Collagen evolution of collagens was a fundamental step in the early evolution of life, supporting the coalescence of multicellular life forms. Collagen D-banding is viable as periodic formation of ridging on all fibrils forming collagen. D-bands are created due to the semi-crystalline formation of the collagen within the fibrils. The pattern exhibited by D-banding is consistently independent of fibril diameter. When undergoing deformation, collagen fibrils may lose their D-banding, making the disappearance of the d-bands an indicator of the type of damage undergone by then tendon fibrils. Collagen Collagen is the main structural protein in the extracellular space in the various
Alpha-keratin disassemble into non-filamentous keratin precursors that can diffuse throughout the cell cytoplasm. These keratin filaments will be able to be used in future keratin synthesis, either to re-organize the final structure or create a different keratin complex. When the cell has been filled with the correct keratin and structured correctly, it undergoes keratin stabilization and dies, a form of programmed cell death. This results in a fully matured, non-vascular keratin cell. These fully matured, or cornified, alpha-keratin cells are the main components of hair, the outer layer of nails and horns, and the epidermis layer of the skin. The property