What is the main role of structural proteins?

Structural proteins play a crucial role in providing support and shape to various structures within organisms. They are key components of cells and tissues, contributing to the integrity and architecture of biological systems. For instance, collagen, a well-known structural protein, forms the basis of connective tissues such as tendons and skin, giving them strength and elasticity. Likewise, keratin serves a similar purpose in hair, nails, and the outer layer of skin.

The other options are associated with different types of proteins and their functions. Enzymes, which are a type of protein, specifically speed up chemical reactions, while transport proteins are responsible for moving substances across cell membranes or within the bloodstream. Storage proteins, on the other hand, serve to reserve energy and other molecules for future use, such as ferritin storing iron. Thus, the main focus of structural proteins is distinctly on maintaining the shape and structural stability of cells and tissues.