Question 1

Cells secrete materials to the exterior environment through the process of

Accepted Answer

A)  exocytosis. 
B)  facilitated diffusion. 
C)  phagocytosis. 
D)  active transport. 
E)  endocytosis. 
A)  exocytosis. 
B)  facilitated diffusion. 
C)  phagocytosis. 
D)  active transport. 
E)  endocytosis.

Question 2

An important difference between phagocytosis and receptor-mediated endocytosis is that

Accepted Answer

A)  in phagocytosis, the membrane forms coated vesicles. 
B)  vesicles do not form in receptor-mediated endocytosis. 
C)  dissolved substances can be taken up by phagocytosis. 
D)  receptor-mediated endocytosis is more specific. 
E)  macromolecules can enter through receptor-mediated endocytosis. 
A)  in phagocytosis, the membrane forms coated vesicles. 
B)  vesicles do not form in receptor-mediated endocytosis. 
C)  dissolved substances can be taken up by phagocytosis. 
D)  receptor-mediated endocytosis is more specific. 
E)  macromolecules can enter through receptor-mediated endocytosis.

Question 3

Plants depend on their cell walls to limit the amount of water entering their cells and maintain _______, which helps keep plants upright.

Accepted Answer

A)  osmosis 
B)  aquaporins 
C)  turgor pressure 
D)  simple diffusion 
E)  equilibrium 
A)  osmosis 
B)  aquaporins 
C)  turgor pressure 
D)  simple diffusion 
E)  equilibrium

Question 4

In animals, the solute balance of the plasma surrounding blood cells must be carefully maintained so that the blood cells are not affected by changes in fluid or solute balance.If the plasma becomes hypotonic compared with the blood cells, what will be the effect?

Accepted Answer

A)  The blood cells will swell and possibly burst. 
B)  The blood cells will lose water and shrink. 
C)  Water will move from the blood cell into the plasma. 
D)  Solutes will move from the blood cell into the plasma. 
E)  Solutes will move from the plasma into the blood cell. 
A)  The blood cells will swell and possibly burst. 
B)  The blood cells will lose water and shrink. 
C)  Water will move from the blood cell into the plasma. 
D)  Solutes will move from the blood cell into the plasma. 
E)  Solutes will move from the plasma into the blood cell.

Question 5

Receptor-mediated endocytosis is the mechanism for the import of

Accepted Answer

A)  clathrin. 
B)  all macromolecules. 
C)  large ions. 
D)  cholesterol. 
E)  integral membrane proteins. 
A)  clathrin. 
B)  all macromolecules. 
C)  large ions. 
D)  cholesterol. 
E)  integral membrane proteins.

Question 6

For each molecule of ATP consumed during active transport of sodium and potassium, there is an import of _______ ion(s) and an export of _______ ion(s).

Accepted Answer

A)  two Na+; three K+ 
B)  two Na+; one K+ 
C)  one K+; three Na+ 
D)  two K+; three Na+ 
E)  three K+; two Na+ 
A)  two Na+; three K+ 
B)  two Na+; one K+ 
C)  one K+; three Na+ 
D)  two K+; three Na+ 
E)  three K+; two Na+

Question 7

Which analogy could best be used to describe the molecular structures interacting at the point of attachment between two animal cells physically bound to one another?

Accepted Answer

A)  A spoon placed into soup 
B)  A key inserted into a lock 
C)  A fish scooped into a net 
D)  A nail hammered into wood 
E)  A box loaded into a truck 
A)  A spoon placed into soup 
B)  A key inserted into a lock 
C)  A fish scooped into a net 
D)  A nail hammered into wood 
E)  A box loaded into a truck

Question 8

Regardless of the specific type of molecule or particle being transported, endocytosis always involves

Accepted Answer

A)  phagocytosis. 
B)  pinocytosis. 
C)  receptor proteins. 
D)  membrane invagination. 
E)  phagosomes. 
A)  phagocytosis. 
B)  pinocytosis. 
C)  receptor proteins. 
D)  membrane invagination. 
E)  phagosomes.

Question 9

If tight junctions were replaced by desmosomes in cells lining the bladder,

Accepted Answer

A)  dissolved substances would move freely through the extracellular matrix. 
B)  membrane protein migration would be restricted. 
C)  intercellular spaces would be sealed off. 
D)  the number of gap junctions would increase. 
E)  pressure on the desmosomes would increase. 
A)  dissolved substances would move freely through the extracellular matrix. 
B)  membrane protein migration would be restricted. 
C)  intercellular spaces would be sealed off. 
D)  the number of gap junctions would increase. 
E)  pressure on the desmosomes would increase.

Question 10

The main difference between osmosis and diffusion is that

Accepted Answer

A)  diffusion is passive transport, whereas osmosis is active transport. 
B)  diffusion is more efficient than osmosis over longer distances. 
C)  osmosis refers to the movement of materials across a semipermeable membrane, but diffusion does not involve a membrane. 
D)  osmosis refers specifically to the movement of water, whereas diffusion refers to the movement of any molecules. 
E)  the process of osmosis varies according to the kinds of particles present, but diffusion does not. 
A)  diffusion is passive transport, whereas osmosis is active transport. 
B)  diffusion is more efficient than osmosis over longer distances. 
C)  osmosis refers to the movement of materials across a semipermeable membrane, but diffusion does not involve a membrane. 
D)  osmosis refers specifically to the movement of water, whereas diffusion refers to the movement of any molecules. 
E)  the process of osmosis varies according to the kinds of particles present, but diffusion does not.

Question 11

Facilitated diffusion and active transport both

Accepted Answer

A)  require ATP. 
B)  require the use of proteins as carriers or channels. 
C)  carry ions and not small molecules. 
D)  increase without limit as the concentration gradient increases. 
E)  depend on the solubility of the solute in lipids. 
A)  require ATP. 
B)  require the use of proteins as carriers or channels. 
C)  carry ions and not small molecules. 
D)  increase without limit as the concentration gradient increases. 
E)  depend on the solubility of the solute in lipids.

Question 12

Cells can move substances from their cytoplasms into the external environment via

Accepted Answer

A)  exocytosis. 
B)  pinocytosis. 
C)  phagocytosis. 
D)  receptor-mediated endocytosis. 
E)  endocytosis. 
A)  exocytosis. 
B)  pinocytosis. 
C)  phagocytosis. 
D)  receptor-mediated endocytosis. 
E)  endocytosis.

Question 13

White blood cells can defend the body against invaders through

Accepted Answer

A)  phagocytosis. 
B)  pinocytosis. 
C)  active transport. 
D)  exocytosis. 
E)  receptor-mediated endocytosis. 
A)  phagocytosis. 
B)  pinocytosis. 
C)  active transport. 
D)  exocytosis. 
E)  receptor-mediated endocytosis.

Question 14

A researcher studying a line of mouse skin cells has identified an oligosaccharide group attached to the cells' surfaces.What experiment should the researcher perform to test whether this oligosaccharide is important in cell-cell recognition?

Accepted Answer

A)  Isolate membrane proteins from the mouse skin cells, and determine what percentage of these contain the oligosaccharide being investigated. 
B)  Introduce genetic mutations that prevent synthesis of all membrane proteins, and observe whether this results in loss of the mouse skin cells' ability to recognize other cells. 
C)  Attach a fluorescent probe to a protein known to bind to the oligosaccharide, then incubate the protein with mouse skin cells and observe the cells using fluorescence microscopy. 
D)  Run a broad survey of many other types of cells to see which cells express this oligosaccharide and are able to bind to the mouse skin cells being investigated. 
E)  Treat the mouse skin cells with enzymes that hydrolyze bonds between sugar molecules, and observe whether treated cells no longer recognize other cells. 
A)  Isolate membrane proteins from the mouse skin cells, and determine what percentage of these contain the oligosaccharide being investigated. 
B)  Introduce genetic mutations that prevent synthesis of all membrane proteins, and observe whether this results in loss of the mouse skin cells' ability to recognize other cells. 
C)  Attach a fluorescent probe to a protein known to bind to the oligosaccharide, then incubate the protein with mouse skin cells and observe the cells using fluorescence microscopy. 
D)  Run a broad survey of many other types of cells to see which cells express this oligosaccharide and are able to bind to the mouse skin cells being investigated. 
E)  Treat the mouse skin cells with enzymes that hydrolyze bonds between sugar molecules, and observe whether treated cells no longer recognize other cells.

Question 15

Refer to the figure below.   Which statement about the lipid bilayer shown in the figure is false?

Accepted Answer

A)  The area labeled A contains hydrophilic portions of fatty acids. 
B)  The area labeled A contains polar groups that can interact with water. 
C)  The area labeled B contains hydrophobic regions of fatty acids. 
D)  The area labeled B allows for the movement of charged particles. 
E)  The area labeled B allows for the diffusion of lipid-soluble particles. 
A)  The area labeled A contains hydrophilic portions of fatty acids. 
B)  The area labeled A contains polar groups that can interact with water. 
C)  The area labeled B contains hydrophobic regions of fatty acids. 
D)  The area labeled B allows for the movement of charged particles. 
E)  The area labeled B allows for the diffusion of lipid-soluble particles.

Question 16

Refer to the figure below showing the structure of a phospholipid molecule.   Which statement explains how this molecule is involved in the makeup of a cell membrane?

Accepted Answer

A)  Part A forms the polar head that associates with water, while parts B, C, and D form the nonpolar tails that associate with other nonpolar tails of other phospholipids in the membrane. 
B)  Part B forms the polar head that associates with water, while parts C and D form the nonpolar tails that associate with other nonpolar tails of other phospholipids in the membrane. 
C)  Parts A, B, and D form the polar head that associates with water, while part C forms the nonpolar tail that associates with other nonpolar tails of other phospholipids in the membrane. 
D)  Parts A, C, and D form the polar head that associates with water, while part B forms the nonpolar tail that associates with other nonpolar tails of other phospholipids in the membrane. 
E)  Parts B and D form the polar head that associates with water, while parts A and C form the nonpolar tail that associates with other nonpolar tails of other phospholipids in the membrane. 
A)  Part A forms the polar head that associates with water, while parts B, C, and D form the nonpolar tails that associate with other nonpolar tails of other phospholipids in the membrane. 
B)  Part B forms the polar head that associates with water, while parts C and D form the nonpolar tails that associate with other nonpolar tails of other phospholipids in the membrane. 
C)  Parts A, B, and D form the polar head that associates with water, while part C forms the nonpolar tail that associates with other nonpolar tails of other phospholipids in the membrane. 
D)  Parts A, C, and D form the polar head that associates with water, while part B forms the nonpolar tail that associates with other nonpolar tails of other phospholipids in the membrane. 
E)  Parts B and D form the polar head that associates with water, while parts A and C form the nonpolar tail that associates with other nonpolar tails of other phospholipids in the membrane.

Question 17

You are working in a lab that is studying cell recognition and cell attachment in a red sponge.You need to culture individual cells in a medium that promotes cell recognition and attachment of isolated cells.Which of the following would you add to the culture medium?

Accepted Answer

A)  Cellulose beads 
B)  Glycolipids 
C)  Glycoproteins from a different species of sponge 
D)  A species-specific polysaccharide 
E)  Complementary binding surfaces 
A)  Cellulose beads 
B)  Glycolipids 
C)  Glycoproteins from a different species of sponge 
D)  A species-specific polysaccharide 
E)  Complementary binding surfaces

Question 18

Refer to the figure and table below.     At low temperatures, cell membranes become quite immobile and solid-like.If the temperature is gradually increased, a membrane undergoes small changes until a large change in fluidity is observed.The midpoint temperature corresponding to this large change is called the melting temperature.The graph shows how a cell membrane's melting temperature (Tm) is measured.The table shows melting temperature data collected from membranes composed of phospholipids containing different fatty acids.Which statement is consistent with these data?

Accepted Answer

A)  Increasing chain length or introducing double bonds into fatty acids in membrane phospholipids increases temperature-dependent membrane fluidity. 
B)  Increasing chain length or omitting double bonds from fatty acids in membrane phospholipids increases temperature-dependent membrane fluidity. 
C)  Decreasing chain length or introducing double bonds into fatty acids in membrane phospholipids increases temperature-dependent membrane fluidity. 
D)  Decreasing chain length of fatty acids in membrane phospholipids increases membrane fluidity, but introducing double bonds has no effect on temperature-dependent membrane fluidity. 
E)  Increasing chain length of fatty acids in membrane phospholipids increases temperature-dependent membrane fluidity, but introducing double bonds has no effect on fluidity. 
A)  Increasing chain length or introducing double bonds into fatty acids in membrane phospholipids increases temperature-dependent membrane fluidity. 
B)  Increasing chain length or omitting double bonds from fatty acids in membrane phospholipids increases temperature-dependent membrane fluidity. 
C)  Decreasing chain length or introducing double bonds into fatty acids in membrane phospholipids increases temperature-dependent membrane fluidity. 
D)  Decreasing chain length of fatty acids in membrane phospholipids increases membrane fluidity, but introducing double bonds has no effect on temperature-dependent membrane fluidity. 
E)  Increasing chain length of fatty acids in membrane phospholipids increases temperature-dependent membrane fluidity, but introducing double bonds has no effect on fluidity.

Question 19

If a red blood cell with an internal salt concentration of about 0.85 percent is placed in a solution that is 4 percent salt,

Accepted Answer

A)  the cell will lose water and shrivel. 
B)  the cell will gain water and burst. 
C)  the turgor pressure in the cell will increase greatly. 
D)  the turgor pressure in the cell will decrease greatly. 
E)  the cell will remain unchanged. 
A)  the cell will lose water and shrivel. 
B)  the cell will gain water and burst. 
C)  the turgor pressure in the cell will increase greatly. 
D)  the turgor pressure in the cell will decrease greatly. 
E)  the cell will remain unchanged.

Question 20

A marathon runner has just arrived in the emergency room with severe dehydration, and the physician must decide which type of solution to pump into his veins: pure water, 0.9 percent saline, or 1.5 percent saline.Blood cells are approximately 0.9 percent saline.Describe what is likely to happen to the blood cells when they are exposed to each solution.

Accepted Answer

In pure water, the blood cells will take

Exam 6: Cell Membranes

Cells secrete materials to the exterior environment through the process of

An important difference between phagocytosis and receptor-mediated endocytosis is that

Plants depend on their cell walls to limit the amount of water entering their cells and maintain _______, which helps keep plants upright.

In animals, the solute balance of the plasma surrounding blood cells must be carefully maintained so that the blood cells are not affected by changes in fluid or solute balance.If the plasma becomes hypotonic compared with the blood cells, what will be the effect?

Receptor-mediated endocytosis is the mechanism for the import of

For each molecule of ATP consumed during active transport of sodium and potassium, there is an import of _______ ion(s) and an export of _______ ion(s).

Which analogy could best be used to describe the molecular structures interacting at the point of attachment between two animal cells physically bound to one another?

Regardless of the specific type of molecule or particle being transported, endocytosis always involves

If tight junctions were replaced by desmosomes in cells lining the bladder,

The main difference between osmosis and diffusion is that

Facilitated diffusion and active transport both

Cells can move substances from their cytoplasms into the external environment via

White blood cells can defend the body against invaders through

A researcher studying a line of mouse skin cells has identified an oligosaccharide group attached to the cells' surfaces.What experiment should the researcher perform to test whether this oligosaccharide is important in cell-cell recognition?

Refer to the figure below. Which statement about the lipid bilayer shown in the figure is false?

Refer to the figure below showing the structure of a phospholipid molecule. Which statement explains how this molecule is involved in the makeup of a cell membrane?

You are working in a lab that is studying cell recognition and cell attachment in a red sponge.You need to culture individual cells in a medium that promotes cell recognition and attachment of isolated cells.Which of the following would you add to the culture medium?

If a red blood cell with an internal salt concentration of about 0.85 percent is placed in a solution that is 4 percent salt,

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For each molecule of ATP consumed during active transport of sodium and potassium, there is an import of _ ion(s) and an export of _ ion(s).