Flashcards
Nitrogen Cycle
Cards in this deck (13)
- 1what are the four stages?ammonification, nitrification, nitrogen fixation and denitrification.
- 2what is nitrogen fixation?a process where nitrogen gas is converted into nitrogen-containing compounds.
industrially or by lightning. - 3what are the two main forms nitrogen fixation is carried out by microorganismsfree-living nitrogen-fixing bacteria
mutualistic nitrogen-fixing bacteria - 4what are free living nitrogen-fixing bacteriathey reduce gaseous nitrogen to ammonia which they use to manufacture amino acids. nitrogen rich compounds are released from them when they die + decau
- 5what are mutualistic nitrogen-fixing bacteriathey live in nodules on the roots of plants such as peas and beans. they obtain carbohydrates from the plant and the plant acquires amino acids from the bacteria
- 6what is ammonificationthe production of ammonia from organic ammonium containing compounds.
e.g. urea, proteins, nucleic acid and vitamins. - 7how does ammonification happen1- saprobiotic microorganisms (fungi/bacteria) feed on the materials,
2- decaying/breaking down the proteins/waste products,
3- this releases ammonia
4- forming ammonium ions in the soil. - 8what is nitrificationit is the oxidation of ammonium ions to nitrate ions, releasing energy
in free-living soil microorganisms - 9what are the two stages of nitrification1- oxidation of ammonium ions to nitrite ions NO2-
2- oxidation of nitrite ions to nitrate ions NO3- - 10what happens to the nitrates from nitrificationget absorbed by plants
- 11what is denitrificationwhen in anaerobic conditions denitrifying bacteria use nitrates and release nitrogen into the air
- 12why is denitrification bad for farmersit reduces the availab//ility of/ nitrogen containing compounds for plants and so they must keep the crop soil well aerated
- 13what is a saprobiotic microorganisman organism that obtains its food from the dead/decaying remains of other organisms.
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- A Level BIOLOGY A2 (UNIT 4) Flashcards on Nitrogen Cycle, created by Max B on 22/10/2015.
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- Max B
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