The structure of cell membrane Molecules that make the membrane Structure of the membrane Properties of membrane Cell membrane OR plasma membrane • Separates the cell from its surroundings • Selectively permeable-allow some substances to cross easily than others Bread and butter sandwich • If I pour water on top of this sandwich, what will happen? Phospholipid bilayer • Phospholipids have hydrophilic heads and hydrophobic tails. • Hydrophilic –loves water • Hydrophobic-fears water © 2016 Pearson Education, Inc. Properties of membrane • https://edpuzzle.com/media/ 618027292f520f4175593ae8 • Phospholipids and soap molecules are similar • Soap contain just one layerHydrophobic and hydrophilic • They are fluid and resealableself repair Fluid mosaic model Fluid mosaic model Proteins floating in the fluid of phospholipids. Fibers of extracellular matrix (ECM) Figure 5.2 Glycoprotein Carbohydrate Glycolipid EXTRACELLULAR SIDE OF MEMBRANE Phospholipid Cholesterol Microfilaments Peripheral of cytoskeleton proteins © 2016 Pearson Education, Inc. Integral protein CYTOPLASMIC SIDE OF MEMBRANE Types of protein • The proteins and lipids can shift laterally • Some proteins move more slowly and some are anchored in place • Integral proteins penetrate the hydrophobic interior of the lipid bilayer • Integral proteins that span the membrane are called transmembrane proteins • Peripheral proteins are loosely bound to the surface of the membrane © 2016 Pearson Education, Inc. Effect of temperature At cold-cell membrane switch from fluid to solid At warm temperature – movement of phospholipids becomes unrestrained. Role of cholesterol • At cold temperature, cholesterol maintains the fluidity by preventing tight packing Role of cholesterol • At warm temperature (such as 37°C) cholesterol restrains the movement of phospholipids Plasma membrane -3D • https://edpuzzle.com/media/ 5b88345d15d9e340e5300319 Class activity Draw the structure of cell membrane and label it Discuss in the group and explain the following words Selectively permeable Hydrophilic Hydrophobic Fluid mosaic Polar and non polar
