Question

Describe the differences between substrate-level phosphorylation and chemiosmotic (oxidative) phosphorylation as mechanisms of ATP formation. Where in a prokaryotic cell does each occur? What are the substrates that are used to form ATP? What is the source of energy for ATP synthesis?

Answer 1

substrate-level phosphorylation is the direct transfer of phosphate groups from a substrate to ADP to make ATP, it occurs in the cytoplasm, the enzymes which catalyze the reaction is soluble in the cytoplasm, breaking of bond in the substrate provides energy for the synthesis of ATP.

In oxidative phosphorylation is the synthesis of ATP from ADP and Pi, the enzyme which catalyzes the reaction is the ATP synthase located in the membrane, it uses the energy stored in the H+ gradient to make ATP from ADP and Pi.

substrate-level phosphorylation occurs in the cytoplasm in both prokaryotes and eukaryotes and oxidative phosphorylation occurs in the mitochondrial inner membrane in eukaryotes and in the plasma membrane in the prokaryotes, the ATPs are synthesized to the cell.