Number of ATP molecules synthesized through substrate level phosphorylation during aerobic respiration of one glucose molecule is:
Substrate level phosphorylation occurs in the form of glycolysis and Krebs cycle. During glycolysis, substrate level phosphorylation occurs in two steps and as two molecules are involved, it finally produces 4 ATP from a single glucose molecule.
As the molecules move towards Krebs cycle the substrate level phosphorylation occurs in a single step. Due to the presence of two molecules, the ATP produced during Krebs cycle in this manner will be 2 ATP molecules.
Therefore, total ATP molecules obtained from substrate-level phosphorylation during aerobic respiration of a glucose molecule will be 4+2 = 6 molecules.