Question

Approximately how many net molecules of ATP are used or generated by gluconeogenesis as compared to net ATP used or generated by glycolysis?

Answer 1

During glycolysis, one ATP is utilized during the conversion of Glucose to Glucose 6-phosphate and one ATP is required for the synthesis of Fructose 1,6-bisphosphate from Fructose 6-phosphate.

Two ATP are generated when two molecules of 1,3-Bisphosphoglycerate are converted to 3-Phosphoglycerate and two ATP are generated when Phosphoenolpyruvate is converted into Pyruvate.

Two NADH are synthesized when Glyceraldehyde 3-phosphate is converted to 1,3-Bisphosphoglycerate.

So overall yield of ATP is 4-2 = 2.

During gluconeogenesis, pyruvate is converted into phosphoenolpyruvate through oxaloacetate. This conversion required two ATP per pyruvate molecules.

One ATP is required when 3-Phosphoglycerate is converted to 1,3-Bisphosphoglycerate.

So, a total of 6 ATP are required to make glucose from pyruvate via gluconeogenesis.

So the net molecules of ATP used by gluconeogenesis are 6 and 2 ATP are generated during glycolysis,