Enzyme Catalysis and Metabolic Pathways — NEET Biology
📚 Practice ConceptIn the absence of any enzyme this reaction is very slow, with about 200 molecules of H2CO3 being formed in an hour. However, by using the enzyme present within the cytoplasm called carbonic anhydrase, the reaction speeds dramatically with about 600,000 molecules being formed every second. The enzyme has accelerated the reaction rate by about 10 million times. The power of enzymes is incredible indeed! There are thousands of types of enzymes each catalysing a unique chemical or metabolic reaction. A multistep chemical reaction, when each of the steps is catalysed by the same enzyme complex or different enzymes, is called a metabolic pathway. For example,
Assertion (A): Carbonic anhydrase catalyzes the formation of carbonic acid from CO2 and water. Reason (R): Without enzyme catalysis, this reaction produces bicarbonate ions very slowly.
View solution & NCERT explanation
Correct answer: C — If assertion is true but reason is false.
The Assertion is true as NCERT describes carbonic anhydrase catalyzing carbonic acid formation. However, NCERT states “In the absence of any enzyme this reaction is very slow, with about 200 molecules of H2CO3 being formed in an hour” - the Reason incorrectly mentions bicarbonate ions as the direct product instead of carbonic acid (H2CO3).
What does NCERT say about absence any enzyme this?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.