In the z-scheme, water is the initial electron donor and NADP+ is the final electron acceptor.
<u>Explanation:
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It is a process of photosynthesis. It occurs in photosynthetic chemical reaction. The z scheme is basically a term for representing the oxidation and reduction reaction occurring in plants during photosynthesis.
The water present in the chlorophyll pigment donates electrons and become the initial electron donor. Those electrons get transferred to NADP+ and forms NADPH. Thus, water acts as electron donor initially and so the final electron is NADP+.