4.10: Describe the Stages in the Nitrogen Cycle, Including the Roles of Nitrogen Fixing Bacteria, Decomposers, Nitrifying Bacteria and Denitrifying Bacteria (Specific Names of Bacteria are Not Required)

NITROGEN CYCLE: Describes the Movement of Nitrogen Compounds in the Environment

THE NITROGEN CYCLE

Diagram Showing the Nitrogen Cycle

EXPLANATION: NITROGEN FIXATION Nitrogen Gas in the Atmosphere is Too Unreactive to be Used Directly so Needs to be Converted into Soluble Ions Nitrogen Fixing Bacteria in Root Nodules of Legumes will Convert Nitrogen Gas into Nitrates for Use Lightning will Convert Nitrogen Gas into Nitrates Haber Process will Convert Nitrogen Gas into Ammonia, in which Nitrifying Bacteria will Convert into Nitrites, then Nitrates ABSORPTION BY PLANTS Plants will Absorb Nitrates through the Roots by Active Transport Nitrate Ions Help Produce Amino Acids which will become Protein, Becoming Part of Plants Biomass MOVING ALONG FOOD CHAINS Animals will Eat Plants and Nitrogen from the Plant’s Protein will become Protein in the Animal Nitrogen is also Passed from One Animal to Another by Feeding DEATH OF ORGANISMS Decomposers (Bacteria and Fungi) will Break Down urea, Egested Material and Dead Bodies and Nitrogen Compounds will be Returned to the Soil as Ammonium Ions Nitrifying Bacteria will Convert Ammonium Ions into Nitrites, then Nitrates for Plants to Absorb DENITRIFICATION Denitrifying Bacteria in the Soil will Break Down Nitrates and Return Nitrogen Gas into the Air This Occurs in Waterlogged Soil so can be Prevented by Reducing Drainage