The Nitrogen Cycle - advanced

Recall the chemical formula for atmospheric nitrogen gas.

• NO₃^

• NO₂^

• N₂

• NO

Select the percentage of nitrogen in the atmosphere

• 78%

• 70%

• 110%

• 24%

Clarify what nitrogen compounds are used for in living things

• Amino acids and carbohydrates

• DNA and amino acids

• Carbohydrates

• Carbohydrates and DNA

Describe what the process of nitrogen fixation involves

• Converting ammonium into nitrates

• Converting nitrogen into ammonium and then into nitrates

• Converting nitrites and nitrates into nitrogen

• Converting nitrites into nitrates

Use the image provided to name the organism that allows nitrogen in the atmosphere to be accessed by plants

• Other plants

• Rabbits

• Viruses

• Bacteria

Recall the ways that nitrogen enters the hydrosphere

• run-off water carrying nitrates from the lithosphere

• erosion of sedimentary rock

• osmosis

• directly from the atmosphere

What happens to nitrogen before phytoplankton can absorb it?

• must reach the phytoplankton directly

• must be converted into N₂

• must be eaten by an animal

• must be converted to nitrates

While walking in a park one day, you notice a fallen dead tree on the side of the path. You mourn its death, but know that its nitrogen will live on, even though the tree is gone.

Describe what will become of the nitrogen in this tree and how the nitrogen will flow through all the spheres - lithosphere, hydrosphere, biosphere and atmosphere.

Make sure that you consider the nitrogen compound found in each sphere and what process achieves this. Use the image provided (5 marks)

Describe two ways that humans impact the nitrogen cycle (2 marks)