What is the net gain of ATP from one molecule of glucose during glycolysis?

The net gain of ATP from one molecule of glucose during glycolysis is 2 ATP. Glycolysis is the process that occurs in the cytoplasm where glucose, a six-carbon sugar, is broken down into two molecules of pyruvate.

During the initial steps of glycolysis, two ATP molecules are consumed to activate glucose and its derivatives. However, the pathway subsequently produces four ATP molecules through substrate-level phosphorylation. Therefore, when calculating the net gain, you take the four ATP produced and subtract the two ATP that were invested, resulting in a net gain of 2 ATP.

It's important to note that while glycolysis produces additional energy carriers, such as NADH, these are involved in later stages of cellular respiration and do not impact the net ATP yield specifically from glycolysis. Other options in the original question refer to total ATP yield from cellular respiration, including processes occurring after glycolysis, such as the citric acid cycle and oxidative phosphorylation. Thus, they do not accurately represent the specific ATP gain from glycolysis alone.