Enzymes – Online MCQs Test – Biology MCAT

Enzymes-Medical College Admission Test Preparation Notes

MCAT Biology Notes from Chapter 7 [Enzymes] for Medical College Entry Test Preparation

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

Substrate

Enzyme

Cofactor

Coenzyme

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

They are inorganic catalyst.

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

They are specific both in their nature and action.

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

3. Fischer in 1898 proposed:

Key-Lock Theory

Catalyst Fit Theory

Enzyme Lock Theory

Induce Fit Theory

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

Holoenzyme

All of the above

Apoenzyme

Coenzyme

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

pH has no effect on enzyme activity.

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

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

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

6. A co-enzyme constitutes:

90% portion of entire enzyme molecule

1% portion of half enzyme molecule

1% portion of entire enzyme molecule

5% portion of half enzyme molecule

7. 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.

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.

Non-competitive inhibitors often bind to the enzyme irreversibly.

8. “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:

Competitive Inhibition

Activation

Non-competitive Inhibition

Feed-back Inhibition

9. Enzymes can be denatured at:

Low temperature & High pressure

Low pressure only

High temperature & Low pressure

High temperature only

10. In plants enzymes are present

Only in leaves

In all the living cells of paint body

Only in parenchyma

Only in flowers

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

Coenzyme

Prosthetic group

Cofactor

Activator

12. The organic prosthetic groups in holoenzymes are called:

Co-factors

Co-enzymes

Co-activators

Holo-group

13. Non-competitive inhibitor is one which:

Binds away from the active site of an enzyme

Competes to the active site of enzyme

Binds close the active site of an enzyme

Normally binds to active site of an enzyme

14. Coenzyme can function

In association with a vitamin

In association with a protein

Independently of the Apo-enzyme

In association with an Apo-enzyme

15. Naturally, most of the enzymes are:

Proteins

Vitamins

Lipids

Carbohydrates

16. Enzyme having different molecular arrangement but similar functions is

HoIo-enzyme

Apo-enzyme

Co-enzyme

Iso-enzyme

17. Which of the following statements is not correct?

All enzymes are proteins

All proteins are enzymes

All enzymes are biocatalysts

All enzymes are thermo-labile

18. When an enzyme-induced product inhibits enzymatic activity, inhibition is called

Feedback inhibition

Competitive inhibition

Non-competitive inhibition

None of the above

19. Enzyme hydroxylase is included in class:

Lyases

Hydrolases

Transferases

Oxidoreductases

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

Ribosomes

Ribozymes

Ribozames

Ribozomes

Online MCQs Test preparation for Biology MCAT (Medical College Admission Test Preparation Notes) helps students practice effectively. These multiple-choice questions are taken from Chapter 7 “Enzymes” of the Biology MCAT textbook.

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