In photosystem I, the first electron acceptor is
- an iron-sulphur protein
- ferredoxin
- cytochrome
- plastocyanin
Answer
(1) an iron-sulphur protein
Solution
As per NCERT, the reaction centre of PS I (P700) absorbs light, gets excited and its electrons are transferred to an electron acceptor molecule, then passed down the electron transport chain to NADP+.
∵ The electrons released by P700 are accepted by a bound iron-sulphur protein complex, and only then passed to ferredoxin and finally to NADP+ ⇒ ferredoxin is a later acceptor.
∵ Cytochrome b6f and plastocyanin carry electrons from PS II towards PS I (donor side) ⇒ (3) and (4) are wrong.
Answer: (1)