Photosynthesis Flashcards
photosynthesis
the process by which plants make their own food
what is the chloroplasts’ role in photosynthesis
contains a green pigment called chlorophyll which allows for the absorption of sunlight
what colours does chlorophyll reflect
green
yellow
role of photosynthesis
make food for plant +animal
oxygen produced is used in respiration
removes carbon dioxide from air
what is the balanced chemical equation of photosynthesis
6CO2 + 6H2O+ LIGHT ——->C6H 12O6 + 6O2
Where specifically is chlorophyll found?
in the thylakoid membrane
what are the requirements for photosynthesis to occur
carbon dioxide
water
light energy
chlorophyll
source of carbon dioxide
external environment (from the atmosphere)
internally from plant respiration
where is carbon dioxide absorbed
through the stomata of the leaf
source of water
absorbed from soil through roots by osmosis
what is the sun
primary source of energy on earth
source of light
sunlight
artificial light in greenhouses
end products of photosynthesis
glucose + oxygen
give a brief summary of stage 1 of photosynthesis
water is split
light is absorbed
light energises electrons
give a brief summary of what happens in stage 2 of photosynthesis
glucose is formed
which stage is light dependent and which is not
stage 1= light dependant
stage 2 = not
what is water splitting also known as?
photolysis
what is the purpose of the light stage
prepares ATP for dark stage
where does the light stage occur
thylakoid membrane
explain photolysis
some of the trapped light energy is used to split water to oxygen, protons + electrons
explain the fate of protons in photolysis
protons:
stored in a proton pool
used to convert NADP+ to NADPH
fate of electrons in photolysis
to join with NADP+ to form NADP-
fate of oxygen in photolysis
oxygen:
excreted through stomata
used in respiration
explain how light is absorbed
each pigment of chlorophyll absorbs a certain wavelength of light.
because chlorophyll has many pigments it means more colours can be absorbed and more light energy is produced
why are plants green?
green light is not absorbed and is reflected
how is light energy transferred to electrons
all energy absorbed is transferred to the reaction centre chlorophyll located next to an electron acceptor
they enter into 1 of 2 pathways
this energy energises the electrons, as they jump from one EA to another EA
describe cyclic phosphorylation
one electron passes from EA to EA and returns back to the original reaction centre chlorophyll
the energy released is used to join ADP+P to form ATP
explain non-cyclic phosphorylation
2 electrons pass from EA to EA and do not return to the reaction centre chlorophyll
the energy released is used to join ADP+ P to form ATP
the low energy electrons join with NADP+ to form NADP- and a proton is added forming NADPH
splitting of water occurs to gain more electrons
does the dark stage need light?
no
where does the dark stage take place
stroma of the chloroplast
what is stage 2 controlled by?
controlled by enzymes to speed up the process
explain the Calvin cycle (dark stage)
co2 enters Calvin cycle
carbon dioxide is reduced to glucose
ATP breaks down to ADP+P releasing energy
NADPH breaks down into NADP+ +2e + H
the electrons and protons are used to make glucose
what are the requirements for the light stage to occur
water and sunlight
what are the requirements for the dark stage to occur
co2 ATP NADPH
end product of the dark stage
glucose
