In type I collagen, telopeptide corresponds to-

Ans. D. Both COOH and NH2-terminals superhelical conformationStructure of collagen molecule:-Pro-collagen is comprised of two alpha-1 chains and one alpha-2 chain intertwined into a triple helix. Pro-peptide domains at the carboxy-terminals and amino-terminals are cleaved, resulting in formation of mature collagen. When collagen is degraded, during physiological turnover or pathological adverse remodeling, telopeptide (from the amino- terminals or carboxy-terminals) are cleaved and released into the plasma.Urinary crosslinked N-terminal telopeptide and C terminal telopeptide of type 1 collagen are used as markers of bone resorption in osteoporosis.