photosynthesis Flashcards
word equation for photosynthesis
carbon dioxide + water –> (light) makes oxygen and glucose
balanced symbol equation for photosynthesis
6CO2 + 6H2O -> C6H12O6 + 6O2
what type of chemical reaction is photosynthesis
endothermic -> requires energy
in this case: light energy
function of thin and broad leaves
large SA for light absorption and short diffusion pathway for gases
function of palisade cells being long and thin
maximas light absorption
more can fit in a leaf
function of many chloroplasts
increase the amount of chlorophyll and therefore the amount of light absorbed
function of the spongey mesophyll containing air spaces
rapid diffusion of gases in and out
short diffusion pathway
function of stomata being surrounded by guard cells
can control water loss and gas exchange
function of network of vascular tissue in veins
provides water from roots and transports sugras from leaves to root
3 factors affecting rate of photosynthesis
light intensity, temperature, carbon dioxide concentration
how do you know if photosynthesis in a plant has taken place
add iodine solution to test for starch, because glucose produced in photosynthesis is stored as starch
RP: effect of light on starch production. why do we use a plant which has been kept in the dark for 24 hours?
to get rid of any starch which is already present in the leaves before the experiment. starch would be converted into glucose for respiration
RP: effect of light on starch production
what would be a suitable control experiment?
a plant which has been left in the dark -to show that light is needed for photosynthesis
RP: effect of light on starch production.
why do we boil the leaf at the start?
kill leaf and stop it from photosynthesising
RP: effect of light on starch production
purpose of placing leaf into boiling ethanol
extract chlorophyll from leaf so results from starch test are more visible
RP: effect of light on starch production.
why did you soak leaf in hot water after ethanol
soften the leaf so it can be spread out on tile
factors which affect rate of photosynthesis
light intensity, CO2 concentration and temperature
when would light be a limiting factor
at night
how does temperature affect rate of photosynthesis
particles gain kinetic energy creating more enzyme substrate complexes.
what happens once the optimum temperature is reached
enzymes begin to denature and their active sight loses its complimentary shape to the substrate, fewer enzyme substrate complexes. rate of photosynthesis decreases
how does light intensity affect rate of photosynthesis
higher the light intensity, higher the rate of photosynthesis but only up to a certain point. after certain point, light is no longer a limiting factor
increase in CO2 concentration causes what
rate of photosynthesis to increase
methods of controlling limited factors (light, CO2, temperature)
raising CO2: paraffin burner or burn fuel
temperature: thermostat
light int: light with timer, lamps which emit correct wave length of llight
suspending roots in water
errors and improvements in RP 6 - effect of light int on rate of photosynthesis
bubbles may be diff sizes - use gas syringe
may count number of bubbles incorrectly - film it and watch it again and recount
lamp may emit heat - use an LED lamp or one which doesnt emit heat
whats the square law
Light intensity is = to 1/distanced squared (m)
use of glucose in plants
-converted into fats and oils for energy storage
-combined with nitrates in the soil for amino acids and then proteins
-converted into sucrose for transport around the plant
-used in respiration to release energy for cell
use of many glucose molecules joined together
-cellulose for strength in cell walls
-starch for storage (insoluble, won’t affect osmosis in cells)
how is the palisade layer adapted for photosynthesis
packed with many chloroplasts to absorb as much light for photosynthesis
why is light needed for photosynthesis
provides energy
light energy turns into chemical energy
uses of sugar in plants
-converted into glucose to form starch for storage
-converted into fat for energy storage
-provides chemical energy for respiration
-used to produce cellulose to strengthen cell walls
-combined with nitrate ions absorbed from the soil to produce amino acids for protein synthesis
what happens when sugar is combined with nitrate ions
amino acid is produced for protein synthesis
