Question

How many times does substrate-level phosphorylation occur in glycolysis?

A) 0
B) 1
C) 2
D) 3

Answer 1

During stage 2 of glycolysis, which is the energy payoff phase, substrate-level phosphorylation occurs twice.

Step-by-step explanation:

During stage 2 of glycolysis, also known as the energy payoff phase, substrate-level phosphorylation occurs twice. In this process, ATP is produced by transferring a phosphate group from a high-energy molecule to ADP. The enzyme Phosphoglycerate kinase catalyzes the first substrate-level phosphorylation, converting 1,3-Bisphosphoglycerate into ATP and 3-phosphoglycerate. The second substrate-level phosphorylation occurs when Phosphofructokinase converts D-Fructose-6-phosphate into D-Fructose-1,6-bisphosphate, producing ATP.