Deamination

How this is marked

Two scoring points: it happens in the liver, and it produces urea from excess amino acids (which cannot be stored). Students lose marks by saying it removes 'amino acids' rather than the nitrogen-containing part, or by placing it in the kidney. The kidney removes urea from the blood; the liver makes it. Urea is then excreted by the kidney in urine.

In an exam answer

Explaining what happens to excess protein: 'Excess amino acids are deaminated in the liver, where the nitrogen-containing part is removed to form urea, which is then excreted by the kidneys.'

Full topic guide: Excretion in humans