Grana are small, disc-shaped structures found within the chloroplasts of plant cells. They are composed of stacks of thylakoids, which are membrane-bound compartments that contain chlorophyll, the green pigment essential for photosynthesis. The arrangement of grana increases the surface area available for light absorption, allowing plants to efficiently convert sunlight into energy. In the process of photosynthesis, grana play a crucial role in capturing light energy and converting it into chemical energy. This energy is then used to produce glucose from carbon dioxide and water. The overall process is vital for plant growth and contributes to the oxygen supply in the atmosphere, benefiting all living organisms, including humans.