Nutrient Cycle

Question 1

What is the basic sequence of all nutrient cycles?

Answer 1

Producer takes up the nutrients
Producer incorporates it into complex molecules
when they are eaten this is passed on to the consumer and then up the food chain
When consumer dies the sapribionts break the molecule down and release nutrients back into the soil

Question 2

Describe what ideal soil is like

Answer 2

many air spaces, well-drained with higher organic matter and high levels of nitrifying bacteria

Question 3

What is nitrogen used for

Answer 3

Making amino acids or nucleic acid

Question 4

Can Nitrogen be obtained form the environment?

Answer 4

No, ions are absorbed via active transport in the roots

Question 5

Name the four stages of the Nitrogen Cycle

Answer 5

Nitrogen fixation
Ammoniafixation
Denitrification
Nitrification

Question 6

Describe Nitrogen fixation

Answer 6

Nitrogen gas is converted into nitrogen-containing compounds by aerobic microorganisms or lightning strike

Question 7

Describe the two types of bacteria involved in nitrogen fixation

Answer 7

Free-Living Bacteria= reduces N2 (g) to Ammonia to manufacture amino acids

Mutualistic Nitrogen-fixing Bacteria = live in nodules on the roots of plants, they get carbohydrates from plant and plant get amino acid

Question 8

Describe Ammoniafixation

Answer 8

Production of ammonia from organic nitrogen-containing compounds
when Sparibionat breaks down waste and dead matter into NH3 which forms NH4+ in the soil

Question 9

Describe Nitrification

Answer 9

Aerobic oxidation to release energy

NH4+ -> NO2-
NO2- -> NO3-

Question 10

Describe Denitrification

Answer 10

Anaerobic bacteria in low O2 concentrations covert soil nitrates into gaseous Nitrogen

Question 11

What is Phosphorus used for?

Answer 11

ATP and nucleic acid

Question 12

What is the main difference between the Nitrogen and Phosphorus Cycle?

Answer 12

The Phosphorus Cycle has no gases phase

Question 13

Describe the Phosphorus cycle roughly

Answer 13

P in rocks is eroded to be dissolved in lakes and then is absorbed by plants and digested by animals then returned in remains and waste.

Question 14

How does most Phosphorus exist?

Answer 14

as PO4+ in sedimentary rock deposits

Question 15

What is the role of Mycorrhizae?

Answer 15

a mutualistic behaviour

where the fungi extension of root increase the surface area for absorption of H20 and minerals

Question 16

Why does Mycorrihzae benefit the plant?

Answer 16

Better resistance to drought and easier uptake of ions

Question 17

What are the 2 types of fertilisers?

Answer 17

Natural and Artificial

Question 18

Why are minerals needed and what do they cause?

Answer 18

Needed for growth to make plants taller, greater leaf area, increased rate of photosynthesis and increased crop productivity

Question 19

What are Natural/organic fertilisers made from?

Answer 19

dead and decaying plants and animal remains/waste

Question 20

What are Artificial /inorganic fertilisers made from?

Answer 20

mined from rocks w/ K P N

gives a guaranteed composition

Question 21

What bad effects can fertilisers have?

Answer 21

Reduced Species Diversity
Leaching
Eutrophication

Question 22

Describe Leaching
What is it?
And what health risks does it have?

Answer 22

a process where nutrients are removed from the soil and rainwater carries the dissolved nutrients beyond the plants
Very high NO3- con. in H20 = less efficient O2 transport in babies and links stomach cancer

Question 23

Define Eutrophication

Answer 23

the process by which nutrient concentrations increase in bodies of water

Question 24

Describe the stages of Eutrophication

Answer 24

1) NO3- is no longer a limiting factor as nutrients from fertilisers enter the water
2) Algae bloom occurs at the surface which blocks light
3) No photosynthesis, so plants die.
4) Greater Saprobiotic decomposition occurs as 5)Microorganisms respire aerobically (use up oxygen)
6) Less oxygen for fish to respire limiting factor, therefore they die
7) Increase in anaerobic microorganisms; release hydrogen sulphide/ nitrates/ toxic waste
8) Water becomes putrid

Question 25

Describe a process carried out by microorganisms which adds ammonium ions to soil.

Answer 25

Protein / amino acids broken down

By saprobionts / saprobiotic (microorganisms).

Question 26

Suggest two ways in which crop rotation may lead to high crop yields.

Answer 26

1.Grow crops / plants with nitrogen-fixing (bacteria);

2. (Different crops use) different minerals / salts / nutrients / ions (from the
   soil) ;
3. (Different crops have) different pests / pathogens / diseases.