Quiz 8 Key
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1-4. Answer with diffusion through (B) the bilayer; (N) a channel; (R) a carrier.
Answer with only one even if two are correct. Use each letter at least once.

    N      requires a protein that does not change conformation

    R      alanine moves across a membrane

  B N     not saturable

    B       CO2 moves across a membrane

5-6. ΔGT = R T ln (C2/C1) + Z F ΔV. Answer with R, T, C2, C1, Z, F, or ΔV.

    C1     [solute] outside a cell when the solute is moving out → in

   ΔV     the membrane potential

7-8. The concentration term = R T ln (C2/C1), and the charge term = Z F ΔV.
Shortly after a meal, [lysine]extracellular is much greater than [lysine]intracellular .
Answer with (>) greater than; (<) less than; or (=) equal to.

Moving lysine into the cell has a concentration term      <        0 and a charge term     <     0.

9-10. Draw the structure of lysine at pH 7.

NOTE: I'm not going to show the structures of the amino acids. It is important, though, to recognize that lysine at pH 7 has a net charge of +1; that's the reason the charge term for moving lysine into the cell is negative [= (+1) F (− membrane potential)].

1-4. Answer with diffusion through (B) the bilayer; (N) a channel; (R) a carrier.
Answer with only one even if two are correct. Use each letter at least once.

    B       O2 moves across a membrane

    N      involves a gated protein

     R      requires a protein that changes
               conformation

  N R    K+ moves across a membrane

5-6. ΔGT = R T ln (C2/C1) + Z F ΔV. Answer with R, T, C2, C1, Z, F, or ΔV.

    R      8.314 J/mol

    Z      +2 for moving calcium

7-8. The concentration term = R T ln (C2/C1), and the charge term = Z F ΔV.
For red blood cells in the lungs [HCO3]intracellular is much greater than [HCO3]extracellular .
Answer with (>) greater than; (<) less than; or (=) equal to.

Moving HCO3 into the cell has a concentration term      >       0 and a charge term      >*      0.

*When I made up the quiz, I thought of moving only HCO3-, which would have a positive charge term [= (−1) F (− membrane potential)]. As I graded this, I realized that in that case the question should have been "Moving only HCO3 into the cell..." Since the question was less explicit, and we had just covered the bicarbonate-chloride co-transporter, = 0 is also acceptable.

9-10. Draw the structure of tyrosine at pH 7.

1-4. Answer with diffusion through (B) the bilayer; (N) a channel; (R) a carrier.
Answer with only one even if two are correct. Use each letter at least once.

    R      saturable

    R      lysine moves across a membrane

    B       CO2 moves across a
               membrane

  N R    requires a protein with a specific binding site

5-6. ΔGT = R T ln (C2/C1) + Z F ΔV. Answer with R, T, C2, C1, Z, F, or ΔV.

    Z      −1 for moving bicarbonate

    F       96,480 J/V-mol

7-8. The concentration term = R T ln (C2/C1), and the charge term = Z F ΔV.
Shortly after a meal, [glucose]extracellular is much greater than [glucose]intracellular .
Answer with (>) greater than; (<) less than; or (=) equal to.

     Moving glucose into the cell has a charge term     <     0 and a concentration term      =      0.

9-10. Draw the structure of threonine at pH 7.

1-4. Answer with diffusion through (B) the bilayer; (N) a channel; (R) a carrier.
Answer with only one even if two are correct. Use each letter at least once.

    N      involves a gated protein

    B       does not require a protein

  N R    Na+ moves across a membrane

    R      glucose moves across a membrane

5-6. ΔGT = R T ln (C2/C1) + Z F ΔV. Answer with R, T, C2, C1 1 , Z, F, or ΔV.

    T       298 K

   C2      [solute] inside a cell when the solute is moving out → in

7-8. The concentration term = R T ln (C2/C1), and the charge term = Z F ΔV.
For red blood cells in the tissues [HCO3]extracellular is much greater than [HCO3]intracellular .
Answer with (>) greater than; (<) less than; or (=) equal to.

Moving HCO3into the cell has a concentration term      <       0 and a charge term     >*        0.

9-10. Draw the structure of histidine at pH 7.

*When I made up the quiz, I thought of moving only HCO3-, which would have a positive charge term [= (−1) F (− membrane potential)]. As I graded this, I realized that in that case the question should have been "Moving only HCO3 into the cell..." Since the question was less explicit, and we had just covered the bicarbonate-chloride co-transporter, = 0 is also acceptable.

 

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