Question

How many ATP's are gained by complete oxidation of phosphoglyceric acid

Answer 1

• Each phosphoglyceric acid produces one pyruvic acid during glycolysis. Each pyruvic acid is converted to acetyl CoA and this results in the production of an NADH. Acetyl CoA undergoes complete oxidation through the Krebs cycle. The net gain of high-energy compounds from one cycle is 3 NADH, 1 FADH${}_2$, and 1 GTP; the GTP may subsequently be used to produce ATP. As each NADH is equivalent to 03 ATP and each FADH${}_2$ is equivalent to 02 ATP, total ATP molecules produced are 3 + 3×3 + 3×2 + 2 + 1 = 21 ATP. Also, 1 ATP is used during the conversion of phosphoenolpyruvate to pyruvic acid, hence the net gain of ATP is 20.