Which statement best describes autotrophs?

Which statement best describes autotrophs?

• A. Autotrophs rely on organic compounds produced by others.
• B. Autotrophs convert chemical energy into ATP.
• C. Autotrophs require sunlight to drive chemical energy.
• D. Autotrophs convert energy from sunlight into chemical energy.

Answer: (D)

Autotrophs make their own organic matter by using energy to drive chemical reactions that assemble carbon-containing compounds. In photoautotrophs, light energy is captured and converted into chemical energy in molecules like ATP and NADPH, which then power the synthesis of sugars from carbon dioxide. This capture-and-conversion of light into chemical energy is the defining process that lets autotrophs build organic material from inorganic sources. Some autotrophs can use chemical energy instead of light (chemosynthesis), but the core idea described here—using energy from a source to create chemical energy that drives carbon fixation and synthesis—best describes autotrophs. The other statements either point to heterotrophs, or misstate the energy flow or the light requirement.

Autotrophs make their own organic matter by using energy to drive chemical reactions that assemble carbon-containing compounds. In photoautotrophs, light energy is captured and converted into chemical energy in molecules like ATP and NADPH, which then power the synthesis of sugars from carbon dioxide. This capture-and-conversion of light into chemical energy is the defining process that lets autotrophs build organic material from inorganic sources. Some autotrophs can use chemical energy instead of light (chemosynthesis), but the core idea described here—using energy from a source to create chemical energy that drives carbon fixation and synthesis—best describes autotrophs. The other statements either point to heterotrophs, or misstate the energy flow or the light requirement.