Nitrogen Cycle

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Nitrogen Cycle Questions
1. Nitrogen is both the __most abundant element__ and in organisms it is the raw material of two main macromolecules __ammonia and nitrite which build proteins and _nitrates which build your genetic material, DNA. 2. In the atmosphere it is found in the form of N2 which is __nitrogen gas____. 3. These Nitrogen molecules then need to go through a process called __nitrogen fixation__ in order to be converted into molecules that living organisms can use readily. 4. Two forms of Nitrogen that are more readily used by organisms are __ammonia___ NH4+ and __nitrates__ also called NO3-. 5. A very small percentage is fixed through lightening, but most of the Nitrogen fixation on planet Earth comes from plants. Legumes, which are in the bean family, have bacteria living in little root nodules that work right in the soil to take up and convert the Nitrogen so that the roots of the plants can absorb it. Then you get it when you eat the plants or if you also eat animals you Nitrogen from the meat also. These bacteria in the root nodules have an enzyme called ___nitrogenase____ that helps them split the Nitrogen molecules into other forms. 6. The process the microbes go through to break the mainly toxic ammonia molecule into __nitrite__ (NO2- ) and ___nitrate__ (NO3-) is called ___nitrification__. 7. When these smaller molecules are taken up into plant tissue the term is __Assimilation__. 8. When decomposers (the microorganisms that do most of Earth’s recycling) break down decaying organic matter and waste depositing it back into Earth to be used gain this is called ___Ammonification____. 9. The term that names the process by which Nitrate or ( _ NO3-_ ) is converted back into atmospheric Nitrogen (N2) is __Denitrification___. 10. Free-living anaerobic (meaning does not need oxygen) bacteria, nitrogen-fixing legume bacteria, and which other organism can also fix Nitrogen? __cyanobacteria__. 11. What might be one way a human might unintentionally, but...
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