In chemosynthesis, what do chemosynthetic bacteria convert into food (organic molecules)?

• A. Sunlight energy absorbed by chlorophyll
• B. Inorganic chemicals (e.g., $H_{2}S$, $N_{\mathrm{H}}3$, or $F^{e}2+$)
• C. Preformed organic molecules taken up from the environment (heterotrophy)
• D. Carbon dioxide converted directly into ATP without any energy source

Answer: (B)

Verified step by step guidance

1. Understand that chemosynthesis is a process by which certain bacteria produce organic molecules (food) using energy derived from the oxidation of inorganic chemicals, rather than sunlight as in photosynthesis.
2. Identify the source of energy for chemosynthetic bacteria, which comes from inorganic chemicals such as hydrogen sulfide (H\_2S), ammonia (NH\_3), or ferrous iron (Fe^{2+}).
3. Recognize that these inorganic chemicals are oxidized by the bacteria, releasing energy that is then used to fix carbon dioxide (CO\_2) into organic molecules.
4. Note that unlike photosynthesis, chemosynthesis does not rely on sunlight or chlorophyll; instead, it uses chemical energy from inorganic compounds to drive the synthesis of food.
5. Summarize that chemosynthetic bacteria convert inorganic chemicals into organic molecules by using the energy released from the oxidation of these chemicals to fix CO\_2 into food.