In photosynthetic electron transport system, Mn ions are associate with

Options

A. `CF_(0)-CF_(1)` complex
B. Cyt `b_(6)-` Cyt f complex
C. Oxygen evolving complex
D. Plastoquinone.

Answer

**Step-by-Step Solution:**

1. **Understanding the Photosynthetic Electron Transport System:**
- The photosynthetic electron transport system is a series of protein complexes and other molecules that transfer electrons during the light reactions of photosynthesis.

2. **Identifying the Role of Manganese Ions:**
- Manganese ions (Mn) play a crucial role in the process of photosynthesis, particularly in the oxygen-evolving complex (OEC) of photosystem II (PSII).

3. **Function of the Oxygen Evolving Complex:**
- The oxygen-evolving complex is responsible for the splitting of water molecules (photolysis) to release oxygen. This process requires manganese ions.

4. **Association of Manganese with Photosystem II:**
- It is known that PSII contains a manganese protein that is essential for the early stages of oxygen evolution. This complex typically contains 4 manganese atoms that are necessary for the complete process of oxygen evolution.

5. **Conclusion:**
- Based on the above points, we can conclude that in the photosynthetic electron transport system, manganese ions are associated with the oxygen-evolving complex.

**Final Answer:**
In the photosynthetic electron transport system, manganese ions are associated with the oxygen-evolving complex.

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