Nitrogen Cycle Worksheet - Grade 12
Explore the intricate processes of the nitrogen cycle, including nitrogen fixation, nitrification, assimilation, ammonification, and denitrification, with this comprehensive Grade 12 science worksheet.
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Nitrogen Cycle Worksheet
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Read each question carefully and answer to the best of your ability. Refer to the provided diagram of the nitrogen cycle for assistance.
1. The conversion of atmospheric nitrogen (N2) into ammonia (NH3) by bacteria is called .
2. Nitrification is a two-step process where ammonia is first converted to and then to .
3. Plants absorb nitrogen primarily in the form of and .
4. The process by which decomposers convert organic nitrogen back into ammonia is known as .
5. Denitrification is the process where nitrates are converted back into gas, which is then released into the atmosphere.
6. Which of the following organisms are primarily responsible for nitrogen fixation?
Fungi
Animals
Bacteria
Viruses
7. Which process converts nitrites (NO2-) to nitrates (NO3-)?
Ammonification
Denitrification
Nitrification
Assimilation
8. Atmospheric nitrogen (N2) is directly usable by most plants and animals.
True
False
9. Lightning can convert atmospheric nitrogen into usable forms for plants.
True
False
10. Explain the role of decomposers in the nitrogen cycle.
11. Describe how human activities can impact the natural nitrogen cycle, providing at least two examples.
Match each term on the left with its correct description on the right.
12. Nitrogen Fixation
a. Conversion of nitrates to atmospheric nitrogen
13. Nitrification
b. Conversion of atmospheric nitrogen to ammonia
14. Assimilation
c. Conversion of ammonia to nitrites and then nitrates
15. Ammonification
d. Incorporation of nitrates into organic molecules by plants
16. Denitrification
e. Conversion of organic nitrogen to ammonia by decomposers