Final answer:
In glycolysis, ATP is synthesized via substrate-level phosphorylation, where a phosphate group is directly transferred from an intermediate metabolic compound to ADP, forming ATP.
Step-by-step explanation:
Synthesis of ATP in Glycolysis
The synthesis of ATP in glycolysis occurs through a process known as substrate-level phosphorylation. This process involves the transfer of a phosphate group from a high-energy substrate molecule to ADP, forming ATP. A classic example within glycolysis is the conversion of 1,3-bisphosphoglycerate (1,3 diPG) to 3-phosphoglycerate where a phosphate group is transferred to ADP to form ATP. This process happens twice for each glucose molecule that undergoes glycolysis, resulting in the net production of 2 ATP molecules via substrate-level phosphorylation.
The term 'substrate-level phosphorylation' differentiates this process from other mechanisms such as oxidative phosphorylation, which is another way that cells generate ATP, but it occurs in the mitochondria during the electron transport chain and chemiosmosis. Substrate-level phosphorylation is notable for its direct transfer of phosphate to ADP without the need for an electron transport chain, making it crucial in conditions where oxygen is scarce or during anaerobic respiration. It is a more immediate method of ATP production that can occur in the cytoplasm during glycolysis and also in the citric acid cycle.