2.9 Photosynthesis Flashcards
what kind of nutrition is photosynthesis an example of
authotrophic nutrition (opposite of hetertrophs)- use light or chemical energy and inorganic molecules to synthesize complex organic molecules
not just plants do this e.g. also protoctista such as seaweed and algae
you can also have chemoauthrohps suhc as nitrosomonas which are nitryfing bacteria
how does photosynthesis work
converts sunlgiht energy –> chemical energy (glucose)
sucrose is the disaccardi which is used to translocate as it is bulkier and so not as soluble as glucose
photosynthesis releases o2 into the atmosphere, as a waste product. This is also use in respiration so at some point we have a compensation point when all O2 / CO2 produced is being used up
draw a chromsome and where is it surprisingly found / not found
not in the upper epidermis but in the sepal
chlorophyll is a complex molecule that needs magnesium - it fits into the cholorplast
there are many forms of chorophyll - the primary pigment for most photosyntheic pigments are carotenoids (orange) adn xanthophyll (brown) in autumn as the cholorplasts break down due to the change in temp and light
what does the absorption spectrum and action spectrum show for photosynthesis
absorption spectrum shows at whihc wavelenghts light is absorbed by the lead
action spectrum - which wavelengths of light trigger photosynthesis
talk me through the biochemistry of photosynthesis
it is a multi step reaction iwth complex chemical pathways
overall equation is
6CO2+6H2O–> C6H12O6+6O2
where O2 is a waste gas and teh co2 dn h2o never have molecular interaction
the glucose with become sucrose to be transported easily and made in starch
insunlight the following process (photolysis of water occurs )
H20 –> 4e- + 4p+ + O2
In the thylakoid of the membrane the pigments are merged together to form a photosystem, primary pigemnts are in the circulr bit and secondary pigments such as carotenoids are in the other bit
When sunlight shines the cholorplast loses an e- as it gets excited. THis leaves a vacancy in the chlorphyll molecule (+charge). Therefore we have electrons from the water molecule take up ths space. This is when the water shatters into its component piece. The photosystem is once again stable.
The positive H+ is combined with NADP to form NADPH which is sused in teh calvin cycle (the seocnd stage of photosynthesis). This is then when the CO2 comes into play.
what facotrs affect photosynthesis
temp - once temp impacts an enzyme thechange is pretty permanent - above optimum temp enzymes denature - inked to tertiarty structures which are involved in calvin cycle
PH - pH change is not quite as permanent
light intensity - limiting factor could be co2 conc or temp or number of cholorphyll
Co2 conc - in atmopshere usable amount is 0.03 -0.04%, in glass house CO2 is produced by e.g. burning to maximise this
WE WANT TO REACH THE COMPENSATION POINT
