Question 1

In cells lining the stomach, the movement of chloride ions into the cells is coupled to the transport of bicarbonate ions out of the cells.This type of transport system most likely uses

Accepted Answer

A)  a uniporter. 
B)  a symporter. 
C)  a protein pump. 
D)  an antiporter. 
E)  graded diffusion.

Question 2

Which statement about osmosis is false?

Accepted Answer

A)  Osmosis refers to the movement of water along a concentration gradient. 
B)  In osmosis, water moves in a direction from low solute concentrations to high solute concentrations. 
C)  The movement of water across a membrane can affect the turgor pressure of some cells. 
D)  If osmosis occurs across a membrane, then diffusion is not occurring. 
E)  Water may move through membrane channels during the process of osmosis.

Question 3

The compounds in a biological membrane that form a barrier to the movement of hydrophilic materials across the membrane are

Accepted Answer

A)  integral membrane proteins. 
B)  carbohydrates. 
C)  lipids. 
D)  nucleic acids. 
E)  peripheral membrane proteins.

Question 4

Refer to the two figures below.  The figures show the interaction of the same human muscle cell with oxygen and carbon dioxide.Which statement is correct and supported by these figures?

Accepted Answer

A)  When a substance is present at a high concentration outside of a cell, the substance diffuses into the cell, but when a substance builds up inside a cell, it must be pumped out. 
B)  The arrows in the two figures indicate that molecules move in only one direction and never in the opposite direction during diffusion. 
C)  Once the concentrations of a substance are equal on both sides of the membrane, particles stop moving and diffusion stops. 
D)  Diffusion across the cell membrane occurs in cases of small nonpolar molecules and involves a net movement of molecules in the direction from high to low concentration. 
E)  Diffusion of substances across a cell membrane differs from diffusion of substances in solution in that equilibrium is achieved only in the case of the cell membrane.

Question 5

Refer to the figure below.  This diagram can be used to describe two cellular processes that involve membrane proteins.As shown in box A, the process of cell recognition refers to the specific interactions between carbohydrate groups and amino acid groups that allow one cell to identify another cell.As shown in box B, the process of cell _______ results from the strong linkage of two membrane-embedded molecules from two different cells.

Accepted Answer

The answer of Refer to the figure below.  This...

Question 6

The function of the clathrin molecules that coat vesicles in receptor-mediated endocytosis is to

Accepted Answer

A)  recognize specific molecules. 
B)  provide strength and stability. 
C)  contain dissolved substances. 
D)  fuse with the plasma membrane. 
E)  fuse with a lysosome.

Question 7

The speed and direction of ions as they move through channels in the cell membrane are determined by the

Accepted Answer

A)  concentration gradient. 
B)  ability of the ions to bind water. 
C)  number of channel proteins present. 
D)  size and charge of the ions. 
E)  thickness of the cell membrane.

Question 8

Temperature has an effect on the fluidity of plasma membranes.Some organisms are able to maintain their membranes' fluidity when it is extremely cold by

Accepted Answer

A)  replacing saturated fatty acids with unsaturated fatty acids. 
B)  closing protein channels. 
C)  increasing the number of transmembrane protein channels. 
D)  increasing the number of cholesterol molecules present. 
E)  using fatty acids with longer tails.

Question 9

In a biological membrane, the phospholipids are arranged in a _______, with the _______.

Accepted Answer

A)  bilayer; fatty acid tails pointing toward each other 
B)  bilayer; fatty acid tails facing outward 
C)  single layer; fatty acid tails facing the interior of the cell 
D)  single layer; phosphorus-containing region facing the interior of the cell 
E)  bilayer; phosphorus groups in the interior of the membrane

Question 10

The process of osmosis allows water molecules to pass through specialized channels in membranes.Which statement about osmosis is true?

Accepted Answer

A)  The direction of osmosis depends on temperature. 
B)  Water will move across a membrane to a region with less solute. 
C)  Water will move across a membrane to a region with more solute. 
D)  If the membrane does not allow solutes to pass, water will be equal on both sides. 
E)  A higher solute concentration on one side of a membrane indicates a higher water concentration on that side.

Question 11

Refer to the figure below.  Areas A and B are separated by a membrane that is permeable to a substance X.Which set of conditions will result in the greatest rate of diffusion of X into area A?

Accepted Answer

A)  The concentration of X in A is 5 mM; the concentration of X in B is 1 F1F1F1S1F1F1F10M. 
B)  The concentration of X in A is 10 mM; the concentration of X in B is 2 M. 
C)  The concentration of X in A is 50 mM; the concentration of X in B is 60 mM. 
D)  The concentration of X in A is 200 mM; the concentration of X in B is 250 mM. 
E)  The concentration of X in A is 1 M; the concentration of X in B is 500 mM.

Question 12

Which experimental observation would provide evidence that a bacterial membrane protein transfers the sugar lactose into the cell via secondary active transport?

Accepted Answer

A)  The membrane protein undergoes a conformational change when it binds lactose. 
B)  The membrane protein binds lactose but has no nucleotide binding site. 
C)  The membrane protein transfers lactose against its concentration gradient. 
D)  The membrane protein binds to sodium ions at a site different from the lactose site. 
E)  The membrane protein from the bacterium shares many structural similarities with the corresponding membrane protein from yeast.

Question 13

When plant cells are placed in a hypotonic solution, water enters the cells and exerts pressure against the cell wall.This force is called _______.

Accepted Answer

The answer of When plant cells are placed in a...

Question 14

Refer to the figure below.  The molecule outlined by a black box represents a phospholipid, which has a phosphate head and two fatty acid tails.The head is _______ because it readily interacts with the aqueous environment.

Accepted Answer

The answer of Refer to the figure below.  The...

Question 15

Many animal cells have a sodium-potassium pump that moves Na+ ions out of the cell and K+ ions in.This is an example of a(n)

Accepted Answer

A)  uniporter. 
B)  carrier protein. 
C)  symporter. 
D)  channel protein. 
E)  antiporter.

Question 16

If the hydrophilic side chains of a transmembrane protein were removed, the protein would most likely

Accepted Answer

A)  remain within the phospholipid bilayer. 
B)  extend farther into the cytoplasm. 
C)  protrude into the extracellular space. 
D)  remain anchored to the cytoskeleton. 
E)  become a peripheral protein.

Question 17

Male and female reproductive cells in animals can recognize each other via specific glycoproteins present on their cell surfaces.Each cell produces a different glycoprotein that recognizes the other.This is an example of _______ binding.

Accepted Answer

A)  recognition 
B)  species-specific 
C)  homotypic 
D)  heterotypic 
E)  complementary

Question 18

Refer to the table below.  The table shows data collected from analyses of the phospholipid compositions of cell membranes isolated from four different animal species.Based on these data, species _______ is the one most likely to live in the Arctic.

Accepted Answer

The answer of Refer to the table below.  The...

Question 19

Refer to the figures below.  The correct sequence of figures for showing the process of endocytosis is _______.

Accepted Answer

The answer of Refer to the figures below.  The...

Question 20

Refer to the table below summarizing information about two membrane proteins.  Diffusion coefficients indicate the rates at which proteins diffuse laterally through the cell membrane.What property of cell membranes is illustrated by a comparison of the information shown about these two proteins, and how does this property fit in with the current model used to describe the cell membrane?

Accepted Answer

The answer of Refer to the table below summarizing information...

Exam 6: Cell Membranes

In cells lining the stomach, the movement of chloride ions into the cells is coupled to the transport of bicarbonate ions out of the cells.This type of transport system most likely uses

Which statement about osmosis is false?

The compounds in a biological membrane that form a barrier to the movement of hydrophilic materials across the membrane are

Refer to the two figures below. The figures show the interaction of the same human muscle cell with oxygen and carbon dioxide.Which statement is correct and supported by these figures?

The function of the clathrin molecules that coat vesicles in receptor-mediated endocytosis is to

The speed and direction of ions as they move through channels in the cell membrane are determined by the

Temperature has an effect on the fluidity of plasma membranes.Some organisms are able to maintain their membranes' fluidity when it is extremely cold by

In a biological membrane, the phospholipids are arranged in a _, with the _.

The process of osmosis allows water molecules to pass through specialized channels in membranes.Which statement about osmosis is true?

Refer to the figure below. Areas A and B are separated by a membrane that is permeable to a substance X.Which set of conditions will result in the greatest rate of diffusion of X into area A?

Which experimental observation would provide evidence that a bacterial membrane protein transfers the sugar lactose into the cell via secondary active transport?

When plant cells are placed in a hypotonic solution, water enters the cells and exerts pressure against the cell wall.This force is called _______.

Refer to the figure below. The molecule outlined by a black box represents a phospholipid, which has a phosphate head and two fatty acid tails.The head is _______ because it readily interacts with the aqueous environment.

Many animal cells have a sodium-potassium pump that moves Na⁺ ions out of the cell and K⁺ ions in.This is an example of a(n)

If the hydrophilic side chains of a transmembrane protein were removed, the protein would most likely

Male and female reproductive cells in animals can recognize each other via specific glycoproteins present on their cell surfaces.Each cell produces a different glycoprotein that recognizes the other.This is an example of _______ binding.

Refer to the table below. The table shows data collected from analyses of the phospholipid compositions of cell membranes isolated from four different animal species.Based on these data, species _______ is the one most likely to live in the Arctic.

Refer to the figures below. The correct sequence of figures for showing the process of endocytosis is _______.