Nitrogen cycle

Cards (19)

  • The process to convert nitrogen gass into ammonia is known as nitrogen fixation
  • The bacteria responsible for nitrogen fixation are known as nitrogen-fixing bacteria
  • The 2 nitrogen fixing bacteria you need to know is:
    in plants: Rhizobium where the ammonia is immediately used by the plant
    in soil: azotobacter
  • How is nitrogen gas converted into ammonium ions?
    Nitrogen-fixing bacteria in the soil like azotobacter convert nitrogen into ammonia and ammonia in the soil is converted to ammonium ions
  • Rhizobium in found in the root modules of some plants and allow them to form ammonia and be used by the plant directly
  • Rhizobium and plants are an example of a symbiotic relationship
  • The process of converting ammonium ions to nitrates is called nitrification
    ammonium ions -> nitrites -> nitrates
  • The bacteria responsible for nitrification are classed as nitrifying bacteria
  • Names of nitrifying bacteria:
    ammonium ions -> nitrites : Nitrosomonas
    nitrites -> Nitrate : Nitrobacter
  • Nitrifying bacteria need oxygen as they aerobically respire and nitrification requires oxygen
  • Describe how ammonium ions are converted into a nitrogen-containing compound which plants can absorb
    Plants absorb nitrogen through nitrates in the soil. First, Nitrosomonas convert ammonium ions to nitrite. Nitrobacter then converts nitrite to nitrate. The process of converting ammonium ions to nitrate is known as nitrification. The bacteria that carry out nitrification are called nitrifying bacteria.
  • nitrogen consumed by plants or animals return to the soil by death or excretion and the dead matter is fed on by decomposers called saprobionts and convert the nitrogen containing compounds into ammonia which react with the water in the soil to reform ammonia ions that can undergo nitrification to become nitrates again
  • The process where waste is processed by decomposers and converted into ammonia is known as ammonification
  • denitrification is the process of nitrates being converted back into nitrogen gas
  • Denitrification occurs when denitrifying bacteria anaerobically respire
  • the name for the decomposers that convert waste nitrogen compounds are saprobionts
  • In terms of hydrogen:
    oxidation is loss
    reduction is gain
  • Complete the diagram
    A) rhizobium
    B) azotobacter
    C) Nitrogen fixation
    D) ammonium ions
    E) nitrites
    F) nitrates
    G) Nitrification
    H) Decomposers
    I) denitrifying bacteria
    J) denitrication
    K) nitrogen gas
  • Plants use nitrate to make proteins and nucleic acids