The total number of ATP molecules produced from one molecule of glucose during cellular respiration can vary depending on the specific conditions and the efficiency of the processes involved. However, under optimal conditions in eukaryotic cells, the typical yield is:
- Glycolysis produces 2 ATP (net gain) and also generates 2 NADH.
- The conversion of pyruvate to acetyl-CoA produces 2 NADH (1 for each pyruvate, and there are 2 pyruvates from one glucose).
- The Krebs cycle (Citric acid cycle) produces 2 ATP (one for each acetyl-CoA) and generates additional NADH and FADH2: 6 NADH and 2 FADH2 per glucose.
When these NADH and FADH2 are processed through the electron transport chain:
- Each NADH can produce approximately 2.5 ATP (through oxidative phosphorylation).
- Each FADH2 can produce approximately 1.5 ATP.
Putting these together:
- From glycolysis: 2 ATP + 2 NADH → 2 ATP + 5 ATP = 7 ATP
- From pyruvate conversion: 2 NADH → 5 ATP
- From the Krebs cycle: 2 ATP + 6 NADH + 2 FADH2 → 2 ATP + 15 ATP + 3 ATP = 20 ATP
Adding it all together: 7 ATP (glycolysis) + 5 ATP (pyruvate) + 20 ATP (Krebs cycle) = 32 ATP
However, the commonly cited yield is often rounded off to 36 ATP in textbooks.
Thus, the most reasonable answer in this context would be 36 ATP produced per molecule of glucose under ideal conditions. The other answers (2, 6, and 24) do not usually represent the total ATP yield from complete cellular respiration of one glucose molecule.