1. The Nitrogen Cycle
Why do organism need nitrogen?
What are the different forms of naturally Nitrogen?
All organisms require nitrogen to make amino acids, which in turn are used to build proteins.
Many different forms of nitrogen occur naturally in the biosphere
Nitrogen gas (N2)
Nitrate ions (NO3 -)
Nitrite ions (NO2 -)
Ammonia (NH3)

2. What are the processes involved in the nitrogen cycle?
Vocabulary
Nitrogen fixation
Denitrification
Nitrification
There are several kinds of processes involved in the nitrogen cycle.
Nitrogen fixation is the process of converting gas into ammonia (NH3). This process is done by bacteria and by lighting.
Denitrification is the process of converting nitrates (NO3 -) and nitrites (NO2 -) into nitrogen gas.
Nitrification is the process of converting ammonia (NH3) into nitrites (NO2 -) and nitrates (NO3 -)

3. Bacteria or lighting converts the N2 gas into ammonia (NH3)
Bacteria or lighting converts the N2 gas into ammonia (NH3). Other bacteria in the soil convert the NH3 into nitrates and nitrites. Producers use the nitrates and nitrites to make proteins. Consumers then eat the producers and reuse the nitrogen to make their own proteins.
When organism die, decomposers return the nitrogen to the soil as ammonia.

4. Vocabulary
Denitrification
The nitrates may be taken up again by producers. Other soil bacteria convert nitrates into nitrogen gas in a process know as denitrification. This process releases nitrogen into the atmosphere once again.

5. The Nitrogen Cycle
N2 in Atmosphere
NO3-
and NO2-
NH3