1. Chloroplasts: These are the primary sites of photosynthesis. They contain chlorophyll, a green pigment that absorbs light energy. Chloroplasts have a complex internal structure with thylakoid membranes where light-dependent reactions occur, and a stroma where the Calvin cycle (light-independent reactions) takes place.

2. Thylakoids: These are flattened, sac-like structures within chloroplasts. They are arranged in stacks called grana, and their membranes contain chlorophyll and other pigments necessary for capturing light energy. The thylakoid membrane is where the light-dependent reactions of photosynthesis occur.