Which of the following electron carrier constrains copper ?

Options

A. Ferredoxin
B. Cytochrome
C. Plastocyanin
D. Cytochrome I

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which electron carrier contains copper. This means we need to identify a protein involved in electron transfer during photosynthesis that has copper as part of its structure.

2. **Identifying Electron Carriers**: In photosynthesis, there are several known electron carriers. The options provided include:
- Ferredoxin
- Cytochrome
- Plastocyanin
- Hydrochrome

3. **Analyzing Each Option**:
- **Ferredoxin**: This is an iron-sulfur protein that does not contain copper. Therefore, it is not the correct answer.
- **Cytochrome**: This group of proteins typically contains heme groups with iron, not copper. Thus, it is also not the correct answer.
- **Plastocyanin**: This is a copper-containing protein that plays a crucial role in the electron transport chain during photosynthesis. It is the correct answer.
- **Hydrochrome**: This term is not commonly associated with a specific electron carrier in photosynthesis and does not contain copper. Therefore, it is not the correct answer.

4. **Conclusion**: After analyzing all the options, the only electron carrier that contains copper is **Plastocyanin**.

**Final Answer**: Plastocyanin

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