The end product of oxidative phosphorylation is:

Options

A. `ATP + H_2O`
B. oxygen
C. ADP
D. NADH

Explanation

**Step-by-Step Solution:**

1. **Understanding Oxidative Phosphorylation**:
- Oxidative phosphorylation is a crucial process in cellular respiration that occurs in the mitochondria. It involves the transfer of electrons through a series of proteins known as the electron transport chain.

2. **Role of Oxygen**:
- During oxidative phosphorylation, oxygen acts as the final electron acceptor. This means that oxygen is essential for the process, but it does not become an end product.

3. **Formation of Water**:
- As electrons are transferred to oxygen, they combine with protons (H+) to form water (H2O). Thus, water is one of the products of this process.

4. **ATP Synthesis**:
- The energy released during the electron transfer is used to pump protons across the mitochondrial membrane, creating a proton gradient. This gradient drives the synthesis of ATP from ADP (adenosine diphosphate) and inorganic phosphate (Pi) through the enzyme ATP synthase.

5. **Identifying the End Products**:
- The end products of oxidative phosphorylation are therefore ATP and water. While ADP is involved in the process, it is not an end product since it is converted into ATP.

6. **Conclusion**:
- The correct answer to the question is that the end products of oxidative phosphorylation are ATP and water (H2O).

**Final Answer**: The end product of oxidative phosphorylation is ATP plus H2O (adenosine triphosphate and water).

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