What is an autotroph?

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What is an autotroph?

Autotrophs are organisms that fix carbon from inorganic carbon, CO2, into organic matter. They don’t rely on preformed organic molecules from other organisms; instead, they use energy from light or from inorganic chemical reactions to power the carbon-fixation process. That defining trait is why using CO2 as the carbon source is the correct description. It captures the essence of autotrophy: the carbon comes from CO2, not from consuming other organisms. Heterotrophs, by contrast, obtain their carbon from preformed organic molecules made by others, which is why they’re not autotrophs. Some organisms can oxidize methane for energy, but they typically fix carbon from CO2, not from methane itself, so that statement doesn’t define autotrophy. Nitrogen fixation isn’t an energy source; it’s a metabolic process that requires energy and reducing power, while autotrophs get their energy from light or inorganic compounds.

Autotrophs are organisms that fix carbon from inorganic carbon, CO2, into organic matter. They don’t rely on preformed organic molecules from other organisms; instead, they use energy from light or from inorganic chemical reactions to power the carbon-fixation process.

That defining trait is why using CO2 as the carbon source is the correct description. It captures the essence of autotrophy: the carbon comes from CO2, not from consuming other organisms.

Heterotrophs, by contrast, obtain their carbon from preformed organic molecules made by others, which is why they’re not autotrophs. Some organisms can oxidize methane for energy, but they typically fix carbon from CO2, not from methane itself, so that statement doesn’t define autotrophy. Nitrogen fixation isn’t an energy source; it’s a metabolic process that requires energy and reducing power, while autotrophs get their energy from light or inorganic compounds.

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