Which of the following statements is correct for an enzyme?
(A) It is a biocatalyst.
(B) It can catalyze any chemical reaction.
(C) Almost all enzymes are globular proteins.
(D) They reduce the magnitude of activation energy.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A), (C) and (D) only
Enzymes are biocatalysts: they speed up the reactions in living cells under mild conditions. Almost all of them are globular proteins, and each works on a particular reaction and substrate.
(A) It is a biocatalyst. — Correct. Enzymes are catalysts produced by living cells and needed only in small amounts.
(B) It can catalyze any chemical reaction. — Incorrect. Enzymes are highly specific: each acts on a particular reaction and substrate. Maltase, for example, hydrolyses only maltose into glucose.
(C) Almost all enzymes are globular proteins. — Correct. Their compact, folded shape forms the active site that holds the substrate.
(D) They reduce the magnitude of activation energy. — Correct. Like chemical catalysts, they lower the activation energy; for the hydrolysis of sucrose it falls from 6.22 kJ mol−1 (acid) to 2.15 kJ mol−1 with the enzyme sucrase.
NCERT (2026-27 edition):
Enzymes – “… This occurs with the help of certain biocatalysts called enzymes. Almost all the enzymes are globular proteins. Enzymes are very specific for a particular reaction and for a particular substrate.”
Mechanism of Enzyme Action – “Enzymes are needed only in small quantities for the progress of a reaction. Similar to the action of chemical catalysts, enzymes are said to reduce the magnitude of activation energy.”