mineral nutrition Flashcards
what was a major discovery in biology
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
what are the 6 elements all living things are composed of
1) carbon
2) hydrogen
3) nitrogen
4) oxygen
5) phosphorus
6) sulphur
what are macro and micro nutrients
macro = needed in large amounts 30umol or more
micro = needed in trace amounts = less than 30umol
what is avogadros number
6.022 x 10^23
what is nitrogen used for
proteins
nucelic acids
chlorophyll
what does a lack of nitrogen lead to
chlorosis
what is potassium used for
enzyme activator
stomatal regulation
what is calcium used for
middle lamella
movement of substances through cell membranes
what is phosphorous used for
respiration
cell divison
high energy compounds
what is magnesium used for
chlorophyll
enzyme activator
what is sulphur used for
some amino acids
iron- sulphur proteins in electron transfer
what is iron used for
respiration
chlorophyll formation
why is manganese important
enzyme actovation
photolysis
outline the uptake of inorganic nutirents
- 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
why is ion uptake an active process
the composition of roots is different to the soil with higher concentrations, therefore ions must be taken against a chemical gradient needing energy
what are mycorrhiza
the inimate mutualsitic and symbiotic association between roots and fungus which help roots obtain mineral nutrients whilst fungus recieves sugars
what are the two types of mycorrhiza
1) endomycorrhiza
2) ectmycorrhiza
what is an endomycorrhiza
when the fungus penetrates the outercortex and makes initimate contact with the cell membrane but doesnt enter the protoplasm
what is an ecotmycorrhiza
when the fungus forms a sheath/mantle around the root and grows between cells forming a hartig net
what are orchid mycrohizza
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
what forms of nitrogen are available for plants
1) nitrate
2) ammonium
3) nitrogen
4) organic nitrogen
outline nitrate assimilation
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
what is ferrodoxin
an iron sulphur porotein which mediates electron transfer
what allows nitgoren fixation
1) root symbiosis by legumes and rhizobium bacteria
2) leaf symbiosis using cyanobacteria
outline the process of nitrogen fixation in legumes
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
what are the short term effects of nitrogen pollution
acts as a fertiliser increasing growth
what are the long term effects of nitgoren pollution
- disrupt C:N rations
- eutrophication
- acid rain
- favour invasive species cauing phase shifts in plant communities
