BIOL-K - Biology BIOL-K 101 Lecture Notes - Lecture 8: Proteoglycan, Extracellular Matrix, Fibronectin
4 Oct 2016
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Document Summary
Cell membranes are fluid mosaics of lipids and proteins. Phospholipids: most abundant lipid in the plasma membrane. Phospholipid bilayer is a stable boundary between two aqueous compartments. Cell must exchange materials with its surroundings, a process which is controlled by the plasma membrane. Plasma membranes are selectively permeable, regulating the cells molecular traffic. Hydrophobic (nonpolar) molecules, such as co2 and o2 can dissolve in the phospholipid bilayer and pass through the membrane rapidly. Hydrophilic (polar) molecules including ions, water, and other polar molecules do not cross the membrane easily. Membranes have a distinct inside (p-face) and outside (e-face) The asymmetrical distribution of proteins, lipids, and associated carbohydrates on the plasma membrane is determined when the membrane is built by the er and golgi apparatus. Most cells synthesize and secrete materials that are external to the membrane. No cell walls, but are covered in an elaborate extracellular matrix. Extracellular matrix made up of glycoproteins, such as collagen, proteoglycans, and fibronectin.
