国外大学细胞生物学课件 英文课件2.ppt

W2011 D103 Cell Biology - lecture 2 ? Suetterlin and MacGregor - all rights reserved. 1 1. T he lipid bilayer and its characteristics 2. Membrane p roteins Lecture 2: Biological membranes W2011 D103 Cell Biology - lecture 2 ? Suetterlin and MacGregor - all rights reserved. 2 Separate inside from outside permeability barrier Growth, movement, change of shape munication with its environment Flexible ( fluid ) Allow molecule exchange with the environment Selectively permeability What is the function of a membrane? W2011 D103 Cell Biology - lecture 2 ? Suetterlin and MacGregor - all rights reserved. 3 The membrane system of a eukaryotic cell W2011 D103 Cell Biology - lecture 2 ? Suetterlin and MacGregor - all rights reserved. 4 Lipids assemble into bilayers in which proteins form the ponents of signal transduction and transport. Fluid mosaic model of biological membranes first described in 1972 by Singer and Nicolson W2011 D103 Cell Biology - lecture 2 ? Suetterlin and MacGregor - all rights reserved. 5 Example: phosphatidyl- Choline (PC) Membrane lipids differ in - head group - length of hydrophobic tail - degree of saturation of the hydrophobic tail - backbone (glycerol or sphingosine) Lipids are anization of lipids in a bilayer W2011 D103 Cell Biology - lecture 2 ? Suetterlin and MacGregor - all rights reserved. 6 W2011 D103 Cell Biology - lecture 2 ? Suetterlin and MacGregor - all rights reserved. 7 rigid, amphiphatic steroid found in both leaflets What is cholesterol? W2011 D103 Cell Biology - lecture 2 ? Suetterlin and MacGregor - all rights reserved. 8 Lipids arrange in a way so that their hydrophobic tails are away from H 2O and their hydrophilic heads face H 2O. ?Energetically most favorable The behavior of lipids in aqueous environment W2011 D103 Cell Biology - lecture 2 ? Suetterlin and MacGregor - all rights reserved. 9 The structure of a lipid determines its packaging in an aqueous environment. Do all lipids form b