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.
What is the process of decomposition?
Plant and animal proteins are converted into ammonium ions (NH4+).
What is another name for decomposition?
Ammonification
What are the two ways that nitrogen fixation can take place?
Through nitrogen fixing bacteria and through lightning.
