Nitrogen cycle Flashcards
Name nitrogen fixing bacteria
Rhizobium and Azotobacter
What do rhizobium do?
Convert nitrogen gas (N2) into ammonium ion (NH4+)
Are rhizobium aerobic or anaerobic?
ANAEROBIC
What is nitrification?
The aerobic process of converting ammonium ions (NH4+) into nitrite ions (NO2-) (done by Nitrosomas) and nitrite ions (NO2-) into nitrate ions (NO3-) (done by Nitrobacter).
Is nitrification aerobic or anaerobic? Explain
AEROBIC - both nitrosomonas and nitrobacter (the two bacteria involved) require O2 to convert ammonium ion into nitrite ions (NO2-) and nitrite ions (NO2-) into nitrate ions (NO3-).
What do nitrosomonas do?
Convert ammonium ions (NH4+) into nitrite ions (NO2-) using O2.
What do nitrobacter do?
Convert nitrite ions (NO2-) into nitrate ions (NO3-) using O2
What is denitrification?
ANAEROBIC process where nitrate ions (NO3-) are converted to nitrogen gas (N2), by pseudomonas.
What do pseudomonas do?
Convert nitrate ions (NO3-) to nitrogen gas (N2) anaerobically.
Is denitrification anaerobic or aerobic?
Anaerobic - it can hence happen in waterlogged soils.
How does ploughing a field effect the nitrogen cycle?
Increases aeration -> increases nitrification since nitrification is aerobic. Ammonium ions (NH4+) are converted to nitrite ions (NO2-) which are converted to nitrate ions (NO3-).
How does waterlogged soil effect the nitrogen cycle?
Increases ‘anaerobic condition’ -> increases denitrification and decreases nitrification as they are anaerobic and aerobic respectively. Fewer ammonium ions (NH4+) are converted to nitrate ions (NO3-) and more nitrate ions (NO3-) are converted to nitrogen gas (N2).
What is nitrogen fixation?
The conversion of atmospheric nitrogen gas (N2) to Ammonium ions (NH4+).
What forms of nitrogen are absorbed by plants?
Ammonium ions (NH4+) and Nitrate ions (NO3-)
What do plants do with nitrogen?
They use it for protein synthesis and the production of amino acids to build proteins.
