(lithotrophic) adj. describing organisms (known as autotrophs) that synthesize their organic materials from carbon dioxide and nitrates or ammonium compounds, using an external source of energy. Photoautotrophic organisms, including green plants and some bacteria, derive their energy from sunlight; chemoautotrophic (or chemosynthetic) organisms obtain energy from inorganic chemical reactions. All autotrophic bacteria are nonparasitic. Compare heterotrophic.
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