The light dependent reaction occurs on the thylakoid membrane of plants. The thylakoid membrane is found on the innermost membrane of chloroplasts. Each thylakoid membrane is folded to form disks known as grana, many of which are found in each chloroplast.
Chlorophyll A and Chlorophyll B are pigments that absorb energy wavelengths from the sun. Each of these pigments absorb different wavelengths, meaning the plant can maximize the amount of energy taken into each chloroplast.
The purpose of photosynthesis is to convert water and carbon dioxide into sugar and oxygen. Energy from sunlight catalyzes this reaction by providing the energy stimulus. The sugar is used by the plant as a form of energy while oxygen is released into the atmosphere.