Urea synthesis occurs in:

Options

A. Kidney
B. Liver
C. Brain
D. Muscles

Answer

**Step-by-Step Solution:**

1. **Understanding Urea Synthesis:**
- Urea is a nitrogenous waste product formed in the human body. It is produced as a result of the breakdown of proteins and amino acids.

2. **Identifying the Toxicity of Ammonia:**
- Ammonia, which is a byproduct of protein metabolism, is highly toxic to the body. Therefore, it needs to be converted into a less toxic form for safe elimination.

3. **Role of the Liver:**
- The liver is the primary organ responsible for the conversion of ammonia to urea. This process occurs in specialized cells called hepatocytes.

4. **The Ornithine Cycle:**
- The conversion of ammonia to urea occurs through a series of biochemical reactions known as the Ornithine Cycle (or Urea Cycle). This cycle takes place within the liver cells.

5. **Final Steps of Urea Processing:**
- Once synthesized, urea is transported from the liver to the kidneys. The kidneys filter the blood, allowing urea to be excreted from the body as urine.

6. **Conclusion:**
- Therefore, the synthesis of urea occurs in the liver.

**Final Answer: Urea synthesis occurs in the liver.**

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