Enzymes – Online MCQs Test – Biology MCAT

1. Enzymes can:

React with acidic substances only as they are proteins.

React with alkaline substances only as they are proteins.

No react with acidic and alkaline substances as they are proteins.

React with acidic and alkaline substances both.

2. Co-enzymes include:

Acylglycerol

Phospholipids

Manganese

Flavin mononucleotide

3. Enzymes are useful to plants because.

They are building blocks of chlorophyll.

They are essential for the metabolic processes

They are used up in reactions.

They enhance absorption of water and salts.

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

Non reversible

Competitive inhibition

Feedback inhibition

Non-competitive inhibition

5. A cofactor made of inorganic ion which is detachable is called

Cofactor

Activator

Prosthetic group

Coenzyme

6. In plants enzymes are present

Only in parenchyma

Only in flowers

Only in leaves

In all the living cells of paint body

7. A conjugate enzyme having both protein part and non-protein part is called

Activator

Co-enzyme

Holo-enzyme

Apo-enzyme

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

Nervous System

Digestive System

Respiratory system

Cardivascular System

9. Enzymes function because of their particular shape or conformation. Which level of protein structure is most directly responsible for the shape of a protein?

Secondary

Tertiary

Primary

Quaternary

10. temperature of enzymes present in human body is __________Optimal

47°C

27°C

37°C

33°C

11. An enzyme can be synthesized by chemical bonding together molecules of

Amino acids

CO₂

Carbohydrates

Lipases

12. Enzyme, Glycosidases is included in class:

Hydrolases

Transferases

Lyases

Ligases

13. A co-enzyme constitutes:

5% portion of half enzyme molecule

1% portion of half enzyme molecule

1% portion of entire enzyme molecule

90% portion of entire enzyme molecule

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

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

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

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

Non-competitive inhibitors often bind to the enzyme irreversibly.

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

Substrate

Enzyme

Coenzyme

Cofactor

16. Enzyme molecules are:

Heat sensitive but not pH sensitive

pH sensitive but not heat sensitive

Both pH and heat sensitive

neither pH nor heat sensitive

17. Competitive Inhibitor is one which:

Normally binds to active site of an enzyme

Binds away from the active site of an enzyme

Competes for the active site of an enzyme

Binds close to the active site of an enzyme

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

They are specific both in their nature and action.

They are inorganic catalyst.

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

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

19. Which statements are correct for all enzymes?

2 and 4 only

1, 2, 3 and 4

1, 2 and 3 only

1 and 4 only

20. Sometimes, the activator functions

Inhibitors

Protectors

Apo-enzymes

Co-enzymes

Enzymes-Medical College Admission Test Preparation Notes