question_answer

Which of the following is not an intermediate in Krebs cycle?

A)                  Acetic acid                         

B)                  Succinyl Coenzyme - A

C)                  Malic acid

D)                  Citric acid

Correct Answer: A

Solution :

                 Acetic acid is not involved in Krebs cycle.                 In Krebs cycle oxaloacetate is the acceptor molecule. It is a 4-carbon dicarboxylic acid. Substrate extract of Krebs cycle is acetyl Co-A. The first product is 6 carbon chemical called Citric acid and the first dicarboxylic 5 carbon compound is a-ketoglutaric acid, conversion of succinyl Co-A to succinate releases ATP.