Plastids are a diverse group of organelles found primarily within the cells of plants and some protists. These organelles are structurally responsible for essential metabolic processes, most notably photosynthesis, through the specialized internal structures that facilitate light-dependent reactions. Beyond energy conversion, plastids are also involved in the storage of various compounds, serving as repositories for starches, oils, and pigments. Functionally, the group includes types such as chloroplasts, which contain chlorophyll and are the primary site of energy capture, and chromoplasts and leucoplasts, which specialize in pigmentation or general storage, respectively. The varying morphologies and biochemical roles underscore their foundational importance in eukaryotic cellular life.