ch8 membrane transportaion

Card Set Information

Author:
doncheto
ID:
238684
Filename:
ch8 membrane transportaion
Updated:
2013-10-07 01:25:59
Tags:
memebrane
Folders:

Description:
sdfs
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user doncheto on FreezingBlue Flashcards. What would you like to do?


  1. How do channel and carrier proteins differ?
    • –Channel proteins 
    • •Select solutes based on size and
    • electric charge
    • –Most of the smaller channels
    • transport ions
    • –Some are larger and less specific
    • •Continuous passage when open
    • •Passive transport only

    • –Carrier proteins (aka
    • transporters or permeases)
    • •Select specific solutes at
    • binding sites, undergo conformational change after binding
    • •Slower
    • •Exhibit saturation kinetics
    • •Subject to competitive inhibition
    • •Passive and active transport
  2. How do passive and active transport differ?
    • •Passive transport
    • –Down a concentration or
    • electrochemical gradient (from a region of higher to lower free energy)
    • –Moves toward equilibrium
    • –No energy input
    • •Active transport
    • –Against a gradient
    • Requires energy
  3. Of the four different transport mechanisms discussed,
    which ones are examples of passive transport and which ones are examples of
    active transport?
  4. Which transport mechanism(s) utilize carrier
    proteins? Which one(s) utilize channel proteins?
    • facilitated diffusion requires- carrier and
    • channel proteins.
    • Active transport uses carrier proteins
  5. Understand all four transport mechanisms.
  6. How do the following molecules get through the
    cell membrane (simple diffusion, facilitated diffusion, active transport,
    or two of these mechanisms): water, glycerol, O2, CO2,
    glucose, amino acids, ions, oils, ethanol, steroids?
    • simple diffusion- H2O, glycerol, small nonpolar (O2, and CO2), large nonpolar (oils, steroids)
    • facilitated diffusion- glucose, water, ions,glycerol, animo acids 
    • active transport- glucose, ions
  7. What are some factors that affect the rate of
    diffusion and how (directly or inversely proportional)?
    • –Concentration gradient
    • –Surface area (of the membrane)
    • –Temperature
    • –Solubility (in phospholipid bilayer)
    • •Polarity of particle
    • •Charge of the particle
    • –Size of particle
    • –Distance (membrane thickness)
  8. Know the meaning of semipermeable or selectively permeable, osmosis, hypotonic,
    hypertonic, and isotonic.
    • semipermeable- certain types of molecules can get through
    • osmosis-is diffusion of water
    • across a selectively permeable membrane.
    • Water will move
    • toward the region with higher impermeable solute concentration.
    • hypertonic- higher concentration of solutes outside the cell
    • hypotonic- lower concentration of solutes outside the cell
    • isotonic- equal concentration
  9. Know Slide 12.
  10. Understand Table 8-1. For example, how do the
    kinetic properties of carrier-mediated transport differ from that of simple
    diffusion
    facilitated diffusion requires membrane protein, saturation kinetics, competitive inhibition
  11. Understand Fig. 8-5
  12. What are uniport, symport, and antiport?
  13. What type of transport proteins are
    transporters? Permeases? Porins? And aquaporin?
    • -Facilitated diffusion
    • •Transport protein allows movement of solute
    • –Carrier Proteins (Transporters, Permeases)

    • –-Channel Proteins
    • –Porins
    • •Larger pores and less specific
    • •Allow passage of various
    • hydrophilic solutes
    • •Transmembrane segment is a β barrel
    • –Aquaporins
    • •Facilitate rapid movement of
    • water into and out of cells
  14. How does glucose transporter GLUT1 work?


    • Can transport in
    • either direction
    • [Glucose] is kept low
    • inside the cell because incoming glucose gets phosphorylated to glucose-6-phosphate
  15. Is this transport an example of simple diffusion,
    facilitated diffusion, or active transport?
    facilitated diffusion
  16. Does this transport utilize carrier proteins or
    channel proteins?
    carrier protein
  17. Can this transport occur in either direction or
    is it unidirectional?
    either
  18. What is achieved when the transported glucose
    gets phosphorylated immediately upon entering the cell?
    The concentration of glucose is kept low
  19. How does chloride bicarbonate exchanger work? Is
    this transport an example of simple diffusion, facilitated diffusion, or active
    transport?
    • facilitated, antiport
  20. Does this transport utilize carrier proteins or
    channel proteins?
    channel proteins
  21. In which direction does it move Cl-
    and HCO3- in the capillaries in the muscle?
    • HCO3- moves outside
    • Cl- moves in
  22. In which direction does it move Cl-
    and HCO3- in the capillaries in the lungs?
    • HCO3- moves in the cell
    • Cl- moves out
  23. Be able to explain why the direction is reversed
    in these two locations of the body. Understand Fig. 8-3
    because the blood plasma in lungs has higher o2 and low co2

    its the opposite in other tissue
  24. What are the three types of transmembrane channel
    proteins? What type of molecule does each transport?
    • –Ion channels
    • •Form narrow aqueous pores lined
    • by polar groups
    • •Most are selective ion channels
    • (by size and charge), some only allow a single type of ion to pass through.
    • •Rapid rate of transport
    • –Porins
    • •Larger pores and less specific
    • •Allow passage of various
    • hydrophilic solutes
    • •Transmembrane segment is a β barrel
    • –Aquaporins
    • •Facilitate rapid movement of
    • water into and out of cells
  25. How do leak
    ion channels and gated ion channels differ?
    • –While a few channel proteins are
    • “leak channels” (i.e.: generally open), most are “gated channels”.
    • –Gated channels spend more time in
    • open state when stimuli are present.
    • •Voltage-gated
    • •Ligand-gated
    • •Mechanically-gated
  26. What are the three types of gated ion channels
    and what kind of stimuli will activate their opening?
  27. What are “pumps”? What are coupled transporters?
    pumps are direct/active transport that use ATP hydrolysis directly

    • coupled- indirect/secondary active transport
    • –Simultaneous transport of two solutes (one down its gradient
    • and one up its gradient)
  28. There are three types of active transport that
    differ in their driving force, what are they?
    Na+/K+ ATPase pump -ATP hydrolysis

    • Na+/Glucose Symporter-Simultaneous
    • transport of two solutes (one down its gradient and one up its gradient

    H+ ATPase pump -they use light
  29. How does Na+/K+ ATPase
    work? How many Na+ and K+ ions does it transport in
    each cycle and in which direction? Is this transport an example of primary/direct
    active transport, secondary/indirect active transport, or light-driven
    active transport?
    • uses ATP to transfer each ion against its gradient. 2 k+ in and 3 Na+ out.
    • pump k in
    • primary/direct
  30. The electrochemical gradient of which ion is
    often used to drive the secondary active transport of solutes across the
    animal cell plasma membrane? How about for the plant, fungal, and
    bacterial cells?
    K+, H+
  31. How does Na+/glucose symporter work?
    Is this transport an example of facilitated diffusion, primary/direct
    active transport, secondary/indirect active transport, or light-driven
    active transport?
    • seconday/indirect active transport
  32. Know all three transport proteins in slide 34.
    What solutes do they transport and in which direction? On which domain (apical
    or basolateral) of the intestinal epithelial cell is each found? For what
    purposes do they serve at these locations?
  33. How does bacteriorhodopsin work? How is this
    transport proteins embedded in the cell membrane?
    light driven photon pump,7 transmembrane alpha helices
  34. What roles does Na+/K+
    ATPase play in the cell?
    • –Maintains appropriate
    • intracellular concentrations of Na+ and K+ ions
    • •High extracellular [Na+] serves as driving force
    • for the uptake of sugars and amino acids
    • –Maintains membrane potential
    • –Maintains osmotic balance and
    • regulates cell volume

What would you like to do?

Home > Flashcards > Print Preview