Lecture #79 & 80

  1. osmosis
    • permeable to water but no solute
    • different from diffusion because it has a semipermeable membrane
  2. what is the cytoplasm osmolarity of a regular cell ?
    300 m Osmole
  3. what reflection coefficent is completely permeable?
  4. water only moves in respone to what?
    towards an increased osmotic gradient
  5. what is fick's first law equation
    • rate of solute movement is equal to concentration times reflection coefficent
    • J=θ* [osmolarity of solute]
  6. simple diffusion characteristics
    • linear increase / non saturable 
    • hydrophobic/ lipophilic
    • use no proteins
    • no inhibitors
    • no substrate selectivity
  7. facilitate transport features
    • saturable 
    • move hydrophilic solutes 
    • can be active ( use ATP)or facilitated ( w/o ATP)
    • use a protein
    • specific inhibitors and substrate selectivity
  8. What are the fastest type of facilitate transporters
    channel aka pores
  9. active transporters, and diffusive transporter fit under the category of?
  10. what some example of facilitated diffusive transporters
    • uniporters
    • symporter
    • antiporters
  11. what are the differences between primary active transport and passive transport
    • 1st active
    • - uphill or against gradient movement 
    • - uses ATP

    • passive:
    • -no ATP
    • moves down gradient
  12. how are channels/pores regulated?
    • by gating ( different factors that affect open and closed state?
    • pore lined with selective binding sites
  13. channel conductance
    how much current can pass through a single pore  per unit time
  14. how is open probability caculated ?
    percent open/percent closed
  15. what is intracellular ligand gating?
    GABA or acetylcholine activated gates
  16. what is extracellular ligand gaintg?
    Ca or ATpP channels
  17. what molecules control voltage gated
    Na+ k+ Cl0 and Ca2+
  18. how do carrier usually transport
    • due to a conformational chane
    • this can have asymetry carrying capacity based on what surface the the binding site is on
  19. how does the NAK ATPase acrive transport carrier work?
    • 3 NA is movin out
    • 2 k is moving in 
    • and 1 ATP is used
  20. why are primary active transporters like Na-K ATPas so useful
    They generate a transmemebrane gradient that drive passive transport of other solutes
  21. compared to pores/channel, carrier transport in what speed
    • much faster
    • >10^6 ions movement /second
  22. characteristic of channels/pores
    • only move passively ( down gradient)
    • aquesion soltuion filled pore spans the memebrane

    gated regulation
  23. basic properties of channels
    • open probability 
    • channel density
    • channel conductance
    • gating
  24. what kind of carrier moves na and glucose
    symporter moving them in the same direction down their gradietn
  25. what allows human to retain water
    • different concentration og ions inside versus outside of the cell 
    • electronegative inside vs. outside
    • this is maintained by immobile negavtive chareges of protain
    • and NaKAtpase
  26. when calculating the nerst equation you only need to calculate for which ion and why
    k because K is the primary ion that cntributes to the resting potential because the otehr ions have very little permeability
  27. what is th nerst equation (simplified)
    -61log(concentration inside/conc. outside)=____mV
  28. what are leaks /
    when a molecule leaks into the cell via passive diffusion transport
  29. what are pumps
    intracellular q levels keep low because active transporter start to move Q out of the cell up/against its gradient
  30. what is net updtake
    • more solute is moving in that out
    • intracellular concentraionof ion is increasing while extracellular is decreasing
  31. what is equailibrium
    • equal transport inside and out of cell 
    • same amoutn in and out
  32. what is subtrate depletion
    • capillay is always releasing intot he interstitum since interstium is off a much large volume
    • these compartments never reach equilibrium
  33. alpha intercalated cell function
    secrete Ht
  34. B-interclated cells
    secrete basic HCo3 secreting
Card Set
Lecture #79 & 80
membrane transport physiology