BIOL 1000 Lecture 6: Cell Membrane and Signals
23 Oct 2016
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Document Summary
Membrane functions: barrier to water-soluble (polar) molecules, charged molecules and large molecules, separate inside from outside. Inside organelle vs cytosol: maintain ion gradients, for energy conservation and signalling, regulates transport in and out of organelle or cell. Involved in signalling i. e. relay signals from outside to inside of the cell. The arrangement of one layer is different from the other (monolayer) Types of phospholipids composing one monolayer differs from the other monolayer. Important for function: different phospholipids required for diff jobs (cellular functions) When the membrane pinches off the phospholipids rearranges itself to close the hole (after endocytosis) because the membrane"s fluid: the repair and formation occurs rapidly. Micelles: lipid molecules that arrange themselves in spherical form. Response to amphipathic nature of fatty acids. Membrane is not static: lots of movement. Lateral diffusion and "flip-flop" (rarely occurs: newly formed phospholipids are disorganized and the enzymes (flipases) and fixes the orientation of the lipids.
