The primary pigment molecule of PS I is

Options

A. `P_(700)`
B. `P_(680)`
C. `P_(670)`
D. Chlb

Answer

**Step-by-Step Solution:**

1. **Understanding Photosystems**: Photosystems are complexes involved in the light-dependent reactions of photosynthesis. There are two main types: Photosystem I (PS I) and Photosystem II (PS II).

2. **Identifying the Role of PS I**: Photosystem I is primarily involved in the light reactions of photosynthesis, where it plays a crucial role in converting light energy into chemical energy.

3. **Recognizing the Primary Pigment**: The primary pigment molecule in photosystems is responsible for capturing light energy. In Photosystem I, this pigment is essential for the absorption of light.

4. **Determining the Specific Pigment**: The primary pigment molecule of Photosystem I is chlorophyll B. It is important to note that chlorophyll A is also present in photosynthesis but is not the primary pigment in PS I.

5. **Understanding the Function of Chlorophyll B**: Chlorophyll B assists in capturing light energy, particularly in the blue and red wavelengths, while reflecting green light, which is why plants appear green.

6. **Conclusion**: Therefore, the answer to the question "The primary pigment molecule of PS I is" is **Chlorophyll B**.

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