The role of lipids in organism structure is multifaceted, contributing to cell membrane composition, energy storage, and insulation. Lipids, such as phospholipids and cholesterol, form the bilayer of cell membranes, providing structural integrity and regulating the movement of substances in and out of cells. Additionally, lipids serve as energy reserves, stored in adipose tissue, and help maintain body temperature by providing thermal insulation. Their diverse functions highlight the importance of lipids in biology and overall organism health.