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Cell Membrane: Structure and Function. The Plasma Membrane. Cell membrane and nuclear membrane are plasma membranes Semi-permeable Phospholipid bilayer with proteins Fluid-mosaic model http://www.susanahalpine.com/anim/Life/memb.htm. Cell Membrane. Phospholipid bilayer. Lipid. Phospho.
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The Plasma Membrane • Cell membrane and nuclear membrane are plasma membranes • Semi-permeable • Phospholipid bilayer with proteins • Fluid-mosaic model • http://www.susanahalpine.com/anim/Life/memb.htm
Cell Membrane • Phospholipid bilayer Lipid Phospho Layer 1 Layer 2 Two layers = bilayer
Why bother with two layers? Water loving (hydrophilic) outside Water fearing (hydrophobic) inside Fears water Loves water Layer 1 Layer 2
Membrane Proteins • Channel protein • Carrier protein • Cell recognition protein • Enzymatic protein • Receptor Protein http://en.wikipedia.org/wiki/File:Fluid_Mosaic.svg
Transport Proteins1) Channel or 2) Carrier Channel Protein Side View Top down When open allows sugars, salts, and amino acids to pass http://phet.colorado.edu/en/simulation/membrane-channels DOI:10.2210/pdb2jqy/pdb
Receives a special molecule Opens the closed gate Extracellular End Intracellular End • Carrier Protein 10.2210/pdb2bg9/pdb
3) Cell Recognition Protein What blood type are you? A, B, AB or O? Extracellular DOI:10.2210/pdb2edo/pdb
4) Enzymatic Proteins Angiotensin II Makes a molecule that increases blood pressure
5) Membrane Proteins- Receptor Protein Acetylcholine Receptor Extracellular Intracellular Do you like to move your muscles? 10.2210/pdb2bg9/pdb
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: http://www.bio.davidson.edu/people/macampbell/111/memb-swf/membranes.swf (link on homework page)