cycles within ecosystems (nitrogen cycle)

Question 1

name the 4 stages of the nitrogen cycle

Answer 1

1. nitrogen fixation
2. decomposition
3. nitrification
4. denitrification

Question 2

describe nitrogen fixation

Answer 2

1. nitrogen fixing bacteria convert nitrogen gas in the air/atmosphere into nitrate ions. the nitrate ions are then taken up and converted into amino acids and DNA by plants.

Question 3

where are nitrogen fixing bacteria located

Answer 3

nitrogen fixing bacteria are located free in the soil and on legume root nodules.

Question 4

describe decomposition

Answer 4

2. decomposers break down dead organisms/waste matter. urea molecules are broken down into smaller molecules and the nitrogen is released in ammonium ions.

Question 5

describe nitrification

Answer 5

3. nitrifying bacteria in the soil convert ammonium ions into nitrite ions and then nitrate ions. plants take these ions up, then animals eat plants.

Question 6

describe denitrification

Answer 6

4. denitrifying bacteria convert nitrate ions in the soil back into nitrogen gas which then escapes into the air

Question 7

name two other processes which result in nitrogen gas in the air being converted into nitrate ions

Answer 7

lightning and synthesis of proteins