Enzymes – Online MCQs Test – Biology MCAT

1. In non-competitive inhibition, the binding site other than the active site is called:

Prosthetic site

Allo-enzyme site

Prosteric site

Allosteric site

2. Sometimes, the activator functions

Inhibitors

Co-enzymes

Apo-enzymes

Protectors

3. Competitive Inhibitor is one which:

Binds away from the active site of an enzyme

Binds close to the active site of an enzyme

Normally binds to active site of an enzyme

Competes for the active site of an enzyme

4. Zinc (Zn⁺²) is an inorganic activator for the enzyme:

Phosphatas

Carbonic Anhydrase

Esterase

Amylase

5. Which of the following is not an attribute of enzymes?

They speed up the rate of biochemical reactions.

They are used up in reactions.

They are proteinaceous in nature.

They are specific in nature.

6. Enzyme, Glycosidases is included in class:

Hydrolases

Ligases

Transferases

Lyases

7. The pesticides DDT and parathion are inhibitors of key enzymes in the

Respiratory system

Nervous System

Cardivascular System

Digestive System

8. Which statements are correct for all enzymes?

1, 2, 3 and 4

1, 2 and 3 only

1 and 4 only

2 and 4 only

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

Synthesis of cell-wall

Synthesis of proteins

Cellular respiration

ATP hydrolysis

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

Ribozymes

Ribozomes

Ribosomes

Ribozames

11. Enzyme is a Greek word which means:

in fungi

in bacteria

in yeast

in virus

12. Synthetases are enzymes included in class:

Hydrolases

Ligases

Lyases

Transferase

13. At low concentration of substrate the reaction rate is directly proportional to the available.

Coenzyme

Enzyme

Cofactor

Substrate

14. Regarding nature of enzymes, which one of the following is correct?

Simple enzyme consists of protein and non-protein part.

Enzymes are modified lipids.

Conjugated enzyme consists of non-protein part.

Amylase is an enzyme which entirely consists of protein.

15. Regarding factors affecting enzyme activity, which of the following statement is correct?

Rate of reaction decreases with an increase in enzyme concentration until enzyme saturate.

pH has no effect on enzyme activity.

Substrate and enzyme concentration are inversely proportional upto a certain maximum velocity.

Substrate and enzyme concentration are directly proportional upto a certain maximum velocity.

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

Ligases

Lyases

Hydrolases

Transferase

17. The important role play by enzymes during reaction is

Lower down energy of activation of reaction

Increase energy of activation of reaction

no effect on energy of activation of reaction

Maintain energy of activation of reaction

18. Which of the following statements is not correct?

All proteins are enzymes

All enzymes are thermo-labile

All enzymes are proteins

All enzymes are biocatalysts

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

Proteino-enzyme

Proenzyme

Protoenzyme

Apoenzyme

20. Regarding enzyme molecules:

Greater in size than the substrate

No relation with substrate

Of same size as substrate

Smaller in size than the substrate

Enzymes-Medical College Admission Test Preparation Notes