How does vitamin C deficiency affect collagen synthesis?
Hydroxylation reactions require vitamin C. Without these, there is weak cross-linking and loss of collagen tensile strength. 23. What is the order of events in collagen synthesis? A: Transcription, translation, signal peptide (N-terminus) directs peptide into RER, hydroxylations, glycosylations, disulfide bonds form at C-terminus of three chains, triple helix formation, export to extracellular matrix, cleavage of N- and C-terminal regions of the triple helix, and assembly of multiple triple helices into fibrils with cross-links. 24. How is collagen recycled? A: Collagenases in the extracellular matrix break it down. It is phagocytosed and broken down further. It is recycled every few months. 25. What is Ehlers-Danlos syndrome? A: A group of defects in collagen synthesis that lead to stretchy skin and loose joints. 26. What is osteogenesis imperfecta? A: Also called brittle bone syndrome, leads to multiple bone fractures early in life. Can be confused with child abuse. 27. Where is elas
