How is gluconeogenesis related to glycolysis?
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.