Question

What is the net ATP gain or loss when going from the appropriate number of glucose molecules to a C₂₈ fatty acid? Consider all NAD(P)/NAD(P)H and FAD/FADH₂ in terms of the total ATP gained or lost?

Answer 1

Number of carbon atoms = 28
Number of beta oxidation cycles = (28/2)-1 = 13
Number of Acetyl CoA produced = 28/2 = 14
Number of NADH produced = 14
Number of FADH2 produced = 14

1 Acetyl CoA produces 3 NADH, 1 FADH2, and 1 ATP via the TCA cycle.
14 Acetyl CoA = 42 NADH, 14 FADH2, and 14 ATP
1 NADH = 2.5 ATP
1 FADH2 = 1.5 ATP
1 Acetyl CoA = 10 ATP

Total ATP production:
14 Acetyl CoA = 140 ATP
14 NADH = 35 ATP
14 FADH2 = 21 ATP
Total = 196 ATP
Activation = -2 ATP
Net gain = 194 ATP