Enzymes – Online MCQs Test – Biology MCAT

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

Apoenzyme

Proenzyme

Protoenzyme

Proteino-enzyme

2. Non-protein part of an enzyme is Known as

Coenzyme

Apoenzyme

Holoenzyme

All of the above

3. Class hdyrolases includes:

Phosphatase

Oxidase

Epimerase

Hydroxylase

4. Synthetases are enzymes included in class:

Hydrolases

Ligases

Lyases

Transferase

5. temperature of enzymes present in human body is __________Optimal

33°C

27°C

37°C

47°C

6. Fischer in 1898 proposed:

Key-Lock Theory

Catalyst Fit Theory

Enzyme Lock Theory

Induce Fit Theory

7. Most vitamins are:

Competitive inhibitors

Co-factors

Non-competitive inhibitors

Co-enzymes

8. Concerning effects of Radiation on enzymes:

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

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

9. Vitamins are essential for the body because:

Co enzyme of enzyme is synthesized from them

Prosthetic groups of enzymes are synthesized from them

They are part of some enzyme

Some activators have direct link with them

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

Coenzyme

Cofactor

Substrate

Enzyme

11. A co-enzyme constitutes:

5% portion of half enzyme molecule

90% portion of entire enzyme molecule

1% portion of half enzyme molecule

1% portion of entire enzyme molecule

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

13. Enzymes are useful to plants because.

They enhance absorption of water and salts.

They are building blocks of chlorophyll.

They are essential for the metabolic processes

They are used up in reactions.

14. Which of the following lacks enzymes?

Fungi

Viruses

Prokaryotes

Algae

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

Ho a-group

Co-factors

Co-activators

Co-enzymes

16. Enzyme having different molecular arrangement but similar functions is

Iso-enzyme

Apo-enzyme

HoIo-enzyme

Co-enzyme

17. All of the following are correct about enzymes EXCEPT

They denature at high temperatures

They are assisted by vitamins and minerals

They are proteins

The mechanism by which enzymes work is known as lock and key

18. If enzyme concentration is low than substrate, pH and temperature values are equal to requirement then which of the following will increase rate of reaction.

Increase in concentration of enzyme

Increase in temperature

Increase in pH

Increase in concentration of substrate

19. Regarding enzyme molecules:

Of same size as substrate

Greater in size than the substrate

Smaller in size than the substrate

No relation with substrate

20. Which of the following statements is not correct?

All enzymes are thermo-labile

All enzymes are proteins

All enzymes are biocatalysts

All proteins are enzymes

Enzymes-Medical College Admission Test Preparation Notes