the nitrogen cycle Flashcards
how muc hnitrogen is in the atmosphere and why cant this be used
78% in the atmosphere however there are few organisms that use nitrogen gas directly
how do plants take up the nitrogen they need
they take it up as nitrate ions from the soils which is actively transported through the root hair cells
how do animals take in the nitrogen theny need
by taking and eating producers and digesting the producers
in natural ecosystems how are the nitrate concentrations restored
by recycling the nitrate containing compounds
in argricultural systems how are the nitrate ions restored
by the addition of fetrlizers
what is ammonification
production of ammonia from organinic nitrogen containing compounds eg urea , protiens and nucleic acids which can be found in feaces , and the saprobionts break them down
what is nitrification
when the ammonium ions are converted into nitrite ions and then nitrate ions the bacteria that does this gains energy and forms atp from these exothermic processes
what does nitrifying bacteria do
they turn ammonium ions ito nitrite ions and then turn the nitritre ions into nitrate ions
what is essential for the nitrifying bacteria
these reactions are oxidation reactions so they require oxygen with soils with air spaces and no water loggage so the soil must be kept aerated
what is nitrogen fixation
nitrogen gas is converted into nitrogen containing compounds it can happen in harber process, when lightning strikes or by microorganisms
what do free living nitrogen bacteria do
they reduce gaseous nitrofen to ammonia which can then be used to manufacture amino acids which are release when these die
what do mutualistic nitrogen fixing bacteria do
they live on the nodules of the plants they acquire sugars from the plant and plants obtain amino acids from the bacteria
what is denitrification
conversion of soil nitrates back into nitrogen
when does denitrification occur
when the soil becomes water logged and there is less oxygen and the type pof microorganism changes and produces anaerobic denitrifying bacteria
what can denitrification do to crops
they can be unproductive due to the loss of the nitrate ions from the soils
