Nitrogen Cycle Flashcards
1
Q
Nitrogen cycle
A
Manufactures proteins, nucleic acids, other nitrogen containing compounds ….
- Ammonification
- Production of ammonia from organic nitrogen containing compounds e.g urea, proteins, nucleic acids, vitamins
- saprobiontic microorganisms feed on dead organisms, faeces, release ammonia, forms ammonium ions in the soil - Nitrification
- Nitrifying bacteria converts ammonium ions to nitrate ions (oxidation release energy)
- oxidation of ammonium ions to nitrite ions
- oxidation of nitrite ions to nitrate ions
- requires O2, farmers need to keep soil aerated by ploughing, good drainage - Nitrogen fixation
- nitrogen gas converted into nitrogen containing compounds
- free living nitrogen fixing bacteria = nitrogen gas to ammonia, used to manufacture aa, nitrogen compounds released when they die + decay
- mutualistic nitrogen fixing bacteria = live in nodules on roots, nitrogen inside, transforms to useful substance for plant e.g carbohydrates - Denitrification
- soils become waterlogged, less O2, fewer aerobic nitrifying + nitrogen fixing bacteria
- increase in denitrifying bacteria = convert soil nitrates to nitrogen gas, reduces nitrogen containing compounds, soil must be aerated to stop this
2
Q
Phosphorus cycle
A
- Geographical uplifting of rocks being phosphate ions
- Weathering + erosion of rocks, phosphate ions dissolve, plants absorb into biomass
- Phosphate ions pass into animals who feed on plants
- Some excreted as waste
- Plants and animals die, decomposers release phosphate ions into water and soil
- Transported to streams, rivers, oceans forms sedimentary rock again