urea science definition

The chief nitrogen-containing waste product excreted in the urine of mammals and some fish. It is the final nitrogenous product in the breakdown of proteins by the body, during which amino groups (NH₂) are removed from amino acids and converted into ammonium ions (NH₄), which are toxic at high concentrations. The liver then converts the ammonium ions into urea. Urea is also made artificially for use in fertilizers and medicine. Chemical formula: CON₂H₄.