Urea Cycle

1. Ammonia bad
   1. in brain
   2. ions
2. Excretory strategies
   1. Ammonotelic
   2. Ureotelic
   3. Uricotelic
3. History
4. Pre-step
   1. carbamoyl phosphate synthase I (CPS I)
   2. carbamoyl phosphate
5. Urea cycle
   1. Step 1
      1. ornithine transcarbamoylase
      2. citruline
   2. Step 2
      1. argininosuccinate synthase
      2. argininosuccinate
   3. Step 3
      1. arginosuccinase
      2. arginine + fumarate
   4. Step 4
      1. arginase
      2. urea + ornithine
6. Clinical Insights
   1. Inherited defects
   2. Liver damage
   3. Hibernation