Nitrogen Cycle
The nitrogen cycle is the cycle in which nitrogen transforms
from one substance to another so it can be used properly. This
cycle begins with nitrogen floating in the air. This nitrogen is
then either fixed by bacteria or fixed by lightning. When struck
by lightning it allows nitrogen to mix with oxygen creating NO3_.
This substance is then absorbed by soil. From the soil it is
absorbed by roots. In the root nodules the nitrogen is mixed
with other compounds to form N*. The plant has now used this
nitrogen by turning it into nitrates, nitrites, and ammonia. Then
an animal like a mouse comes along and eats part of this plant.
The nitrogen compound is now being used by the animal. When
this animal creates feces or dies the N* is slowly released back
into the atmosphere. On the way up a different kind of bacteria
is on the job creating the N* back into N2. And then it starts all
over again.
This cycle is very important because plants and animals need it
to survive. If there was no nitrogen then nothing would be able
to survive. Therefore this cycle may not be the most important,
but still plays a big role in ecosystems.
Nitrogen interacts with living organisms. If it didn’t, nothing
would live. The nitrogen goes through a cycle. Plants absorb it
and get eaten by animals, and then those animals get eaten by
other animals, which leads us into a food chain.
The cycle is taking place everywhere you look, in the classroom,
outside, and even right in front of your face. This is taking place
everywhere you’ve ever been and can think of right now.
Fun Facts:
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About 78% of the Earth’s atmosphere is made of nitrogen.
Before nitrogen gets fixed its atomic number is N2.
Nitrogen is the 5th most common gas.
Ammonium ions NH4+
Nitrogen Test
1. What kinds of things fix nitrogen?
____________and__________
2. Name 2 places where nitrogen is found.
___________and___________
Circle one:
What is the sub atomic number before being mixed with
oxygen:
N2
NO3_
NH4+
How much of the atmosphere is nitrogen:
100%
78%
52%
How does nitrogen return to the atmosphere:
Dead or decaying animals or plants fossil fuels being burnt
True or False:
Nitrogen is 5th most common gas
_________________
The element nitrogen is used for plant and animal life
_________________
Multiple Choice:
N2 is fixed by what in the root nodules
a. Nothing
b. Bacteria
c. Chlorophyll
What eats plants to get the nitrogen needed:
a. rocks
b. bugs
c. animals
d. bugs and animals
Name 2 things that happen in the nitrogen cycle?
__________________________________________________
__________________________________________________
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Answer sheet
1. Bacteria and lightning
2. Soil, plants, roots, air, stems, leaves, dead or decaying things,
waste, water, animals
3. N2
4. 78%
5. Dead or decaying animals or plants
6. True
7. True
8. B.
9. D.
10.
Anything in cycle check diagram