Plants and other photosynthetic organisms are the only organisms capable of using the light energy from sun to produce their food. This unique process is called PHOTOSYNTHESIS and it is possible because of the possession of green pigments called CHLOROPHYLL found in their Chloroplast. The process of photosynthesis occurs in two stages; light stage and light-independent stage.
In the light stage which occurs in the thylakoid membrane, plants convert light energy to ATP (chemical energy). This is done when their Chlorophyll molecules becomes activated when struck by photons of light from sun.
The activated chlorophyll then splits water molecules in a process called "PHOTOLYSIS OF WATER" to yield protons (H+). These protons get accumulated in the thylakoid. The passage of protons along the gradient forms a PROTON PUMP. The energy generation from this pump causes the synthesis of ATP from ADP and inorganic phosphate (Pi).
