37.21 Nitrogen Cycle Flashcards
How is Nitrogen Cycle cycled
nitrogen gas
Chemical formula of nitrogen gas
N2
What is nitrogen a limiting factor of
plants
What molecules are nitrogen important ingredients of
proteins and nucleic acids
How many abiotic reservoirs does nitrogen have
2
What are the 2 abiotic reservoirs of nitrogen
the atmosphere and soil
Is nitrogen cycled globally or locally
both because its abiotic reservoirs are soil and the atmosphere
How much of the atmosphere is nitrogen
80%
Can plants absorb nitrogen in its N2 form
no
Nitrogen Fixation
the conversion of atmospheric nitrogen (N2) to nitrogen compounds (NH4+ and NO3-) that plants can absorb and use
What organism does nitrogen fixation
bacteria
Can animals use N2 in its N2 form
no
What kind of atom is N2
a diatomic atom
Diatomic Atom
an atom that always pairs with at least itself and is never found alone
How many steps does the nitrogen cycle have
8
What is the first step of the nitrogen cycle
Nitrogen Fixing Bacteria that live symbiotically in the root nodules of some species of plants supply their hosts with a usable source of nitrogen
Legumes
the largest group of plants that has this mutualistic relationship with bacteria which supplies them with a usable source of nitrogen
What is the second step of the nitrogen cycle
Nitrogen-fixing bacteria converts N2 to ammonia, which then picks up another H+ to become ammonium .
Chemical formula of ammonia
NH3
Chemical formula of ammonium
NH4+
What is the third step of the nitrogen cycle
Nitrifying bacteria in the soil convert some of the NH4+ to nitrites and then into nitrates which is more easily usable by plants
What form of nitrogen is usable by plants
nitrates
Chemical Formula for nitrates
NO3-
Chemical Formula for nitrites
NO2-
Are nitrites usable by plants
no
What is the 4th step of the nitrogen cycle
Plants use the nitrate to synthesize molecules such as amino acids, which make proteins and nucleic acids which make nucleotides
What is the 5th step of the nitrogen cycle
Herbivores eat plants and digest the proteins to build the protein it needs
Carnivores and omnivores gain nitrogen from their prey and do the same thing as the herbivores
Despite the losing of nitrogen in step 5 what else happens?
Nitrogen containing waste products are also made during metabolism
Where is nitrogen-fixing bacteria found
in soil, lagoons, and bean plants
What is the 6th step of the nitrogen cycle
Organisms that are not consumed eventually die and become detritus which is decomposed by prokaryotes and fungi. Decomposition releases NH4+ from organic compounds back into the soil, replenishing the soil reservoir of NH4+
What happens to the NH4+ created during decomposition after it goes back into the soil
it goes back to the nitrogen fixing bacteria and nitrifying bacteria (Goes back into the cycle that was earlier in the nitrogen cycle)
What is the last step of the nitrogen cycle
Denitrifying Bacteria strip the oxygen from NO3-, releasing N2 back into the atmosphere in low oxygen conditions
What is dentrifying bacteria aka
Dentrifiers
What is the cycle of how nitrogen cycles chemically
N2 –> NH3 –> (NH4+) –> (N02-) –> (NO3-) –> (NH4+) –> (NO2-) –> (NO3-) –> Ns
How do human activities also disrupt the nitrogen cycle
by adding more nitrogen than what is added by natural processes by combustion of fossil fuels and coal power plants which produce nitrogen oxides
Nitrogen Oxides
NO and N2
Outside of the nitrogen cycle how are some NH4+ and NO3-
in the atmosphere by chemical reactions including N2 and ammonia
