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Nitrogen Cycle Worksheet
Name: ______________________
Intro:
Living organisms are made of atoms – mostly Carbon (C), Hydrogen (H), Oxygen (O), Phosphorus (P),
Sulfur (S) and Nitrogen (N). Today we will learn all about the cycling of Nitrogen in ecosystem.
Where can you find Nitrogen?
Nitrogen can exists as either solid, liquid or gas. In the atmosphere nitrogen gas (N2) makes up 78% of the
atmosphere. However, nitrogen must be converted or FIXED by bacteria before it can be used by others.
Task #1:
Go to our class’ wikispaces and look at today’s agenda. Visit the 1st website noted there to get an overview of
the nitrogen cycle. Then visit the 2nd website to get detailed information on the various steps of Nitrogen
Cycle to complete this worksheet. http://www.teachersdomain.org/asset/lsps07_int_nitrogen/
Press the “play” button to start and pause the animation.
Roll over your mouse to various objects to get detailed explanations for each object.
Nitrogen fixation:
Nitrogen fixation occurs when _________________ converts N2 gas into _________________________ that
living things can take up.
Nitrogen-fixing bacteria, such as the ones found in roots of legumes (ex: soybean plants) supply nitrogen
to the plant. In exchange, the bacteria receive _______________________________________
Ammonification:
In this step, bacteria in soil or fungi will convert nitrogen into _____________________________
Nitrification:
A 2-step process:
1) Soil bacteria converts _______________________ into ___________________
2) Soil bacteria then convert nitrite ions into _____________________________
Denitrification:
In this process __________________________ are converted to _________________ gas, which are then
released to the atmosphere.
Assimilation:
This occurs when ________________________________________________________________________
Task #2:
From what you have learned, draw your own Nitrogen Cycle diagram that shows all of the 5 steps involved.