Photosystem is composed of

Options

A. Light harvesting complex
B. Reaction centre
C. Accessory pigments
D. both B and C

Answer

**Step-by-Step Solution:**

1. **Understanding Photosystem**: A photosystem is a complex involved in the process of photosynthesis, specifically in the light-dependent reactions. It is often referred to as a light-harvesting complex.

2. **Components of Photosystem**: The photosystem is primarily composed of two main components:
- **Reaction Center**: This is a special chlorophyll A molecule that plays a crucial role in the photosystem. It absorbs light energy and releases electrons, which is essential for the light reactions of photosynthesis.
- **Accessory Pigments**: Surrounding the reaction center are various other pigments, such as chlorophyll B and carotenoids. These pigments do not directly eject electrons but capture light energy and transfer it to the reaction center through a process known as resonance energy transfer.

3. **Function of Components**:
- The **reaction center** is responsible for the primary light reaction, where it ejects electrons upon absorbing light energy.
- The **accessory pigments** enhance the light-absorbing capacity of the photosystem by capturing additional light energy and transferring it to the reaction center.

4. **Conclusion**: Therefore, the photosystem is composed of both the reaction center and accessory pigments.

5. **Final Answer**: The correct answer is that the photosystem is composed of both B (reaction center) and C (accessory pigments).

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