Photosynthesis consists of two steps including, light dependent reaction and dark reaction. In the light dependent reaction, sunlight is trapped and then the solar energy is converted into potential energy. The main products of this reaction are oxygen gas, ATP and NADPH. During the reaction ADP molecules are formed then converted into NADP+ and finally into NADPH. ATP and NADPH are known as high energy molecules. Light dependent photosynthesis reaction is very important because it produces the energy which is used in making the food during photosynthesis. This complete reaction occurs in the thylakoid membrane.