Biology 1002B Lecture Notes - Lecture 5: Fluid Mosaic Model, Lipid Bilayer, Cell Membrane
16 Oct 2013
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Document Summary
One of the keys to the evolution of life was the development of the cell or plasma membrane. Plasma membrane: selectively permeable barrier, allows for the uptake of key nutrients and elimination of waste products while still maintaining a protected environment for cellular processes to occur. Development of this membrane allowed for compartmentalization of processes and increased complexity. Current view of membrane based on: fluid mosaic model. Membranes are not rigid but consists of proteins in a mixture of lipids the consistency of olive oil. Lipid molecules vibrate, flex back and forth, very rarely does a lipid go between the two layers. There is much exchange in molecules within a layer. Maintaining membrane in fluid state is very important to its function. Most membranes contain an assortment of different types of proteins. Proteins much larger than lipid molecules, therefore move much slower. Some proteins anchor the cytoskeleton and don"t move.
