In Which Reactions of Cellular Respiration Does Substrate-Level Phosphorylation Occur

Question

In which reactions of cellular respiration does substrate-level phosphorylation occur?
A) only in glycolysis
B) only in the citric acid cycle
C) only in the electron transport chain
D) in both glycolysis and the citric acid cycle

Accepted Answer

Substrate-level phosphorylation occurs in both glycolysis and the citric acid cycle, where ATP is directly synthesized from ADP and an inorganic phosphate by the transfer of a high-energy phosphate group from a phosphorylated intermediate.