Final answer:
The process described is the urea cycle, where amino acids are metabolized in the liver to form organic compounds and urea, with urea being the excreted waste product containing nitrogen.
Step-by-step explanation:
The process by which amino acids are broken down and converted to organic compounds and urea in the mammalian liver is known as the urea cycle. In this cycle, the amino groups from amino acids are first removed, converted to ammonia, and then to urea, which is the main nitrogenous waste product excreted by mammals. The steps in the urea cycle involve several enzymes that catalyze the conversion of ammonia into urea. This cycle not only helps in the excretion of nitrogen from the body but also contributes to the metabolic process by which the carbon skeletons of amino acids are used to form compounds that can enter the citric acid cycle for energy production.