Final answer:
The transfer of a high-energy phosphate group from a phosphorylated organic molecule to ADP is known as substrate-level phosphorylation, which directly forms ATP during processes such as glycolysis.
Step-by-step explanation:
The transfer of a high-energy phosphate group from a phosphorylated organic molecule to ADP is called substrate-level phosphorylation. This process involves the direct transfer of a phosphate group from an organic molecule to ADP, thereby generating ATP. In glycolysis, for example, this type of phosphorylation occurs when enzymes like phosphoglycerate kinase and pyruvate kinase catalyze the transfer of a phosphate group from compounds such as 1,3-bisphosphoglycerate and phosphoenolpyruvate to ADP, resulting in the formation of ATP. It is a mechanism that differs from oxidative phosphorylation, wherein the phosphorylation of ADP to form ATP is coupled with the transfer of electrons through the electron transport chain and oxygen is involved as the final electron acceptor.