light dependant stage - lqc 12b Flashcards
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describe step 1
light hits a chlorophyll PSII molecule embedded in thylakoid membrane, 2 electrons become excited and exist at higher energy level
describe step 2
electrons leave chlorophyll PSII and pass to first electron carrier in electron transport chain
describe step 3
electrons pass down the electron transport chain from one electron carrier to the next in a series of redox reactions as energy level of electrons fall energy is lost
describe step 4
energy is used to synthesise ATP, H+ passes through ATP synthase into stroma which results in phosphorylation of ADP this is phosphorylation and is a condensation reaction
describe step 5
light hits PSI and another 2 electrons become excited and raised to higher energy level, these leave the chlorophyll and pass down the 2nd electron transport chain. 2 electrons from PSII replace those lost from PSI
describe step 6
in the thylakoid space, photolysis occurs. the electrons released replace those lost from PSII, 2.5 O2 to create O2 (a waste product)
describe step 7
the hydrogen ions (H+) from photolysis pass through ATP synthase and join with the electrons from the electron transport chain to reduce NADP to form reduced NADP (NADPH)