Transcript The Nitrogen Cycle

The Nitrogen Cycle
How the element nitrogen makes it
through the ecosystem
The Nitrogen Cycle
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Description of the Nitrogen
Cycle
• N2 gas in the atmosphere must be taken in
by symbiotic bacteria in the roots of plants
(legumes) through nitrogen fixation. Then
other bacteria change the nitrogen so it can
be taken up by plants. Animals eat plants
and get nitrogen. When plants and animals
die, bacteria do a process called
denitrification which puts nitrogen back in
the atmosphere.
Vocabulary
• Nitrogen Fixation: process that bacteria
use to take up N2 gas from the atmosphere.
• Legume: Plant that puts nitrogen in the soil
because it has symbiotic bacteria living in
its root nodules.
• Denitrification: process that bacteria use
to return N2 gas to the atmosphere.
Biotic and Abiotic Factors
• Biotic Factors:
–
–
–
–
Bacteria
Plants
Animals
Decomposers
• Abiotic Factors:
– Fertilizers add nitrogen
to soil
– N2 gas, nitrates,
nitrites,
Review of a protein
• Elements: CHONS
• Monomers: Amino acids
• Polymers: Polypeptides-chains of amino acids
• Functions: Enzymes,
structure, transport-proteins have many
functions!
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Crop Rotation
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• Farmers must rotate crops
to make sure the soil
contains the proper
amount of nitrogen.
• Usually farmers switch
legumes like beans (which
give nitrogen to the soil)
with other plants like
corn/tomatoes which take
nitrogen from the soil.