The initial metabolic pathway of cellular respiration in which a series of reactions happening in the cytosol results in the conversion of a monosaccharide, often glucose, into pyruvate, and the concomitant production of a relatively small amount of high-energy biomolecule, such as ATP
Cellular respiration is a series of metabolic processes wherein the biochemical energy is harvested from organic substance (e.g. glucose) and stored in energy-carriers (e.g. ATP) for use in energy-requiring activities of the cell. The major steps or processes of cellular respiration are (1) glycolysis, (2) Krebs cycle, and (3) oxidative phosphorylation.
The most common and well-known type of glycolysis is the Embden-Meyerhof-Parnas pathway, which was first describe by Gustav Embden , Otto Meyerhof, and Jakub Karol Parnas. Other alternative pathways are exemplified by the Entner-Doudoroff pathway and the pentose phosphate pathway.
In Embden-Meyerhof-Parnas pathway, glycolysis is comprised of two phases: (1) the energy-investment phase (where ATP is consumed) and (2) the energy-payoff phase (where ATP is produced). The splitting of sugar during the energy-investment phase characterizes glycolysis in this regard since glucose is split into two triose phosphate molecules: glyceraldehyde phosphate and dihydroxyacetone phosphate. The glyceraldehyde phosphate proceeds to the energy-payoff phase whereas its isomer, dihydroxyacetone phosphate, has to be converted to glyceraldehyde phosphate (via isomerase) before it can proceed.
Word origin: Greek glykys ("sweet", referring to sugar) + Iyein ("to loosen")
- glycolytic (adjective, of, relating to, or pertaining to glycolysis).