Photosynthesis occurs in two distinct stages, the Light-dependent stage and light-independent stage. The light dependent stage generally involves capturing the light energy from sun to produce ATP and NADPH. It occurs in the thylakoid membrane of the CHLOROPLAST.
The light-dependent reaction cannot occur without a large complex of protein and pigment molecules (light-absorbing) called PHOTOSYSTEMS. The photosystems are structured to harvest photons of light, which triggers electron donation by Chlorophyll, photolysis of water and subsequently creation of proton pump to yield ATP and reduction of NADP+ to NADPH. Photosystems consist of Photosystem I (P680) and II (P700).
