How many ATP are produced in glycolysis per glucose molecule?

In glycolysis, the catabolic pathway that breaks down glucose to produce energy, a net gain of 2 ATP molecules is generated per glucose molecule. The process occurs in the cytoplasm and involves several enzymatic reactions that convert glucose into pyruvate.

During the initial phase of glycolysis, two ATP molecules are consumed to phosphorylate glucose and its derivatives, which is essential for sugar breakdown. As the cycle continues, four ATP molecules are produced through substrate-level phosphorylation in the latter half of glycolysis, specifically during the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate and during the conversion of phosphoenolpyruvate to pyruvate.

However, since two ATP molecules are used in the initial steps, the total net gain of ATP produced from one glucose molecule during glycolysis is 4 ATP generated minus the 2 ATP consumed, leading to a net yield of 2 ATP. This balance is crucial for understanding how ATP levels are maintained in cells, especially during early stages of cellular respiration.