The final electron acceptor of the electron transport chain that functions in oxidative phosphorylation is :

Options

A. A) pyruvic acid
B. B) oxygen
C. C) water
D. D) `NaD^(+)`

Explanation

**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, specifically in oxidative phosphorylation.

2. **Role of Electron Carriers:**
- During cellular respiration, electrons are transferred from electron donors (like NADH and FADH2) to the ETC. These electrons are passed through various complexes in the chain.

3. **Hydrogen Ion Movement:**
- As electrons move through the complexes, they help pump hydrogen ions (H+) from the mitochondrial matrix into the intermembrane space, creating a proton gradient.

4. **Final Electron Acceptors:**
- At the end of the electron transport chain, the electrons need to be accepted by a final electron acceptor to maintain the flow of electrons through the chain.

5. **Identifying the Final Electron Acceptor:**
- The options provided are:
- A) Pyruvic acid
- B) Oxygen
- C) Water
- D) NAD+
- Among these, oxygen is the most suitable option as it is the final electron acceptor in the electron transport chain.

6. **Formation of Water:**
- When oxygen accepts the electrons, it reacts with hydrogen ions (H+) to form water (H2O). This reaction is crucial as it prevents the backup of electrons in the chain, allowing for continued ATP production.

7. **Conclusion:**
- Therefore, the final electron acceptor of the electron transport chain that functions in oxidative phosphorylation is **oxygen** (option B).

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