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CAMPBELL
BIOLOGY
TENTH
EDITION
Reece • Urry • Cain • Wasserman • Minorsky • Jackson
7
Membrane
Structure and
Function
Clicker Questions by
Scott Meissner
© 2014 Pearson Education, Inc.
Which of the following best describes the structure of a biological
membrane?
a) two layers of phospholipids with proteins embedded
between the two layers
b) a mixture of covalently linked phospholipids and proteins
that determines which solutes can cross the membrane
and which cannot
c)
two layers of phospholipids with proteins either spanning
the layers or on the surface of the layers
d) a fluid structure in which phospholipids and proteins move
freely between sides of the membrane
e) two layers of phospholipids (with opposite orientations of
the phospholipids in each layer) with each layer covered
on the outside with proteins
© 2014 Pearson Education, Inc.
Which of the following best describes the structure of a biological
membrane?
a) two layers of phospholipids with proteins embedded
between the two layers
b) a mixture of covalently linked phospholipids and proteins
that determines which solutes can cross the membrane
and which cannot
c) two layers of phospholipids with proteins either spanning
the layers or on the surface of the layers
d) a fluid structure in which phospholipids and proteins move
freely between sides of the membrane
e) two layers of phospholipids (with opposite orientations of
the phospholipids in each layer) with each layer covered
on the outside with proteins
© 2014 Pearson Education, Inc.
Which of the following statements about osmosis is correct?
a) If a cell is placed in an isotonic solution, more water will
enter the cell than leaves the cell.
b) Osmotic movement of water into a cell would likely occur
if the cell accumulates water from its environment.
c)
The presence of aquaporins (proteins that form water
channels in the membrane) should speed up the process
of osmosis.
d) If a solution outside the cell is hypertonic compared to the
cytoplasm, water will move into the cell by osmosis.
e) Osmosis is the diffusion of water from a region of lower water
concentration to a region of higher water concentration.
© 2014 Pearson Education, Inc.
Which of the following statements about osmosis is correct?
a) If a cell is placed in an isotonic solution, more water will
enter the cell than leaves the cell.
b) Osmotic movement of water into a cell would likely occur
if the cell accumulates water from its environment.
c) The presence of aquaporins (proteins that form water
channels in the membrane) should speed up the process
of osmosis.
d) If a solution outside the cell is hypertonic compared to the
cytoplasm, water will move into the cell by osmosis.
e) Osmosis is the diffusion of water from a region of lower water
concentration to a region of higher water concentration.
© 2014 Pearson Education, Inc.
Which of the following amino acids would most likely be
present in the outer side of a transmembrane domain of
an integral membrane protein?
a) a charged amino acid like lysine
b) a polar amino acid like serine
c) a special amino acid like glycine or proline
d) a hydrophobic amino acid like valine
e) any of the above, with no preference
© 2014 Pearson Education, Inc.
Which of the following amino acids would most likely be
present in the outer side of a transmembrane domain of
an integral membrane protein?
a) a charged amino acid like lysine
b) a polar amino acid like serine
c) a special amino acid like glycine or proline
d) a hydrophobic amino acid like valine
e) any of the above, with no preference
© 2014 Pearson Education, Inc.
Which of the following molecules will diffuse most
quickly across a lipid bilayer membrane? [Hint: Which
one has a nonpolar covalent bond that leads to no
partial charge on the atoms?]
a) H2O
b) O2
c) H2PO4
d) glucose
e) Na
© 2014 Pearson Education, Inc.
Which of the following molecules will diffuse most
quickly across a lipid bilayer membrane? [Hint: Which
one has a nonpolar covalent bond that leads to no
partial charge on the atoms?]
a) H2O
b) O2
c) H2PO4
d) glucose
e) Na
© 2014 Pearson Education, Inc.
Cells (e.g., bacteria) are taken up by other cells (e.g.,
an immune cell) by which of the following?
a) pinocytosis
b) exocytosis
c) receptor-mediated endocytosis
d) phagocytosis
e) facilitated diffusion
© 2014 Pearson Education, Inc.
Cells (e.g., bacteria) are taken up by other cells (e.g.,
an immune cell) by which of the following?
a) pinocytosis
b) exocytosis
c) receptor-mediated endocytosis
d) phagocytosis
e) facilitated diffusion
© 2014 Pearson Education, Inc.
Consider the amino acids along the  helices of a
membrane spanning protein (see figure). Those facing the
fatty acid chains would be expected to be _____, while
those facing the inner pore would often be ______.
a) acidic; basic
b) hydrophilic;
hydrophobic
c) aromatic; acidic
d) hydrophobic;
hydrophilic
e) cysteines;
glycines
© 2014 Pearson Education, Inc.
Consider the amino acids along the  helices of a
membrane spanning protein (see figure). Those facing the
fatty acid chains would be expected to be _____, while
those facing the inner pore would often be ______.
a) acidic; basic
b) hydrophilic;
hydrophobic
c) aromatic; acidic
d) hydrophobic;
hydrophilic
e) cysteines;
glycines
© 2014 Pearson Education, Inc.
Based on the current model of the membrane, which
statement is incorrect?
a) Glycoproteins tend to have oligosaccharides on their
outward facing side.
b) Transmembrane proteins often bind with cytosolic
proteins, but not with extracellular molecules.
c) The combinations of phospholipids in the two faces
of the membrane often differ.
d) Phospholipids tend to move faster laterally along the
membrane than do the proteins.
e) Some transmembrane proteins function as active
transport systems.
© 2014 Pearson Education, Inc.
Based on the current model of the membrane, which
statement is incorrect?
a) Glycoproteins tend to have oligosaccharides on their
outward facing side.
b) Transmembrane proteins often bind with cytosolic
proteins, but not with extracellular molecules.
c) The combinations of phospholipids in the two faces
of the membrane often differ.
d) Phospholipids tend to move faster laterally along the
membrane than do the proteins.
e) Some transmembrane proteins function as active
transport systems.
© 2014 Pearson Education, Inc.
Assume that each of the following items experiences a
similar magnitude of energy difference driving their
diffusion across a pure lipid bilayer. If ranked in order
from fastest to slowest, which of the following items
would likely be second in terms of how much of it
crosses the bilayer in a given time?
a) molecular oxygen
b) sucrose
c) insulin
d) glucose
e) water
© 2014 Pearson Education, Inc.
Assume that each of the following items experiences a
similar magnitude of energy difference driving their
diffusion across a pure lipid bilayer. If ranked in order
from fastest to slowest, which of the following items
would likely be second in terms of how much of it
crosses the bilayer in a given time?
a) molecular oxygen
b) sucrose
c) insulin
d) glucose
e) water
© 2014 Pearson Education, Inc.
As shown on the next slide, two solutions with similar solute
concentration are separated by a membrane that allows only
water to pass, and one solution is of greater volume than the
other. Which choice best describes what will happen next?
a) The energy in the pressure gradient will drive water to the
left side, which will cause the solute concentration on the
right side to increase.
b) Water will pass to the right side and increase its volume.
c)
Any water that passes to the left side will create a tension
on the right side, pulling the water back to the right side.
d) The water will flow to the left side, down its pressure gradient,
until the two sides achieve equal height.
e) Since there is no concentration gradient present, there will
be no net movement of water.
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
Two solutions with similar solute concentration are separated by
a membrane that allows only water to pass, and one solution is
of greater volume than the other. Which choice best describes
what will happen next?
a) The energy in the pressure gradient will drive water to the
left side, which will cause the solute concentration on the
right side to increase.
b) Water will pass to the right side and increase its volume.
c)
Any water that passes to the left side will create a tension
on the right side, pulling the water back to the right side.
d) The water will flow to the left side, down its pressure gradient,
until the two sides achieve equal height.
e) Since there is no concentration gradient present, there will
be no net movement of water.
© 2014 Pearson Education, Inc.
One strategy used by many animal species to avoid the
need for their body cells to have either a stiff external cell
wall or active contractile vacuoles is to
a) have membranes that are impermeable to water and
keep it from entering their cells.
b) use aquaporins to actively pump water out through a
hydrophilic pore.
c) keep the concentration of solutes in their cytosol the
same as that found in pond water.
d) maintain a high internal pressure to constantly push
extra water out of cells.
e) carefully regulate the solute concentration of the
extracellular solution to which their cells are exposed.
© 2014 Pearson Education, Inc.
One strategy used by many animal species to avoid the
need for their body cells to have either a stiff external cell
wall or active contractile vacuoles is to
a) have membranes that are impermeable to water and
keep it from entering their cells.
b) use aquaporins to actively pump water out through a
hydrophilic pore.
c) keep the concentration of solutes in their cytosol the
same as that found in pond water.
d) maintain a high internal pressure to constantly push
extra water out of cells.
e) carefully regulate the solute concentration of the
extracellular solution to which their cells are exposed.
© 2014 Pearson Education, Inc.
An artificial liposome, whose membrane contains no
proteins, is loaded with a 0.03 M sucrose solution and put
into pure water (see figure on next slide). Which choice best
describes what will quickly happen next?
a) Since there are no membrane proteins, nothing will
cross the membrane.
b) Sucrose will diffuse out of the liposome.
c) Water will diffuse down its concentration gradient
into the liposome, causing it to burst.
d) Water will enter the liposome, diluting the sucrose
concentration there down to 0 M.
e) The pressure of the surrounding solution will push water
out of the liposome, causing it to shrink over time.
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
An artificial liposome, whose membrane contains no
proteins, is loaded with a 0.03 M sucrose solution and put
into pure water. Which choice best describes what will
quickly happen next?
a) Since there are no membrane proteins, nothing will
cross the membrane.
b) Sucrose will diffuse out of the liposome.
c) Water will diffuse down its concentration gradient
into the liposome, causing it to burst.
d) Water will enter the liposome, diluting the sucrose
concentration there down to 0 M.
e) The pressure of the surrounding solution will push water
out of the liposome, causing it to shrink over time.
© 2014 Pearson Education, Inc.
A correct distinction between facilitated diffusion and active transport
of a substance across a biological membrane is that
a)
active transport requires conformational changes in the
transport protein associated with the transport process,
and facilitated diffusion does not.
b)
active transport requires an integral membrane protein to
carry out the transport, and facilitated diffusion does not.
c)
facilitated diffusion requires a protein lined pore in the
membrane, and active transport does not.
d)
facilitated diffusion depends on an existing energy gradient
acting on the transported substance, while active transport
makes such a gradient.
e)
facilitated diffusion requires cellular energy (often from ATP
hydrolysis), but active transport does not.
© 2014 Pearson Education, Inc.
A correct distinction between facilitated diffusion and active transport
of a substance across a biological membrane is that
a)
active transport requires conformational changes in the
transport protein associated with the transport process,
and facilitated diffusion does not.
b)
active transport requires an integral membrane protein to
carry out the transport, and facilitated diffusion does not.
c)
facilitated diffusion requires a protein lined pore in the
membrane, and active transport does not.
d)
facilitated diffusion depends on an existing energy gradient
acting on the transported substance, while active transport
makes such a gradient.
e)
facilitated diffusion requires cellular energy (often from ATP
hydrolysis), but active transport does not.
© 2014 Pearson Education, Inc.
Consider various transport systems in a hypothetical
cell (see figure). Which one of these systems would
both be a passive system and not alter the membrane
potential through its operation?
a) A
b) B
c) C
d) D
e) E
© 2014 Pearson Education, Inc.
Consider various transport systems in a hypothetical
cell (see figure). Which one of these systems would
both be a passive system and not alter the membrane
potential through its operation?
a) A
b) B
c) C
d) D
e) E
© 2014 Pearson Education, Inc.
In the hypothetical cell with the membrane transport
systems and conditions shown (see figure), which
represents a sodium ion channel, and energy gradients in
what form influence the direction of movement of sodium
ions through this channel?
a) A; concentration gradient
b) B; concentration and
electrical gradients
c) C; concentration gradient
d) D; electrical gradient
e) E; concentration and
electrical gradients
© 2014 Pearson Education, Inc.
In the hypothetical cell with the membrane transport
systems and conditions shown (see figure), which
represents a sodium ion channel, and energy gradients in
what form influence the direction of movement of sodium
ions through this channel?
a) A; concentration gradient
b) B; concentration and
electrical gradients
c) C; concentration gradient
d) D; electrical gradient
e) E; concentration and
electrical gradients
© 2014 Pearson Education, Inc.
Receptor-mediated endocytosis produces vesicles that
a) typically deliver the items they take up to the nucleus of
the cell.
b) carry macromolecules and cells for delivery to the
lysosomal compartment.
c) assist in the removal of certain items from the cytosol
of the cell.
d) when formed cause there to be more total surface area
available in the plasma membrane.
e) have receptors which can indicate at their cytosolic
side if ligands are bound or not on their extracellular/
lumen side.
© 2014 Pearson Education, Inc.
Receptor-mediated endocytosis produces vesicles that
a) typically deliver the items they take up to the nucleus of
the cell.
b) carry macromolecules and cells for delivery to the
lysosomal compartment.
c) assist in the removal of certain items from the cytosol
of the cell.
d) when formed cause there to be more total surface area
available in the plasma membrane.
e) have receptors which can indicate at their cytosolic
side if ligands are bound or not on their extracellular/
lumen side.
© 2014 Pearson Education, Inc.