2.3 Cell membrane

• What are carbohydrate chains often used as in cell membranes?

  Receptors
• What is the primary function of cell membranes?

  Controls what enters and exits the cell
• What is another name for the cell membrane?

  Cell surface membrane
• What surrounds most cell organelles?

  Cell membranes
• What is the thickness of the phospholipid bilayer?

  About 7-10 nm thick
• How are hydrophilic heads oriented in the phospholipid bilayer?

  Towards the water of tissue fluid
• How do hydrophobic fatty acid chains orientate in the phospholipid bilayer?

  Away from the water
• What is the accepted theory of cell membrane structure?

  The "Fluid Mosaic" model
• What does "Fluid" refer to in the Fluid Mosaic model?

  Proteins can move laterally
• What does "Mosaic" refer to in the Fluid Mosaic model?

  Close fitting arrangement of components
• What is the function of membrane proteins?

  Create pores for water and chemicals
• What do channel proteins do?

  Create pores for diffusion
• What is the role of carrier proteins?

  Facilitated diffusion and active transport
• What is a glycoprotein?

  A protein attached to a polysaccharide chain
• What do glycolipids help with?

  Cell recognition
• What stabilizes the cell membrane?

  Cholesterol
• What is the effect of cholesterol on phospholipids?

  Reduces lateral movement of phospholipids
• What are the main components of the cell membrane structure?

  • Phospholipid bilayer
  • Integral proteins
  • Extrinsic proteins
  • Carbohydrates
  • Cholesterol
• What are the types of membrane proteins and their functions?

  • Channel proteins: Create pores for diffusion
  • Carrier proteins: Facilitate diffusion and active transport
  • Glycoproteins: Help in cell recognition and act as receptors
• What are the roles of carbohydrates and cholesterol in the cell membrane?

  • Carbohydrates: Serve as receptors and aid in recognition
  • Cholesterol: Stabilizes the membrane and reduces movement
• extrinsic proteins are on the surface or partially
• intrinsic proteins completely span the membrane