1. Nitrogen Cycle Practice

2. Explain why living things need nitrogen.
To make protein
Enzymes
Antibodies
Muscle

3. Explain why nitrogen atoms are able to cycle.
Atoms are not created or destroyed during chemical reactions
Only bonds change
Re-arranged N N N N N

4. The nitrogen cycle is driven by chemical reactions performed by .
bacteria

5. Identify the nitrogen-containing molecule below.
Ammonia (NH3)

6. State the location of this molecule in nature.
Soil

7. Identify the nitrogen-containing molecule below.
Protein

8. State the location of this molecule in nature.
Living things (plants and animals)

9. Identify the nitrogen-containing molecule below.
Nitrogen gas (N2)

10. State the location of this molecule in nature.
Atmosphere/air

11. Explain why living things cannot use N2 gas directly to make protein.
Triple bond

12. During the nitrogen cycle, N2 gas must be transformed into .
NH3

13. This chemical reaction is called .
nitrogen fixation

14. Explain what it means to say that the N2 is “fixed.”
Made useable

15. The ONLY type of organism that can fix nitrogen are
that live in the .
bacteria
soil
Nitrogen-fixing bacteria

16. Explain how nitrogen-fixing bacteria are able to split N2.
Enzyme
Lowers the A.E. H H H N N H H H

17. Nitrogen fixation moves nitrogen from the to the .
atmosphere
soil

18. Identify the process below.
Denitrification

19. State which type of organism performs this reaction.
A second type of soil bacteria

20. Denitrification moves nitrogen from the back to the.
soil
atmosphere

21. Label the bio and geo parts of the carbon cycle.

22. Which chemical reaction removes nitrogen from the soil?
Denitrification

23. Other that denitrification, how else is nitrogen removed from the soil?
Absorbed by roots

24. Which two processes add nitrogen to the soil? #25 in SG
Nitrogen fixation
Pooping/dying

25. How is nitrogen passed from autotrophs to heterotrophs?
Eating