After the energy from the sun is converted and packaged into ATP and NADPH, the cell has the fuel needed to build carbohydrate molecules. The carbohydrate molecules made will have a backbone of carbon atoms. In the light-dependent reactions, energy from sunlight is absorbed by chlorophyll and that energy is converted into stored chemical energy. In the light-independent reactions, the chemical energy harvested during the light-dependent reactions drives the assembly of sugar molecules from carbon dioxide. The light-dependent reac-tions require light and water, occur in the thylakoids, and produce ATP and NADPH. The light-independent reactions require carbon dioxide, occur in the stroma, and produce high-energy sugars. The light-dependent reactions produce ATP and NADPH; the light-independent reactions use energy stored in ATP and NADPH. Light dependent reactions occur in Grana of Chloroplasts, Light Independent reactions occur in Stroma of Chloroplasts. Hence Chloroplasts are required for both the light-dependent and light-independent reactions to proceed.
