Grana, thylakoids, and stromal are all components found in chloroplasts. Grana are stacks of thylakoid discs that contain chlorophyll and other pigments for capturing light energy during photosynthesis. Thylakoids are flattened membrane sacs within the grana where the light-dependent reactions of photosynthesis take place. Stromal refers to the non-membrane part of the chloroplast, which contains enzymes and other molecules involved in the light-independent reactions of photosynthesis.