cycless

Question 1

Topic 3: The Nitrogen Cycle

Question 3

70% of all earths gases is nitrogen. Nitrogen is important in the production of proteins and nucleic acids (DNA and RNA). Nitrogen cannot be used directly form the atmosphere and needs to be broken into other chemical forms to be used. Bacteria can use nitrogen directly from the atmosphere.

Question 5

For nitrogen to be used it needs to be broken down through nitrogen-fixing where it can be broken down into nitrates or ammonium.

Question 7

There are 3 ways of nitrogen-fixing:

Question 9

Industrial processes: Expensive. Artificial fertilisers are made this way.

Question 11

Lightning: converts small amounts of nitrogen to nitrates.

Question 13

Nodules (beans and legumes): the bacteria living in the roots of legumes.

Question 15

Processes of the Nitrogen cycle:

Question 17

Nitrogen Fixation: atmospheric nitrogen gas is converted into inorganic nitrogen compounds. Nitrogen- fixing bacteria in the root nodules of legumes converts nitrogen to nitrates. Lightning also converts nitrogen into nitrates.

Question 19

Nitrogen Assimilation: the nitrates dissolve in water in the soil. Plants absorb nitrates through the roots to make proteins. Plant proteins are eaten by consumers and converted to animal proteins.

Question 21

Ammonification: consumers release nitrogen in the form of urine or faeces. These are returned to the soil through decomposers forming ammonia.

Question 23

Nitrification: the ammonia is converted to nitrites by nitrite bacteria. Nitrites are then converted back to nitrates.

Question 25

Denitrification: the nitrates are converted to nitrogen by denitrifying bacter ia.