Ferredoxin is

Options

A. A polynucleotide with iron and sulfur
B. Chlorophyll without Mg
C. A polypeptide with iron and sulfur
D. A copper contain protein

Answer

**Step-by-Step Solution:**

1. **Understanding Ferredoxin**: Ferredoxin is a protein that plays a crucial role in electron transport in photosynthesis and other metabolic processes. It is primarily composed of iron and sulfur.

2. **Analyzing the Options**: The question provides four options regarding what ferredoxin is:
- A) Polynucleotide with iron and sulfur
- B) Chlorophyll without magnesium
- C) Polypeptide with iron and sulfur
- D) Copper-containing protein

3. **Breaking Down the Term**: The term "ferredoxin" can be broken down into two Latin roots: "ferrum" (meaning iron) and "sulfur" (meaning sulfur). This indicates that ferredoxin contains both iron and sulfur.

4. **Identifying the Correct Structure**: Ferredoxin is specifically a polypeptide that contains clusters of iron and sulfur atoms. This means that it is not a polynucleotide (which is made of nucleotides), nor is it chlorophyll or a copper-containing protein.

5. **Choosing the Correct Option**: Based on the analysis:
- Option A is incorrect because it refers to a polynucleotide.
- Option B is incorrect as it mentions chlorophyll, which is unrelated to ferredoxin.
- Option C is correct because it accurately describes ferredoxin as a polypeptide with iron and sulfur.
- Option D is incorrect since ferredoxin does not contain copper.

6. **Final Answer**: Therefore, the correct answer is **C) A polypeptide with iron and sulfur**.

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