Question

In, which one of the following reactions of glycolysis, oxidation takes place?

• A. Glucose 6-phosphate to i. ose 6-phosphate
• B. Fructose 6-phosphate to fructose 1,6-bisphosphate
• C. 1,3-bisphosphoglycerate to 3-phosphogyceric acid
• D. 3-phosphoglyceraldehyde to 1,3-bisphospholgycerate
• E. 2-phosphoglycerate to phosphoenol pyruvate

Answer 1

Answer: (D)

Glycolysis has two phases - preparatory and pay off. Oxidation of glyceraldehyde 3-phosphate to 1,3-biphosphoglycerate takes place during pay off (energy conserving) phase.
In the presence of enzyme glyceraldehyde 3-phosphate dehydrogenase, glyceraldehyde 3-phosphate is oxidised through removal of hydrogen and addition of phosphate from inorganic source to form 1,3-biphosphoglycerate. $NAD^+$ is hydrogen acceptor. It produces NADH.