In which of the following ways are photosynthesis and cellular respiration alike?

• A. Both convert glucose into carbon dioxide and water.
• B. Both occur only in plant cells.
• C. Both use sunlight directly to produce glucose.
• D. Both involve the production of ATP through electron transport chains.

Answer: (D)

Verified step by step guidance

1. Step 1: Begin by understanding the processes of photosynthesis and cellular respiration. Photosynthesis is the process by which plants, algae, and some bacteria convert sunlight into chemical energy stored in glucose. Cellular respiration is the process by which cells break down glucose to produce ATP, the energy currency of the cell.
2. Step 2: Recognize the role of electron transport chains in both processes. In photosynthesis, the electron transport chain is part of the light-dependent reactions, where sunlight excites electrons, and these electrons move through protein complexes to generate ATP and NADPH. In cellular respiration, the electron transport chain is located in the mitochondria and is used to produce ATP by transferring electrons from NADH and FADH2 to oxygen.
3. Step 3: Compare the similarities between the two processes. Both photosynthesis and cellular respiration involve electron transport chains as a mechanism to produce ATP. This is a key similarity that connects the two processes.
4. Step 4: Eliminate the incorrect options. For example, photosynthesis does not convert glucose into carbon dioxide and water; that is a characteristic of cellular respiration. Both processes do not occur only in plant cells, as cellular respiration occurs in all eukaryotic cells. Photosynthesis uses sunlight directly to produce glucose, but cellular respiration does not.
5. Step 5: Conclude that the correct answer is: 'Both involve the production of ATP through electron transport chains,' as this is the fundamental similarity between photosynthesis and cellular respiration.