NEET Biology: Biochemistry questions with solutions

Q1. Who proposed cAMP mediated 'Cascade model' of enzyme regulation?

1. Fischer
2. Sutherland
3. Sumner
4. Koshland

Answer: Sutherland

Earl Sutherland proposed the cAMP-mediated cascade model of enzyme regulation. He showed that cAMP acts as a second messenger in signal transduction, amplifying hormonal effects inside cells.

Q2. Assertion Coenzymes can be vitamins or minerals. Reason NAD is an example of a coenzyme.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
3. Assertion is correct but Reason is incorrect.
4. Assertion is incorrect but Reason is correct.

Answer: Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.

The assertion is correct because coenzymes are organic non-protein helpers, and many are derived from vitamins; minerals are generally cofactors, not coenzymes. The reason is also correct because NAD is a coenzyme, but it does not explain the assertion about vitamins or minerals.