Which organism uses CO2 as a carbon source?

Which organism uses CO2 as a carbon source?

• A. Autotroph
• B. Heterotroph
• C. Chemotroph
• D. Saprotroph

Answer: (A)

Using carbon dioxide as a carbon source means the organism fixes inorganic carbon to build organic molecules. That describes autotrophs. Autotrophs obtain their carbon from CO2 and can capture energy from light (photoautotrophs, like plants and many algae) or from chemical reactions (chemoautotrophs, like certain bacteria). In contrast, heterotrophs rely on preformed organic carbon from other organisms. Saprotrophs are a subtype of heterotrophs that feed on dead organic matter. Chemotrophs refer to how an organism obtains energy, not directly to its carbon source, so they don’t define carbon source on their own. Therefore, the organism using CO2 as a carbon source is autotroph.

Using carbon dioxide as a carbon source means the organism fixes inorganic carbon to build organic molecules. That describes autotrophs. Autotrophs obtain their carbon from CO2 and can capture energy from light (photoautotrophs, like plants and many algae) or from chemical reactions (chemoautotrophs, like certain bacteria). In contrast, heterotrophs rely on preformed organic carbon from other organisms. Saprotrophs are a subtype of heterotrophs that feed on dead organic matter. Chemotrophs refer to how an organism obtains energy, not directly to its carbon source, so they don’t define carbon source on their own. Therefore, the organism using CO2 as a carbon source is autotroph.