Glycolysis

Definition

Glycolysis is a metabolic pathway (i.e., a series of controlled chemical reactions occurring in a cell) that starts with glucose and converts it to pyruvic acid CH₃COCOOH), or equivalently pyruvate ions CH₃COCOO^- and protons (H⁺ions).

Item	Value
Type of cells in which glycolysis occurs	all cells
Substrate (input or reactant) for the process	Glucose $C_{6}H_{12}O_{6}$ (glucose is a monosaccharide, i.e., a simple sugar)
Products of the process	Pyruvic acid $CH_{3}COCOOH$ in ionized form
Energy change	The process releases energy (how much?). The released energy is stored chemically by converting ADP to ATP.
Phases of glycolysis pathway	There are two phases: the preparatory phase where energy needs to be provided (the energy is provided by converting ATP to ADP) and the pay-off phase where energy is released (the released energy is stored by converting ADP to ATP). The energy released in the pay-off phase is greater than the energy used in the preparatory phase, so overall we have more ATP and less ADP in the end than in the beginning.
Types of glycolysis pathways	Embden-Meyerhof-Parnas pathway (EMP pathway) (this is the one found in most organisms), Entner–Doudoroff pathway, and some others. By default, when we talk of glycolysis, we refer to the EMP pathway. Note that all eukaryotic cells use the EMP pathway.