# Describe how excess amino acids are processed in the body and how the waste product is removed.

> Pearson Edexcel International GCSE Biology (4BI1) — 2.13 Excretion: humans · Describe · 4 marks

> The human body cannot store excess amino acids. When more protein is consumed than the body needs, the surplus amino acids must be broken down.

## Mark scheme (4 marks)

1. Excess amino acids are broken down / deaminated in the liver
2. The amino / nitrogen-containing part is converted into urea (in the liver)
3. Urea is transported in the blood (from the liver) to the kidneys
4. The kidneys filter urea from the blood and it is excreted in urine

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