Nitrogen Cycle Flashcards

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1
Q

Nitrogen cycle

A

Manufactures proteins, nucleic acids, other nitrogen containing compounds ….

  1. 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
  2. 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
  3. 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
  4. 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
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2
Q

Phosphorus cycle

A
  1. Geographical uplifting of rocks being phosphate ions
  2. Weathering + erosion of rocks, phosphate ions dissolve, plants absorb into biomass
  3. Phosphate ions pass into animals who feed on plants
  4. Some excreted as waste
  5. Plants and animals die, decomposers release phosphate ions into water and soil
  6. Transported to streams, rivers, oceans forms sedimentary rock again
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