Outline - Membrane Structure


1.3.U1  Phospholipids form bilayers in water due to the amphipathic properties of phospholipid molecules.
  • Draw a simplified diagram of the structure of the phospholipid, including a phosphate-glycerol head and two fatty acid tails.
  • Define hydrophilic and hydrophobic.
  • Define amphipathic and outline the amphipathic properties of phospholipids.
  • Explain why phospholipids form bilayers in water, with reference to hydrophilic phosphate heads and two hydrophobic hydrocarbon tails.​
1.3.U2  Membrane proteins are diverse in terms of structure, position in the membranes and function.
  • State the primary function of the cell membrane.
  • Contrast the structure of integral and peripheral proteins.
  • List at least four functions (with example) of membrane bound proteins.
  • Contrast the two types of transport proteins:  pumps and channels.​
1.3.U3  Cholesterol is a component of animal cell membranes.
  • Identify the structure of cholesterol in molecular diagrams.
  • Describe the structural placement of cholesterol within the cell membrane.​
1.3.A1  Cholesterol in mammalian membranes reduces membrane fluidity and permeability to some solutes.
  • Outline how temperature affects cell membrane fluidity.
  • Describe the function of cholesterol molecules in the cell membrane.​
1.3.S1  Drawing of the fluid mosaic model.
  • Draw and label the structure of membranes.  Include:  
    • Phospholipid bilayer
    • Integral proteins shown spanning the membrane
    • Peripheral proteins on membrane surface
    • Protein channels with a pore
    • Glycoproteins with a carbohydrate side chain
    • Cholesterol between phospholipids in the hydrophobic region​
1.3.S2  Analysis of evidence from electron microscopy that led to the proposal of the Davson-Danielli model.
  • Describe the observations and conclusions drawn by Davson and Danielli in discovering the structure of cell membranes.​
1.3.S3  Analysis of the falsification of the Davson-Danielli model that led to the Singer-Nicolson model.
  • Describe conclusions about cell membrane structure drawn from freeze-etched electron micrograph images of the cell membrane.
  • Describe conclusions about cell membrane structure drawn from cell fusion experiments.
  • Describe conclusions about cell membrane structure drawn from improvements in techniques for determining the structure of membrane proteins.
  • Compare the Davson-Danielli model of membrane structure with the Singer-Nicolson model.​
1.3.NOS1  Using models as representations of the real world-there are alternative models of membrane structures.
  • Explain what models are and their purposes in science.
  • Explain why models have limitations.
  • Summarize why scientific models change over time.
1.3.NOS2  Falsification of theories with one theory being superseded by another-evidence falsified the Davson-Danielli model.
  • Describe why the understanding of cell membrane structure has changed over time.​​ ​