Question

What are the products of one turn of the Krebs cycle?

A. 1 CO2, 2 NADH, 1 FADH2, 1 ATP
B. 2 CO2, 3 NADH, 1 FADH2, 1 ATP
C. 2 CO2, 6 NADH, 2 FADH2, 2 ATP
D. 4 CO2, 6 NADH, 2 FADH2, 2 ATP

Answer 1

The products of one turn of the Krebs cycle are 2 CO2, 3 NADH, 1 FADH2, and 1 ATP (or GTP). Option B is the correct answer. Two turns of the Krebs cycle are required to process a single glucose molecule.

Step-by-step explanation:

The Krebs cycle, also known as the citric acid cycle, is a key part of cellular respiration that operates in the presence of oxygen. During one turn of the Krebs cycle, the products generated are:

• 2 molecules of CO2
• 3 molecules of NADH
• 1 molecule of FADH2
• 1 molecule of ATP or GTP (the equivalent of ATP)

This means that the correct answer to the question is option B: 2 CO2, 3 NADH, 1 FADH2, 1 ATP. Two turns of the Krebs cycle are needed to process one molecule of glucose, because each glucose molecule is split into two pyruvate molecules during glycolysis, which are then converted into two molecules of acetyl CoA. Each acetyl CoA enters the Krebs cycle separately, resulting in a total of 4 CO2, 6 NADH, 2 FADH2, and 2 ATP (or GTP) after two complete turns.