Nitrogen Cycle Webquest
Objectives: Students will be able to…
Order the three chemical reactions that take place in the nitrogen cycle
Identify the reactants and products of each chemical reaction
Explain why the nitrogen cycle is necessary for humans
Directions:
Use the “starter” link posted below, your textbook, reading notes (pages 752 to 755) and any other RELIABLE
source to answer the following questions about the nitrogen cycle in your biology journal.
“Starter” Link: http://www.physicalgeography.net/fundamentals/9s.html
1. How is nitrogen important in our lives? In other words, what do humans use nitrogen for?
2. Nitrogen makes up _____________________________________ of the air we breathe.
3. Why are nitrogen-fixing bacteria contributions to the nitrogen cycle so important? In your answer, be sure
to define nitrogen fixation and explain where these bacteria can be found. What chemical forms of nitrogen
are involved?
4. How do animals get the nitrogen they need?
5. How does the human use of fertilizer impact the nitrogen cycle?
6. How does a plant take in the nitrogen it needs? In your answer, be sure to define and include nitrification
and assimilation. What chemical forms of nitrogen are involved?
7. Once in plants and animals, explain how nitrogen returns to the atmosphere. In your answer, define the
process of denitrification and the chemical forms of nitrogen involved.