light-dependent reaction and light-independent reaction
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Non-cyclic photophosphorylation
step 1
light energy is absorbed by PSII
excites electrons
move to higher energy level
move along ETC to PSI
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Non-cyclic photophosphorylation
step 2
Light energy splits water into protons, electrons and O2 to replace electrons in PSII
equation: H2O - 2H^+ + 1/2 O2
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Non-cyclic photophosphorylation
step 3
excited electrons from PSII loose energy as they move down ETC
energy is used to transport protons into thylakoid via proton pumps
creates concentration gradient between thylakoid and stroma
ATP synthase allows protons to move into stroma
combines ADP wi
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Non-cyclic photophosphorylation
step 4
light energy absorbed by PSI
excites electrons to higher energy level
electrons transferred to NADP with proton from stroma to produce reduced NADP
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Cyclic photophosphorylation
only uses PSI
called cyclic = chlorophyll molecule isn't passed onto NADP but passed back to PSI via electron carriers
produces = only small amounts of ATP
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light-independent (calvin cycle)
stage 1
CO2 enters leaf via stomata + diffuses into stroma
here it is combined with RuBP
= unstable 6 carbon molecule
breaks down into 2, 3-carbon molecules =GP
RuBisCO catalyses reaction between CO2 and RuBP
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light-independent (calvin cycle)
stage 2
ATP from light dependent allows GP to form TP
reaction also requires H+ from reduced NADP
TP is converted into useful compounds such as glucose
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light-independent (calvin cycle)
stage 3
5/6 molecules of TP produced are used to regenerate RuBP which also uses the rest of ATP from light dependent
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What organic compounds do TP and GP make
carbs - hexose sugar (glucose) = two TP
lipids - produced from glycerol = TP + fatty acids (synthesised from GP)
amino acids - GP
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What does GP stand for?
Gylcerate 3-phosphate
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What does TP stand for?
Triose Phosphate
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What does RuBP stand for?
Ribulose bisphosphate
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what does RuBisCO stand for?
Ribulose bisphosphate carboxylase
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How many turn of the Calvin cycle do you need?
three turns = six molecules of TP ( because 2 TP are made from every 1 CO2 molecule used)
5/6 molecules of TP are used to regenerate RuBP
Hexose sugar = 6 carbons - 2 molecules of TP that can be used to make one hexose sugar
NEED 6 TURNS OF CYCLE = 18 AT
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Other cards in this set
Card 2
Front
Non-cyclic photophosphorylation
step 1
Back
light energy is absorbed by PSII
excites electrons
move to higher energy level
move along ETC to PSI
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