Download Cell Membrane

Cell Membrane
Structure and Function
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.
Phospholipid Molecule
Polar head
Non-polar tails
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.
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/Hughes/tutorial/cellme
mbranes/orient2.swf……..
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.
• 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