Thylakoiden

Thylakoids are membrane-bound compartments found within chloroplasts and cyanobacteria. These flattened sacs play a crucial role in photosynthesis, the process by which light energy is converted into chemical energy. Within the thylakoid membranes, pigments like chlorophyll are embedded, enabling them to capture photons from sunlight. The thylakoid membrane encloses an internal space called the thylakoid lumen. The stacked structures formed by thylakoids are known as grana (singular: granum), while unstacked, interconnected thylakoids are called stroma lamellae. During the light-dependent reactions of photosynthesis, light energy is used to split water molecules, release oxygen, and generate ATP and NADPH. These energy-carrying molecules are then used in the light-independent reactions (Calvin cycle) which occur in the stroma, the fluid-filled space surrounding the thylakoids. The intricate arrangement of thylakoids maximizes the surface area available for light absorption and efficient energy transfer.