Nitrogenous Wastes

AAs

Constructing proteins and other nitrogen-containing molecules for use of certain cells, can also be oxidized for energy or converted to fats and carbohydrates

When AAs are oxidized or converted

made into other molecules, amino (NH2) group must be removed. Nitrogen-containing compounds produced as results of proteins and AA breakdowns are toxic and must be removed

Nitrogenous wastes are excreted in the form of…

Ammonia (NH3), Urea, Uric Acid

Ammonia (NH3)

formed immediately after amino group is removed from AA, often in intestines during digestion, process requires very little energy. highly soluble in H2O but very toxic

Urea

Excreted nitrogenous wastes in form of urea because it’s less toxic than NH3, can be moderately concentrated to conserve H2O. Produced in liver by process requiring more energy than NH3, reducing the toxicity of waste

Uric Acid

End product of specific protein digestion, neither very toxic nor very soluble in water. However, high levels in blood can lead to gouty arthritis or formation of kidney stones. Excreted along with urea

Ureters

pathways for urine that extend from each pelvis to urinary bladder

Uninary bladder

“holding tank” for urine awaiting excretion

Urethra

pathway for external urine excretion