Question

Photo-oxidation of water in photosynthesis is in the association with
A. Cytochrome $b6$
B. Pigment system- I
C. Pigment system- II
D. Plastocyanin

Answer 1

On the inner side of the membrane, photolysis of water molecules takes place and hydrogen ions (protons) are formed. Water molecules accumulate within the thylakoid lumen. The PS-II reaction centre ($P680$) is oxidized by passing the electron to the primary acceptor. The presence of $M{{n}^{++}},\text{ }Ca+\text{ }and\text{ }Cl$ plays an important role in the photosynthetic process.

Complete answer: $PS-II$, which is permanently located on the inner side of the thylakoid membrane is associated with the water-splitting complex. Water is broken down into hydrogen ions, electrons and oxygen. Within the lumen of the thylakoid, the protons and oxygen produced by the splitting of water are released. Water photolysis is the splitting of water molecules in the presence of sunlight into hydrogen and oxygen. $PS-II$ consumes light energy during the course of photosynthesis. The electrons are energized and absorbed by the electron acceptor to the excited state. When the electron enters the ground state, the separation of water molecules happens due to the presence of photons. The electron-hole in P- during non-cyclic electron flow $680$ (pigment system reaction centre- II) is filled with electrons obtained by water photolysis. Photolysis is an oxidative process that means the splitting of water to form oxygen, protons and electrons in the presence of light. As a result, oxygen evolution happens and the electron travels to $PS-II$via the Mn-protein. Water photolysis is carried out to satisfy the need for electrons supplied to photosystem I in the Z scheme by $PS-II$. Water division is associated with $PS-II$, in which water is divided into ${{H}^{+}},\text{ }\left[ O \right]$ and electrons, and oxygen, one of the net photosynthesis products, is also formed.
Hence, the correct answer is option C.

Note: Complex light-harvesting helps to make photosynthesis more effective by collecting light from various wavelengths. In photosynthesis, both red and blue light is absorbed, but the red light is more efficient. Photosystem-II contains essential pigments linked to water photolysis in blue-green algae.