<prompt> Which of the following are intracellular events occurring in fibroblast during synthesis of collagen:Hydrolysis of procollagen to collagenGlycosylation of prolineFormation of triple helixFormation of covalent cross link b w fibrils  <response>: C i.e. Formation Collagen is a triple helical structureQ in which 3 a chains are wound into right handed superhelix with occurance of glycine residue at every 3rd positionQ of triple helix of a-chain. Vitamin C ascorbic acid is necessary as cofactor for hydroxylation of proline lysine while procollagen is conveed into collagen during post translational modificationQ.Removal of leader or signal sequence to form pro a- chains, hydroxylation not hydrolysis of proline lysine residues, glycosylation of some hydroxylysine not proline residues with glucose or glucosyl galctose, interchain and intrachain disulfide bond formation at carboxy terminal propeptide extension while amino terminal extension propeptide forms only intrachain disulfide bonds and triple helix formationQ are intracellular events of collagen formation.Cleavage of amino carboxy terminal propeptide extensions by N C procollagen peptidases releasing triple helical tropocollagen; spontaneous self assembly of tropocollagen molecules to form collagen fibrils; assembly of collagen fibrils in orderd, quaer overlapping, parallel, staggered alignment; oxidative deamination of E aminogroups of lysyl and hydroxyl lysyl residues to aldehydes; and formation of intra and inter chain covalent cross links Schiff bases and aldehyde condensation products 1t mature collagen formation are extracellular events of collagen formation. 