Question

The electrons, that are removed from photosystem-II and photosystem-I during z-scheme, must be replaced. This is achieved by electrons released

• A. By photosystem-I and NADP⁺
• B. By splitting of water and NADPH
• C. By ATP and photosystem-II
• D. By splitting of water and photosystem-II

Answer 1

Answer: (D)

Photosystem II is associated with oxygen-evolving complex - that has 4 Mg ions, one calcium ion and one chlorine ion - that splits water molecules to 4H⁺ and O₂. Hence photosystem II obtain electron by splitting of water.
Photosystem I gets an electron from photosystem II. This Z-scheme is also called cyclic photophosphorylation.