The urea cycle
Main purpose of this cycle is the production of urea, the end product that is excreted as waist from the body. It is important that you understand that via this cycle the body - bit by bit - can lose superfluous nitrogen. Normally, Nitrogen enters the body via amino acids.
This cycle is connected to the Krebs cycle (combustion of sugar in many steps) and this cooperation creates a metabolism (a strong catabolism).
The urea cycle simultaneously serves the katabolism of old amino acids.
The waist leaves the body via urine.