Question 1

The Na,K-ATPase carrier transports sodium ions out of cells and potassium ions into cells on a one-to-one basis.

Accepted Answer

A) True 
 B)False

Question 2

The fate of all endocytotic vesicles is digestion of their contents by lysosomal enzymes.

Accepted Answer

A) True 
 B)False

Question 3

Which of the following statements regarding the structure and function of cell membranes is correct?

Accepted Answer

A)  The phospholipid bilayer is arranged so that the hydrophilic heads of the phospholipid molecule face the extra- and intracellular fluids
B)  Some proteins integrated into the membrane serve as channels for the passage of nonpolar molecules through the membrane
C)  Some proteins integrated into the membrane function as channels associated with transport of ions through the membrane
D)  Both the phospholipid bilayer is arranged so that the hydrophilic heads of the phospholipid molecule face the extra- and intracellular fluids and some proteins integrated into the membrane function as channels associated with transport of ions through the membrane are correct
E)  All of the choices are correctF) B) and C)
G) C) and D)

Question 4

If a cell is placed in a hypotonic solution,it

Accepted Answer

A)  Will swell
B)  Will shrink
C)  Will stay the same size
D)  May swell, shrink or stay the same size, depending upon the concentration of penetrating and nonpenetrating solutes in the solutionE) All of the above
F) None of the above

Question 5

Which of the following are possible combinations of mechanisms for transport of a particle against a concentration gradient across an epithelial cell?

Accepted Answer

A)  Passive diffusion from a lumen into the cell followed by facilitated diffusion from the cell into the blood
B)  Passive diffusion on the apical side into the cell followed by primary active transport on the basolateral side
C)  Secondary active transport on the mucosal side followed by facilitated diffusion on the serosal side
D)  Both passive diffusion from a lumen into the cell followed by facilitated diffusion from the cell into the blood and passive diffusion on the apical side into the cell followed by primary active transport on the basolateral side are correct
E)  Both passive diffusion on the apical side into the cell followed by primary active transport on the basolateral side and secondary active transport on the mucosal side followed by facilitated diffusion on the serosal side are correctF) A) and D)
G) A) and E)

Question 6

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

Accepted Answer

A) True 
 B)False

Question 7

The removal of cholesterol from the blood during times when its concentrations are high

Accepted Answer

A)  Is heavily dependent upon the activity of phagocytosis
B)  Requires that it be bound to circulating lipoproteins which attach to absorbtive cell membranes
C)  Is promoted by the increased production of lipoprotein receptors in the cholesterol absorbing cells
D)  Both requires that it be bound to circulating lipoproteins which attach to absorbtive cell membranes and is promoted by the increased production of lipoprotein receptors in the cholesterol absorbing cells are correct
E)  All of these choices are correctF) B) and D)
G) A) and B)

Question 8

Ion channels in cell membranes

Accepted Answer

A)  Are nonspecific
B)  May open in response to a change in potential difference across the membrane
C)  May open in response to binding a ligand
D)  Both are nonspecific and may open in response to a change in potential difference across the membrane are correct
E)  Both may open in response to a change in potential difference across the membrane and may open in response to binding a ligand are correctF) B) and E)
G) B) and D)

Question 9

Glucose enters most cells by

Accepted Answer

A)  Diffusion through the lipid bilayer
B)  Primary active transport
C)  Secondary active transport
D)  Diffusion through a protein channel
E)  EndocytosisF) B) and D)
G) A) and D)

Question 10

Molecules increase their rate of diffusion as temperature increases.

Accepted Answer

A) True 
 B)False

Question 11

Which of the following statements regarding the movement of molecules across cell membranes is correct?

Accepted Answer

A)  The diffusion of molecules across a cell membrane occurs at a rate that is influenced by the surface area of the membrane and the magnitude of the concentration difference across it
B)  The net flux of molecules that cross cell membranes by diffusion is always from regions of lower concentration to regions of higher concentration
C)  Molecules that enter a cell by diffusion must directly permeate the lipid portion of the plasma membrane, whereas those that enter by facilitated diffusion utilize membrane-bound proteins
D)  Both the diffusion of molecules across a cell membrane occurs at a rate that is influenced by the surface area of the membrane and the magnitude of the concentration difference across it and the net flux of molecules that cross cell membranes by diffusion is always from regions of lower concentration to regions of higher concentration are correct
E)  Both the diffusion of molecules across a cell membrane occurs at a rate that is influenced by the surface area of the membrane and the magnitude of the concentration difference across it and molecules that enter a cell by diffusion must directly permeate the lipid portion of the plasma membrane, whereas those that enter by facilitated diffusion utilize membrane-bound proteins are correctF) B) and D)
G) C) and D)

Question 12

In general,polar molecules diffuse more rapidly across cell membranes than do nonpolar molecules.

Accepted Answer

A) True 
 B)False

Question 13

"Osmosis" refers to the movement of ____________ across semipermeable membranes.

Accepted Answer

A)  Glucose
B)  Charged particles
C)  Lipid molecules
D)  Water
E)  Any substanceF) B) and D)
G) C) and D)

Question 14

The clathrin protein so important to carrying out receptor mediated transport remains with an endosome as it moves deep within the cell and is degraded entirely along with the ingested internal contents.

Accepted Answer

A) True 
 B)False

Question 15

Mediated transport is required in order for glucose,amino acids and fatty acids to pass into cells because these substances cannot diffuse through plasma membranes.

Accepted Answer

A) True 
 B)False

Question 16

Cholesterol levels in the blood are regulated via the activity of the liver utilizing the process known as _____,which can be regulated to increase uptake as the cell ______ the number of cholesterol+ lipoprotein receptors on its surface.

Accepted Answer

A)  Phagosomolysis, increases
B)  Endosomolysis, decreases
C)  Receptor mediated endocytosis, increases
D)  Potocytosis, decreases
E)  Pinocytosis, increasesF) B) and E)
G) A) and D)

Question 17

In general,polar molecules diffuse more rapidly through the lipid bilayer part of cell membranes than do nonpolar molecules.This statement is

Accepted Answer

A)  True
B)  False.Polar molecules diffuse through less rapidly because the bilayer is polar throughout its width
C)  False.Polar molecules diffuse through less rapidly because the bilayer is nonpolar throughout its width
D)  False.Nonpolar molecules diffuse through more rapidly because much of the bilayer is nonpolar
E)  False.The rate of diffusion of nonpolar and polar molecules through the bilayer is essentially the same as long as the molecules are the same sizeF) C) and D)
G) A) and D)

Question 18

Which of the following statements about epithelial cells and epithelial transport is correct?

Accepted Answer

A)  Epithelial cells are polarized
B)  Epithelial cells lining the small intestine have Na, K-ATPase pumps only in their basolateral membranes
C)  The "active" component of active transport across epithelial cells occurs only from the lumen side into the cells
D)  Both epithelial cells are polarized and epithelial cells lining the small intestine have Na, K-ATPase pumps only in their basolateral membranes are correct
E)  Both epithelial cells are polarized and the "active" component of active transport across epithelial cells occurs only from the lumen side into the cells are correctF) A) and B)
G) B) and D)

Question 19

Potocytosis

Accepted Answer

A)  Involves simple diffusion of low molecular weight molecules across the plasma membrane, following a concentration gradient
B)  Is triggered by ligands which lead to the formation of caveolae delivering low molecular weight molecules directly to the cytosol
C)  Is the process which directly regulates and often limits receptor mediated endocytosis to remain within homeostatic parameters
D)  Involves active transport of high molecular weight lipoprotein complexes through the participation of clathrin in the formation of endosomal vesicles
E)  Both is triggered by ligands which lead to the formation of caveolae delivering low molecular weight molecules directly to the cytosol and is the process which directly regulates and often limits receptor mediated endocytosis to remain within homeostatic parameters are correctF) A) and D)
G) C) and D)

Question 20

The Na,K pump is an enzyme that phosphorylates itself.

Accepted Answer

A) True 
 B)False

Exam 4: Movement of Molecules Across Cell Membranes

Which of the following statements regarding the structure and function of cell membranes is correct?

Correct AnswerverifiedShow Answer

The Na,K pump is an enzyme that phosphorylates itself.

Correct AnswerverifiedShow Answer

Which of the following are possible combinations of mechanisms for transport of a particle against a concentration gradient across an epithelial cell?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

The removal of cholesterol from the blood during times when its concentrations are high

Correct AnswerverifiedShow Answer

The clathrin protein so important to carrying out receptor mediated transport remains with an endosome as it moves deep within the cell and is degraded entirely along with the ingested internal contents.

Correct AnswerverifiedShow Answer

Potocytosis

Correct AnswerverifiedShow Answer

If a cell is placed in a hypotonic solution,it

Correct AnswerverifiedShow Answer

"Osmosis" refers to the movement of ____________ across semipermeable membranes.

Correct AnswerverifiedShow Answer

Glucose enters most cells by

Correct AnswerverifiedShow Answer

Ion channels in cell membranes

Correct AnswerverifiedShow Answer

Molecules increase their rate of diffusion as temperature increases.

Correct AnswerverifiedShow Answer

In general,polar molecules diffuse more rapidly across cell membranes than do nonpolar molecules.

Correct AnswerverifiedShow Answer

The fate of all endocytotic vesicles is digestion of their contents by lysosomal enzymes.

Correct AnswerverifiedShow Answer

Which of the following statements regarding the movement of molecules across cell membranes is correct?

Correct AnswerverifiedShow Answer

In general,polar molecules diffuse more rapidly through the lipid bilayer part of cell membranes than do nonpolar molecules.This statement is

Correct AnswerverifiedShow Answer

The Na,K-ATPase carrier transports sodium ions out of cells and potassium ions into cells on a one-to-one basis.

Correct AnswerverifiedShow Answer

Cholesterol levels in the blood are regulated via the activity of the liver utilizing the process known as _____,which can be regulated to increase uptake as the cell ______ the number of cholesterol+ lipoprotein receptors on its surface.

Correct AnswerverifiedShow Answer

Mediated transport is required in order for glucose,amino acids and fatty acids to pass into cells because these substances cannot diffuse through plasma membranes.

Correct AnswerverifiedShow Answer

Which of the following statements about epithelial cells and epithelial transport is correct?

Correct AnswerverifiedShow Answer

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Cholesterol levels in the blood are regulated via the activity of the liver utilizing the process known as _,which can be regulated to increase uptake as the cell __ the number of cholesterol+ lipoprotein receptors on its surface.

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