Thylakoids are membrane-bound structures found within the chloroplasts of plant cells. They are essential for the process of photosynthesis, where they capture light energy and convert it into chemical energy. Thylakoids are organized into stacks called grana, which increase their surface area for light absorption. Each thylakoid contains chlorophyll, the green pigment that plays a crucial role in capturing sunlight. The thylakoid membranes house proteins and other molecules involved in the light-dependent reactions of photosynthesis, producing ATP and NADPH that are used in the subsequent light-independent reactions to synthesize glucose.