mineral nutrition

Question 1

what was a major discovery in biology

Answer 1

that living things are composed on the same types of chemical elements as non-living things therefore life is chemically based and obeys the universal physical and chemical laws

Question 2

what are the 6 elements all living things are composed of

Answer 2

1) carbon
2) hydrogen
3) nitrogen
4) oxygen
5) phosphorus
6) sulphur

Question 3

what are macro and micro nutrients

Answer 3

macro = needed in large amounts 30umol or more
micro = needed in trace amounts = less than 30umol

Question 4

what is avogadros number

Answer 4

6.022 x 10^23

Question 5

what is nitrogen used for

Answer 5

proteins
nucelic acids
chlorophyll

Question 6

what does a lack of nitrogen lead to

Answer 6

chlorosis

Question 7

what is potassium used for

Answer 7

enzyme activator
stomatal regulation

Question 8

what is calcium used for

Answer 8

middle lamella
movement of substances through cell membranes

Question 9

what is phosphorous used for

Answer 9

respiration
cell divison
high energy compounds

Question 10

what is magnesium used for

Answer 10

chlorophyll
enzyme activator

Question 11

what is sulphur used for

Answer 11

some amino acids
iron- sulphur proteins in electron transfer

Question 12

what is iron used for

Answer 12

respiration
chlorophyll formation

Question 13

why is manganese important

Answer 13

enzyme actovation
photolysis

Question 14

outline the uptake of inorganic nutirents

Answer 14

• takes place in the epidermis of roots by an active process
• often aided by mycorrhiza
• transport through mostly the symplast pathway where they are then loaded into the xylem

Question 15

why is ion uptake an active process

Answer 15

the composition of roots is different to the soil with higher concentrations, therefore ions must be taken against a chemical gradient needing energy

Question 16

what are mycorrhiza

Answer 16

the inimate mutualsitic and symbiotic association between roots and fungus which help roots obtain mineral nutrients whilst fungus recieves sugars

Question 17

what are the two types of mycorrhiza

Answer 17

1) endomycorrhiza
2) ectmycorrhiza

Question 18

what is an endomycorrhiza

Answer 18

when the fungus penetrates the outercortex and makes initimate contact with the cell membrane but doesnt enter the protoplasm

Question 19

what is an ecotmycorrhiza

Answer 19

when the fungus forms a sheath/mantle around the root and grows between cells forming a hartig net

Question 20

what are orchid mycrohizza

Answer 20

over 20,000 species, all orchids get their food from fungi at some point in their life cycle where the fungi provides carbon during germination

Question 21

what forms of nitrogen are available for plants

Answer 21

1) nitrate
2) ammonium
3) nitrogen
4) organic nitrogen

Question 22

outline nitrate assimilation

Answer 22

1) negative ion taken up agaisnt the electrochemical gradient
2) inside the cell it is reduced by 2 electrons and nitrate reductase to form NO2
3) ferredozin mediated more electron transfer are reduced NO2 to NH4 then amino acids

Question 23

what is ferrodoxin

Answer 23

an iron sulphur porotein which mediates electron transfer

Question 24

what allows nitgoren fixation

Answer 24

1) root symbiosis by legumes and rhizobium bacteria
2) leaf symbiosis using cyanobacteria

Question 25

outline the process of nitrogen fixation in legumes

Answer 25

1) nitrogenase activity is inhibited by oxygen
2) nodule cells make leghameoglbin which binds oxygen
3) rhizobium form and infection thread through the root hair so when root cells undergo mitosis a nodule is formed with anaerobic conditions

Question 26

what are the short term effects of nitrogen pollution

Answer 26

acts as a fertiliser increasing growth

Question 27

what are the long term effects of nitgoren pollution

Answer 27

• disrupt C:N rations
• eutrophication
• acid rain
• favour invasive species cauing phase shifts in plant communities