The role of the thylakoid membrane in chloroplasts is to facilitate the process of photosynthesis. These membranes house chlorophyll and other pigments that capture light energy. During the light-dependent reactions of photosynthesis, the thylakoid membranes convert this light energy into chemical energy, producing ATP and NADPH. This energy is then used in the light-independent reactions (Calvin cycle) to synthesize glucose from carbon dioxide. Thus, thylakoid membranes are essential for energy conversion in plant cells.