In the context of energy conversion in living organisms, how are photosynthesis and chemosynthesis similar?

• A. Both processes use an electron transport chain to generate ATP and reduce $N_2$ into ammonia as the final carbon product.
• B. Both processes convert inorganic carbon (often $C_{O}2$) into organic molecules by using energy from an external source (light or chemical reactions).
• C. Both processes break down glucose to release energy, producing $C_{O}2$ and $H_{2}O$ as end products.
• D. Both processes require sunlight as the primary energy source and occur only in chloroplasts.

Answer: (B)

Verified step by step guidance

1. Identify the main function of both photosynthesis and chemosynthesis: both processes convert inorganic carbon into organic molecules, which is essential for building cellular structures and storing energy.
2. Understand the energy source for each process: photosynthesis uses light energy, while chemosynthesis uses energy derived from chemical reactions involving inorganic molecules.
3. Recognize that both processes involve carbon fixation, typically converting carbon dioxide (\(\mathrm{CO_2}\)) into organic compounds like glucose or other carbohydrates.
4. Note that both processes use an electron transport chain to help generate ATP, which provides the energy needed for carbon fixation and other cellular activities.
5. Conclude that the similarity lies in their ability to convert inorganic carbon into organic molecules using energy from an external source, despite differences in the energy source (light vs. chemical reactions).