Glycolysis is a metabolic pathway allowing the conversion of glucose to pyruvate, producing two NADH molecules and the net production of two ATP molecules. At rest, this allows the production of adequate ATP for basic cellular function. The pyruvate molecule produced by the pathway can be converted back to glucose by gluconeogenesis.
When additional energy is required, pyruvate can be fed into the link reaction, and then the Krebs cycle. This allows the production of more ATP molecules. When combined with the electron transport chain, 32 ATPs can be synthesised from one glucose molecule.