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In photosystem-I, the first electron acceptor is -
A
Ferredoxin
B
Cytochrome
C
Plastocyanin
D
An iron sulphur protein
Detailed Solution
In photosystem I the reaction centre is chlorophyll a with an absorption peak at 700 nm (P700).
When P700 absorbs light, its electron is excited and is passed to a primary electron acceptor.
This acceptor is an iron-sulphur protein (Fe-S), often written as A or FRS (ferredoxin reducing substance).
From the iron-sulphur protein the electron is passed to ferredoxin and then, through the enzyme ferredoxin-NADP reductase, to $NADP^+$, which is reduced to NADPH.
So ferredoxin comes after the iron-sulphur protein.
Plastocyanin is the electron donor to photosystem I, and the cytochrome complex lies between the two photosystems.
So in photosystem I the first electron acceptor is an iron sulphur protein.
When P700 absorbs light, its electron is excited and is passed to a primary electron acceptor.
This acceptor is an iron-sulphur protein (Fe-S), often written as A or FRS (ferredoxin reducing substance).
From the iron-sulphur protein the electron is passed to ferredoxin and then, through the enzyme ferredoxin-NADP reductase, to $NADP^+$, which is reduced to NADPH.
So ferredoxin comes after the iron-sulphur protein.
Plastocyanin is the electron donor to photosystem I, and the cytochrome complex lies between the two photosystems.
So in photosystem I the first electron acceptor is an iron sulphur protein.