Chapter 5 the dynamic cell membrane

Chapter 5 the - Myelin encloses nerve cells 1:70 Have hydrophilic regions(domains and stick out into extracellular or cytoplasm and hydrdophobic

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Chapter 5 the dynamic cell membrane What is the structure of a biological membrane? Section 5.1 1. Lipids- physical integrity of the membrane and create barrier to the rapid passage of hydrophobic materials ie water and ions- fluid mosaic model. Proteins- move materials and receive chem. signals from external environ. Carbs- attached to lipids or proteins 2. Lipids- usually phospholipids, when head is hydrophilic and tail is hydrophobic- helps biological membranes fuse during vesicle formation, phagocytosis etc. about 25 percent of lipids in a membrane may be cholesterol. Flexible, not rigid with fluid interior. Flip flop from one side to the other of a membrane is rare since hydrophilic would have to go through hydrophobic. Short chain and unsaturated fatty acids are more rigid than long chain saturated. Increase temp= more fluid. 3. Proteins- one for every 24 phospholipids. Inner membrane of mitochondrion is 1:15.
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Unformatted text preview: Myelin- encloses nerve cells 1:70. Have hydrophilic regions (domains) and stick out into extracellular or cytoplasm and hydrdophobic regions interact with fatty acid chains. Fluid mosaic model- proteins and lipids are independent and interact noncovalently. Polar=polar and non=non. Move around within the bilayer but have limitations, must stay in a place where they can do their job. a. Integral membrane proteins- hydrophobic domains and penetrate the phospholipid bilayer. b. Peripheral- not embedded in the bilayer. Interact only with the heads. c. Transmembrane- integral proteins that protrude on both sides 4. Phospholipids- synthesized on the surface of the smooth ER, membrane proteins- inserted into the rough ER as they form on ribosomes, functioning membranes- rough ER bud off and join cis of Golgi and find themselves in tran then bud to join plasma membrane...
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This note was uploaded on 01/26/2011 for the course BIO 0150 taught by Professor Roberts during the Fall '09 term at Pittsburgh.

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