Question 1

The Na/K ATPase pump is an enzyme that phosphorylates itself.

Accepted Answer

A) True 
 B)False

Question 2

The permeability of the plasma membrane to mineral ions:

Accepted Answer

A)   is not influenced by channels formed by proteins.
B)   is the same in all cell types.
C)   is affected by differences in electrical charge on the two sides of the membrane.
D)   is zero in all living cells.
E)   is only possible because of the hydrophobic interior of the lipid bilayer.F) B) and D)
G) A) and E)

Question 3

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 4

Because of the active transport of Na+ and K+, the intracellular concentration of Na+ is lower than the extracellular concentration, whereas the reverse is true for K+.

Accepted Answer

A) True 
 B)False

Question 5

Which is a form of cellular transport that involves the movement of molecules into cells without passing through the plasma membrane's structural matrix?

Accepted Answer

A)   diffusion
B)   osmosis
C)   facilitated diffusion
D)   endocytosis
E)   apoptosisF) B) and E)
G) C) and D)

Question 6

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

Accepted Answer

A) True 
 B)False

Question 7

All other factors being equal, the rate of diffusion across a permeable surface will be greater for small molecules than for larger ones.

Accepted Answer

A) True 
 B)False

Question 8

Adding one gram of NaCl to one liter of water will lower the water concentration twice as much as adding one gram of glucose.

Accepted Answer

A) True 
 B)False

Question 9

Phagocytic leukocytes use phagocytosis to engulf foreign bacteria and destroy them within ribosomes.

Accepted Answer

A) True 
 B)False

Question 10

What will happen if a normal cell is placed in a hyperosmotic solution?

Accepted Answer

A)   It will swell in size.
B)   It will shrink in size.
C)   It will stay the same size.
D)   It may swell, shrink, or stay the same size, depending upon the concentration of penetrating and nonpenetrating solutes in the solution.E) A) and D)
F) None of the above

Question 11

In the body, K+ ions behave as if they are penetrating solutes because they are actively transported into cells.

Accepted Answer

A) True 
 B)False

Question 12

By what transport mechanism does glucose enter most cells?

Accepted Answer

A)   diffusion through the lipid bilayer
B)   primary active transport
C)   secondary active transport
D)   diffusion through a protein channel
E)   facilitated diffusionF) C) and D)
G) A) and E)

Question 13

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, because polar molecules diffuse through less rapidly because the bilayer is polar throughout its width.
C)   false, because polar molecules diffuse through less rapidly because the bilayer is nonpolar throughout its width.
D)   false, because nonpolar molecules diffuse through more rapidly because much of the bilayer is nonpolar.
E)   false, because the rate of diffusion of nonpolar and polar molecules through the bilayer is essentially the same as long as the molecules are the same size.F) A) and D)
G) A) and B)

Question 14

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

Accepted Answer

A) True 
 B)False

Question 15

The intracellular concentration of water in the cells of the body is normally the same as the extracellular concentration of water.

Accepted Answer

A) True 
 B)False

Question 16

A cell is placed into a 1 millimolar solution of substance X and over time you witness the concentration of X inside the cell increase to 5 millimolar. What is the best explanation for this observation?

Accepted Answer

A)   X is moving into the cell by simple diffusion.
B)   X is moving into the cell by diffusion through a protein channel.
C)   X is moving into the cell by facilitated diffusion.
D)   X is moving into the cell by primary active transport.
E)   Water is leaving the cell by osmosis.F) C) and D)
G) A) and C)

Question 17

In most of the cells in the body there is an electrical difference such that the inside of cells is positive with respect to the outside.

Accepted Answer

A) True 
 B)False

Question 18

Pinocytosis is a method by which molecules can leave cells whose membranes are impermeable to the molecules.

Accepted Answer

A) True 
 B)False

Question 19

Which is true regarding the mediated transport of a substance across a plasma membrane?

Accepted Answer

A)   It depends upon the binding of that substance to a specific site on the membrane protein.
B)   It depends upon movement of proteins from one side of the membrane to the other.
C)   It always increases in direct proportion to the increasing concentration of the substance on one side of the membrane.
D)   Both "depends upon the binding of that substance to a specific site on the membrane protein" and "depends upon movement of proteins from one side of the membrane to the other" are correct.
E)   All of the choices are correct.F) B) and D)
G) A) and B)

Question 20

In the body, Na+ ions behave as if they are nonpenetrating solutes because they are actively transported out of cells.

Accepted Answer

A) True 
 B)False

Exam 4: Movement of Molecules Across Cell Membranes

The Na/K ATPase pump is an enzyme that phosphorylates itself.

Correct AnswerverifiedShow Answer

Pinocytosis is a method by which molecules can leave cells whose membranes are impermeable to the molecules.

Correct AnswerverifiedShow Answer

In the body, K+ ions behave as if they are penetrating solutes because they are actively transported into cells.

Correct AnswerverifiedShow Answer

Which is true regarding the mediated transport of a substance across a plasma membrane?

Correct AnswerverifiedShow Answer

In most of the cells in the body there is an electrical difference such that the inside of cells is positive with respect to the outside.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A cell is placed into a 1 millimolar solution of substance X and over time you witness the concentration of X inside the cell increase to 5 millimolar. What is the best explanation for this observation?

Correct AnswerverifiedShow Answer

All other factors being equal, the rate of diffusion across a permeable surface will be greater for small molecules than for larger ones.

Correct AnswerverifiedShow Answer

The permeability of the plasma membrane to mineral ions:

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

In the body, Na+ ions behave as if they are nonpenetrating solutes because they are actively transported out of cells.

Correct AnswerverifiedShow Answer

Phagocytic leukocytes use phagocytosis to engulf foreign bacteria and destroy them within ribosomes.

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

Which is a form of cellular transport that involves the movement of molecules into cells without passing through the plasma membrane's structural matrix?

Correct AnswerverifiedShow Answer

What will happen if a normal cell is placed in a hyperosmotic solution?

Correct AnswerverifiedShow Answer

Because of the active transport of Na+ and K+, the intracellular concentration of Na+ is lower than the extracellular concentration, whereas the reverse is true for K+.

Correct AnswerverifiedShow Answer

The intracellular concentration of water in the cells of the body is normally the same as the extracellular concentration of water.

Correct AnswerverifiedShow Answer

Adding one gram of NaCl to one liter of water will lower the water concentration twice as much as adding one gram of glucose.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

By what transport mechanism does glucose enter most cells?

Correct AnswerverifiedShow Answer

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Because of the active transport of Na⁺ and K⁺, the intracellular concentration of Na⁺ is lower than the extracellular concentration, whereas the reverse is true for K⁺.

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