Deamination occurs in the?

1. Analyze the question The question asks which organ carries out deamination. Deamination is the removal of the amino group (-NH₂) from amino acids.

2. Explain the concept The body cannot store excess amino acids. When there are more than the body needs for building proteins, the extra amino acids are broken down:

• The amino group (-NH₂) is removed. This is deamination.
• The amino group is converted to ammonia (NH₃), which is toxic.
• Ammonia is quickly converted to urea through the ornithine (urea) cycle.
• The remaining carbon part (a keto acid) is used for energy or converted to glycogen or fat.

All of this happens mainly in the liver.

3. Step-by-step solution

• Kidney: it filters urea from the blood and excretes it as urine. It does not make urea by deamination.
• Pancreas: it produces digestive enzymes and hormones (insulin, glucagon). It is not involved in deamination.
• Spleen: it destroys old red blood cells and stores blood. It is not involved in deamination.
• Liver: it removes amino groups from excess amino acids and forms urea. This is correct.

4. Answer The correct option is D. Liver.

5. Exam tip Remember: "Liver = Lots of chemistry." The liver deaminates, makes urea, stores glycogen, and detoxifies. The kidney only excretes the urea. Questions that ask where something is made or converted usually point to the liver, while questions about removal from the body point to the kidney.