Type II collagen is specific for cartilaginous tissues. It is essential for the normal embryonic development of the skeleton, for linear growth and for the ability of cartilage to resist compressive forces (By similarity). Homotrimers of alpha 1(II) chains. The C-terminal propeptide, also known as COLFI domain, have crucial roles in tissue growth and repair by controlling both the intracellular assembly of procollagen molecules and the extracellular assembly of collagen fibrils. It binds a calcium ion which is essential for its function (By similarity). Contains mostly 4-hydroxyproline. Prolines at the third position of the tripeptide repeating unit (G-X-P) are 4-hydroxylated in some or all of the chains. Contains 3-hydroxyproline at a few sites. This modification occurs on the first proline residue in the sequence motif Gly-Pro-Hyp, where Hyp is 4-hydroxyproline. Lysine residues at the third position of the tripeptide repeating unit (G-X-Y) are 5-hydroxylated in some or all of the chains. O-glycosylated on hydroxylated lysine residues. The O-linked glycan consists of a Glc-Gal disaccharide. Belongs to the fibrillar collagen family.