Chemistry
How the Urea Cycle Removes Excess Nitrogen from the Body
Quick fact
The urea cycle converts highly toxic ammonia into water-soluble urea, which is then excreted in urine; this cycle consumes 4 ATP per urea molecule and is the only way mammals can safely eliminate excess nitrogen.
Why this is interesting
When you eat a high-protein meal, your body breaks down amino acids—but the leftover nitrogen is toxic. So how does your body safely dispose of it?