Which of the following best describes the primary function of photosynthesis in plants?

• A. To absorb oxygen and release carbon dioxide
• B. To break down glucose and release energy
• C. To produce ATP directly from sunlight without any intermediate molecules
• D. To convert light energy into chemical energy stored in glucose

Answer: (D)

Verified step by step guidance

1. Understand the process of photosynthesis: Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy stored in glucose molecules. This process occurs in the chloroplasts of plant cells and involves two main stages: the light-dependent reactions and the Calvin cycle.
2. Clarify the role of light energy: During the light-dependent reactions, light energy is absorbed by chlorophyll and other pigments in the thylakoid membranes of the chloroplast. This energy is used to produce ATP and NADPH, which are energy carriers.
3. Explain the synthesis of glucose: In the Calvin cycle (light-independent reactions), the ATP and NADPH produced in the light-dependent reactions are used to convert carbon dioxide (CO₂) from the atmosphere into glucose (C₆H₁₂O₆), a form of chemical energy that can be stored and used by the plant.
4. Eliminate incorrect options: The first option, 'To absorb oxygen and release carbon dioxide,' describes respiration, not photosynthesis. The second option, 'To break down glucose and release energy,' refers to cellular respiration, not the synthesis of glucose. The third option, 'To produce ATP directly from sunlight without any intermediate molecules,' is incorrect because ATP production involves intermediate steps and molecules.
5. Identify the correct answer: The correct description of the primary function of photosynthesis is 'To convert light energy into chemical energy stored in glucose,' as this highlights the transformation of energy into a usable and storable form for the plant.