In biochemistry, a metabolic pathway is a series of chemical reactions occurring within a cell. In each pathway, a principal chemical is modified by chemical reactions. Enzymes catalyze these reactions, and often require dietary minerals, vitamins and other cofactors in order to function properly. Because of the many chemicals that may be involved, pathways can be quite elaborate. In addition, many pathways can exist within a cell. This collection of pathways is called the metabolic network. Pathways are important to the maintenance of homeostasis within an organism. Metabolism is a step by step modification of the initial molecule to shape it into another product. The result can be used in one of three ways.
- Stored by the cell.
- Be used immediately, as a metabolic product.
- Initiate another metabolic pathway, called a flux generating step.
A molecule called a substrate enters a metabolic pathway depending on the needs of the cell and the availability of the substrate. An increase in concentration of anabolical and catabolical end products would slow the metabolic rate for that particular pathway.
