2Molecular Forms of Nitrogen Nitrogen gasN2NH4+NO3-NO2-AmmoniumNitrateNitrite
3Nitrogen Changing Processes The process by which nitrogen-fixing bacteria in the roots of legumes change atmospheric nitrogen to nitrates is called _______________________The process by which N2 or organic nitrogen is changed to ammonium is called____________________The two-step process of changing ammonium to nitrate is called _______________________The process of changing nitrate into atmospheric nitrogen is called __________________The process of changing nitrates into organic nitrogen is called ______________________Nitrogen fixationAmmonificationNitrificationDenitrificationAssimilation
13Nitrogen Cycle Summary ProcessBacteriaN Changed fromN changed toNitrogen FixationAmmonificationNitrification step 1Nitrification step 2AssimilationN/ADenitrificationNitrogen-fixing bacteria in legume rootsNitrogen in airNitrateNitrogen-fixing bacteria in soilNitrogen in airAmmoniumOrganic nitrogenDecay bacteria and fungiAmmoniumNitriteNitrifiying bacteriaNitriteNitrateOrganic nitrogenNitrateDenitrifying bacteriaNitrogen in airNitrate
14Discussion Questions1. The atmosphere is 78% nitrogen: why do you think plants and animals can't use nitrogen as it is found in the atmosphere?2. Explain what is meant by nitrogen fixation.3. What is the role of bacteria in the nitrogen cycle?4. Why don't legumes need nitrogen-containing fertilizers?5. Why is nitrogen so important for living things?
15Nitrogen gas nitrates organic nitrogen gas Ammomium Ammonification Nitrogen fixation is the process that changes nitrogen from ______________. The type of bacteria able to “fix” nitrogen are called___________________________. Nitrogen fixing bacteria in legume roots allowfor nitrogen to be used by legume plants and become ____________________nitrogen.2. Nitrogen fixing bacteria in the soil change nitrogen from _________________to ____________________ by a process called _________________________.3. The nitrifying bacteria in the first white circle change nitrogen from__________________________ to _____________________________ in aprocess called ________________________________.nitratesorganicnitrogen gasAmmomiumAmmonificationAmmomiumnitritenitrification
16nitrates nitrite assimilated organic decay bacteria fungi ammonium 4. This process is continued by a second group of nitrifying bacteria that changenitrogen from _________________________ to _________________________.5. Nitrates can follow one of two paths. If it is taken into a plant, it will be_____________________________ into _____________________ nitrogen.The chipmunk gets the nitrogen it needs by eating plants. Nitrogen containingorganic wastes from either plants or animals will be broken down by___________________________ and ___________________________ into__________________________________.6. Denitrifying bacteria change nitrogen from ______________________________ to_______________________________ returning it to the atmosphere.nitratesnitriteassimilatedorganicdecay bacteriafungiammoniumnitratenitrogen gas