Structure of cell membrane

• Functions

  • Seperates cell content form outside environment
  • Seperates content from cytoplasm
  • Cell recognition & signalling
  • Holding components of some metabolic paths in place
  • Regulates transport of materials in and out of cell
• Fats and water

  • Don‘t mix
  • Water is polar
  • Fats are non polar & hydrophobic
• Lipids

  • Phospholipids = Glycerol backbone, 2 fatty acids & 1 phosphate
  • Fatty acid = polar
  • Phosphate = non polar

  Cell Membrane = phospholipid bimembrane
• Fluid Mosaic

  Fluid - molecules in membrane can move freely within layer

  Mosaic - pattern produced by scattered protein molecules when viewed from above
• Intrinsic Proteins - through the whole membrane
• Extrinsic proteins - found on surface of membrane
• Glycoprotein (extrinsic)

  • Protein + carbohydrate
  • Allow cells to communicate
  • Groups of cells have own glycoproteins recognised by immune system
  • Act as receivers for messages e.g. hormones
• Cholesterol - help give membrane mechanical strength