Cell Membrane
Basic Membrane Structure Selective permeability Amphipathic~ hydrophobic & hydrophilic regions 1930’s-50’s- Davison- Danielli “sandwich” model Singer-Nicolson: fluid mosaic model
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
Anatomy of a phospholipid
Movement in the Membrane Cholesterol gives some support, but phospholipids still move freely throughout the membrane
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
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
Types of Membrane Proteins
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