urea cycle

views updated May 14 2018

urea cycle (ornithine cycle) The series of biochemical reactions that converts ammonia, which is highly toxic, and carbon dioxide to the much less toxic urea during the excretion of metabolic nitrogen derived from the deamination of excess amino acids. These reactions take place in the liver in mammals and, to a lesser extent, in some other animals. The urea is ultimately excreted in solution in urine.

urea cycle

views updated May 18 2018

urea cycle (ornithine cycle) A cyclic series of reactions by which carbon dioxide and ammonia, the latter derived from amino groups from amino-acid catabolism, are converted to urea prior to excretion.

ornithine cycle

views updated Jun 08 2018

ornithine cycle See UREA CYCLE.

ornithine cycle

views updated Jun 27 2018

ornithine cycle See urea cycle.