1. Cell Membrane: Structure and Function

2. The Plasma Membrane
Cell membrane and nuclear membrane are plasma membranes
Semi-permeable
Phospholipid bilayer with proteins
Fluid-mosaic model

3. Cell Membrane Phospholipid bilayer Two layers = bilayer Lipid Phospho

4. Why bother with two layers?
Water loving (hydrophilic) outside Water fearing (hydrophobic) inside
Fears water
Loves water
Layer 1
Layer 2

5. Membrane Proteins Channel protein Carrier protein Enzymatic protein
Cell recognition protein
Enzymatic protein
Receptor Protein

6. Transport Proteins 1) Channel or 2) Carrier
Channel Protein
Side View
Top down
When open allows sugars, salts, and amino
acids to pass
DOI: /pdb2jqy/pdb

7. Carrier Protein Extracellular End Intracellular End
Receives a special molecule
Opens the closed gate
Extracellular End
Intracellular End
Carrier Protein
/pdb2bg9/pdb

8. Channel vs. Carrier Proteins
Channel Carrier

9. 3) Cell Recognition Protein
What blood type are you? A, B, AB or O?
Extracellular
DOI: /pdb2edo/pdb

10. 4) Enzymatic Proteins Angiotensin II Makes a molecule that
increases blood pressure

11. 5) Membrane Proteins- Receptor Protein
Acetylcholine
Receptor
Extracellular
Intracellular
Do you like to move
your muscles?
/pdb2bg9/pdb

12. Summary
Proteins play a large role in the function of cells (therefore our lives)
Different types of protein structures have different functions
Small examples given there are many thousands of proteins in nature
Tutorial/self-check: (link on homework page)