Histo Lecture 3

  1. Definition of Diffusion
    Movement along concentration graident (high to low conc.); no ATP required
  2. Simple Diffusion
    Direct passage through membrane
  3. Facilitated Diffusion
    Utilizes membrane protein for import
  4. Active Transport
    Requires energy; typically moving against concentration gradient
  5. 2 Types of Active Transport
    Primary and Secondary
  6. What materials can pass directly through phospholipid bilayer?
    Lipid soluble molecules

    e.g. Oxygen, carbon dioxide, alcohol
  7. Some water soluble molecules (water, proteins, some ions) pass through the cell membrane using ______ ______ pores
    channel protein
  8. Name 3 of the 6 factors that can influence Simple Diffusion
    • -Amount of substance availability
    • -Lipid solubility of diffusing substance
    • -Number and size of membrane opening (channels)
    • -Velocity of kinetic motion of molecules (greater temp = faster diffusion)
    • -Molecular weight - smaller particles move faster
    • -Distance- shorter distance = faster diffusion
  9. Nickname for Facilitated Diffusion
    Carrier mediated diffusion
  10. Facilitated Diffusion requires interaction with what type of protein?
    Carrier protein
  11. How do carrier proteins move molecules through the membrane?
    • -No energy required
    • -Conformational change in protein causes molecule to move through membrane
    • -Molecule must be moving along concentration gradient
  12. Osmosis
    • Net movement of water along its concentration gradient
    • (Requires semi-permeable membrane!)
  13. Osmotic pressure
    Driving force for osmosis across a membrane
  14. Osmotic pressure behavior in solute concentrations
    • -Directly related to solute concentrations of two fluids in compartments
    • -Water tends to move from low to high solute concentration
  15. Hydrostatic pressure
    Force that water transmits via its weight or via its flow through a vessel.

    Tends to eualize with osmotic pressure to prevent too much loss/gain of water from cells/tissues
  16. What is Active Transport?
    Transport of substances across cell membrane which require energy expenditure
  17. Types of molecules carried in Active Transport
    Ions and large molecules (sugars & proteins)
  18. Primary Active Transport
    Direct utilization of ATP as energy source
  19. Secondary Active Transport
    Energy comes from stored energy of ionic concentration gradient between intra/extracellular environments
  20. Both Primary and secondary active transport utilize what type of protein?
    Carrier proteins
  21. Sodium Potassium Pumps
    -Important for maintaing voltage across the cell membrane
  22. Co-Transport
    Both molecules required for binding to protein must be present for transport to occur
  23. Counter Transport
    • Molecules are transported in opposite directions across the cell membrane.
    • -Sodium potassium pump
  24. Endocytosis
    Passage of material into a cell moving through cell membrane
  25. 3 Types of Endocytosis
    • -Phagocytosis
    • -Pinocytosis
    • -Receptor Mediated Endocytosis
  26. Phagocytosis
    Uptake of particular material

    Only "recognized" particles are engulfed
  27. Pinocytosis
    Uptake of soluble molecules (water)

    Non-specific engulfment of molecules
  28. Receptor Mediated Endocytosis
    Uptake of specific molecules using specific membrane proteins (clathrins)
  29. Exocytosis
    Secreting proteins made by cell
Card Set
Histo Lecture 3
Cell Transport