The light stage is the first stage of photosynthesis. Light energy is essential for this stage to occur. The light stage takes place in the grana of the chloroplast as this is where the chlorophyll is located. When light energy is absorbed it is transferred to electrons within the chlorophyll. These electrons become energised. The energy from these energised electrons is used to generate ATP. The three products of the light stage are ATP, NADPH and oxygen.