Biology (Chapter 5)

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Biology (Chapter 5)
2012-10-10 22:36:34

Biology Notes
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  1. Fluid Mosaic Model
    • 1972
    • This model proposed that the plasma membrane, as well as all membranes, are thin, pliable, bilayers of phospholipids with embedded proteins. 
  2. Selectively Permeable 
    • Refers to cellular membranes
    • They permit some substances to pass through, but block others 
  3. Phospholipid Bilayer
    A thin polar membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around cells.
  4. Hydrophobic
    Water hating, avoids water
  5. Hydrophilic
    Water loving, attracts to water
  6. Integral Proteins
    Penetrate and are embedded in the phospholipid bilayer, they have one or more hydrophobic regions or domains consisiting of an Alpha-Helix or Beta-Pleated sheet region of the polypeptide. 
  7. Transmembrane Proteins
    Integral proteins that extend from one side of the membrane to the other
  8. Pheripheral Proteins 
    Are not embedded in the bilayer, instead they are attached to the inside or the outside surface of the membrane 
  9. Carrier Proteins
    Bind specifically with the molecule they assist and are usually selective for one type of molecule
  10. Channel Proteins
    Integral proteins that typically have a hydrophillic interior that provides an aquaous channel for polar molecules, or specific ions to pass when the channel is open 
  11. Glycolipids
    Phospholipids of the membrane with attached carbohydrate chains
  12. Glycoproteins
    Embedded proteins with attached carbohydrate chains
  13. Passive Transport 
    Requires no cell energy
  14. Active Transport
    Requires cell energy
  15. Diffusion
    • Active Transport
    • A molecular Event, whereby molecules move down a concentration gradient from an area of high concentration to low concentration
  16. Osmosis
    • Active Transport
    • A diffusion of water
  17. Solution
    A solvent + a solute 
  18. Solvent
    (Water) the substance usually liquid in nature into which other substances dissolve
  19. Solute
    The substance that is being dissolved
  20. Equilibrium
    When the concentration on both sides of a membrane is equal
  21. Hypotonic Solution
    When the concentration of solute molecules in the cell's environement, outside of the cell is lower than the concentration of solute within the cell 
  22. Hypertonic Solution
    When the concentration of solute molecules in the cell's environment, outside of the cell is higher than the concentration of solute within the cell
  23. Isotonic Solution
    When the concentration of solutes inside and outside the cell are equal
  24. Cytolysis
    The dissolution or destruction of a cell
  25. Plasmolysis
    the process in plant cells where the cytoplasm pulls away from the cell wall due to the loss of water through osmosis
  26. Aquaporins
    Specialized channels for the movement of water 
  27. Facilitated Diffusion
    Requires a helper molecule in order to move a polar substance down the concentration gradient from high concentration to low concentration
  28. Cell Surface Receptors
    Specialized integral membrane proteins that take part in communication between the cell and the outside world
  29. Sodium Potassium Pump
    • (Na+/K+) 
    • Potassium is constantly pumped INTO the cell against the concentration gradient while Sodium ions are constantly pumped OUT of the cell against a similar concentration gradient
  30. Alpha Helix Pleated Sheet
  31. Beta Helix Pleated Sheet
  32. Endocytosis
    Collective term that describes the process of ingesting solid or fluid material by the cell
  33. Receptor Mediated Endocytosis
    Highly specific for the molecules that are transported, proteins of the plasma membrane specifically bind particular molecules which may be present in the cellular fluid in low concentrations
  34. Phagotcytosis
    • "Cell Eating"
    • Material brought inside is solid by nature
  35. Pinocytosis
    • "Cell Drinking" 
    • Material brought inside is liquid by nature
  36. Exocytosis
    The passage of large molecules, waste, neurotransmitters, hormones, and digestive enzymes out of the cell
  37. Vesicle
    A bubble-like membranous structure that stores and transports cellular products, and digests metabolic wastes within the cell
  38. Coupled Transport
    The linked, simultaneous transport of two substances across a cell membrane (or another intracellular membrane)