1. TEM picture of a real cell membrane.
Cell Membranes
All cells have a cell membrane
Controls (regulates) what comes in and out of the cell to maintain an internal balance called homeostasis
Provides protection and support for the cell
TEM picture of a real cell membrane.

2. Lipid Bilayer -2 layers of phospholipids
Cell Membranes
Structure of cell membrane
Lipid Bilayer -2 layers of phospholipids
Phosphate head is polar (water loving)
Fatty acid tails non-polar (water fearing)
Proteins embedded in membrane
Phospholipid
Lipid Bilayer

3. Cell Membranes
Cell membranes have pores (holes) in it
Selectively permeable: Allows some molecules to pass and keeps other molecules out
Sometimes referred to as semi-permeable
The structure helps it be selective!
Pores

4. Fluid Mosaic Model Proteins Polar heads love water & dissolve.
Each individual cell
exists in a fluid
environment and the
cytoplasm within the
cell also has a fluid
environment. The
presence of a liquid
makes it possible for
substances (oxygen,
nutrients, and waste
products) to move in
and out of the cell.
Non-polar tails hide from water.
Carbohydrate cell markers
Proteins

5. Structure of the Cell Membrane
Outside of cell
Carbohydrate
chains
Proteins
Lipid
Bilayer
Transport
Protein
Phospholipids
Inside of cell
(cytoplasm)