BRAINCAKENitrogen Fixation
Nitrogen fixation is the conversion of nitrogen gas (N2) from the atmosphere into ammonia (NH3), which forms ammonium ions (NH4+) in solution. This makes nitrogen available to living organisms.
Breaking the strong triple bond in N2 needs a lot of energy. Nitrogen-fixing bacteria do it using the enzyme nitrogenase, with ATP from respiration.
There are two main groups of nitrogen-fixing bacteria:
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Key terms in this lesson
- nitrogenase
- The enzyme, found in nitrogen-fixing bacteria, that catalyses the conversion of nitrogen gas into ammonia.
- root nodule
- A swelling on the root of a leguminous plant containing mutualistic nitrogen-fixing bacteria such as Rhizobium.
More in Nutrient Cycles
- Nutrient Cycles
- Role of Saprobionts
- The Nitrogen Cycle
- Ammonification
- Nitrification
- Denitrification
- The Phosphorus Cycle
- Mycorrhizae
All 13 lessons in Nutrient Cycles · All AQA A-level Biology topics