In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle. First, however, the pyruvate (1) loses a carbon, which is given off as a molecule of CO₂, (2) is oxidized to form a two-carbon compound called acetate, and (3) is bonded to coenzyme A. Which of the following sets of products result from these reactions?
A) acetyl CoA, O₂, and ATP
B) acetyl CoA, FADH₂, and CO₂
C) acetyl CoA, NADH, and CO₂
D) acetyl CoA, NAD⁺, ATP, and CO₂

Question

Quizplus · Accepted Answer

The products of the reactions described are acetyl CoA, NADH, and CO₂. This is because the pyruvate loses a carbon as CO₂, is oxidized to form acetate, and is bonded to coenzyme A to create acetyl CoA. During these reactions, NAD⁺ is reduced to NADH. FADH₂ is not produced until later in the citric acid cycle, and ATP is not directly produced during this part of the cycle.

In the Presence of Oxygen, the Three-Carbon Compound Pyruvate Can