part 2

• Phospholipid bilayer


  • Acts as a barrier to separate the contents of the cell from the external environment
  • Allows the diffusion of oxygen and other substances into the cell
• Channel proteins


  • Protein molecules with channels or canals or pores in them for the ions to pass through into the cytoplasm
• Carrier proteins


  • Protein molecules that act as carriers to carry large molecules like glucose into the cell and can change shape to allow the molecules to pass through the plasma membrane
• Glycoproteins


  Protein molecules which have a carbohydrate chain attached to them
• Glycolipids


  Lipids which have a carbohydrate chain attached to them
• Functions of glycoproteins and glycolipids


  • Bind to hormones and act as receptors
  • Help to stabilize the plasma membrane structure
  • Function as antigens for cell identification
• Cholesterol


  • Makes the phospholipid bilayer more flexible and elastic
  • Strengthens the phospholipid bilayer
  • Makes the plasma membrane less permeable to ions and water-soluble molecules