Number of cytochrome molecules required for the transfer of a pair of electrons through ETS is

Options

A. 1
B. 2
C. 3
D. 4

Answer

To determine the number of cytochrome molecules required for the transfer of a pair of electrons through the electron transport system (ETS), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Cytochromes**:
- Cytochromes are iron-containing proteins that are embedded in the inner mitochondrial membrane. They play a crucial role in the electron transport chain (ETC) during cellular respiration.

2. **Function of Cytochromes**:
- Cytochromes act as electron carriers in the ETC. They are essential for the transfer of electrons from one molecule to another, facilitating the process of oxidative phosphorylation.

3. **Electron Transfer Capacity**:
- Each cytochrome can transfer only one electron at a time. This is a key point in understanding how many cytochromes are needed for transferring a pair of electrons.

4. **Calculating the Number of Cytochromes**:
- Since one cytochrome can only transfer one electron, to transfer two electrons (which constitutes a pair), we need two cytochrome molecules. This means that for simultaneous transfer of a pair of electrons, two cytochromes are required.

5. **Conclusion**:
- Therefore, the number of cytochrome molecules required for the transfer of a pair of electrons through the ETS is **2**.

### Final Answer:
The number of cytochrome molecules required for the transfer of a pair of electrons through the electron transport system is **2**.

---