In Substrate-Level Phosphorylation, the Phosphate Used to Make ATP from ADP

Question

In substrate-level phosphorylation, the phosphate used to make ATP from ADP comes from
A) Inorganic phosphate in the cytoplasm
B) Inorganic phosphate in the matrix of the m itochondria
C) Phosphate in the DNA backbone
D) A phosphorylated metabolic intermediate
E) ADP

Accepted Answer

In substrate-level phosphorylation, the phosphate group transferred to ADP to form ATP comes from a phosphorylated metabolic intermediate, not from inorganic phosphate or any other source listed. This process occurs in the cytoplasm during glycolysis and in the mitochondria during the Krebs cycle.