Nitrogen Cycle Notes
1.
Why do plants and animals need nitrogen (N)?
To build protein molecules
2. What molecule in the atmosphere is nitrogen normally found in?
N2
3. What molecule in the ground is nitrogen found when there is no oxygen around? NH3
4. What molecule in the ground is nitrogen found when there is oxygen around? NO3
5. What organic molecule in nitrogen found in? Amino acids, proteins
6. What are two ways that atmospheric nitrogen gets into the ground?
Nitrogen – fixing bacteria, lightning
7. What organisms (living things) do the nitrogen fixation for plants? Bacteria
8. Why don’t farmers have to put nitrogen fertilizer on soybeans?
Soybeans are legumes; have nitrogen-fixing bacteria
9. Where do plants get their nitrogen? The ground (NO3)
10. How do primary consumers get their nitrogen? By eating plant protein
11. How do secondary consumers get their nitrogen? By eating animal protein
12. What is another term for primary consumer? Herbivore
13. What is another term for a secondary consumer? Carnivore
14. Where does a plant’s or animal’s nitrogen go when it dies?
The ground, after bacteria decompose the organism
15. What breaks the dead organism’s body back into inorganic nitrogen?
Bacteria
16. How does extra nitrogen get into our water ecosystems (rivers, estuaries, MS Sound)?
Burning fossil fuels, Sewage (animal or human waste), Decay, Fertilizers
17. Why is extra nitrogen in the Gulf of Mexico a problem?
A) Extra nitrogen causes algal blooms
B) Algae blocks sunlight for photosynthesis
C) When the algae dies, bacteria use up the oxygen when it breaks it down (eutrophication)