Question

Respiratory formation of ATP during the reactions 1,3-diphosphoglyceric acid-->3-phosphoglyceric acid and phosphoenol pyruvate -->Pyruvate is

• A. Oxidative phosphorylation
• B. Substrate level phosphorylation
• C. Respiratory phosphorylation
• D. Chemical phosphorylation

Answer 1

The correct option is B Substrate level phosphorylation

Formation of ATP directly from metabolites is known as substrate level phosphorylation. In the process of glycolysis, the sixth and last steps involve the formation of ATP by substrate level phosphorylation.

1. In the sixth step of glycolysis, high energy phosphate group on carbon 1 of 1,3-diphosphoglyceric acid is transferred to a molecule of ADP converting it into an ATP molecule. 1,3 diphosphoglyceric acid changes to 3-phosphoglyceric acid due to loss of a phosphate group.

2. In the last step, high energy phosphate group of phosphoenolpyruvate is transferred to a molecule of ADP with the help of an enzyme, pyruvate kinase in the presence of magnesium ions and potassium ions. This produces pyruvate and a molecule of ATP.

Thus, the correct answer is option B.