Structural proteins provide which primary role?

• A. Catalyze
• B. Provide stability and movement
• C. Regulate gene expression
• D. Transport molecules

Answer: (B)

Structural proteins are the components that give cells and tissues their shape, rigidity, and mechanical resilience, while also enabling movement through the cytoskeleton. Inside the cell, actin filaments, intermediate filaments, and microtubules form a network that supports structure, organizes components, and, with motor proteins like myosin, kinesin, and dynein, drives movement and transport. Outside the cell, collagen and other extracellular matrix proteins provide stability and strength to tissues. This combination of scaffolding and dynamics is why their primary role is to provide stability and movement. Other protein types handle catalysis, gene regulation, or transport, but structural proteins chiefly sustain form and enable movement.