Q29-44E - Organic Chemistry (Mcmurry)

Question

Why aren’t the glycolysis and gluconeogenesis pathways the exact reverse of each other?

Step-by-Step Solution

Answer

Since the glycolysis and gluconeogenesis pathways have different values so that they aren’t the exact reverse of each other.

Step 1: Define each term (glycolysis and gluconeogenesis).

Glycolysis: It is a cytoplasmic pathway that provides energy by breaking down glucose into two three-carbon molecules. It is an energetically spontaneous process.

Gluconeogenesis: It is a metabolic pathway that produces glucose from non-carbohydrate substrates like glycerol, amino acids and lactate. It is also an energetically spontaneous process.

Step 2: Find the correct reasons for this problem.

The glycolysis pathway has a negative$∆\mathrm{G}\text{'}$ value because it is an energetically feasible process, whereas the exact reverse reaction of the glycolysis pathway has a positive $∆\mathrm{G}\text{'}$value because it is not energetically feasible. Gluconeogenes is path way is another favourable process to produce glucose because it has a negative $∆\mathrm{G}\text{'}$value. Hence, the glycolysis and gluconeogenesis pathways aren’t the exact reverse of each other.