Cytochromes are

Options

A. Simple proteins
B. S-containing proteins
C. Conjugated proteins
D. Cu-containing proteins

Answer

**Step-by-Step Solution:**

1. **Understanding Cytochromes**: Begin by defining what cytochromes are. Cytochromes are proteins that contain a heme group, which includes iron. They play a crucial role in the electron transport chain (ETC) during cellular respiration.

2. **Identifying the Options**: The question provides four options:
- Simple protein
- Sulfur-containing protein
- Conjugated protein
- Copper-containing protein

3. **Analyzing Each Option**:
- **Simple Protein**: Simple proteins consist only of amino acids. Since cytochromes contain iron and a heme group, they do not qualify as simple proteins. Thus, this option is incorrect.
- **Sulfur-containing Protein**: Cytochromes do not contain sulfur. Therefore, this option is also incorrect.
- **Copper-containing Protein**: Cytochromes do not contain copper; they are characterized by the presence of iron. Thus, this option is incorrect as well.
- **Conjugated Protein**: Conjugated proteins are those that contain a non-protein component (like a metal ion). Since cytochromes contain iron as part of their heme group, they are classified as conjugated proteins.

4. **Conclusion**: After analyzing all the options, the correct classification of cytochromes is that they are conjugated proteins due to their iron-containing heme groups.

**Final Answer**: Cytochromes are conjugated proteins.

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