How is gluconeogenesis related to glycolysis?

Question

Daniel Allen · Accepted Answer

Gluconeogenesis is the reverse of glycolysis.

Glycolysis is the conversion of glucose to pyruvate.

All the steps of glycolysis are reversible, and the reverse pathway, the conversion of pyruvate to glucose, is called gluconeogenesis (from "glucose" + Greek neos, "new" + Greek genesis "creation").

The steps in red (below) represent glycolysis.

The reverse steps (in blue) represent gluconeogenesis.

Glucose must be available to the cells at all times, so the body has a system to maintain blood glucose concentrations.

When blood glucose levels fall, glycogen stores in the liver are converted to glucose.

When glycogen is depleted, the body uses gluconeogenesis as an alternate energy source

The main source material for gluconeogenesis is the breakdown of proteins to amino acids.

For example, alanine, cysteine, glycine, serine, and threonine can all be converted to pyruvate, while aspartate and asparagine produce oxaloacetate.

Daniel Allen · Answer

undefined While glycolysis is the breakdown of glucose, gluconeogenesis is the synthesis of glucose from non-carbohydrate sources. Although they function in opposite directions, they share certain enzymes.

Jeremiah Allen · Answer

undefined Gluconeogenesis is the metabolic process through which glucose is synthesized from non-carbohydrate precursors, such as lactate, glycerol, or amino acids. It is essentially the reverse of glycolysis, which is the breakdown of glucose into pyruvate. While glycolysis occurs primarily in the cytoplasm, gluconeogenesis occurs mainly in the liver and to a lesser extent in the kidneys. Both processes involve a series of enzymatic reactions, but they proceed in opposite directions and serve different metabolic purposes. Gluconeogenesis allows the body to maintain blood glucose levels during periods of fasting or prolonged exercise when glucose reserves are depleted.