Answer:
Phosphorylation
Step-by-step explanation:
Here, one phosphate group is removed from 1,3-bisphosphoglycerate to phosphorylate adenosine diphosphate (ADP) to form/produce adenosine triphosphate (ATP) and 3-phosphoglycerate as product in the glycolytic pathway.
NOTE: Phosphorylation is the process of adding phosphate to an organic compound. Here (in the question), the phosphate added to ADP, makes it to become ATP.