Cytochrome is a

Options

A. Mg pyrrole ring
B. Hemoprotein
C. Fe porphyrin ring
D. Alloy of nichrome

Answer

### Step-by-Step Solution:

1. **Understanding Cytochrome**:
- Cytochrome is a type of protein that plays a crucial role in cellular respiration. It is involved in the electron transport chain, which is a series of reactions that produce energy in the form of ATP.

2. **Identifying the Structure**:
- Cytochromes are characterized by the presence of a heme group, which contains an iron atom. This iron is essential for the transfer of electrons during oxidation-reduction reactions.

3. **Analyzing the Options**:
- The options provided are:
1. Magnesium pyrrole ring
2. Haemoprotein
3. Iron porphyrin ring
4. Alloy of nichrome
- We need to determine which of these best describes cytochrome.

4. **Evaluating the Options**:
- **Magnesium pyrrole ring**: This is not related to cytochrome, as magnesium is not a component of cytochrome.
- **Haemoprotein**: While cytochromes can be classified as haemoproteins, this term is broader and includes other proteins that contain heme.
- **Iron porphyrin ring**: This accurately describes the structure of cytochrome, as it contains an iron atom within a porphyrin ring.
- **Alloy of nichrome**: This is unrelated to cytochrome and pertains to materials used in electrical applications.

5. **Conclusion**:
- Based on the analysis, the most accurate description of cytochrome is "iron porphyrin ring." Therefore, the correct answer is option number three: **Iron porphyrin ring**.