Enzymes are biological catalysts that are: MCQ with Answer and Explanation

Enzymes are biological catalysts that are:
A. Mostly carbohydrates
B. Mostly lipids
C. Mostly nucleic acids
D. Mostly proteins
Answer: Option D
Solution (By JKExamLibrary)
Enzymes are complex organic molecules that act as biological catalysts in living organisms. Chemically, most enzymes are globular proteins. They are highly specific to their substrates and work optimally at body temperature and near-neutral pH, unlike many industrial catalysts that require extreme conditions.

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Practice More chemistry Questions

Question #1
Assertion (A): A catalyst does not change the equilibrium yield of a reaction. Reason (R): A catalyst speeds up both the forward and backward reactions equally.
A. A is true but R is false.
B. Both A and R are true and R is the correct explanation of A.
C. A is false but R is true.
D. Both A and R are true but R is NOT the correct explanation of A.

Correct Answer: Option B


Explanation:
A catalyst lowers the activation energy for both the forward and reverse reactions by the same amount. Therefore, it increases the rates of both reactions equally, allowing the system to reach equilibrium faster, but without changing the final equilibrium concentrations (yield). Both statements are correct and R explains A.

This question belongs to: Science chemistry
Question #2
Which of the following pairs represents isobars?
A. Argon-40 and Calcium-40
B. Chlorine-35 and Chlorine-37
C. Hydrogen and Deuterium
D. Carbon-12 and Carbon-14

Correct Answer: Option A


Explanation:
Isobars are atoms of different elements with the same mass number but different atomic numbers. Argon (Z=18) and Calcium (Z=20) both have a mass number of 40, making them isobars. Options A, B, and D are isotopes, as they represent the same element with different mass numbers.

This question belongs to: Science chemistry
Question #3
Sulphuric acid is known as:
A. Aqua fortis
B. Oil of vitriol
C. Muriatic acid
D. Carbolic acid

Correct Answer: Option B


Explanation:
Sulphuric acid (H₂SO₄) was historically called oil of vitriol. Hydrochloric acid was muriatic acid, nitric acid was aqua fortis, carbolic acid is phenol.

This question belongs to: Science chemistry