Question 1

Describe the factors that affect the rate of passive transport of molecules across a membrane.

Accepted Answer

The rate at which a molecule will passiv...

Question 2

All of the following statements concerning severe hyperglycemia's effect on serum Na+ levels are true, EXCEPT

Accepted Answer

A)   levels are measured as a concentration, so as water decreases, levels increase.
B)   administering a hypertonic saline would help compensate for the decreased Na+ levels.
C)   as insulin is administered, serum Na+ levels will return to normal.
D)   the amount of Na+ is really unchanged since the water has only changed location and not left the body.
E)   the Na+ levels would appear decreased as the ICF water leaves for the hyperosmotic ECF.

Question 3

What effect does a cell's overall thickness have on its permeability?

Accepted Answer

A)   The cell's permeability is directly proportional to the thickness traversed.
B)   As the cell's thickness increases, its permeability decreases.
C)   As the cell's thickness increases, its permeability increases.
D)   Only the cell's membrane thickness, not that of its cytoplasm, have an effect on its permeability.
E)   The larger a cell becomes, the greater its proportional surface area, which increases the cell's permeability.

Question 4

If a positively charged ion is more concentrated inside the cell, the electrical forces required to balance the chemical gradient would be directed________ . Thus, the equilibrium potential for this
Ion would be________ charged.

Accepted Answer

A)   outward : positively
B)   outward : neutrally
C)   inward : negatively
D)   outward : negatively
E)   inward : positively

Question 5

When solute is actively transported across epithelium, what usually follows?

Accepted Answer

A)   water movement in the same direction
B)   active transport of the solute in the opposite direction
C)   water movement in the opposite direction
D)   passive transport of the solute in the opposite direction
E)   passive transport of solute in the same direction

Question 6

Which of the following is a reflection of the unequal distribution of positive and negative ions across the plasma membrane?

Accepted Answer

A)   chemical gradient
B)   chemical driving force
C)   electrochemical driving force
D)   extracellular potential
E)   membrane potential

Question 7

Transporting a substance against its concentration gradient requires

Accepted Answer

A)   a transporter that is facilitated in its diffusion.
B)   a channel that is specific for that substance.
C)   countertransport with another molecule against its concentration gradient.
D)   cotransport with another molecule against its concentration gradient.
E)   a transporter that uses energy.

Question 8

As a cell's metabolism increases, so does its O2 consumption, giving rise to what product at a ratio of 2:1?

Accepted Answer

A)   lactic acid
B)   ATP
C)   H2O
D)   pyruvic acid
E)   CO2

Question 9

Describe the process whereby the Na+/K+ pump is involved in moving those ions across a membrane.

Accepted Answer

The Na⁺binding site on the Na⁺/K⁺pump faces...

Question 10

Which of the following statements about Ca2+ pumps is FALSE?

Accepted Answer

A)   It is a form of primary active transport.
B)   Calcium is actively transported from an organelle into the cytosol.
C)   Calcium is actively transported from the cytosol into the extracellular fluid.
D)   The pump is also an ATPase.
E)   It maintains low cytosolic calcium levels.

Question 11

Molecules tend to move spontaneously_______ their chemical gradient.

Accepted Answer

A)   up
B)   around
C)   down
D)   over
E)   through

Question 12

In facilitated diffusion, a molecule is moved

Accepted Answer

A)   against its concentration gradient with the assistance of a protein carrier molecule and requires energy.
B)   down its concentration gradient with the assistance of a protein carrier molecule, and no energy is required.
C)   against its concentration gradient while Na is moved with its concentration gradient.
D)   against its concentration gradient with the assistance of a protein carrier molecule, but no energy is required.
E)   with its concentration gradient while Na is moved against its concentration gradient.

Question 13

When the Na+/ K+ pump moves its bound molecules of Na+ to the outside of the membrane, it

Accepted Answer

A)   releases the bound ATP to return to its normal confirmation.
B)   pumps more K+ back into the cell than the amount of Na+ that just came out.
C)   cannot return to the inside empty -handed, so it must bind two K+ first.
D)   immediately returns to the inside of the cell, ready to transport more Na+ back outside.
E)   binds to ATP to release the energy required to power the return trip.

Question 14

The movement of water across a membrane is always a passive process.

Accepted Answer

A) True 
 B)False

Question 15

Most of the time, the body is neutral with respect to its electrical charge due to the equal distribution of anions and cations within the body.

Accepted Answer

A) True 
 B)False

Question 16

What is the meaning of carrier proteins and pumps becoming saturated?

Accepted Answer

A)   Saturation kinetics (demonstrated graphically as a line curving upward as a function of concentration)  indicates that transport will increase as concentrations increase.
B)   These transporters have become entirely depleted and can no longer transport without further ATP production.
C)   These transporters have reached a maximal net flux, beyond which further increases in concentration no longer affect their rate.
D)   These transporters have reached the point where only an increase in the transported molecule will change the net flux.
E)   They have a hydrogen molecule at every possible carbon bond and are, therefore, a solid at room temperature.

Question 17

The chemical force for which of the following ions is directed into the cell?

Accepted Answer

A)   sodium only
B)   calcium only
C)   potassium only
D)   both potassium and sodium
E)   both sodium and calcium

Question 18

An anion is found in greater concentration inside the cell than outside. Which of the following statements BEST describes forces acting on the anion at the resting membrane potential ( -70 mV) ?

Accepted Answer

A)   The chemical force is directed into the cell and the electrical force is directed out of the cell.
B)   Both the chemical and electrical forces are directed out of the cell.
C)   The chemical force is directed out of the cell and the electrical force is directed into the cell.
D)   Both the chemical and electrical forces are directed into the cell.
E)   There is insufficient information to answer this question.

Question 19

A cotransporter uses an ion's concentration gradient to move a second ion or molecule in the same direction as the first.

Accepted Answer

A) True 
 B)False

Question 20

When molecules are passively transported across a membrane, the direction of their movement is dictated by the molecule's tendency to move

Accepted Answer

A)   into a cell.
B)   from lower to higher energy.
C)   from higher to lower energy.
D)   out of a cell.
E)   in both directions; there is no preference.

Exam 4: Cell Membrane Transport

Molecules tend to move spontaneously_______ their chemical gradient.

Correct AnswerverifiedShow Answer

All of the following statements concerning severe hyperglycemia's effect on serum Na+ levels are true, EXCEPT

Correct AnswerverifiedShow Answer

In facilitated diffusion, a molecule is moved

Correct AnswerverifiedShow Answer

When solute is actively transported across epithelium, what usually follows?

Correct AnswerverifiedShow Answer

When the Na+/ K+ pump moves its bound molecules of Na+ to the outside of the membrane, it

Correct AnswerverifiedShow Answer

Describe the process whereby the Na+/K+ pump is involved in moving those ions across a membrane.

Correct AnswerverifiedThe Na+ binding site on the Na+/K+ pump faces...View AnswerShow Answer

Most of the time, the body is neutral with respect to its electrical charge due to the equal distribution of anions and cations within the body.

Correct AnswerverifiedShow Answer

An anion is found in greater concentration inside the cell than outside. Which of the following statements BEST describes forces acting on the anion at the resting membrane potential ( -70 mV) ?

Correct AnswerverifiedShow Answer

Describe the factors that affect the rate of passive transport of molecules across a membrane.

Correct AnswerverifiedThe rate at which a molecule will passiv...View AnswerShow Answer

When molecules are passively transported across a membrane, the direction of their movement is dictated by the molecule's tendency to move

Correct AnswerverifiedShow Answer

The chemical force for which of the following ions is directed into the cell?

Correct AnswerverifiedShow Answer

As a cell's metabolism increases, so does its O2 consumption, giving rise to what product at a ratio of 2:1?

Correct AnswerverifiedShow Answer

Transporting a substance against its concentration gradient requires

Correct AnswerverifiedShow Answer

A cotransporter uses an ion's concentration gradient to move a second ion or molecule in the same direction as the first.

Correct AnswerverifiedShow Answer

If a positively charged ion is more concentrated inside the cell, the electrical forces required to balance the chemical gradient would be directed________ . Thus, the equilibrium potential for this Ion would be________ charged.

Correct AnswerverifiedShow Answer

What is the meaning of carrier proteins and pumps becoming saturated?

Correct AnswerverifiedShow Answer

What effect does a cell's overall thickness have on its permeability?

Correct AnswerverifiedShow Answer

Which of the following statements about Ca2+ pumps is FALSE?

Correct AnswerverifiedShow Answer

Which of the following is a reflection of the unequal distribution of positive and negative ions across the plasma membrane?

Correct AnswerverifiedShow Answer

The movement of water across a membrane is always a passive process.

Correct AnswerverifiedShow Answer

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All of the following statements concerning severe hyperglycemia's effect on serum Na⁺levels are true, EXCEPT

Correct Answer
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Correct Answer
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Correct Answer
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When the Na⁺/ K⁺pump moves its bound molecules of Na⁺to the outside of the membrane, it

Correct Answer
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Describe the process whereby the Na⁺/K⁺pump is involved in moving those ions across a membrane.

Correct Answer
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The Na⁺binding site on the Na⁺/K⁺pump faces...
View Answer

Correct Answer
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Correct Answer
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The rate at which a molecule will passiv...
View Answer

Correct Answer
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Correct Answer
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As a cell's metabolism increases, so does its O₂consumption, giving rise to what product at a ratio of 2:1?

Correct Answer
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Correct Answer
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Correct Answer
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If a positively charged ion is more concentrated inside the cell, the electrical forces required to balance the chemical gradient would be directed . Thus, the equilibrium potential for this Ion would be charged.

Correct Answer
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Correct Answer
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Correct Answer
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Which of the following statements about Ca²⁺pumps is FALSE?

Correct Answer
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Correct Answer
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