Which of the following acts as a mobile carrier for transfer of electrons between complex Ill and IV ?

Options

A. Cyt a
B. Cyt b
C. Cyt c
D. Cyt d.

Answer

To solve the question regarding which molecule acts as a mobile carrier for the transfer of electrons between complex III and complex IV in the electron transport chain, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Electron Transport Chain (ETC)**:
- The electron transport chain is a series of protein complexes located in the inner mitochondrial membrane. It plays a crucial role in cellular respiration by transferring electrons derived from NADH and FADH2 to oxygen, ultimately producing ATP.

2. **Identifying the Complexes**:
- In the ETC, there are several complexes, namely Complex I (NADH dehydrogenase), Complex II (succinate dehydrogenase), Complex III (cytochrome bc1 complex), and Complex IV (cytochrome c oxidase).

3. **Role of Mobile Carriers**:
- Mobile carriers are molecules that transport electrons between the fixed complexes in the ETC. They are essential for the efficient transfer of electrons and maintaining the flow of the electron transport process.

4. **Evaluating the Options**:
- The options provided are:
- A) Cytochrome a
- B) Cytochrome b
- C) Cytochrome c
- D) Cytochrome d

5. **Identifying the Correct Mobile Carrier**:
- Among the options, cytochrome c is known to be the mobile carrier that transfers electrons from Complex III to Complex IV. It is a small heme-containing protein that can move freely in the intermembrane space of the mitochondria.

6. **Conclusion**:
- Therefore, the correct answer to the question is **cytochrome c**.

### Final Answer:
**Cytochrome c acts as a mobile carrier for the transfer of electrons between complex III and complex IV.**

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