Question

from where are two amino groups of urea derived?

Answer 1

NH4+ and aspartate, the forms in which nitrogen enters the urea cycle, are produced from amino acids in the liver by a series of transamination and deamination reactions.

Answer 2

The two amino groups in urea are derived from $NH_{3}$ and aspartate.

• The end product of the amino-acid metabolism is urea. The nitrogen present in the amino acids when converted to ammonia becomes toxic hence, it is instead converted to urea and detoxified.
• The synthesis of urea is a cyclic process with five steps.
• The carbon atom is provided by carbon dioxide.