Enzymes – Online MCQs Test – Biology MCAT

1. Enzyme hydroxylase is included in class:

Lyases

Transferases

Hydrolases

Oxidoreductases

2. 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

3. Co-enzymes include:

Acylglycerol

Flavin mononucleotide

Manganese

Phospholipids

4. Co-factors include:

Phospholipids

Flavin mononucleotide

Magnesium

Acylglycerol

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

Phosphatase

Esterase

Amylase

Carbonic Anhydrase

6. The important role play by enzymes during reaction is

Increase energy of activation of reaction

no effect on energy of activation of reaction

Maintain energy of activation of reaction

Lower down energy of activation of reaction

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

Hydrolases

Ligases

Lyases

Transferase

8. Non-competitive inhibitor is one which:

Normally binds to active site of an enzyme

Binds close the active site of an enzyme

Competes to the active site of enzyme

Binds away from the active site of an enzyme

9. Most vitamins are:

Non-competitive inhibitors

Co-enzymes

Competitive inhibitors

Co-factors

10. Enzymes are useful to plants because.

They are building blocks of chlorophyll.

They are essential for the metabolic processes

They are used up in reactions.

They enhance absorption of water and salts.

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

Feedback inhibition

Non-competitive inhibition

Competitive inhibition

None of the above

12. Enzymes are classified into _________classes:

Six

Three

Four

Five

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

Inhibitors

Apo-enzymes

Co-enzymes

Activators

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

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

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

pH has no effect on enzyme activity.

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

15. Enzyme is a Greek word which means:

in bacteria

in virus

in fungi

in yeast

16. Enzymes are basically or all enzymes contain

Proteins

Vitamins

Fats

Sugars

17. Any factor that can alter the chemistry an shape of an enzyme can affect us rate of.

Hydrolysis

Catalysis

Photolysis

Activity

18. Concerning enzyme activity at O°C, which of the following statement is correct?

Activity is reduced to minimum but enzymes are not destroyed.

Activity is reduced to minimum but enzymes are destroyed.

Activity is increased to maximum but enzymes are destroyed.

Activity is increased to maximum but enzymes are not destroyed.

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

Apoenzyme

Prosthetic group

Protosthetic group

Holoenzymes

20. 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

Quaternary

Tertiary

Primary

Enzymes-Medical College Admission Test Preparation Notes