X-rays

15. Co-enzymes include:

Manganese

Phospholipids

Acylglycerol

Flavin mononucleotide

16. Most vitamins are:

Competitive inhibitors

Co-factors

Co-enzymes

Non-competitive inhibitors

17. Coenzyme can function

Independently of the Apo-enzyme

In association with a protein

In association with a vitamin

In association with an Apo-enzyme

18. Blocking of active site of an enzyme temporarily is a kind of:

Non-competitive inhibition

Non reversible

Competitive inhibition

Feedback inhibition

19. In case of conjugated enzymes the non-protein part is called:

Apoenzyme

Protosthetic group

Prosthetic group

Holoenzymes

20. If the non-protein part is covalently bonded to an enzyme. it is knows as

Prosthetic group

Coenzyme

Apo-enzyme

Activator

Enzymes-Medical College Admission Test Preparation Notes