Which one of the following is metabolic waste of protein metabolism

Options

A. `NH_(3), "urea," and CO_(2)`
B. Urea, oxygen, and `N_(2)`
C. Urea, ammonia, and alanine
D. Urea, ammonia, and creatinine

Answer

To determine the metabolic waste of protein metabolism, we need to analyze the options provided and identify which substances are byproducts of protein breakdown.

### Step-by-Step Solution:

1. **Understanding Metabolic Waste**:
- Metabolic waste refers to substances that are produced during metabolism but are not utilized by the body. These substances need to be eliminated.

2. **Identifying Protein Metabolism Byproducts**:
- When proteins are metabolized, they undergo deamination, where the amino group is removed. This process generates ammonia, which is toxic and needs to be converted into less harmful substances like urea.

3. **Analyzing the Options**:
- **Option 1**: Urea, ammonia, and carbon dioxide.
- Urea and ammonia are indeed metabolic wastes, but carbon dioxide is a waste product of carbohydrate and fat metabolism, not specifically protein metabolism.
- **Option 2**: Urea, oxygen, nitrogen.
- Urea is a waste product, but oxygen is essential for respiration and is not a waste. Nitrogen is a component of amino acids but is not excreted as a waste product.
- **Option 3**: Urea, ammonia, and alanine.
- Urea and ammonia are metabolic wastes, but alanine is an amino acid that is utilized by the body and not a waste product.
- **Option 4**: Urea, ammonia, and creatinine.
- Urea and ammonia are metabolic wastes from protein metabolism, and creatinine is a waste product formed from muscle metabolism and is also excreted.

4. **Conclusion**:
- The correct answer is **Option 4: Urea, ammonia, and creatinine**. These substances are metabolic wastes produced during protein metabolism.

### Final Answer:
The metabolic waste of protein metabolism is **Urea, Ammonia, and Creatinine** (Option 4).