Oxidative phosphorylation is done by

Options

A. Mitochondria
B. Chloroplast
C. Plastids
D. Ribosomes

Answer

**Step-by-Step Solution:**

1. **Understanding Oxidative Phosphorylation**: Oxidative phosphorylation is a metabolic process that produces ATP (adenosine triphosphate), the energy currency of the cell, through the electron transport chain and chemiosmosis.

2. **Identifying the Organelles**: The main organelle responsible for oxidative phosphorylation in eukaryotic cells is the mitochondria. This is where the electron transport chain is located, which is essential for this process.

3. **Role of Mitochondria**: Mitochondria are often referred to as the "powerhouses" of the cell because they generate most of the cell's supply of adenosine triphosphate (ATP) through oxidative phosphorylation.

4. **Excluding Other Organelles**:
- **Chloroplasts**: These are involved in photosynthesis, not oxidative phosphorylation.
- **Plastids**: While some plastids are involved in storage, they do not play a role in oxidative phosphorylation.
- **Ribosomes**: These are responsible for protein synthesis and do not participate in ATP production.

5. **Conclusion**: Based on the information gathered, the correct answer to the question "Oxidative phosphorylation is done by" is the mitochondria.

**Final Answer**: Mitochondria

---