Question

Glycolysis and gluconeogenesis are opposed pathways in that they begin or end with the same metabolites and share common intermediates and/or enzymes. Yet, for energetic reasons, the two processes cannot be the exact reverse of each other. How is this possible?

1) Because not every intermediate or enzyme participates in both pathways, conditions will dictate which pathway is stimulated while the other is inhibited.
2) Levels of ATP will dictate which pathway is operational.
3) Both pathways make use of substrate cycles.

Only 1 and 2 are correct.
Only 1 and 3 are correct.
Only 2 and 3 are correct.
All three statements are correct.

Answer 1

All three statements are correct.

Step-by-step explanation:

Glycolysis may be defined as a biochemical pathway used to obtain energy by the oxidation of glucose molecule. Gluconeogenesis may be defined as the metabolic pathway of generation of glucose from the non carbohydrate source.

These two process are not reverse of each other since all enzymes are not the same for both the pathway. The ATP levels decide the which pathway starts at the specific condition. The substrate cycle are used in gluconeogenesis and glycolysis pathway.

Thus, the correct answer is option (4).