Question

During pyruvate processing, two carbons from pyruvate combine with ____.

a. co2
b. coenzyme a
c. adp
d. nad+

Answer 1

Two carbons from pyruvate combine with coenzyme A to form acetyl CoA during oxidative decarboxylation, and NAD+ is reduced to NADH.

Step-by-step explanation:

During pyruvate processing, two carbons from pyruvate combine with coenzyme A to form acetyl CoA, which then enters the Krebs cycle. This process is referred to as oxidative decarboxylation where a carboxyl group is released from pyruvate as carbon dioxide, and the remaining two-carbon unit combines with coenzyme A. Alongside this reaction, the enzyme complex pyruvate dehydrogenase also facilitates the transfer of electrons to NAD+, reducing it to NADH, which carries the electrons to later stages of cellular respiration for ATP production.

Answer 2

The correct answer is b: Coenzyme A.

During the process of pyruvate oxidation, acetyl CoA molecule is produced. Pyruvate oxidation is the link between glycolysis and Krebs cycle and it converts pyruvate (three-carbon molecule) into acetyl-CoA ( two-carbon molecule attached to Coenzyme A). NADH is produced and one CO2 released. AcetylCoA is the substrate for the next stage of cellular respiration, citric acid cycle.