Final answer:
The phosphate group is introduced in the last step of the scheme to transfer a high-energy phosphate to ADP, forming ATP. This process is known as substrate-level phosphorylation.
Step-by-step explanation:
The phosphate group is introduced in the last step of the scheme to transfer a high-energy phosphate to ADP, forming ATP.
In glycolysis, this occurs in step 7 where 1,3-bisphosphoglycerate donates a high-energy phosphate to ADP, resulting in the formation of ATP. This is an example of substrate-level phosphorylation, where the phosphate group is transferred from one molecule to another to generate ATP.