The light dependent reactions of photosynthesis require the energy in sunlight to proceed. Structures called photosystems which contain chlorophyll absorb the light from the sun to generate excited electrons, which are transferred to electron carriers ATP and NADH.
These electron carriers are used in the light-independent reactions of photosynthesis.
During this process, the high energy electrons are passed to an acceptor molecule and replaced with an electron from water. This splitting of water produces H+ ions and oxygen as a byproduct. The splitting of water is called photolysis
