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In Z-scheme of electron transport, water splitting complex supplies electrons to
A. PhotosystemI
B. Plastoquinone
C. Pheophytin
D. PhotosystemII

Answer
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Hint: During the non-cyclic flow of electrons, the two photosystems are connected in the series as PSII and PSI. The Z-scheme or non-cyclic flow of electrons begins with the absorption of a photon by PSIIfollowed byPSII. When PSII absorbs the photon, it excites and transfer the electrons to Pheophytin which in turn passes the electron to PSI.

Complete answer:
Step 1: The splitting of water is catalysed by the oxygen evolving complex (OEC), a protein complex present on the luminal surface of the thylakoid membrane. OEC oxidizes water and passes on the 4 electrons one at a time to the p680 (PSII).
Step 2: After receiving the electron, p680 excites to p680. This excited reaction centre then passes on the electrons to Pheophytin, a chlorophyll in which the Magnesium ion in the centre has been replaced by two hydrogen atoms. Pheophytin transfers the electrons to the PlastoquinoneQAand QB. Plastoquinone pass the electrons to the Cytochromeb6fcomplex which in turn passes these electrons to the Plastocyanin, a blue-coloured Copper containing protein.
Step 3: PSI receives the electrons from Plastocyanin and after absorption of a photon get excited from p700 to p700. The excited PSI then passes these electrons to the primary electron acceptor A0 which then passes the electrons to A1 which is a phylloquinone also called VitaminK1.
Step 4: A1 then pass the electrons to a series of Iron-sulfur proteins (FXFAandFB) which finally transfers the electrons to soluble Ferredoxin followed by FNR (Flavoprotein- Ferredoxin-NADP reductase) which reduces the NADP+to NADPH.

Hence, the correct answer is option (D).

Note: The PSI was discovered by Louis Duysens and the PSII was discovered by Pierre Joliot. These two photosystems contain many pigments which help to trap light energy and convert them to chemical energy.