Last `e^(-)` acceptor during `ETS` is

Options

A. `O_(2)`
B. cyt a
C. cyt `a_(2)`
D. cyt `a_(3)`

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the last electron acceptor during the Electron Transport System (ETS) in respiration.

2. **Defining ETS**: The Electron Transport System (ETS) is a series of protein complexes located in the inner mitochondrial membrane that facilitate the transfer of electrons derived from nutrients. This process is crucial for ATP production.

3. **Identifying Electron Acceptors**: In the ETS, electrons are transferred from one carrier to another. The question provides four options for the last electron acceptor:
- Oxygen
- Cytochrome A
- Cytochrome A2
- Cytochrome A3

4. **Determining the Final Electron Acceptor**: The final electron acceptor in the ETS is essential for the completion of the electron transport chain. It is known that oxygen acts as the terminal electron acceptor.

5. **Formation of Water**: When oxygen accepts electrons, it combines with protons (H+) to form water (H2O). This reaction is crucial for maintaining the flow of electrons through the ETS and for the production of ATP.

6. **Conclusion**: Based on the understanding of the ETS and the role of oxygen, the correct answer to the question is that the last electron acceptor during the ETS is **oxygen**.

**Final Answer**: The last electron acceptor during ETS is **oxygen**.

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