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. Penicillin blocks the active site of an enzyme that many bacteria use for:

Synthesis of proteins

Synthesis of cell-wall

ATP hydrolysis

Cellular respiration

2. Which statements are correct for all enzymes?

1, 2, 3 and 4

2 and 4 only

1, 2 and 3 only

1 and 4 only

3. Regarding nature of enzymes, which one of the following is correct?

Amylase is an enzyme which entirely consists of protein.

Simple enzyme consists of protein and non-protein part.

Conjugated enzyme consists of non-protein part.

Enzymes are modified lipids.

4. Koshland in 1959 proposed:

Catalyst Fit Theory

Key-Lock Theory

Induce Fit Theory

Enzyme Lock Theory

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

Friedrich and Thomas Cech

Friedrich Wilhem Kuhne only

Thomas Cech only

Sidney Altman & Thomas Cech

6. All of the following are correct about enzymes EXCEPT

They are assisted by vitamins and minerals

They are proteins

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

They denature at high temperatures

7. Enzymes can:

No react with acidic and alkaline substances as they are proteins.

React with acidic substances only as they are proteins.

React with acidic and alkaline substances both.

React with alkaline substances only as they are proteins.

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

Competitive inhibition

Non-competitive inhibition

None of the above

Feedback inhibition

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

Ligases

Lyases

Hydrolases

Transferase

10. Non-protein part of an enzyme is Known as

Apoenzyme

All of the above

Coenzyme

Holoenzyme

11. Enzyme molecules are:

Heat sensitive but not pH sensitive

neither pH nor heat sensitive

pH sensitive but not heat sensitive

Both pH and heat sensitive

12. Fischer in 1898 proposed:

Enzyme Lock Theory

Key-Lock Theory

Induce Fit Theory

Catalyst Fit Theory

13. Enzymes which alters the structure but not the atomic composition of substrate by moving a group from one position to another is one molecule are included in class:

Isomerases

Hydrolases

Transferase

Lyases

14. Synthetases are enzymes included in class:

Transferase

Hydrolases

Ligases

Lyases

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

Globular shape

Allosteric site

Amino acids

Cofactor

16. Which of the following is not an attribute of enzymes?

They are proteinaceous in nature.

They are used up in reactions.

They speed up the rate of biochemical reactions.

They are specific in nature.

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

18. If enzyme concentration is low than substrate, pH and temperature values are equal to requirement then which of the following will increase rate of reaction.

Increase in concentration of substrate

Increase in concentration of enzyme

Increase in temperature

Increase in pH

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

pH has no effect on enzyme activity.

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

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

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

20. Vitamins are essential for the body because:

Co enzyme of enzyme is synthesized from them

Prosthetic groups of enzymes are synthesized from them

Some activators have direct link with them

They are part of some enzyme

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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