Which of the following provides energy to ETS by absorption of sunlight ?

Options

A. Chlorophyll
B. Mitochondria
C. ATP
D. Water

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which component provides energy to the Electron Transport System (ETS) through the absorption of sunlight.

2. **Identifying ETS**: The Electron Transport System (ETS) is a series of complexes that transfer electrons from electron donors to electron acceptors via redox reactions. This process is crucial for ATP production in cellular respiration.

3. **Role of Chlorophyll**: Chlorophyll is the pigment found in chloroplasts that absorbs sunlight. It plays a vital role in photosynthesis, particularly in the light-dependent reactions.

4. **Light Reactions**: During the light reactions of photosynthesis, chlorophyll absorbs sunlight, which leads to the production of ATP and NADH. These molecules are essential energy carriers.

5. **Energy Requirement for ETS**: The ETS requires energy to transport electrons. The energy needed for this process comes from the ATP and NADH produced during the light reactions, which are initiated by chlorophyll absorbing sunlight.

6. **Evaluating the Options**:
- **Option A (Chlorophyll)**: Correct, as it absorbs sunlight and provides energy to ETS.
- **Option B (Mitochondria)**: Incorrect, as mitochondria are the site of the ETS but do not absorb sunlight.
- **Option C (ATP)**: Incorrect, as ATP is a product of the ETS, not a source of energy for it.
- **Option D (Water)**: Incorrect, as water provides electrons and protons but does not directly provide energy.

7. **Conclusion**: The correct answer is **Option A: Chlorophyll**, as it is the component that absorbs sunlight and provides the necessary energy for the Electron Transport System.

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