Biosynthesis

Article By:

O'Hagan, David Department of Chemistry, University of Durham, Durham, United Kingdom.

Last reviewed:October 2019

DOI:https://doi.org/10.1036/1097-8542.084250

The synthesis of more complex molecules from simpler ones in cells by utilizing biosynthetic pathways consisting of a series of reactions mediated by enzymes. The overall economy and survival of the cell is governed by the interplay between the energy gained from the breakdown of compounds and that supplied to biosynthetic pathways for the synthesis of compounds having a functional role, such as deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and enzymes. Biosynthetic pathways (see illustration) give rise to two distinct classes of metabolite, primary and secondary. Primary metabolites (DNA, RNA, fatty acids, α-amino acids, chlorophyll in green plants, and so forth) are essential to the metabolic functioning of the cells. Secondary metabolites (antibiotics, antifeedants, alkaloids, pheromones, skunk scent, and so forth) aid the functioning and survival of the whole organism more generally. Unlike primary metabolites, secondary metabolites are often unique to individual organisms or classes of organisms. See also: Enzyme; Metabolism

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