Welcome to the Quiz!
This quiz contains 11 questions from a mix of 1 subtopics.
Which of the following organisms are involved in the nitrogen cycle?
saprobionts
producers
mutualistic bacteria
free-living bacteria
all of the above
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In the process of nitrogen fixation, atmospheric nitrogen gas is converted into:
nitrates
nitrites
amino acids
ammonia
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Which of the following CANNOT fix atmospheric nitrogen gas?
mutualistic bacteria in the root nodules of leguminous plants
free-living bacteria
abiotic processes like lightning and artificial fertilisers
nitrifying bacteria
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In the mutualistic relationship between mutualistic bacteria and leguminous plants, what does the plant provide to the bacteria in exchange for fixed nitrogen?
nitrates
amino acids
carbohydrates
proteins
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In the process of nitrification, what are NH3 and NH4+ oxidised into first and second, respectively?
nitrites (NO2-) then amino acids
nitrites (NO2-) then nitrates (NO3-)
amino acids then nitrites (NO2-)
nitrates (NO3-) then nitrites (NO2-)
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Which bacteria are involved in the two stages of nitrification?
Rhizobium and Azotobacter
Rhizobium and Nitrobacter
Nitrosomonas and Nitrobacter
Nitrosomonas and Azotobacter
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What does denitrification convert back into atmospheric nitrogen gas (N2)?
ammonium ions (NH4+)
nitrates (NO3-)
ammonia (NH3)
nitrites (NO2-)
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Excessive denitrification can lead to:
increased ecosystem health
depleted soil nitrogen
increased soil nitrogen
increased plant growth
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Under which conditions does denitrification occur?
aerobic conditions
high oxygen conditions
low nitrogen conditions
anaerobic conditions
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Which of the following are NOT examples of vital biological molecules that contain nitrogen?
DNA
RNA
carbohydrates
proteins
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What is the process called that converts nitrogen-rich compounds in dead organisms or waste into substances like ammonium ions (NH4+)?
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