Enzymes – Online MCQs Test – Biology MCAT

1. Enzymes are basically or all enzymes contain

Proteins

Vitamins

Sugars

Fats

2. Enzymes can be denatured at:

High temperature only

High temperature & Low pressure

Low temperature & High pressure

Low pressure only

3. temperature of enzymes present in human body is __________Optimal

47°C

27°C

33°C

37°C

4. Enzyme is a Greek word which means:

in virus

in fungi

in yeast

in bacteria

5. All of the following are correct about enzymes EXCEPT

Enzymes lower the energy of activation

Enzymes are assisted by cofactors

Enzymes are organic catalysts

Enzymes are affected by changes in temperature but not changes in pH

6. Which of the following lacks enzymes?

Viruses

Prokaryotes

Algae

Fungi

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

Carbohydrates

Amino acids

CO₂

Lipases

8. The conversion of complex food into simpler and soluble substances by the action of enzymes is

Assimilation

Digestion

Translocation

Ingestion

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

Amylase

Esterase

Carbonic Anhydrase

Phosphatas

10. In plants enzymes are present

Only in flowers

Only in parenchyma

In all the living cells of paint body

Only in leaves

11. An enzyme acts by

Increasing the pH

Increasing the energy of activation

Reducing the energy of activation

Decreasing the pH

12. Who discovered that certain molecules of ribonucleic acid also function as enzymes?

Friedrich Wilhem Kuhne only

Thomas Cech only

Sidney Altman & Thomas Cech

Friedrich and Thomas Cech

13. Biological control for the regulation of most of the enzyme is provided by:

Feed-back Inhibition

Non-competitive Inhibition

Allosteric Inhibition

Competitive Inhibition

14. Competitive Inhibitor is one which:

Binds away from the active site of an enzyme

Normally binds to active site of an enzyme

Binds close to the active site of an enzyme

Competes for the active site of an enzyme

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

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 the substrate and the inhibitor compete for the active site on the enzyme.

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

16. “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

Non-competitive Inhibition

Competitive Inhibition

Feed-back Inhibition

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

Feedback inhibition

Competitive inhibition

Non-competitive inhibition

None of the above

18. Enzyme, Glycosidases is included in class:

Ligases

Hydrolases

Transferases

Lyases

19. All of the following are correct about enzymes EXCEPT

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

They are assisted by vitamins and minerals

They denature at high temperatures

They are proteins

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

Enzymes-Medical College Admission Test Preparation Notes