Nutrient cycle Flashcards
What happens when fossil fuels are burnt
The carbon in the fossil fuels is changed to carbon dioxide and goes into the air
This increases the amount of CO2 in the air
In photosythesis trees put…
More oxygen back into the air than they put back through respration
If trees are cut down…
Less photosynthesis occurs
So less CO2 is removed from the air
If we burn trees
The carbon in their bodies is returned to the air
In the nitrogen cycle, why must N2 (g) be changed into nitrogen compounds like NO3- and NH4+?
Nitrogen fixation
Changing N2 into a more reactive form that plants can use
How does nitrogen fixation happen
- ) Lightning causes nitrogen and water in the air to form NO3- ions (nitrates)
- ) Nitrogen fixing bacteria changes nitrogen gas to ammonium ions (NH4+)
In soil, what does nitrifying bacteria do?
It changes ammonium ions to nitrate ions
Nitrification
In soil when nitrifying bacteria change nitrate ions and ammnium ions
What are nitrate ions used for?
To make amino acids
Amino acids are used to build up different proteins
Denitrification
When a group of bacteria in the soil break down nitrate ions to form N2 gas
deamination
When when dead animal and plant’s proteins and amino acids are broken down by decomposers to produce ammonium ions
