Photosynthesis refers to the fundamental biological process of the conversion of light energy into chemical energy by chlorophyll (a green pigment) containing plants. This seemingly routine process in plants sustains all the biological life and activities on Earth. The first reaction of photosynthesis occurs at a site called photosystem II (PSII), present on the thylakoid membrane in the chloroplast, where light energy is transferred to chlorophyll molecules. PSII comprises a complex group of proteins, including the D1 and D2 reaction center proteins.
Source:
phys.org