Plasma membrane

• The plasma membrane is the outer membrane of the cell
• The structure of the plasma membrane is described by the fluid mosaic model
• Functions of the plasma membrane:

  • Controls the transport of molecules in and out of cells
  • Separates the contents of the cells from the outside environment
  • Allows other cells to recognize the cell as belonging to the body
  • Allows cells to signal to each other
  • Molecules such as hormones or drugs can bind to the membrane
• Key structural fact:

  • The membrane is made of phospholipid bilayer
  • The layer is made of hydrophobic tail that repels water, and hydrophilic head that attracts water
  • Cholesterol is also present that stabilizes the membrane's shape
  • Integral/peripheral proteins for transport of molecules or acts as enzymes
• Types of proteins in the membrane:

  • Integral proteins run through the entire membrane and act as channels
  • Peripheral proteins do not run through the entire membrane and are often enzymes
• Cholesterol maintains the stability of the membrane
• Glycoproteins are carbohydrate molecules conjoined with a protein molecule

  Glycolipids are carbohydrate molecules conjoined with a lipid molecule

  These are involved in recognition, signaling, and acting as receptors
• Label the following

  A) phospholipid

  B) channel protein

  C) carrier protein

  D) glycoprotein

  E) cholesterol

  F) peripheral protein

  G) integral protein

  H) hydrophilic head

  I) hydrophobic tail