Chapter 13: photosynthesis Flashcards
name the two light dependent reactions
- photolysis
- photophosphorylation
what does cyclic photophosphorylation involve?
PS1
what does non-cyclic photophosphorylation involve?
PS1 and PS2
describe cyclic photophosphorylation
- light is absorbed by PS1 and passes to the primary pigment
- electron is excited and leaves the chlorophyll molecule
- it is captured by an electron acceptor and passed back to a chlorophyll molecule via a chain of electron carriers
- ATP passes to PS2
describe non-cyclic photophosphorylation
- light is absorbed by both photosystems
- exited electrons are emitted and absorbed by electron acceptors
- they are passed along electron carriers
- they leave the photosystems positively charged
- ATP is synthesised as electrons lose energy while passing along the chain
- the electrons from PS1 are used to produce NADPH
define ‘photolysis’
the splitting of water
describe the results of the Hill reaction
- demonstrates that isolated chloroplasts had ‘reducing powers’ and freed O2 from water
- the reagent (DCPIP) changed colour from blue-colourless as oxygen was released
describe the three main processes in the Calvin Cycle
- carbon fixation
- reduction
- regeneration
describe carbon fixation
- CO2 meets rubisco enzyme
- the C is fixed to RuBP, forming a 6C molecule
- this splits into 2x GP molecules
describe reduction in the Calvin cycle
- GP –> TP
- ATP –> ADP + Pi
- NADPH –> NADP
describe regeneration in the Calvin cycle
- 5 x 3C TP molecules arrange into 3 x 5C RuBP molecules using ATP
summarise the light-dependent reaction
water is broken down to hydrogen and oxygen using light energy
where does the light-dependent reaction take place?
thylakoid membranes
summarise the light-independent reaction
H2 reacts with CO2 to form glucose. H20 is reformed
where does the light-independent reaction take place?
stroma
