1. What is a polar molecule?
Electrons are shared unequally in a bond and there is a slightly + end of the molecule and a slightly – end
Nonpolar is the opposite-electrons shared equally
IN WATER-Oxygen pulls Hydrogen’s electrons closer to it
Positive end of one water molecule is attracted to negative end of another water molecule

2. Polar Molecules
Polar=Hydrophilic (water)
Nonpolar= hydrophobic(oil)

3. The Cell Membrane Discovered 1972 by Singer and Nicholson
Composed of phospholipids and proteins
Model of membrane is FLUID MOSAIC MODEL
Phospholipids- composed of
Polar head- contains a phosphate group
Nonpolar tail- lipid portion
Looks like a clothespin

4. Phospholipid Bilayer Phospholipids form a 2 layered membrane
Heads point toward outside and inside of cell- water
Tails point toward each other- don’t let water in
Keeps wrong things out, lets right things in
Many reactions take place in the non-polar region

5. Proteins in the Bilayer
4 Kinds-
Transport Proteins- allow passage of materials in and out of cell
Receptor Proteins –transmit info in and out by reacting with chemical signals (hormones)
Marker Proteins- “cellular name tags”
Enzymes- help reactions occur
Proteins float like icebergs in a sea of phospholipids

6. Membrane Proteins
Proteins are shape specific- channel, receptors, and enzymes will only fit a certain type of molecule- makes sure nothing bad gets in
Marker proteins- identify the cell as yours- not a foreign body- i.e. Red Blood Cells (blood types)

7. THE CELL MEMBRANE
MARKER PROTEIN
CHANNEL PROTEIN