The initial substrate molecule for the Krebs cycle is:
A)pyruvic acid
B)acetyl-CoA
C)acetic acid
D)butanediol

Question

Quizplus · Accepted Answer

The initial substrate molecule for the Krebs cycle is acetyl-CoA, which is formed from the breakdown of pyruvate during the transition step. Therefore, choice A (pyruvic acid) is not correct. Acetic acid (choice C) is similar to acetyl-CoA but cannot readily enter the cycle without further modifications. Butanediol (choice D) is not involved in the Krebs cycle at all.

The Initial Substrate Molecule for the Krebs Cycle Is