1. Plasma membrane
    Membrane surrounding the cell
  2. Cytoplasm
    Everything that’s inside the cell
  3. Cytosol
    Fluid inside the cell.
  4. Organelles
    Solid structures in the cell
  5. Nucleus
    Contains DNA instructions for the cell
  6. Characteristics of plasma membrane
    • Composed of phospholipid bilayer.
    • *Flexible
    • *Selectively permeable allowing transfer of substances
  7. Functions of plasma membrane:
    • *Barrier between internal and external environment of the cell.
    • *Movement of substance in and out of a cell
    • *Cellular communication
  8. Arrangement of membrane proteins:
    • *Integral proteins- embedded. This includes the trans membrane protein.
    • *Peripheral proteins- located on the outside surface
  9. Membrane proteins serve many functions:
    • *Ion channels
    • *Transporters
  10. Receptors
    • Bind to ligand
    • *Enzymes
  11. Linkers:
    • Cell identity markers.
    • *MHC proteins.
  12. Membrane fluidity:
    • *Phospholipids are in constant motion.
    • *Plasma membrane and its components can move.
    • *Allows for movement of membrane during growth, maintenance, and repair
  13. Selective permeability:
    • Some molecules can cross plasma membrane and others can’t.
    • *But Ion channels and transporters alter permeability.
  14. Membrane Selectivity:
    • *Permeable to small, uncharged nonpolar molecules. Examples are oxygen and carbon dioxide.
    • *Weakly permeable to small, uncharged polar molecules. Example is water.
    • Impermeable to ions and large molecules.
  15. Gradients across the membrane
  16. *Dependent on selective permeability.
    • *Concentration gradient
    • *Electrical gradients (membrane potential).
    • *Mostly positive (+) outside and negative (-) inside a resting membrane potential.
  17. Active Transport:
    • Requires energy input from the cell
    • *A substance is driven against its concentration or electrical gradient.
  18. Hypotonic solution
    • *ECF has less solutes than ICF.
    • *H2O enters cell faster than it leaves
    • *Cell swells and may burst (lyse).
  19. Hypertonic solution
    • ECF has more solutes than ICF.
    • *Water leaves faster than it enters
    • *Cell shrinks (crenation).
  20. Mechanism of passive transport (no energy
    • Simple diffusion
    • *Facilitated diffusion
    • *Osmosis
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