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. Enzyme having different molecular arrangement but similar functions is

HoIo-enzyme

Co-enzyme

Apo-enzyme

Iso-enzyme

2. The important role play by enzymes during reaction is

no effect on energy of activation of reaction

Lower down energy of activation of reaction

Increase energy of activation of reaction

Maintain energy of activation of reaction

3. Which of the following statements is not correct?

All enzymes are proteins

All enzymes are thermo-labile

All proteins are enzymes

All enzymes are biocatalysts

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

Non reversible

Competitive inhibition

Feedback inhibition

Non-competitive inhibition

5. All of the following are correct about enzymes EXCEPT

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

They denature at high temperatures

They are assisted by vitamins and minerals

They are proteins

6. 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.

7. Concerning temperature affecting enzyme activity, which of the following statement is correct?

Most enzymes are highly active at 37°C

Enzymes are temperature-resistant

Enzymes are completely destroyed at 50°C

Most enzymes are highly active at 50°C

8. Koshland in 1959 proposed:

Key-Lock Theory

Enzyme Lock Theory

Induce Fit Theory

Catalyst Fit Theory

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

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.

They are inorganic catalyst.

They are specific both in their nature and action.

10. Non-competitive inhibitor is one which:

Competes to the active site of enzyme

Binds away from the active site of an enzyme

Binds close the active site of an enzyme

Normally binds to active site of an enzyme

11. Substances which decrease the activity of enzyme are called:

Inhibitors

Activators

Apo-enzymes

Co-enzymes

12. Enzymes are basically or all enzymes contain

Sugars

Fats

Vitamins

Proteins

13. Molecule binds to the active site of an enzyme is:

Allosteric Inhibitor

Competitive Inhibitor

Allosteric Activator

Non-competitive Inhibitor

14. 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 destroyed.

Activity is reduced to minimum but enzymes are not destroyed.

15. Which statements are correct for all enzymes?

2 and 4 only

1, 2, 3 and 4

1 and 4 only

1, 2 and 3 only

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

Carbonic Anhydrase

Esterase

Phosphatas

Amylase

17. Fischer in 1898 proposed:

Catalyst Fit Theory

Key-Lock Theory

Induce Fit Theory

Enzyme Lock Theory

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

Prosthetic site

Allo-enzyme site

Prosteric site

Allosteric site

19. The organic prosthetic groups in holoenzymes are called:

Co-factors

Holo-group

Co-activators

Co-enzymes

20. Enzymes are useful to plants because.

They are essential for the metabolic processes

They are used up in reactions.

They enhance absorption of water and salts.

They are building blocks of chlorophyll.

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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