The Krebs cycle forms many products. Which option lists the correct products of the Krebs cycle after 1 molecule of glucose goes through it?

Question

A. net 4 NADH, 4 ATP, 8 CO2, 4 FADH2
B. 6 NADH, 2 ATP, 4 CO2 and 2 FADH2
C. net 2 NAD+, 2 ATP, 4 CO2, 2 FADH
D. net 1 NADH, 1 ATP, 2 CO2, 1 FADH2

Answer 1

The correct option for the products of the Krebs cycle (also known as the citric acid cycle or TCA cycle) after one molecule of glucose has gone through glycolysis and then two turns of the Krebs cycle is:

B. 6 NADH, 2 ATP, 4 CO2 and 2 FADH2

Here's the reasoning:

• One molecule of glucose yields two molecules of pyruvate during glycolysis, which translates to two turns of the Krebs cycle.
• Each turn of the Krebs cycle produces:
  • 3 NADH
  • 1 FADH2
  • 1 ATP (or GTP)
  • 2 CO2
• Therefore, for two cycles:
  • NADH: 3 x 2 = 6
  • FADH2: 1 x 2 = 2
  • ATP: 1 x 2 = 2
  • CO2: 2 x 2 = 4

Thus, option B reflects the correct products produced by the Krebs cycle after one glucose molecule is metabolized.