The Online Encyclopedia and Dictionary






Metabolic pathway

In biochemistry, a metabolic pathway is a series of chemical reactions occurring within a cell, catalyzed by enzymes, and resulting in either the formation of a metabolic product to be used or stored by the cell (metabolic sink ), or the initiation of another metabolic pathway (then called a flux generating step).



Most metabolic pathways have these common properties:

  • They are irreversible, usually because the first step is a committed step that only runs in one direction.
  • The pathways are regulated, usually by feedback inhibition .
  • Anabolic and catabolic pathways in eukaryotes are separated by either compartmentation or by the use of different enzymes and cofactors.

Major metabolic pathways

Cellular respiration

Main article: Cellular respiration

Several distinct but linked metabolic pathways are used by cells to transfer the energy released by breakdown of fuel molecules to ATP:

  1. Glycolysis
  2. Anaerobic respiration
  3. Krebs cycle / Citric acid cycle
  4. Oxidative phosphorylation

Other pathways

See also

External links

Last updated: 08-17-2005 01:58:26