Nitrogen & Phosphorus Cycle

Question 1

4 key processes in the nitrogen cycle

Answer 1

Ammonification
Nitrification
Nitrogen fixation
Denitrification

Question 2

What organism completes ammonification

Answer 2

Saprobionts

Question 3

What organism completes nitrification

Answer 3

Nitrifying bacteria

Question 4

What organism completes denitrification

Answer 4

Denitrifying bacteria

Question 5

What organism completes nitrogen fixation

Answer 5

Nitrogen fixing bacteria

Question 6

Process of ammonification

Answer 6

Saprobionts break down organic matter (proteins) to ammonia

Question 7

Process of nitrification

Answer 7

Nitrifying bacteria converts ammonia to nitrate ions to nitrite ions

Question 8

Process of denitrification

Answer 8

Denitrifying bacteria convert nitrate ions to nitrogen gas

Question 9

Process of nitrogen fixation

Answer 9

Nitrogen fixing bacteria fixes nitrogen to other compounds by reducing nitrogen gas to ammonia and then to ammonium ions

Question 10

Where does nitrogen fixing bacteria live?

Answer 10

In root nodules of legumious plants

Question 11

Process of phosphorus cycle

Answer 11

Phosphate released from sedimentary rocks due to weathering.

Mycorrhizae important in facilitationg water and inorganic ions. Increases surface area and act as a sponge holding water and minerals.

Natural and artifical fertilisers are used to replace minerals lost in the soil by harvesting plants and removing livestock.

Question 12

How does ploughing affect fertility of soil? [2]

Answer 12

[1] Less nitrate removed

[2] Fewer denitrifying bacteria

Question 13

Two ways how crop rotation leads to high crop yields [2]

Answer 13

[1] Different pests/pathogens

[2] Grow crops with nitrogen fixing bacteria

[3] Different crops use different ions

Question 14

During the LIR, how is carbon dioxide converted into organic substances? [6]

Answer 14

[1] Carbon dioixde combines with RuBP

[2] Produces two GP

[3] Reduced into two TP

[4] Using reduced NADP

[5] Using energy from ATP

[6] TP converted to glucose

Question 15

Why do legumious crops grow better then others? [2]

Answer 15

[1] Nitrogen to ammonia

[2] Produce protein

Question 16

What is deamination?

Answer 16

-NH2 group removed from excess amino acids