Oxidative electron transport occurs in

Options

A. Chloroplasts
B. Outer membrane of mitochondria
C. Cristae
D. Endoplasmic reticulum

Answer

To solve the question "Oxidative electron transport occurs in," we will analyze the options provided and determine the correct answer step by step.

### Step-by-Step Solution:

1. **Understanding Oxidative Electron Transport**:
- Oxidative electron transport refers to the process where electrons are transferred through a series of protein complexes, ultimately leading to ATP production. This process is also known as the electron transport chain (ETC).

2. **Identifying the Location of the Electron Transport Chain**:
- The electron transport chain is primarily located in the mitochondria, which is the powerhouse of the cell.

3. **Examining the Options**:
- **Option 1: Chloroplast**: This organelle is involved in photosynthesis, not in oxidative electron transport.
- **Option 2: Outer membrane of mitochondria**: The outer membrane does not contain the protein complexes required for electron transport.
- **Option 3: Cristae**: The cristae are the folds of the inner mitochondrial membrane where the electron transport chain is located. This structure increases the surface area for the reactions to occur.
- **Option 4: Endoplasmic reticulum**: This organelle is involved in protein and lipid synthesis, not in oxidative electron transport.

4. **Conclusion**:
- Based on the analysis, the correct answer is **Option 3: Cristae**. The cristae of the inner mitochondrial membrane are indeed the site for oxidative electron transport.

### Final Answer:
Oxidative electron transport occurs in **Cristae** (Option 3).

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