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Membranes - Coggle Diagram

- - - - Alpha helices with both hydrophobic and hydrophilic regions. Can have one or several alpha helices
    - - Beta sheet folded in on itself. Center is hydrophobic. Outside is hydrophilic
  - - - Three types in this class are farnesyl, palmitoyl, and GPI anchor
- - - - Polar molecules (like ions) can pass through the membrane down their concentration gradient (high to low) with the assistance of a protein (channel proteins or pore proteins)
        
        Channel proteins
        
        Alpha helical and have a small opening for specific molecules to pass through (very selective)
        
        Selective due to size (very small hole), electrostatic charge screening, and energy of dehydration (strips off water molecules because of carbonyl groups)
        
        Electrostatic repulsion pushes ions through the channels so that none of them gets stuck
        
        Pore proteins
        
        Beta barrels
        
        Less selective (generally allows free diffusion)
        
        Found in mitochondrial and bacterial membranes, but rare in plasma membrane
  - - - ATP is consumed to transport a molecule against it's concentration gradient
    - - If they move in the same direction, it's symport. If they move in opposite directions, it's antiport
      - Secondary transporters use one molecule's concentration gradient to power the other molecule's movement