Question 1

CO₂ is a small,non-polar molecule.It will cross the cell membrane by

Accepted Answer

A)  simple diffusion.
B)  diffusion through a channel.
C)  active transport.
D)  diffusion using a pump. A

Question 2

Which of the following statements regarding the diffusion of a nonpolar solute X across a cell membrane is correct?

Accepted Answer

A)  At equilibrium,the net flux of X across the cell membrane is zero.
B)  At equilibrium,X will cease moving across the cell membrane.
C)  Solute X will be unable to reach equilibrium because it is nonpolar.
D)  Solute X will reach equilibrium,but the concentration will be much higher on the inside of the cell because of the smaller volume.
E)  At equilibrium,movement of X across the membrane will be much faster in one direction than in the other.

Question 3

The final equilibrium state reached by a molecule that enters a cell by facilitated diffusion is the same as that for a molecule that enters the cell by diffusion.

Accepted Answer

A) True 
 B)False

Question 4

The higher the osmolarity of a solution,the higher the concentration of water in it.

Accepted Answer

A) True 
 B)False

Question 5

Which of the following statements regarding endocytosis or exocytosis is correct?

Accepted Answer

A)  Endocytosis is a method by which large molecules may be secreted from a cell.
B)  Exocytosis is a method by which large molecules may be secreted from a cell.
C)  Pinocytosis is a form of endocytosis;phagocytosis is a type of exocytosis.
D)  Pinocytosis is a form of exocytosis;phagocytosis is a type of endocytosis.
E)  Pinocytosis and phagocytosis are both types of exocytosis.

Question 6

Which is true about mediated transport of substances across cell membranes?

Accepted Answer

A)  It involves a specific membrane protein that functions as a carrier molecule.
B)  It always involves the movement of substances against a concentration gradient.
C)  It is always directly coupled to the splitting of ATP molecules.
D)  There is no limit to how fast it can occur as the concentration gradient becomes larger.
E)  It is the main mechanism for transporting hydrophobic molecules across membranes.

Question 7

A portion of cell's plasma membrane is removed during endocytosis.

Accepted Answer

A) True 
 B)False  True

Question 8

Which of the following is a feature that distinguishes active transport from facilitated diffusion?

Accepted Answer

A)  Saturation of transport rate
B)  Requirement for a carrier molecule
C)  Carrier molecules have specificity
D)  Presence of a transport maximum
E)  Requirement for metabolic energy E

Question 9

The human hormone estrogen is highly nonpolar.After being secreted,estrogen will be found

Accepted Answer

A)  at low concentrations in all cells of the body.
B)  at high concentrations just in the cells that express a membrane-bound receptor.
C)  trapped in endocytic vesicles in cells that express a membrane-bound receptor.
D)  in the lysosome of all cells of the body.

Question 10

A disease that resulted in defective Na⁺/K⁺ pumps would have no effect on the absorption of water across an epithelial surface.

Accepted Answer

A) True 
 B)False

Question 11

Cholesterol-containing lipoproteins are cleared from the blood by which process?

Accepted Answer

A)  Second messenger-activated,sterol transgenesis
B)  Hydrophobic phagocytosis
C)  Simple,transcellular membrane diffusion
D)  Na+ gradient-dependent,secondary active transport
E)  Clathrin-dependent,receptor-mediated endocytosis

Question 12

Specific proteins in the membranes mediate movement of lipid-soluble molecules into cells.

Accepted Answer

A) True 
 B)False

Question 13

Most cells can perform pinocytosis,but only a few kinds can perform phagocytosis.

Accepted Answer

A) True 
 B)False

Question 14

If a cell were placed in a solution of 0.15 M NaCl,it would shrink.

Accepted Answer

A) True 
 B)False

Question 15

You examine a cell by electron microscopy and find a molecule on the outside of the cell and in vesicles in the cytoplasm.The most likely explanation is that this substance moved into the cell by

Accepted Answer

A)  diffusion.
B)  osmosis.
C)  facilitated diffusion.
D)  endocytosis.
E)  apoptosis.

Question 16

Which of the following are triggers for ion channels to open?

Accepted Answer

A)  Ligand binding
B)  Change in membrane potential
C)  Stretching of membrane
D)  Movement of solutes across the membrane
E)  Change in water molecule concentration

Question 17

Which of the following is true about the actions of the sodium-potassium pump?

Accepted Answer

A)  The Na⁺/K⁺ pump directly uses ATP
B)  The Na⁺/K⁺ pump creates an electrical disequilibrium.
C)  The Na⁺/K⁺ pump creates chemical disequilibrium.
D)  It is expressed only on select cell types
E)  The Na⁺/K⁺ pump is an example of counter transport.

Question 18

If the ATP-generating mechanisms in a cell are poisoned and the cell depletes its ATP reserves,which would occur first?

Accepted Answer

A)  Primary active transport of molecules would cease.
B)  Secondary active transport of molecules would cease.
C)  Facilitated diffusion of molecules would cease.
D)  Ion concentration gradients would reach equilibrium across the cell membrane.
E)  All transport processes would cease immediately when the ATP was depleted.

Question 19

Most organic solutes cross epithelial membranes by simple diffusion on the lumen side followed by active transport across the blood side of the membrane.

Accepted Answer

A) True 
 B)False

Question 20

Substance X is a mostly polar molecule and Substance Y is a mostly non-polar molecule of a similar size.Which will diffuse from the extracellular fluid to the intracellular fluid faster if they are in equal concentrations outside and inside the cell?

Accepted Answer

A)  Substance X will diffuse faster.
B)  Substance Y will diffuse faster.
C)  Substance X and Substance Y will diffuse at the same rate,as they are of equal size and concentration.

Exam 4: Movement of Solutes and Water Across Cell Membranes

CO₂ is a small,non-polar molecule.It will cross the cell membrane by

Correct AnswerverifiedA

Which of the following statements regarding the diffusion of a nonpolar solute X across a cell membrane is correct?

Correct AnswerverifiedShow Answer

The final equilibrium state reached by a molecule that enters a cell by facilitated diffusion is the same as that for a molecule that enters the cell by diffusion.

Correct AnswerverifiedShow Answer

The higher the osmolarity of a solution,the higher the concentration of water in it.

Correct AnswerverifiedShow Answer

Which of the following statements regarding endocytosis or exocytosis is correct?

Correct AnswerverifiedShow Answer

Which is true about mediated transport of substances across cell membranes?

Correct AnswerverifiedShow Answer

A portion of cell's plasma membrane is removed during endocytosis.

Correct AnswerverifiedTrue

Which of the following is a feature that distinguishes active transport from facilitated diffusion?

Correct AnswerverifiedE

The human hormone estrogen is highly nonpolar.After being secreted,estrogen will be found

Correct AnswerverifiedShow Answer

A disease that resulted in defective Na⁺/K⁺ pumps would have no effect on the absorption of water across an epithelial surface.

Correct AnswerverifiedShow Answer

Cholesterol-containing lipoproteins are cleared from the blood by which process?

Correct AnswerverifiedShow Answer

Specific proteins in the membranes mediate movement of lipid-soluble molecules into cells.

Correct AnswerverifiedShow Answer

Most cells can perform pinocytosis,but only a few kinds can perform phagocytosis.

Correct AnswerverifiedShow Answer

If a cell were placed in a solution of 0.15 M NaCl,it would shrink.

Correct AnswerverifiedShow Answer

You examine a cell by electron microscopy and find a molecule on the outside of the cell and in vesicles in the cytoplasm.The most likely explanation is that this substance moved into the cell by

Correct AnswerverifiedShow Answer

Which of the following are triggers for ion channels to open?

Correct AnswerverifiedShow Answer

Which of the following is true about the actions of the sodium-potassium pump?

Correct AnswerverifiedShow Answer

If the ATP-generating mechanisms in a cell are poisoned and the cell depletes its ATP reserves,which would occur first?

Correct AnswerverifiedShow Answer

Most organic solutes cross epithelial membranes by simple diffusion on the lumen side followed by active transport across the blood side of the membrane.

Correct AnswerverifiedShow Answer

Substance X is a mostly polar molecule and Substance Y is a mostly non-polar molecule of a similar size.Which will diffuse from the extracellular fluid to the intracellular fluid faster if they are in equal concentrations outside and inside the cell?

Correct AnswerverifiedShow Answer

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