Biology / Unit 14 Bio 3663 short lesson, about 20 seconds
The Nitrogen Cycle
Captions available
The idea
The nitrogen cycle moves nitrogen between its inert atmospheric form and biologically usable ones, entering through the fixation of Bio 2585 and returning by denitrification.
In practice
Nitrogen-fixing bacteria in legume root nodules convert nitrogen gas into ammonia usable by the plant.
Where people slip
Most organisms cannot use atmospheric nitrogen directly — fixation is a specialized bacterial bottleneck the cycle depends on.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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