Cell Membrane

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Cell Membrane

• Structure and Function

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The phospholipid molecule
The main building block of the cell membrane is
the phospholipid molecule.
A phospholipid molecule is made up of glycerol
2 fatty acid tails and a phosphate group.
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Phospholipid Molecule
Polar head
A polar molecule ( or polar part of a molecule)
is overall neutral, but it has an uneven
distribution of electrons and so has oppositely
charged areas.
Non-polar tails
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The polar head is hydrophilic and likes water
molecules.
hydro water Philic loving
The fatty acid tails are hydrophobic and do not
mix with water.
Hydro water Phobic afraid of, dreads
Do little activity http//telstar.ote.cmu.edu/Hugh
es/tutorial/cellmembranes/orient2.swf..
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Structure of the membrane

• Phospholipids form a bilayer and are the main
  building blocks of the membrane. It has a very
  limited permeability.
• Cholesterol Binds to the
  phospholipids. Increases strength and restricts
  movement
• Sugars give signature, identify cell as self.
  Foreign invaders are identified by immune system.

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• Proteins are the gatekeepers
• Receptor sites for hormones ( chemical
  messengers) that turn activities on or off
• Transport passively or actively move things in
  or out across the membrane
• Bind neighbouring cells together
• Enzymes that take part in chemical reactions (
  such as in the mitochondria or chloroplasts)
• Aid in cell to cell communication