3.5.4 Nutrient Cycles Flashcards
In which form do plants need nitrogen?
Most organisms can not use nitrogen gas so they must secure their nitrogen in its fixed form
What are the fixed forms of nitrogen?
Nitrate ions: NO3 (2- charge)
Ammonia: NH3
Ammonium: NH4 (+1 charge)
What are the four nitrogen processes? (No explanation)
Nitrogen fixation
Decomposition
Nitfrification
Dentrification
What is nitrogen fixation?
Forming fixed compounds from nitrogen gas
What is decomposition it terms of the nitrogen cycle?
The breaking down of compounds into ammonia
What is nitrification?
The oxidation of ammonia into nitrates
What is dentrification?
The reducing of nitrates into nitrogen gas
What is biological fixation?
Fixation by microbes
What is atmospheric fixation?
Fixation by lightning where the energy combines with oxygen
What is industrial fixation?
Fixing of nitrogen during the Haber process
What is Rhizobium?
A symbiotic bacteria which fixes nitrogen and takes sugars produced by the plant
Contains an enzyme called nitrogenase that converts nitrogen and hydrogen to ammonia
How do animals secure their nitrogen?
From plants through feeding
What is responsible for decomposition in the nitrogen cycle?
Microorganisms
What are the types of nitrifying bacteria?
Genus Nitrosomes: oxidises NH3 to nitrites
Genus Nitrobacter: oxidises nitrites to nitrates
Out of the phosphorous and nitrous cycles, which is faster?
Nitrous