Nutrient cycles

Question 1

2 examples of nutrient cycles

Answer 1

nitrogen cycle
phosphorus cycle

Question 2

where is nitrogen present

Answer 2

as n2 gas in the atmosphere and within biological molecules eg. proteins

Question 3

what is the process of N2 gas to ammonium compounds to nitrates called

Answer 3

nitrogen fixation

Question 4

process of nitrogen fixation

Answer 4

nitrogen gas is converted into ammonium compounds by nitrogen fixing bacteria ( root nodules of legumes)

ammonium is then turned into nitrates which can be absorbed by plants

Question 5

why do plants need nitrates

Answer 5

to build plant proteins

Question 6

what is the Nitrogen from living organisms is returned to the soil in the form of ammonia proccess calles

Answer 6

ammonification

Question 7

ammonification proccess

Answer 7

Nitrogen from living organisms is returned to the soil in the form of ammonia by decomposers (saprobionts)

ammonia then forms ammonium ions

Question 8

nitrification proccess

Answer 8

ammonium ions are converted into nitrates by nitrifying bacteria

Question 9

The ammonium ions in the soil are converted into nitrates by nitrifying bacteria process name

Answer 9

nitrification

Question 10

denitrification proccess

Answer 10

denitrifying bacteria use nitrates in the soil for respiration
this proccess produces nitrogen gas - returning it to the atmosphere

Question 11

why is the production of phosphorus needed

Answer 11

for phospholipids
ATP
nucleic acids

Question 12

how does phosphorus become phosphate ions

Answer 12

phosphorus in rocks is released into the soil and into water sources in the form of phosphate ions (PO₄³⁻) due to weathering

Question 13

how are phosphate ions uptaken

Answer 13

Phosphate ions are taken up from the soil by plants, or absorbed from water by algae

Question 14

how are phosphate ions passed to consumers

Answer 14

Phosphate ions are transferred to consumers during feeding

Question 15

how are phosphate ions released into soil

Answer 15

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

Question 16

how are phosphate ions turned back into phosphorus

Answer 16

The phosphate ions can be taken up and used again by producers, or may be trapped in sediments that may turn into phosphorus-containing rock once again

Question 17

why are additional chemical elements needed for plants

Answer 17

many of the biological molecules in plants cannot be produced from photosynthesis alone. So they must absorb extra ions.

Question 18

method of investigating the effect of minerals on plant growth

Answer 18

Fill each of five tests tube with a set volume of each of the nutrient solutions

Cover the top of each test tube with foil and create a small hole in the foil

For each test tube, take a Bryophyllum plantlet and push the roots through the hole in the foil, ensuring that the roots are submerged in the nutrient solution

Place the test tubes in the same location

After a set period of time, e.g. 2 weeks, observe the plantlets and take qualitative and quantitative measures of their growth

Qualitative measures could include the colour of the plantlets and their leaves, or how wilted the plantlet has become

Question 19

what qualitative methods do we use

Answer 19

Qualitative measures could include the colour of the plantlets and their leaves, or how wilted the plantlet has become

Question 20

what quantative methods do we use

Answer 20

Quantitative measures could include the height or mass of the plantlets, or the length and width of their leaves