Topic 1 - Global Systems - Nitrogen Cycle

Question 1

Nitrogen Cycle

Answer 1

Transforms and circulates nitrogen in various forms through Earth’s spheres.

Question 2

Atmospheric Nitrogen Fixation

Answer 2

Lightning strikes and generates enough energy to separate N2 into NO and NO2.
These smaller molecules dissolve water droplets in clouds forming nitric acid.
Nitric acid is transported to the Earth’s surface through precipitation.

Question 3

Assimilation

Answer 3

Plants take up ammonium and nitrate ions from soil

Question 4

Consumption

Answer 4

Animals acquire organic nitrogen by consuming plants or other animals.

Question 5

Ammonification

Answer 5

Decomposers break down nitrogen compounds in dead organisms and convert them ammonium or ammonia ions, which are released back into the soil.

Question 6

Volcanic Eruptions

Answer 6

Releases nitrogen gas straight into the atmosphere. Heat and pressure created by eruptions leads to transformation of atmospheric nitrogen and nitrogen oxides.
Reacts with water vapour to form precipitation.

Question 7

Denitrification by Bacteria

Answer 7

Which takes the nitrate and nitrite into nitrogen gas. Nitrogen gas is returned to the atmosphere.

Question 8

Nitrogen Fixation by Bacteria

Answer 8

Atmospheric N2 is converted to ammonia or ammonium ions by nitrogen - fixing bacteria found in the soil.

Question 9

Nitrification

Answer 9

When ammonia is converted to nitrite ions through nitrifying bacteria. Nitrite ions are then oxidized into nitrate ions by other nitrifying bacteria.

Question 10

Asslimilation

Answer 10

Ends with plants taking up nitrogen.