What is true of urea biosynthesis

Options

A. Uric acid is starting pointÂ
B.  Urea is synthesized in lysosomes
C. Urea cycle enzymes are located inside mitochondria
D. Urea is synthesized in kidneyÂ

Answer

C

Explanation

 Urea cycle was discovered by Krebs and Hanseleit.
Urea cycle takes place in liver cells.
In urea cycle, `NH_(3)` is converted into urea.
In urea cycle, 2 molecules of `NH_(3)` and 1 molecule of `CO_(2)` is involved.
Urea cycle removes two waste products from the blood in liver, i.e. `NH_(3)` and `CO_(2)`.
Urea `(NH_(2)-CO-NH_(2))` has 2 amino `(-NH_(2))` groups, one derived from `NH_(3)` and other from aspartate.
C-atom of urea is supplied by `C0_(2)`.
One molecule of `NH_(3)` and one molecule of `CO_(2)` reacts to form carbamoyl phosphate. Carbamoyl phosphate reacts with omithine to form citrulline. Citrulline reacts with aspartate to produce arginosuccinate. Arginosuccinate cleaves to give fumarate and arginine. Arginase cleaves to arginine to form urea and omithine.
Ornithine is reused in urea cycle. Urea is transported to kindey for its removal.
3 amino acids participating in urea cycle are ornithine, citrulline and argine.