Where do plants obtain the energy required to synthesize organic molecules during photosynthesis?

• A. From nutrients absorbed through roots
• B. From the heat in the soil
• C. From sunlight absorbed by chlorophyll
• D. From oxygen in the atmosphere

Answer: (C)

Verified step by step guidance

1. Understand the process of photosynthesis: Photosynthesis is the process by which plants convert light energy into chemical energy stored in organic molecules, such as glucose. This process primarily occurs in the chloroplasts of plant cells.
2. Identify the role of chlorophyll: Chlorophyll is a pigment found in the chloroplasts that absorbs sunlight, specifically light in the blue and red wavelengths, and uses this energy to drive the photosynthetic reactions.
3. Clarify the energy source: The energy required for photosynthesis comes from sunlight, not from nutrients absorbed through roots, heat in the soil, or oxygen in the atmosphere. Sunlight is the primary energy source for synthesizing organic molecules.
4. Explain the light-dependent reactions: In the first stage of photosynthesis, known as the light-dependent reactions, sunlight absorbed by chlorophyll is used to generate ATP and NADPH, which are energy carriers needed for the next stage.
5. Connect to the synthesis of organic molecules: In the second stage, called the Calvin cycle (light-independent reactions), ATP and NADPH produced in the light-dependent reactions are used to convert carbon dioxide into glucose and other organic molecules.