The ultimate electron acceptor of respiration in an aerobic organismsis is:

Options

A. Cytochrome
B. Oxygen
C. Hydrogen
D. Glucose

Answer

To solve the question regarding the ultimate electron acceptor of respiration in aerobic organisms, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Aerobic Respiration**:
- Aerobic respiration is a metabolic process that requires oxygen to produce energy. It involves the breakdown of glucose (or other substrates) in the presence of oxygen.

2. **Identifying the Role of Electron Acceptors**:
- In cellular respiration, electrons are transferred through a series of reactions, and an electron acceptor is required to complete the process. The final electron acceptor is crucial for the continuation of the electron transport chain.

3. **Evaluating the Options**:
- **Cytochrome**: While cytochromes are involved in the electron transport chain, they are not the final electron acceptor.
- **Oxygen**: Oxygen is known to be the final electron acceptor in aerobic respiration, where it combines with electrons and protons to form water.
- **Hydrogen**: Hydrogen is not an electron acceptor; it is usually a donor in these reactions.
- **Glucose**: Glucose is the initial substrate that gets oxidized, but it is not the final electron acceptor.

4. **Conclusion**:
- Based on the above evaluations, the ultimate electron acceptor of respiration in aerobic organisms is **oxygen**.

### Final Answer:
The ultimate electron acceptor of respiration in aerobic organisms is **oxygen**.

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