Enzymes – Online MCQs Test – Biology MCAT

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

Tertiary

Secondary

Primary

Quaternary

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

Competitive inhibition

Non reversible

Non-competitive inhibition

Feedback inhibition

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

Holo-enzyme

Activator

Co-enzyme

Apo-enzyme

4. temperature of enzymes present in human body is __________Optimal

37°C

33°C

47°C

27°C

5. Coenzyme can function

In association with a protein

In association with a vitamin

Independently of the Apo-enzyme

In association with an Apo-enzyme

6. Class hdyrolases includes:

Oxidase

Epimerase

Phosphatase

Hydroxylase

7. Sometimes, the activator functions

Apo-enzymes

Co-enzymes

Inhibitors

Protectors

8. Concerning enzyme activity at O°C, which of the following statement is correct?

Activity is increased to maximum but enzymes are not destroyed.

Activity is increased to maximum but enzymes are destroyed.

Activity is reduced to minimum but enzymes are not destroyed.

Activity is reduced to minimum but enzymes are destroyed.

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

Cardivascular System

Nervous System

Digestive System

Respiratory system

10. “When the product is in abundance, it binds competitively with enzyme’s active site, as the product is used up, more product can be produced”, this is an example of:

Activation

Feed-back Inhibition

Competitive Inhibition

Non-competitive Inhibition

11. The inorganic ions which act as a prosthetic group in holoenzymes are called:

Co-factors

Ho a-group

Co-enzymes

Co-activators

12. Enzymes Oxidases and Peroxidases are included in class:

Oxidoreductases

Hydrolases

Transferases

Lyases

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

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.

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

14. Temperature range for maximum functioning of enzymes is:

15—20°C

40-65°C

30 — 45°C

20—30°C

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

They are specific in nature.

They are proteinaceous in nature.

They are used up in reactions.

They speed up the rate of biochemical reactions.

16. In plants enzymes are present

Only in flowers

In all the living cells of paint body

Only in leaves

Only in parenchyma

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

Enzymes are modified lipids.

Simple enzyme consists of protein and non-protein part.

Amylase is an enzyme which entirely consists of protein.

Conjugated enzyme consists of non-protein part.

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

Carbonic Anhydrase

Esterase

Phosphatas

Amylase

19. An enzyme acts by

Increasing the energy of activation

Increasing the pH

Reducing the energy of activation

Decreasing the pH

20. The prosthetic group (metallic cofactor) of various respiratory enzymes is

Enzymes-Medical College Admission Test Preparation Notes