1. The Cell Membrane

2. Selective Permeability:
the cell membrane is said to be semi-permeable or selectively permeable which means it allows some substances to pass but not others

3. Cell Membrane:
forms a boundary between the cell and the outside environment
it controls the passage of materials into and out of the cell
it consists of a double layer of phospholipids
a phospholipid is a lipid made of a phosphate, glycerol, and 2 fatty acid chains
phosphate

4. a phospholipid has a polar “head” and 2 nonpolar “tails”
phosphate
a phospholipid has a polar “head” and nonpolar “tails”
these phospholipids are arranged in a double layer called a lipid bilayer
the polar heads form the outer surfaces of the membrane, whereas, the nonpolar tails make up the interior of the lipid bilayer

5. Lipid Bilayer: Glycerol Hydrophilic Outside of cell = Hydrophobic
Inside of cell =

6. The Fluid Mosaic Model:
describes the arrangement of molecules that make up the cell membrane
the cell membrane is not rigid but fluid
each layer can move from side to side and slide past each other, as a result, it acts like a fluid
the cell membrane also has a variety molecules embedded in it which resembles a mosaic made up of different tiles and textures

7. The Cell Membrane: carbohydrate chain phospholipid protein cholesterol
-helps in identifying cell types
protein
phospholipid
carbohydrate chain
cholesterol
-helps move substances across
the cell membrane
-strengthens cell membrane

8. Different Types of Cell Membrane Proteins:
1. transport proteins – helps move substances into and out of a cell
2. marker proteins – identifies cell type
3. receptor proteins – bind to specific substances
4. enzymes – assists in chemical reaction within the cell