40nm gap in between the tropocollagen molecule incollagen which serve as the site of bone formation is occupied by (AIIMS Nov 2011)
a. Collagen fibrils/aggregates are arranged in different combinations and concentrations in various tissues to provide varying tissue properties. In bone, entire collagen triple helices lie in a parallel, staggered array.
b. Forty nm gaps between the ends of the tropocollagen subunits (approximately equal to the gap region) probably serve as nucleation sites for the deposition of long, hard, fine crystals of the mineral component, which is (approximately) hydroxyapatite, Ca10 (PO4)6(OH)2 with some phosphate.
c. It is in this way that certain kinds of cartilage turn into bone. Type I collagen gives bone its tensile strength.