The function of the enzymes in various chemical reactions:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Act as biological catalysts
The reactions of the body take place under very mild conditions of temperature and pH. They are made fast enough by enzymes, which are biological catalysts, mostly globular proteins. Like any catalyst, an enzyme gives the reaction an alternative path of lower activation energy and is not used up; unlike most catalysts, each enzyme is highly specific for one reaction and one substrate (maltase hydrolyses only maltose).
Why the other options are incorrect
Option (1) Increase activation energy — Incorrect. Enzymes do the opposite: they lower the activation energy, which is why the reaction becomes faster.
Option (2) Biochemical enhancers — Incorrect. There is no such term for enzymes.
Option (3) Decreases the rate of reaction — Incorrect. Enzymes speed reactions up, often by a factor of millions; a substance that slows a reaction is an inhibitor.
NCERT (2026-27 edition):
Enzymes
