nutrient cycles

Question 1

step 1 of the phosphorus cycle

Answer 1

phosphorus in rocks is released into the soil to form phosphate ions by weathering

Question 2

step 2 of the phosphorus cycle

Answer 2

phosphate ions are taken up from the soil by plants or absorbed by algae in the water by absorption

Question 3

step 3 of the phosphorus cycle

Answer 3

phosphate ions are transferred to consumers by feeding up the food chain

Question 4

step 4 of the phosphorus cycle

Answer 4

phosphate ions in waste products and dead organisms are released into the soil during decomposition by saprobionts

Question 5

step 5 of the phosphorus cycle

Answer 5

phosphate ions are taken up and trapped in sediments

Question 6

what is the main reservoir of phosphorus

Answer 6

rocks, in the form of phosphate ions

Question 7

what is mycorrhizae

Answer 7

fungi which allows for a symbiotic relationships between fungi and plant root systems of most plants making the plants drought - resistant

Question 8

what is hyphae

Answer 8

long filaments which make up fungi which increase the surface area, increasing the absorption of water and mineral ions

Question 9

use of phosphorus

Answer 9

nucleic acids, ATP + phospholipids. in the form of phosphate ions

Question 10

what are natural fertilisers

Answer 10

organic matter e.g. manure and compost

Question 11

what are artificial fertilisers

Answer 11

inorganic matter e.g. chemicals

Question 12

pros and cons of fertilisers

Answer 12

+ increases yield of plants
- eutrophication

Question 13

pros and cons of natural fertilisers

Answer 13

+ less likely to burn the plants
+ improves soil quality
+ cheaper
-takes longer for results
- cant control nutrients it contains

Question 14

pros and cons of artificial fertilisers

Answer 14

+ faster results
+ control of the nutrients provided
- can burn the plants
- stricter application method
-expensive

Question 15

what do all fertilisers contain

Answer 15

Nitrogen, Phosphorus and Potassium (NPK fertilisers)

Question 16

how does eutrophication occur

Answer 16

when nitrates are leached into lakes and rivers

Question 17

what is leaching

Answer 17

when water soluble compounds are washed away into rivers or ponds

Question 18

step 1 of eutrophication

Answer 18

mineral ions are leached from fertilised fields stimulation growth of algae in ponds and rivers

Question 19

step 2 of eutrophication

Answer 19

excessive growth of algae forms an algal bloom, blocking light

Question 20

step 3 of eutrophication

Answer 20

this means plants cant photosynthesis so die

Question 21

step 4 of eutrophication

Answer 21

bacteria will feed on the dead matter. the increased number of bacteria reduced conc of oxygen by respiring

Question 22

step 5 of eutrophication

Answer 22

aquatic organisms will die due to the lack of dissolved oxygen

Question 23

how are nutrients lost from the soil

Answer 23

crops take in minerals from the soil, when they are harvested the minerals are not returned to the soil in a nutrient cycle.

Question 24

what is the use of fertilisers

Answer 24

replace lost minerals increasing the efficiency of energy transfers

Question 25

importance of the nitrogen cycle

Answer 25

recycles nitrogen for proteins, DNA and RNA

Question 26

what is the main reservoir of nitrogen

Answer 26

the atmosphere - 78% nitrogen gas

Question 29

what does the nitrogen cycle do

Answer 29

turns nitrogen gas into different forms organisms can use

Question 30

what are the 4 steps of the nitrogen cycle

Answer 30

nitrogen fixation
ammonification
nitrification
denitrification

Question 31

what is nitrogen fixation

Answer 31

converting nitrogen gas into nitrogen containing compounds

Question 32

what occurs during nitrogen fixation

Answer 32

mutualistic bacteria in the root nodules of legumes fix N2 into NH3
nitrogen fixing bacteria in the soil fix N2 into ammonia and used to make amino acids

Question 33

what is ammonification

Answer 33

converting nitrogen - containing compounds into ammonia or ammonium

Question 34

what occurs during ammonification

Answer 34

1.death and excretion of organisms release urea and proteins (which contain nitrogen)
2.saprobionts decompose them into NH4+
3. NH4+ is absorbed and assimilated by plants

Question 35

what is nitrification

Answer 35

NH3 and NH4+ are oxidised into nitrites then nitrates

Question 36

what occurs during nitrification

Answer 36

nitrifying bacteria oxidise NH3 and NH4+ into NO2-
NO2- is further oxidised into NO3-

Question 37

what is denitrification

Answer 37

converting NH3 back into N2

Question 38

what occurs during denitrification

Answer 38

NH3 is converted into N2 by denitrifying bacteria which are anaerobic.

Question 39

when does denitrification occur

Answer 39

in anaerobic conditions, when the soil is water logged where there is not enough oxygen in the oil as it has been displaced by water