Nutrient Cycles – Practice Questions
Water Cycle
1. What are two processes that cause water to enter the atmosphere?
2. Starting at water leaving an ocean, list and describe each step in the water cycle.
3. How can humans affect the water cycle?
Nitrogen Cycle
4. In your own words, describe why the nitrogen cycle is important and how it works.
5. What are the types of bacteria involved in the nitrogen cycle and what do they each do?
6. What is the only “usable” form of nitrogen? Explain.
7. How can humans affect the nitrogen cycle?
Carbon Cycle
8. In your own words, describe how the carbon cycle works.
9. What is the role of photosynthesis in an ecosystem? Why is it needed and what does it release?
10. How are photosynthesis and cellular respiration related?
11. What is the point of cellular respiration? Why is it needed and what does it release?
12. How can humans affect the carbon cycle?
Nitrogen Cycle
atmosphere
nitrogen fixing
78%
plants
ammonia
proteins
animals
waste
denitrifying
plants
1. Our atmosphere is ________________ nitrogen gas.
2. Animals and plants cannot directly use all the nitrogen found in our ____________________________.
3. Only special bacteria can directly use nitrogen in our atmosphere and ‘fix it’ so other organisms can benefit.
These bacteria are called __________________________________ bacteria.
4. Higher organisms in the food chain use nitrogen to make their ______________________.
5. Animal waste decay by the actions of bacteria which create ________________________ products rich in
nitrogen, and useful for plants to use again.
6. _______________________________ bacteria in the soil can break down the ammonia into the gaseous form of
nitrogen, which is not available for use by plants or animals.
7. In another part of the cycle, animals eat _________________________ containing nitrogen, which is again
returned to the soil by animal ________________________ or decaying __________________________ and
____________________________.