1. Cell Membrane

2. Basic Membrane Structure  Selective permeability  Amphipathic~ hydrophobic & hydrophilic regions  1930’s-50’s- Davison- Danielli “sandwich” model  1972- Singer-Nicolson: fluid mosaic model

3. The Players…  Phospholipids~ membrane fluidity  Cholesterol~ membrane stabilization  Integral proteins~ transmembrane proteins  Peripheral proteins~ surface of membrane  Membrane carbohydrates ~ cell to cell recognition l oligosaccharides (cell markers) l glycolipids l glycoproteins

4. Anatomy of a phospholipid

5. Movement in the Membrane  Cholesterol gives some support, but phospholipids still move freely throughout the membrane

6. What are all the big purple blobs floating around??? PROTEINS!!!  Integral Proteins l Embedded in membrane l Transmembrane proteins  Peripheral Proteins l On the surface of the membrane

7. Why Protein? Proteins are mixed molecules  hydrophobic amino acids l stick in the lipid membrane l anchors the protein in membrane  hydrophilic amino acids l stick out in the watery fluid in & around cell l specialized “receptor” for specific molecules

8. Types of Membrane Proteins

9. What about the carbs? Play a key role in cell-cell recognition  ability of a cell to distinguish neighboring cells from another  important in organ & tissue development  basis for rejection of foreign cells by immune system