Question

Molecular oxygen formed during photosynthesis is derived :-

• A. Partially from $C{O}_2$ and partially from $H_{2}O$
• B. Exclusively from $C{O}_2$
• C. Exclusively from $H_{2}O$
• D. None of the above

Answer 1

The correct option is C Exclusively from $H_{2}O$

Photosynthesis is the process by which plants, some bacteria and some protistans use the energy from sunlight to produce glucose from carbon dioxide and water. This glucose can be converted into pyruvate which releases adenosine triphosphate (ATP) by cellular respiration. Oxygen is also formed. Photosynthesis is a two stage process - light dependent reactions and light independent reactions. The Light dependent reactions, a light-dependent series of reactions, which occur in the grana, and require the direct energy of light to make energy-carrier molecules that are used in the second process.
Light energy is trapped by chlorophyll to make ATP (photophosphorylation).
At the same time water is split into oxygen, hydrogen ions and free electrons:
2$H_{2}O$ --> 4$H^{+}$ + $O_2$ + 4$e^{-}$ (photolysis)

So, the correct answer is 'Exclusively from$H_{2}O$