Biology / Unit 11 Bio 2585 short lesson, about 20 seconds
Nitrogen Fixation and the Legume-Rhizobia Symbiosis
Captions available
The idea
Biological nitrogen fixation converts unusable atmospheric nitrogen gas into ammonia, carried out by soil bacteria called rhizobia living symbiotically in legume root nodules.
In practice
A soybean's root nodules house rhizobia that fix nitrogen into ammonia in exchange for sugars the plant supplies from photosynthesis.
Where people slip
Plants cannot fix nitrogen themselves — they lack the enzyme nitrogenase and depend on this symbiosis for usable nitrogen.
Your place on the trail
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