Nitrogen Cycle Flashcards
Why is nitrogen important for living things?
Nitrogen is crucial for building biological molecules like proteins and DNA.
What percentage of the air we breathe is nitrogen?
Over 75%.
What form of nitrogen is present in the air and why can’t it be used by living organisms?
Nitrogen is in the form of N2, which is useless to plants and animals.
What is nitrogen fixation?
The process of absorbing nitrogen from the air and incorporating it into ammonia (NH3).
What role do bacteria play in the nitrogen cycle?
Bacteria convert nitrogen in the air and waste into usable forms like ammonia, nitrite, and nitrate.
What is the end product of ammonia alteration by bacteria in the nitrogen cycle?
Nitrate (NO3).
Fill in the blank: Ammonia is further altered into _______ and then into nitrate.
nitrite.
How do legumes contribute to nitrogen fixation?
They form a symbiotic relationship with nitrogen-fixing bacteria.
What natural phenomenon is capable of fixing nitrogen?
Lightning.
What do plants do with nitrates in the soil?
They absorb them and incorporate the nitrogen into biological compounds.
What is the role of nitrogen in plant growth?
Nitrogen is often a limiting factor in raising crops.
What happens if nitrogen becomes scarce in the ecosystem?
Further growth will be prevented.
What do most fertilizers used in industrial farming contain?
They are full of nitrogen.
How can high amounts of nitrogen enter ecosystems?
Through burning fossil fuels and use of industrial fertilizers.
What effect does burning fossil fuels have on nitrogen levels?
It releases nitrogen into the air, contributing to acid rain.
