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A 71 year old man whose wife died one year ago has been living alone most of the times and started suffering from fatigue, and depressed mood. On examination there were red spots on the thighs and easily bleeding gums were noticed. All other systems were within normal limits. Which of the following is the most likely impaired in this patient?

A- Cleavage of the N and C terminal of procollagen in the extracellular matrix.
B- Formation of the procollagen triple helix in the endoplasmic reticulum.
C- Glycosylation of hydroxylysine on the pro-alpha-collagen chain.
D- Hydroxylation of selected prolines and lysines on the pro-alpha-collagen chain.
E- Self assembly of collagen molecule into collagen fibrils
F- Formation of lysine-hydroxylysine cross linkages a reaction stabilized by lysyl oxidase.
 

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this is Vitamin C def. and vitamin C is need as a cofactor for the hydroxylation of selected prolines and lysines residue on the pro alpha collagen chain . so the ans is D
 

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yeah the answer is D

the symptoms are of scurvy. this exact explanation of scurvy and the function of Vit. C is given in FA. so i guess if we can memorize FA, woohoo!!:)
 
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