BIO 1140 Lecture Notes - Cell Signaling, Glycosylphosphatidylinositol, Cholesterol
Document Summary
Cell membranes-chapter 5: functions of cell membranes, fluid mosaic model. Fluid lipid molecules in which proteins are embedded and freely floating: functions. 1: define boundaries; selectively permeable barrier (lipid soluble molecules can cross the membrane easily, water soluble molecules cannot cross) Regulation of solute transport: active role of moving things in and out of cell and/or organelles, uphill or downhill e. g. na+,k+-atpase (can move solutes across the membrane that normally wouldn"t be able to cross) Responses to external signals: receptors and signal transduction e. g. -adrenoreceptor need to be able to recognize and respond to other cells around them. Cell-to-cell communication: recognition, adhesion, exchange of materials, gap junctions, plasmodesmata, plasma membrane of schwann cell (myelin sheath) 24% lipid: membrane structure, fluid mosaic model, lipid-protein assembly in which components are held together in a thin sheet by non- covalent bonds. Two fluid lipid layers structural backbone, permeability barrier. Key component of permeability barrier: composition.
