Final answer:
Substrate-level phosphorylation involves transferring a phosphate group from a phosphorylated compound to ADP, which forms ATP. This occurs during glycolysis with the help of enzymes such as phosphoglycerate kinase and pyruvate kinase, which facilitate the transfer from high-energy compounds like 1,3-bisphosphoglycerate and PEP.
Step-by-step explanation:
The process described in the question is an example of substrate-level phosphorylation, which is powered by an enzymatic reaction involving the transfer of a phosphate group from a phosphorylated compound (substrate) directly to ADP, thus forming ATP.
This kind of reaction occurs during glycolysis, where enzymes like phosphoglycerate kinase and pyruvate kinase play a crucial role in catalyzing the transfer of phosphate groups to ADP, creating ATP in the process.
For instance, the enzyme phosphoglycerate kinase catalyzes the transfer of a phosphate group from 1,3-bisphosphoglycerate to ADP, yielding ATP. Similarly, the enzyme pyruvate kinase catalyzes the transfer from phosphoenolpyruvate (PEP) to ADP.
Both 1,3-bisphosphoglycerate and PEP are considered high-energy phosphate compounds because they have a great capacity to transfer a phosphate group to ADP.
The phosphorylation of ADP to form ATP is a critical step in cellular metabolism, providing energy for various cellular functions. The ATP is then used as a direct energy source for various processes within the cell.
Importantly, since these reactions are involved in glycolysis and the citric acid cycle, they play a central part in the metabolic breakdown of glucose to extract usable energy.