How do thylakoids contribute to photosynthesis?

Thylakoids play a crucial role in photosynthesis as the sites of the light-dependent reactions. These structures are membrane-bound compartments found within chloroplasts, which are the organelles responsible for photosynthesis in plants and some algae. The light-dependent reactions occur across the thylakoid membranes, where chlorophyll and other pigments capture light energy.

When light is absorbed by chlorophyll, it excites electrons, which then enter an electron transport chain. This process leads to the generation of ATP and NADPH, which are energy-rich molecules that are pivotal for the following light-independent reactions, commonly referred to as the Calvin cycle. The thylakoids are also involved in the splitting of water molecules, a process known as photolysis, which releases oxygen as a byproduct and provides the necessary electrons for the light reactions to continue. Thus, the thylakoids directly facilitate the conversion of solar energy into chemical energy through their unique structure and location, making them essential for the photosynthetic process.