Enzymes – Online MCQs Test – Biology MCAT

1. Enzyme molecules are:

neither pH nor heat sensitive

Both pH and heat sensitive

Heat sensitive but not pH sensitive

pH sensitive but not heat sensitive

2. Co-enzymes include:

Manganese

Phospholipids

Acylglycerol

Flavin mononucleotide

3. “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:

Non-competitive Inhibition

Competitive Inhibition

Feed-back Inhibition

Activation

4. Enzymes function because of their particular shape or conformation. Which level of protein structure is most directly responsible for the shape of a protein?

Secondary

Primary

Tertiary

Quaternary

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

Thomas Cech only

Sidney Altman & Thomas Cech

Friedrich and Thomas Cech

Friedrich Wilhem Kuhne only

6. If the non-protein part is covalently bonded to an enzyme. it is knows as

Activator

Prosthetic group

Coenzyme

Apo-enzyme

7. A conjugate enzyme having both protein part and non-protein part is called

Holo-enzyme

Apo-enzyme

Co-enzyme

Activator

8. Fischer in 1898 proposed:

Key-Lock Theory

Induce Fit Theory

Enzyme Lock Theory

Catalyst Fit Theory

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

Transferase

Ligases

Hydrolases

Lyases

10. Magnesium (Mg⁺²) is an inorganic activators for the enzyme:

Phosphatase

Amylase

Esterase

Carbonic Anhydrase

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

Co-enzymes

Inhibitors

Activators

Apo-enzymes

12. 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.

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.

Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate

13. Most vitamins are:

Co-enzymes

Competitive inhibitors

Non-competitive inhibitors

Co-factors

14. All of the following are correct about enzymes EXCEPT

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

They are proteins

They denature at high temperatures

They are assisted by vitamins and minerals

15. Coenzyme can function

In association with a vitamin

In association with an Apo-enzyme

In association with a protein

Independently of the Apo-enzyme

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

Co-activators

Co-enzymes

Ho a-group

Co-factors

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

Amino acids

Cofactor

Allosteric site

Globular shape

18. Enzyme, Glycosidases is included in class:

Transferases

Lyases

Ligases

Hydrolases

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

Allosteric Inhibitor

Non-competitive Inhibitor

Allosteric Activator

Competitive Inhibitor

20. Non-competitive inhibitor is one which:

Binds away from the active site of an enzyme

Binds close the active site of an enzyme

Competes to the active site of enzyme

Normally binds to active site of an enzyme

Enzymes-Medical College Admission Test Preparation Notes