Oxidative phosphorylation of cytoplasmic `NADH(H^(+))` takes place in

Options

A. Cytosol
B. E.R.
C. Mitochondria
D. Golgi bodies.

Answer

To solve the question regarding where oxidative phosphorylation of cytoplasmic NADH occurs, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding NADH Production**:
- NADH is primarily produced during glycolysis and the Krebs cycle (also known as the citric acid cycle).
- Glycolysis occurs in the cytoplasm, where glucose is broken down into pyruvate, generating NADH in the process.

2. **Role of NADH in Oxidative Phosphorylation**:
- NADH is an electron carrier that donates electrons to the electron transport chain (ETC) during oxidative phosphorylation.
- The electrons from NADH are transferred through a series of protein complexes in the mitochondria.

3. **Location of Oxidative Phosphorylation**:
- Oxidative phosphorylation occurs in the inner mitochondrial membrane.
- The inner mitochondrial membrane houses the electron transport chain and ATP synthase, which are crucial for the process.

4. **Mechanism of Oxidative Phosphorylation**:
- The electrons from NADH are transported through the protein complexes of the ETC, leading to the pumping of protons (H⁺ ions) into the intermembrane space.
- This creates a proton gradient, which drives ATP synthesis as protons flow back into the mitochondrial matrix through ATP synthase.

5. **Conclusion**:
- Therefore, the oxidative phosphorylation of cytoplasmic NADH takes place in the mitochondria.

### Final Answer:
The oxidative phosphorylation of cytoplasmic NADH takes place in the mitochondria.

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