What is the net gain of ATP when each molecule of glucose is converted to two molecules of pyruvic acid?
- Four
- Six
- Two
- Eight
Answer
(3) Two
Solution
Glycolysis: glucose → 2 pyruvic acid.
ATP used: 2 (glucose → glucose-6-phosphate, fructose-6-phosphate → fructose-1,6-bisphosphate).
ATP formed directly: 4 (2 from 1,3-bisphosphoglycerate → 3-phosphoglycerate, 2 from PEP → pyruvic acid).
∴ Net gain = 4 - 2 = 2 ATP.
Answer: (3)