BIOL201 Lecture Notes - Lecture 19: Basal Lamina, Plant Cell, Proteoglycan
8 Apr 2019
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Objectives: multicellular organisms must connect their cells in a tissue together to allow for coordination of function. Different types of attachments can occur depending on the tissue type. Different types and amounts of all 3 categories- collages, proteoglycans and elastins: hard- eg. bone. Lecture 19: procollagen is a precursor to collagen and has non-helical ends that prevent formation of collagen fibers inside the cell. Procollagen is shorter than long collagen fibers found in mature ecm. Has extra aa at n+c termini (don"t polymerize) Collagen fibers are too big to be secreted. Upon secretion, proteases cleave procollagen into collagen self- assemble into fibers: quaternary structure of collagen and complexities of forming collagen fibers. Aa composition: high in hydroxylysine and hydroxyproline = lysine/proline don"t normally form strong h-bonds. Now h-bonds hold the triple helix together: proteoglycan- sugar with some protein, when there"s sugars, there"s water. Polysacc and polypep molecules become hydrated and form a gel-like material.
