Enzymes – Online MCQs Test – Biology MCAT

1. Regarding enzyme molecules:

No relation with substrate

Smaller in size than the substrate

Of same size as substrate

Greater in size than the substrate

2. Decarboxylases and Dehydratases, are enzymes included in class:

Lyases

Hydrolases

Ligases

Transferase

3. Class hdyrolases includes:

Phosphatase

Oxidase

Epimerase

Hydroxylase

4. The protein part of enzyme is known as

All of the above

Holoenzyme

lsoenzyme

Apo-enzyme

5. In case of conjugated enzymes the non-protein part is called:

Apoenzyme

Protosthetic group

Holoenzymes

Prosthetic group

6. Co-factors include:

Flavin mononucleotide

Magnesium

Acylglycerol

Phospholipids

7. 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

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

Sidney Altman & Thomas Cech

Friedrich and Thomas Cech

Thomas Cech only

Friedrich Wilhem Kuhne only

9. An enzyme acts by

Reducing the energy of activation

Decreasing the pH

Increasing the energy of activation

Increasing the pH

10. 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

11. Enzyme molecules are:

Both pH and heat sensitive

pH sensitive but not heat sensitive

Heat sensitive but not pH sensitive

neither pH nor heat sensitive

12. Competitive Inhibitor is one which:

Binds close to the active site of an enzyme

Binds away from the active site of an enzyme

Competes for the active site of an enzyme

Normally binds to active site of an enzyme

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

Allosteric Inhibition

Competitive Inhibition

Non-competitive Inhibition

Feed-back Inhibition

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

Ingestion

Assimilation

Digestion

Translocation

15. Temperature range for maximum functioning of enzymes is:

40-65°C

30 — 45°C

15—20°C

20—30°C

16. The charge and shape of the active site is formed by:

Globular shape

Amino acids

Allosteric site

Cofactor

17. A co-enzyme constitutes:

5% portion of half enzyme molecule

90% portion of entire enzyme molecule

1% portion of entire enzyme molecule

1% portion of half enzyme molecule

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

Co-activators

Co-factors

Co-enzymes

Ho a-group

19. Enzymes are basically or all enzymes contain

Vitamins

Sugars

Proteins

Fats

20. Enzyme, Glycosidases is included in class:

Ligases

Lyases

Hydrolases

Transferases

Enzymes-Medical College Admission Test Preparation Notes