Nitrogen! Its a cycle!

IntroductionThe nitrogen cycle is the process by which nitrogen is converted between its various chemical forms.All life requires Nitrogen compounds ex: amino acids, proteinsAir (79% N) is a major reservoir, but most organisms cant take-up/use N in this formPlants must obtain N in fixed forms such as nitrate or ammonia

ExitPlants and Nitrogen

All plants need nitrogen to makeAmino acidsProteinsDNAExitFixation- BacteriaConversion of Nitrogen to ammoniaAtmospheric N must be fixed in order to be taken up by plants, which can take up ammonia and nitrateMost fixation is done by symbiotic or free-living bacteriaThese bacteria contain the nitrogenase enzyme that combines gaseous N with H to produce ammoniaRhizobium (symbiotic bacteria) live on the nodule of legumes and fix N in exchange for carbohydrates

ExitMineralization/ImmobilizationMineralizationConversion of N compounds to ammoniaN from dead organic matter or animal waste is converted by enzymes in soil microbes and released as ammonium into the soil. ImmobilizationWhen microorganisms and plants assimilate ammonium into their cells to form proteins and nucleic acidThe N is being used by microbes and plants and is literally immobilized in the cycle until the organism dies and it can be re-released to the soil. ExitNitrificationConversion of ammonia to nitrate via oxidation (2 step process)Oxidation carried out by nitrifying bacteriaNitrosomas- ammonia to nitriteNitrobacter- nitrite to nitrateLegumes can also preform nitrificationNitrites and nitrates reach the soil when the leaves of legumes are shed

ExitDenirtificationReduction of nitrates back to NitrogenCompletes the cycle!Preformed by bacterial species in anaerobic condition that use nitrate as an electron acceptor in place of oxygen during respirationExitFixation Atmospheric, IndustrialAtmosphericEnergy of lightning breaks nitrogen molecules and enables their atoms to combine with oxygen in the air forming nitrogen oxides. These dissolve in rain, forming nitrates, that are carried to the earth.Contributes roughly 5 8% of the fixed nitrogen

IndustrialWith an iron catalyst and great temperature and pressure H and N can be combined to form ammonia

ExitContentIntroductionPlants and NitrogenFixationMineralization/ImmobilizationNitrificationDenitrificationVideoSummaryExitBeethoven - Op.7 no.4, Sonata in E-flat major, IV. RondoDejan Sinadinovic291860.66