BIO325H5 Lecture Notes - Lecture 3: Microfibril, Fibril, Keratin
Document Summary
Tendon is a polymer composite of the soft" variety that is hierarchial. Tendon is a highly hierarchical polymer composite of the protein collagen within a matrix of other softer proteins and mucopolysaccharides. Hierarchial refers to nested structure: structure within structure", i. e. , microfibril, sub-fibril, fibril, fascicle, tendon. Success of nature in toughening materials is partly due to the hierarchical architecture of most biological and natural materials, which have characteristic structural features on multiple length scales from molecular to near macroscopic dimensions . Keratins in mammals occur in integumentary structures such as hair, hooves, horns. Like tendon keratin is very hierarchical [structure nested within structure]. The helixes wrap around each other to form coiled-coil protofibrils and eleven of these are packaged together to form a microfibril. In turn the microfibrilsare arranged into macrofibrils, which are held in a matrix that is composed of the other major component of the keratin high-sulphur proteins.
