Membrane Structure and Function part I

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Chapter 5

• Membrane Structure and Function part I
• Page ref. 84-86

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Memorize these words!!!

• inter within ie. Hilo to Honolulu
• intra between, among ie. Hilo to Kona
• extra outside of (extracellular would be
  outside the cell)
• glyco containing sugar/carbohydrates
  (sugar-coated)

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The fluid-mosaic model of the plasma membrane

• The cell membrane is a fluid, phospholipid
  bilayer in which protein molecules are either
  fully or partially embedded. (see fig. 5.1 and
  5.2)

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Plasma membrane functions

• to separate the internal from external
  environment of the cell
• Regulates materials entering and leaving the
  cell.
• Helps the cell, in turn the organism, maintain
  homeostasis

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Plasma membrane structure

• Made up of a phospholipid bilayer
• Phospholipid a molecule with a hydrophilic
  (water-loving) head and a hydrophobic
  (water-fearing) tail

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Plasma Membrane Components

• Cholesterol a lipid found in bilayer, for
  strength of membrane
• Proteins peripheral (inside surface of membrane)
  or integral (embedded in membrane)
• Some integral proteins protrude from one surface
  of bilayer, some protrude from both
  (transmembrane)
• Phospholipids and proteins can have attached
  carbohydrate (sugar) chains. These are called
  glycolipids, and glycoproteins, respectively

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Carbohydrate Chains

• Carbohydrate chains of proteins in animal cell
  give cell a sugar coat called the glycocalyx.
• Functions of the glycocalyx include protection of
  the cell, enables cells to adhere to one another,
  reception of signal molecules, and for
  cell-to-cell recognition

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Fluidity of Plasma Membrane

• Membrane fluidity critical to its functioning
• At body temperature, it has the consistency of
  olive oil
• This allows the cell to do all it needs to do
  it makes the cell pliable

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Homework

• Due Thursday
• All vocab AND
• Reviewing chapter - 1-3
• Testing yourself 2,3,11,12,13,14