Operational definition
Matter-assimilation process.
The incorporation of carbon into the organic molecular structures of a living system.
It includes:
- fixation of inorganic carbon into organic molecules;
- uptake and metabolic transformation of organic carbon;
- incorporation into structural biomass;
- incorporation into functional molecules;
- incorporation into storage compounds.
Carbon oxidation for energy that produces carbon dioxide without incorporation into biomass is not carbon assimilation.
36.1 Inorganic-carbon fixation
CO_2/HCO_3^- → organic biomass
Subclassified by the specific carbon-fixation pathway.
36.2 Organic-carbon assimilation
Organic molecules are:
- imported
- digested
- disassembled
- transformed
- reassembled into biomass
36.3 Mixed-carbon assimilation
Both inorganic carbon fixation and organic-carbon uptake contribute.