Nitrogen fixation — Science definition
The conversion of unusable nitrogen gas (N₂) into ammonia or nitrates that plants can absorb, carried out mainly by certain bacteria (and by lightning).
Where it is taught
- Biogeochemical Cycles — Ecosystems & Conservation Decisions, Life Science: Biology, Grade 10
In use
The gateway is nitrogen fixation: certain bacteria (including Rhizobium, which lives in nodules on the roots of beans, clover, and other legumes) and bolts of lightning convert N₂ into ammonia and nitrates that plants can finally absorb.
Biogeochemical Cycles
Questions using nitrogen fixation
Problem 1
Nitrogen fixation is important because it
- breaks nitrates down into nitrogen gas
- converts nitrogen gas into a form plants can absorb
- releases carbon dioxide into the atmosphere
- turns liquid water into vapor
Answer and explanation
converts nitrogen gas into a form plants can absorb
Nitrogen fixation, done mainly by bacteria, converts unusable N₂ gas into ammonia and nitrates that plants can take up.
Problem 2
Nitrogen fixation converts
- nitrates into nitrogen gas
- atmospheric nitrogen gas into forms organisms can use
- ammonia into protein
- nitrogen into carbon
Answer and explanation
atmospheric nitrogen gas into forms organisms can use
Nitrogen gas is unreactive, and fixation by certain bacteria, by lightning, or industrially converts it into usable compounds.
Taught alongside
- biogeochemical cycle
- carbon cycle
- transpiration
- photosynthesis
- cellular respiration
- nitrification
- denitrification