Question

Which statement is wrong for Krebs cycle?

• A. The cycle starts with condensation of acetyl group (acetyl Co-A) with pyruvic acid to yield citric acid.
• B. There are three points in the cycle where NAD${}^{+}$ is reduced to NADH + H${}^{+}$.
• C. There is one point in the cycle where FAD${}^{+}$ is reduced to FADH${}_2$.
• D. During conversion of succinyl Co-A to succinic acid, a molecule of GTP is synthesised.

Answer 1

Answer: (A)

The cycle starts with condensation of acetyl group (acetyl Co-A) with pyruvic acid to yield citric acid.

Krebs cycle is the reactions that help in converting pyruvic acid to carbon dioxide and water in mitochondria. In the first step, acetyl-CoA undergoes condensation with the oxaloacetic acid to yield citric acid. This reaction is catalyzed by the enzyme citric acid synthetase. Since citric acid is the first intermediate formed in Krebs cycle it is also called citric acid cycle. Thus the correct answer is option A.