What is the total ATP yield from one glucose molecule under aerobic conditions according to the source material?

• A. 34
• B. 38
• C. 30
• D. 26

Answer: (B)

Total ATP yield from glucose under aerobic conditions is found by adding up all the ATP produced during glycolysis, pyruvate oxidation, and the citric acid cycle, using the convention this source material specifies for how many ATP each NADH and FADH2 generates.

Glycolysis gives 2 ATP directly, plus 2 NADH. If each NADH is worth 3 ATP, that adds 6 ATP from the NADH, bringing glycolysis to 8 ATP total.

Pyruvate oxidation produces 2 NADH, which equals 6 ATP.

In the citric acid cycle per glucose, you get 6 NADH (18 ATP), 2 FADH2 (4 ATP), and 2 GTP (2 ATP). That stage contributes 24 ATP.

Add them up: 8 from glycolysis, 6 from pyruvate oxidation, and 24 from the citric cycle, totaling 38 ATP. Note this is based on the older convention (NADH = 3 ATP, FADH2 = 2 ATP). Some modern counts using different shuttle mechanisms give about 30–32 ATP, but the source material here uses 38.