Question

Substrate level phosphorylation does not occur in which of the following reaction of aerobic respiration?

• A. 1,3-BPG → 3-PGA
• B. 3-PGA → 2-PGA
• C. PEP → Pyruvate
• D. Succinyl CoA → Succinate

Answer 1

The correct option is B 3-PGA → 2-PGA

Substrate level phosphorylation refers to the formation of ATP from ADP and a phosphorylated intermediate from ADP and inorganic phosphate, Pi. There are total three reactions in respiration where substrate level phosphorylation occurs, two in glycolysis and one in Kreb’s cycle. The reactions are:

1. In glycolysis:

• When 1,3-bisphosphoglycerate (1,3-BPG) is converted into 3-phosphoglycerate (3-PGA)
• When phosphoenolpyruvate (PEP) is converted into pyruvate

2. In Kerb’s cycle:

• When succinyl-CoA is converted into succinate