In cellular respiration, the final acceptor molecule of proton is :

Options

A. NAD
B. FAD
C. NADP
D. Oxygen

Answer

**Step-by-Step Solution:**

1. **Understanding Cellular Respiration**: Cellular respiration is the process by which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water. It involves several stages, including glycolysis, the Krebs cycle, and the electron transport chain.

2. **Identifying the Final Electron Acceptor**: In the context of cellular respiration, the final acceptor of electrons (and protons) is crucial for the production of ATP. The process involves the transfer of electrons through a series of proteins in the inner mitochondrial membrane.

3. **Evaluating the Options**:
- **NAD (Nicotinamide Adenine Dinucleotide)**: This molecule acts as an electron carrier but is not the final acceptor of protons.
- **FAD (Flavin Adenine Dinucleotide)**: Similar to NAD, FAD is also an electron carrier involved in metabolic reactions but does not serve as the final proton acceptor.
- **NADP (Nicotinamide Adenine Dinucleotide Phosphate)**: This molecule is primarily involved in anabolic reactions and is not the final acceptor in cellular respiration.
- **Oxygen**: Oxygen is the final electron and proton acceptor in the electron transport chain. It combines with electrons and protons to form water, making it the correct answer.

4. **Conclusion**: The final acceptor molecule of protons in cellular respiration is oxygen.

**Final Answer**: Oxygen.

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