heterot

Heterot, short for heterotroph or heterotrophic organism, is a term used in biology to describe organisms that cannot synthesize all required organic carbon compounds from carbon dioxide. Instead, they obtain carbon by consuming preformed organic molecules produced by other organisms. Unlike autotrophs, which fix inorganic carbon to build biomass, heterotrophs rely on external sources of organic matter. The energy they use can come from chemical reactions (chemo-) or from light (photo-), leading to several subcategories such as chemoorganotrophs, chemolithotrophs, photoheterotrophs, and chemoorganoheterotrophs.

Heterotrophs include animals, fungi, many bacteria, and some archaea. In ecosystems, they play key roles as consumers and decomposers, breaking down dead material and recycling nutrients. In microbial ecology, the distinction between autotrophs and heterotrophs helps describe trophic structure and carbon flux.

In metabolism, heterotrophs obtain organic molecules through ingestion, absorption, or uptake of dissolved nutrients; these compounds are then catabolized via pathways such as glycolysis and the tricarboxylic acid cycle to release energy as ATP. Some heterotrophs also perform fermentation in anaerobic environments. The growth and ecological impact of heterotrophs depend on the availability of organic substrates and environmental conditions.

Etymology: from Greek heteros "other" and tropē "nourishment." The term is widely used in ecology and microbiology to classify organisms by carbon source, though many organisms exhibit mixotrophy or facultative modes that blur strict categories.