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Chapter 5: Membrane Structure, Synthesis and Transport - Coggle Diagram

- - - - Lipid-anchored proteins
      - Transmembrane proteins
        
        Approximately 25% of All Genes Encode Transmembrane Proteins
        
        This trend is found throughout all domains of life including archaea, bacteria, and eukaryotes
- - - - more double bonds more fluid
    - - Cholesterol tends to stabilize membranes
        
        more cholesterol less fluid
      - Effects vary depending on temperature
    - - more short more fluid
- - - - Lipids in ER membrane can diffuse laterally to nuclear envelope
      - Transported via vesicles to Golgi, lysosomes, vacuoles, or plasma membrane
      - Lipid exchange proteins – extract lipid from one membrane for insertion in another
- - - - carbohydrate to protein
    - - carbohydrate to lipid
- - - - Requires energy
      - Movement against the gradient
      - Types
        
        Primary active transport
        
        pump
        
        generate ion electrochemical gradients
        
        Actively transports Na+ and K+ against their gradients using the energy from ATP hydrolysis
        
        3 Na+ are exported for every 2 K+ imported into cell
        
        Secondary active transport
        
        Uses a pre-existing gradient to drive transport
    - - Requires no input of energy
        
        Facilitated diffusion
        
        Passive diffusion
    - - Water diffuses through a membrane from an area with more water to an area with less water
      - water movement can make the cell shrink or swell
      - Osmotic pressure
        
        the tendency for water to move into any cell
      - Animal cells
        
        Osmotic Lysis
        
        swelling and bursting of a cell in a hypotonic solution
        
        Crenation
        
        shrinkage of a cell in a hypertonic solution
      - Plant cells
        
        Plasmolysis
        
        plants wilting because water leaves plant cells
        
        cell wall prevents major changes in cell size
        
        Turgor pressure
        
        pushes plasma membrane against cell wall
        
        Maintains shape and size
      - Freshwater protists
        
        have to survive in a strongly hypotonic environment
        
        To prevent osmotic lysis, contractile vacuoles take up water and discharge it outside the cell
        
        maintains a constant cell volume
  - - - Channels
        
        open passageway for direct diffusion
        
        Most are gated
        
        example: Aquaporins
      - Transporters
        
        Conformational change transports solute across membrane
        
        known as carriers
        
        Principal pathway for uptake of organic molecules, such as sugars, amino acids, and nucleotides
        
        Types
        
        Symporter
        
        Antiporter
        
        Uniporter