Question

All the reactions in glycolysis are reversible except

• A. 3-Phosphoglycerate to 1,3-Biphosphoglycerate.
• B. Glucose 6-phosphate to fructose -6-phosphate.
• C. 1,3-Biphosphoglycerate to glyceraldehyde 3-P.
• D. Fructose -6-phosphate to fructose-1,6-diphosphate.

Answer 1

Answer: (D)

Fructose -6-phosphate to fructose-1,6-diphosphate.

In the third step of glycolysis, fructose-6-phosphate is converted to fructose- 1,6-bisphosphate (FBP) where ATP is used. High level of ATP inhibits the enzyme activity as it is an allosteric effector and glycolysis does not occur. But when ATP is at low level it stimulates enzyme and glycolysis occur. Due to the level of ATP on and off process occurs. Thus, the correct answer is option D.