During ETS oxygen is present at the end of respiratory chain as terminal acceptor of electron. It accepts electron from :-

Options

A. A mobile electron carrier
B. Two different electron carriers simultaneously
C. An iron and copper containing electron carrier
D. A mobile H-carrier

Answer

**Step-by-Step Solution:**

1. **Understanding the Electron Transport System (ETS):**
The Electron Transport System (ETS) is the final stage of cellular respiration, which occurs in the mitochondria. It involves a series of protein complexes that transfer electrons through a chain.

**Hint:** Remember that ETS is part of aerobic respiration and occurs in the mitochondria.

2. **Role of Oxygen in ETS:**
In the ETS, oxygen acts as the terminal electron acceptor. This means that at the end of the electron transport chain, oxygen is the molecule that receives the electrons.

**Hint:** Think of oxygen as the final destination for electrons in the respiratory chain.

3. **Electron Transfer Process:**
Electrons are transferred from one molecule to another within the ETS. The process involves various electron carriers, which include protein complexes that accept and donate electrons.

**Hint:** Visualize the electron transport chain as a relay race where electrons are passed from one carrier to the next.

4. **Identifying the Source of Electrons:**
The electrons that oxygen accepts come from the previous electron carriers in the chain. Specifically, the last electron carrier before oxygen is known as Cytochrome c oxidase (also referred to as Cytochrome O3).

**Hint:** Focus on the last electron carrier in the chain that directly interacts with oxygen.

5. **Composition of Cytochrome c oxidase:**
Cytochrome c oxidase contains iron and copper, which are essential for its function as an electron carrier. It facilitates the transfer of electrons to oxygen, resulting in the formation of water.

**Hint:** Remember that the presence of metal ions like iron and copper is crucial for the function of many electron carriers.

6. **Conclusion:**
Therefore, oxygen accepts electrons from Cytochrome c oxidase, which is the correct answer to the question.

**Final Answer:** Oxygen accepts electrons from Cytochrome c oxidase (which contains iron and copper).

---