Which statement best compares photosynthesis and cellular respiration?

• A. Photosynthesis stores energy in glucose molecules, while cellular respiration releases energy from glucose.
• B. Both photosynthesis and cellular respiration occur only in animal cells.
• C. Cellular respiration produces glucose, while photosynthesis breaks it down.
• D. Photosynthesis and cellular respiration both require sunlight as a direct energy source.

Answer: (A)

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 light energy into chemical energy stored in glucose molecules. Cellular respiration, on the other hand, is the process by which cells break down glucose to release energy in the form of ATP.
2. Step 2: Compare the energy flow in both processes. Photosynthesis stores energy by synthesizing glucose from carbon dioxide and water, using sunlight as the energy source. Cellular respiration releases energy by breaking down glucose into carbon dioxide and water, producing ATP as the usable energy form.
3. Step 3: Clarify the organisms involved. Photosynthesis primarily occurs in plants, algae, and some bacteria, while cellular respiration occurs in nearly all living organisms, including plants, animals, fungi, and microorganisms. It is incorrect to say that both processes occur only in animal cells.
4. Step 4: Address the role of glucose. Photosynthesis produces glucose as a product, while cellular respiration breaks down glucose as a reactant to release energy. It is incorrect to state that cellular respiration produces glucose or that photosynthesis breaks it down.
5. Step 5: Examine the energy source. Photosynthesis directly requires sunlight as an energy source to drive the reactions in the chloroplasts. Cellular respiration does not require sunlight; it uses the chemical energy stored in glucose molecules. Therefore, it is incorrect to say that both processes require sunlight as a direct energy source.