1. KEY CONCEPT The cell membrane is a barrier that separates a cell from the external environment.

2. Cell membranes are composed of two phospholipid layers.

3. Cell membranes are composed of two phospholipid layers.
Cell Membrane- forms a boundary between a cell and the outside environment and controls the passage of materials in and out of the cell
The cell membrane has two major functions.
cell membrane

4. Cell membranes are composed of two phospholipid layers.
There are 3 parts to the cell membrane
1) a charged phophate (PO4) group
2) a glycerol
3) a fatty acid
cell membrane
outside cell
inside cell

5. Cell membranes are composed of two phospholipid layers.
The heads are polar and like water (hydrophyllic)
The tails are non-polar and don’t like water (hydrophobic)
This is why the membrane forms two layers
cell membrane
outside cell
inside cell

6. Cell membranes are composed of two phospholipid layers.

7. Cell membranes are composed of two phospholipid layers.
The cell membrane is made of a phospholipid bilayer.
cell membrane

8. Cell membranes are composed of two phospholipid layers.
The cell membrane is made of a phospholipid bilayer.
There are other molecules embedded in the membrane.
Like cholesterol for strength, proteins to control what comes in and out and also as part of cytoskeleton.
cell membrane
protein
cholesterol
carbohydrate
chain
protein channel

9. Cell membranes are composed of two phospholipid layers.
The cell membrane is made of a phospholipid bilayer.
There are other molecules embedded in the membrane.
The fluid mosaic model describes the membrane.
cell membrane
protein
cholesterol
carbohydrate
chain
protein channel

10. Cell membranes are composed of two phospholipid layers.

11. Cell membranes are composed of two phospholipid layers.
The cell membrane is selectively permeable.
Some molecules can cross the membrane while others cannot.

12. Cell membranes are composed of two phospholipid layers.
The cell membrane is selectively permeable.
Some molecules can cross the membrane while others cannot.

13. Molecules can pass through the membrane in several ways, some require E, while others do not
1) Small non-polar molecules pass easily with out E
2) Small polar molecules are transported via proteins using some E
3) Large molecules are transported by vesicles using more E

14. Chemical signals are transmitted across the cell membrane.
Receptor protein-detects a signal molecule and performs an action
Receptors only bind with certain molecules
Receptors bind with a ligand and change shape.
There are two types of receptors.

15. Chemical signals are transmitted across the cell membrane.
Receptors bind with ligands and change shape.
There are two types of receptors.
intracellular receptor
A receptor that is
Inside the cell

16. Chemical signals are transmitted across the cell membrane.
Receptors bind with ligands and change shape.
There are two types of receptors.
intracellular receptor
membrane receptor
Receptor imbedded
In the cell membrane