Green plant light absorption. Animation showing the interaction of sunlight with the stacks of thylakoids green inside a chloroplast. Chloroplasts are the bodies inside plant cells that are responsible for photosynthesis, the light_powered reactions the plant uses to make food. The thylakoids are the structures inside chloroplasts that are the site of the light_dependent reactions of photosynthesis. They contain the green pigment chlorophyll. Chlorophyll appears green as it does not absorb green or yellow light, as shown by the arrows passing through and bouncing off the chloroplast. It has its highest absorption largest arrow at the blue end of the spectrum, and also has a smaller level of absorption at red wavelengths. Plants use light energy to capture atmospheric carbon dioxide and convert it into the sugars they use as building blocks.