Question

Splitting of water is associated with

• A. photosystem I
• B. lumen of thylakoid
• C. both photosystem I and II
• D. inner surface of thylakoid membrane

Answer 1

Answer: (D)

Light reactions occur inside the thylakoids, especially those of grana region. It involves two types of reactions photolysis of water and production of assimilatory power. The phenomenon of breaking up of water into hydrogen and oxygen in the illuminated chloroplasts is called photolysis or photocatalytic splitting of water. Water splitting complex is associated with the $PSII$, which itself is physically located on the inner surface of thylakoid membrane.
$4H_{2}O\rightleftharpoons 4H^{+}+4O{H}^{-}$
$4O{H}^{-}\underset{M{n}^{2+},C{a}^{2+},C{l}^{-}}{\overset{\text{ oxygen evolving complex }}{\to }}2H_{2}O+O_2\uparrow +4e^{-}$