In this chapter you will learn: Define the following terms: amphipathic molecules, aquaporins, diffusion; explain how membrane fluidity is influenced by temperature and membrane composition; distinguish between the following pairs or sets of terms: peripheral and integral membrane proteins, channel and carrier proteins, osmosis, facilitated diffusion, and active transport, hypertonic, hypotonic, and isotonic solutions. | Lecture Biology (7th edition) - Chapter 7: Membrane structure and function Chapter 7 Membrane Structure and Function PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Overview: Life at the Edge • The plasma membrane – Is the boundary that separates the living cell from its nonliving surroundings Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The plasma membrane exhibits selective permeability – It allows some substances to cross it more easily than others Figure Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Concept : Cellular membranes are fluid mosaics of lipids and proteins • Phospholipids – Are the most abundant lipid in the plasma membrane – Are amphipathic, containing both hydrophobic and hydrophilic regions Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The fluid mosaic model of membrane structure – States that a membrane is a fluid structure with a “mosaic” of various proteins embedded in it Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Membrane Models: Scientific Inquiry • Membranes have been chemically analyzed – And found to be composed of proteins and lipids Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Scientists studying the plasma membrane – Reasoned that it must be a phospholipid bilayer WATER Hydrophilic head Hydrophobic tail Figure WATER Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The Davson-Danielli sandwich model of membrane structure – Stated that the membrane was made up of a phospholipid bilayer sandwiched between two protein layers – Was supported by electron microscope pictures of .
