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Light Reaction and Electron Transport
Concepts tested here
- Primary electron acceptor of PS II
All Questions
2008 AIPMT 1 question
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Electrons from excited chlorophyll molecule of photosystem II are accepted first by:In photosystem II the reaction centre chlorophyll a (P680) absorbs red light of 680 nm; its electrons become excited and jump into an orbit farther from the nucleus.
These electrons are picked up by an electron acceptor, which passes them on to an electron transport system consisting of cytochromes.
The first stable acceptors are quinones: the electron passes through pheophytin to the bound plastoquinone QA, then to QB and the mobile plastoquinone (PQ) pool.
From plastoquinone the electrons move downhill to the cytochrome b6-f complex, then to plastocyanin and finally to photosystem I (the Z scheme).
Ferredoxin accepts electrons from photosystem I, not from photosystem II.
Cytochrome-b and cytochrome-f receive the electrons only after the quinone.
So among the given options the electrons from the excited chlorophyll of photosystem II are accepted first by quinone.