NITROGEN CYCLE

Question 1

What is nitrogen fixation? (1)

Answer 1

Uses atmospheric nitrogen and turns it to ammonia

Question 2

What is nitrogen ammonification? (1)

Answer 2

Turns organic nitrogen containing molecules to ammonia and ammonium

Question 3

What is a nitrogen nitrification? (1)

Answer 3

Turns ammonia to nitriles to nitrates

Question 4

What is nitrogen assimilation? (1)

Answer 4

Turns nitrates to amino acids/proteins/nucleic acids

Question 5

What is nitrogen denitrification? (1)

Answer 5

Turns ammonia, ammonium, nitrites and nitrates from the soil into atmospheric nitrogen

Question 6

How is nitrogen fixation completed? (3)

Answer 6

Nitrogen fixation by soil bacteria (nitrogen fixing bacteria)
1 - rhizobium found in root nodules of leguminous plants
2. - azobacter found in aerated soil

Question 7

How is nitrogen ammonification completed? (2)

Answer 7

Production of ammonia from dead and waste matter.
Requires decomposers in the soil such as fungi and bacteria

Question 8

How is nitrogen nitrification completed?

Answer 8

By nitrifying bacteria such as nitrococcus or nitrosomanas

Question 9

what is leaching? (1)

Answer 9

the loss of soluble materials in soil caused by water flow.

Question 10

what is nitrogen-fixing bacteria? (1)

Answer 10

bacteria capable of converting atmospheric nitrogen in to ammonium ions using ATP.

Question 11

why isn’t nitrogen in the atmosphere directly available to plants and animals? (1)

Answer 11

because the bonds in molecules of nitrogen are very strong and a great deal of energy is required to break them, animals and plants cannot do this.

Question 12

how do plants overcome the inability to take up nitrogen directly from the atmosphere? (1)

Answer 12

plants take up nitrogen in the soil in the form of compounds such as nitrate and ammonium ions, from these compounds plants are able to manufacture amino acids they require.

Question 13

how do animals overcome the inability to take nitrogen directly from the atmosphere? (1)

Answer 13

animals take in ‘ready-made’ proteins in their diet, digest them to amino acids and absorb them, the amino acids are then used to rebuild the animals own specific proteins.

Question 14

what is a biogeochemical cycle? (1)

Answer 14

the cycling processes by which essential elements are released and reused.

Question 15

what are the main stages of the nitrogen cycle? (5)

Answer 15

-nitrogen fixation
-nitrogen ammonification
-nitrification
-nitrogen assimilation
-nitrogen denitrification

Question 16

what occurs in nitrogen fixation? (2)

Answer 16

fixation; converts atmospheric nitrogen into forms that can be absorbed by living organisms, such as nitrates and ammonia. This process is performed by nitrogen-fixing bacteria and sometimes by lightning.

Question 17

What occurs in nitrogen ammonification? (1)

Answer 17

Ammonification; the process of converting organic nitrogen compounds such as proteins into ammonia through the action of decomposers.

Question 18

What occurs in nitrogen nitrification? (2)

Answer 18

Nitrification; nitrifying bacteria such as Nitrosomonas and nitrobacter, convert ammonia into nitrites then into nitrates.

Question 19

what occurs in nitrogen assimilation? (1)

Answer 19

Assimilation; plants take up ammonia and incorporate nitrogen into amino acids, nucleic acids and other essential organic compounds.

Question 20

what occurs in nitrogen denitrification? (1)

Answer 20

Denitrification; involves converting ammonia and nitrates into atmospheric nitrogen once more with the use of denitrifying bacteria.

Question 21

what is found in Leguminous plants? (1)

Answer 21

nitrogen fixing bacteria often found in the root of these plants, in the root nodules.