What is the net gain of ATP molecules from glycolysis?

The net gain of ATP molecules from glycolysis is 2 ATP molecules. During glycolysis, a total of 4 ATP molecules are produced through substrate-level phosphorylation. However, the process also consumes 2 ATP molecules in its initial steps to activate glucose and its intermediates. When you subtract the 2 ATP molecules used from the 4 produced, you achieve a net gain of 2 ATP.

This central metabolic pathway is crucial as it sets the stage for further ATP production in cellular respiration. The initial investment of ATP is necessary for those steps that transform glucose into pyruvate, resulting in energy yield when the pyruvate is further processed in the mitochondria.