Protein found in bones and cartilage which gives them flexibility?

Protein found in bones and cartilage which gives them flexibility?

• A. Collagen
• B. Keratin
• C. Elastin
• D. Fibronectin

Answer: (A)

Collagen provides the flexible, strong scaffold in bone and cartilage. It forms a fibrous network that resists pulling forces and allows tissues to bend slightly under load without tearing. In bone, collagen type I fibers create an organic framework that minerals can reinforce, giving rigidity yet some give. In cartilage, collagen type II fibers create a mesh that traps and organizes water and proteoglycans, enabling the tissue to deform when pressed and then return to shape. The other proteins don’t play that same combination of tensile strength and flexibility in these tissues: keratin is the hard structural protein of hair and nails, elastin offers elasticity in tissues that stretch a lot (like skin and blood vessels) but isn’t the primary load-bearing component in bone/cartilage, and fibronectin mainly helps cells attach to the extracellular matrix rather than forming the main flexible scaffold.

Collagen provides the flexible, strong scaffold in bone and cartilage. It forms a fibrous network that resists pulling forces and allows tissues to bend slightly under load without tearing. In bone, collagen type I fibers create an organic framework that minerals can reinforce, giving rigidity yet some give. In cartilage, collagen type II fibers create a mesh that traps and organizes water and proteoglycans, enabling the tissue to deform when pressed and then return to shape. The other proteins don’t play that same combination of tensile strength and flexibility in these tissues: keratin is the hard structural protein of hair and nails, elastin offers elasticity in tissues that stretch a lot (like skin and blood vessels) but isn’t the primary load-bearing component in bone/cartilage, and fibronectin mainly helps cells attach to the extracellular matrix rather than forming the main flexible scaffold.