Consider the following statements about enzymes.
(A) Almost all the enzymes are globular proteins.
(B) The enzymes which catalyse the oxidation of one substrate with simultaneous reduction of another substrate are named as hydrolase enzymes.
(C) Similar to the action of chemical catalysts, enzymes increase the magnitude of the activation energy.
(D) Enzymes are needed in small quantities for the progress of a reaction.
Which of the statements given above are incorrect? Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (B) and (C) only
Enzymes are biocatalysts. They let the reactions of the body take place under very mild conditions, and like other catalysts they work by lowering the energy barrier of the reaction.
(A) Almost all the enzymes are globular proteins. — Correct statement. Chemically, enzymes are globular proteins.
(B) The enzymes which catalyse the oxidation of one substrate with simultaneous reduction of another substrate are named as hydrolase enzymes. — Incorrect statement. An enzyme can be named after the reaction it catalyses. One that brings about oxidation of one substrate together with reduction of another is named an oxidoreductase, not a hydrolase.
(C) Similar to the action of chemical catalysts, enzymes increase the magnitude of the activation energy. — Incorrect statement. Enzymes reduce the activation energy.
For example, the activation energy for the hydrolysis of sucrose is 6.22 kJ mol−1 with acid but only 2.15 kJ mol−1 with the enzyme sucrase.
(D) Enzymes are needed in small quantities for the progress of a reaction. — Correct statement. Enzymes are needed only in small quantities for a reaction to proceed.
NCERT (2026-27 edition):
10.3 Enzymes – “…Almost all the enzymes are globular proteins.”
“Sometimes enzymes are also named after the reaction, where they are used. For example, the enzymes which catalyse the oxidation of one substrate with simultaneous reduction of another substrate are named as oxidoreductase enzymes.”
10.3.1 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. For example, activation energy for acid hydrolysis of sucrose is 6.22 kJ mol–1, while the activation energy is only 2.15 kJ mol–1 when hydrolysed by the enzyme, sucrase.”