Structural proteins are essential components of cells and tissues, providing support and shape. They form the framework of various biological structures, such as collagen in connective tissues and keratin in hair and nails. These proteins are crucial for maintaining the integrity and stability of cells and organs. In addition to their supportive roles, structural proteins also contribute to cellular movement and organization. For example, actin and tubulin are involved in the formation of the cytoskeleton, which helps cells maintain their shape and facilitates movement. Overall, structural proteins are vital for the proper functioning of living organisms.