Question

Splitting of water is associated with
A. Photosystem l
B. Lumen of thylakoid
C. Both photosystem l and ll
D. Inner surface of thylakoid membrane

Answer 1

Light reactions include light absorption, splitting of water, oxygen release and formation of energy chemical intermediates. Water splits into hydrogen and oxygen, creating oxygen as the net product of photosynthesis. It supplies electrons continuously in PSII.

Complete answer:
Light reaction or the photochemical phase takes place in the thylakoids, especially in the grana region. It involves two types of reactions which are- photolysis of water and production of assimilatory power. The phenomenon of breakdown of water and oxygen in the illuminated chloroplasts is referred to as photolysis or photocatalytic splitting of water.
The electrons that were moved from the photosystem II have to be replaced. It can be done so by the electrons that are available due to splitting of water. The splitting of water is associated with PS II, wherein the molecule of water splits into hydrogen ions, oxygen atoms and an electron. Thus, oxygen is referred to as the net product of photosynthesis. This electron has to be replaced by those from photosystem I that are provided by photosystem II.
$2H_2O \to 4H^+ + O_2 + 4e^-$
The water splitting complex is associated with the PS II that itself is physically located on the inner side of the membrane of the thylakoid.

So, the correct answer is option D, inner surface of the thylakoid membrane.

Note:
Splitting of water is a chemical process in which hydrogen and oxygen are the byproducts. Efficient and economical water splitting can take place through technological breakdown that could underpin a hydrogen economy. A version of water splitting takes place in photosynthesis but hydrogen is not produced whereas reverse water splitting is the basis of the hydrogen fuel cell.