Answer: In light dependent reaction, CO2 and water enter the leaf through stomata from the environment. Water molecules splits into oxygen molecule when the light hits the pigment in the membrane of a thylakoid called chloroplast. Then the electrons move down to enzymes. Sunlight allow the enzymes to convert ADP to ATP and NADP+ is converted into NADPH. The ATP and NADPH is used by the calvin cycle to convert carbon dioxide into simple sugar glucose.