Question 1

Transepithelial transport requires a _____ cell layer.

Accepted Answer

A) polarized 
B) sealed 
C) polarized and sealed 
D) permeable

Question 2

Classes of membrane transport proteins include all of the following EXCEPT:

Accepted Answer

A) ATP-powered pumps. 
B) ion channels. 
C) protein translocons. 
D) transporters.

Question 3

What is the expected effect on salt accumulation in the plant vacuole of a mutation in the plant vacuolar ATPase that decreases the H⁺ concentration in the vacuole?

Accepted Answer

A) increased Na⁺ accumulation 
B) decreased Na⁺ accumulation 
C) no effect 
D) complete seed germination failure

Question 4

The many pumps present in the membrane have interconnected and important functions.Which of the following functions is NOT correct?

Accepted Answer

A) A P-class pump is involved in muscle relaxation. 
B) A V-class pump is involved in maintaining the low pH of lysosomes. 
C) A P-class pump is involved in keeping the cytosolic levels of calcium low. 
D) A P-class pump is involved in keeping the cytosolic levels of potassium low.

Question 5

The movement of dietary glucose and sodium from the intestine into the bloodstream relies on which of the following transport mechanisms?

Accepted Answer

A) sodium glucose symporter 
B) transcellular transport 
C) sodium/potassium ATPase 
D) all of the above

Question 6

The resting membrane potential in animal cells depends largely on nongated _____ channels.

Accepted Answer

A) Ca²⁺ 
B) H⁺ 
C) K⁺ 
D) Na⁺

Question 7

Propose a rationale for why the import of sucrose into the plant vacuole is coupled to the export of H⁺ ion into the plant cytosol.

Accepted Answer

The answer of Propose a rationale for why the import...

Question 8

In a laboratory activity,red-labeled glucose,blue-labeled water,and green-labeled ethanol are added to a solution placed over an artificial,pure phospholipid membrane.Which colors will be observed on the other side of the membrane after 10 minutes?

Accepted Answer

A) red 
B) blue 
C) green 
D) b and c

Question 9

How does uniport transport compare with simple diffusion?

Accepted Answer

A) Similar to simple diffusion,uniport transport is nonspecific. 
B) Uniport transport is slower but more specific than simple diffusion. 
C) Uniport transport is much faster and more specific than simple diffusion. 
D) Simple diffusion is reversible but uniport transport is not.

Question 10

When computing the osmotic pressure that must be placed across the membrane to stop the flow of water,what is the glucose osmotic equivalent of 1 M CaCl₂?

Accepted Answer

A) 1 M 
B) 2 M 
C) 3 M 
D) 4 M

Question 11

A mutant channel protein is expressed in an oocyte.Compared to patch clamping experiments in oocytes expressing the normal channel,the length of downward deviations is diminished by half.This indicates:

Accepted Answer

A) the mutant channel doesn't make a functional channel. 
B) the mutant channel doesn't stay open as long. 
C) the mutant channel opens more frequently. 
D) the mutant channel behaves the same as the wild-type channel.

Question 12

Parietal cells acidify the stomach contents while maintaining a neutral cytosolic pH by:

Accepted Answer

A) exporting "excess" cytosolic OH- as HCO₃-. 
B) exchanging HCO₃- for Cl-. 
C) preserving electroneutrality by accompanying the movement of each Cl- ion into the stomach lumen by a K⁺. 
D) all of the above.

Question 13

What is the basic structural organization of an ABC superfamily transport protein?

Accepted Answer

The answer of What is the basic structural organization of...

Question 14

Which of the four classes of ATP-powered pumps share overall similarity: several subunits,the same general organization,and a similar function as H⁺ transporters?

Accepted Answer

A) ABC superfamily and P-class pumps 
B) ABC superfamily and P-class pumps. 
C) F-class pumps and P-class pumps 
D) F-class pumps and V-class pumps

Question 15

Glucose enters erythrocytes via a GLUT-1 uniporter.As the levels of glucose in the bloodstream decrease between meals,what happens to the glucose in the cells?

Accepted Answer

A) Glucose leaves the cell through the GLUT-1 uniporter,traveling down the new concentration gradient. 
B) Glucose remains in the cell because uniporters can only transport in one direction. 
C) Glucose remains in the cell because the GLUT-1 uniporters are gated and the gates close at low glucose concentrations. 
D) Glucose remains in the cell because it has been phosphorylated and no longer has affinity for the GLUT-1 uniporter.

Question 16

Which of the following statement(s)is (are)true of V-class proton pumps?

Accepted Answer

A) They are ATPases. 
B) They are present in membranes of plant vacuoles. 
C) They serve to decrease the pH inside a lysosome. 
D) all of the above

Question 17

What is the approach that plants use to respond to differences in osmotic pressure between the inside and outside of the cell?

Accepted Answer

The answer of What is the approach that plants use...

Question 18

Transepithelial glucose transport uses a symporter to transport glucose up a concentration gradient by:

Accepted Answer

A) coupling glucose transport to proton movement. 
B) coupling glucose transport to Na⁺ movement. 
C) coupling glucose transport to Ca²⁺ movement. 
D) coupling glucose transport to Cl- movement.

Question 19

How does inhibition of the Na⁺/K⁺ ATPase increase the force of heart muscle contraction?

Accepted Answer

A) It increases cytosolic Na⁺ and therefore decreases Ca²⁺ export. 
B) It increases cytosolic K⁺ and therefore decreases Ca²⁺ export. 
C) It decreases cytosolic Na⁺ and therefore decreases Ca²⁺ export. 
D) It decreases cytosolic K⁺ and therefore decreases Ca²⁺ export.

Question 20

Describe in general terms how the muscle Ca²⁺ ATPase pumps Ca²⁺ ions from the cytosol into the sarcoplasmic reticulum (SR).

Accepted Answer

The answer of Describe in general terms how the muscle...

Exam 10: Transmembrane Transport of Ions and Small Molecules