Basic
Part of the Cell Membrane is a Phospholipid
.
The yellow structure represents the
hydrophillic head or water loving section of the
phospholipid.
The blue tails that come off of the sphere
represent the hydrophobic or water fearing
end of the Phospholipid.
Head-Made of PO4
Will bond with water
Tail-Made of Lipid
Will not bond with
water
If you mix phospholipids in water they will form these
double layered structures.
.
The hydrophillic ends will be in contact with water.
The hydrophibic ends will face inwards touching each other.
Floating around in the cell membrane are
different kinds of proteins…
.
Generally these proteins structurally
fall into
catagories...
1.Transport proteins that
regulate transport and diffusion
Transport Proteins Come in 2
Forms…
A.
Channel Protein
Channnel proteins act as a passive
pore. Molecules will move through
the opening in a process called
diffusion. This requires no energy,
molecules move from an area of
high concentration to an area of low
concentration.
B. Carrier Protein
Carrier proteins do not
extend all the way through
the membrane. They move
specific molecules through
the membrane one at a time.
Channel Proteins Move Molecules
in Different Ways…
molecule that is moving naturally into the cell through
diffusion is used to drag another molecule into the
cell. In this example glucose hitches a ride with
sodium.
2. Marker proteins that identify the
cell to other cells
Why Marker Proteins are
Important…
1. Marker proteins extend across the cell membrane and serve to
identify the cell.
2. The immune system uses these proteins to tell friendly cells from
foreign invaders. They are as unique as fingerprints.
3. They play an important role in organ transplants.
4. If the marker proteins on a transplanted organ are different from
those of the original organ the body will reject it as a foreign invader.
Receptor proteins that allow the
cell to receive instructions
1. These proteins are used in intercellular communication.
2. In this picture you can see the a hormone binding to the receptor.
3. This causes the receptor protein release a signal to perform some
action.
Cholesterol is a Part of the Cell Membrane
1. Steroids are sometimes a component of cell membranes in
the form of cholesterol.
2. When it is present it reduces the fluidity of the membrane.
3. Not all membranes contain cholesterol
Plan For Today…
1. Using the Picture on the Smartboard,
draw a picture of the cell membrane
2. Make sure you include phospholipids, all
kinds of proteins, and cholesterol.
3. Color and label all parts properly.
4. Finish and turn in.
The Cell
Membrane
The Cell Membrane
Receptor Proteins
http://www.youtube.com/watch?v=bU4955rL
v_8
Fluid Mosaic Model
http://www.stolaf.edu/people/giannini/flashan
imat/lipids/membrane%20fluidity.swf