In light reaction, plastoquinone facilitates the transfer of electrons from
Answer: (C) PS-II to Cytb6f complex. In the Z-scheme, electrons excited from PS II are picked up by an acceptor and passed down an electron transport chain of cytochromes (the Cyt b6f complex) before reaching PS I.
- A.PS-I to NADP+
- B.PS-I to ATP synthase
- C.PS-II to Cytb6f complex✓
- D.Cytb6f complex to PS-I
Correct Answer
(C) PS-II to Cytb6f complex
Solution & Explanation
In the Z-scheme, electrons excited from PS II are picked up by an acceptor and passed down an electron transport chain of cytochromes (the Cyt b6f complex) before reaching PS I. Plastoquinone is the carrier that ferries these electrons from PS II into the cytochrome b6f complex. Hence the transfer is from PS-II to the Cyt b6f complex. (The 2020 answer here is from an external key, as the original PDF carried no biology key; independent NCERT derivation confirms option C.) NCERT: Class 11 Ch 11, p.139 [139:006-009]: "The electrons are not used up as they pass through the electron transport chain, but are passed on to the pigments of photosystem PS I." (Answer per official NEET key; 2020 paper had no printed biology key.)