NEETBotanyBiomolecules (B)
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Malonate inhibits the catalytic activity of the enzyme succinic dehydrogenase. Reason (R): Malonate closely resembles the substrate succinate in its molecular structure. In the light of the above statements, choose the correct answer from the options given below.
Options
- ABoth (A) and (R) are true but (R) is not the correct explanation of (A)
- BBoth (A) and (R) are true and (R) is the correct explanation of (A)
- C(A) is true but (R) is false
- D(A) is false but (R) is true
Correct answer
B. Both (A) and (R) are true and (R) is the correct explanation of (A)
Step-by-step solution
Assertion (A) is true because malonate acts as a competitive inhibitor of the enzyme succinic dehydrogenase. Reason (R) is also true and is the correct explanation for (A). In competitive inhibition, the inhibitor closely resembles the substrate in its molecular structure and competes with the substrate for the substrate-binding site of the enzyme. Because malonate structurally resembles succinate, it is able to bind to the active site of succinic dehydrogenase, thereby inhibiting its catalytic activity. Answer: Bo