Question 1

Diffusion is the movement of a molecule from an area of high to low concentration.

Accepted Answer

A) True 
 B)False

Question 2

In order to study a cell at lower temperatures,a researcher must artificially increase its membrane fluidity.What would be a reasonable strategy for increasing plasma membrane fluidity at low temperatures?

Accepted Answer

A)  Decrease the composition of cholesterol in the plasma membrane
B)  Increase the composition of phospholipids with saturated fatty acid chains
C)  Decrease the composition of phospholipids with unsaturated fatty acid chains
D)  Decrease the length of the phospholipid fatty acyl tail.
E)  All of the above strategies are reasonableF) A) and D)
G) A) and E)

Question 3

The release of the protein insulin from pancreatic cells occurs by

Accepted Answer

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

Question 4

One can inject dyes of different sizes into a liver cell and determine those molecules that can readily pass through gap junctions.What sized molecules can pass through gap junctions?

Accepted Answer

A)  
B)  >10,000 Daltons
C)  >1,000 Daltons,but 
D)  >5,000 Daltons,but 
E)  >1,500 Daltons,but F) B) and C)
G) A) and B)

Question 5

Water diffuses through certain organs such as the kidneys and bladder much faster than would occur by passive diffusion through a lipid bilayer alone.What accounts for this more rapid rate of water transport in these organs?

Accepted Answer

A)  The composition of lipids changes to promote water transport.
B)  Presence of aquaporin channels for facilitated diffusion of water.
C)  Presence of a water pump.
D)  Presence of an ATP-driven enzyme for water transport.
E)  The presence of molecules that bind water and change its membrane permeability properties.F) A) and B)
G) A) and C)

Question 6

Ion gradients across the membrane drive numerous cellular functions.

Accepted Answer

A) True 
 B)False

Question 7

Scientists unearth a Wooly Mammoth from the Siberian Ice Sheath and discover that a eukaryotic "amoeba"-like cell is still alive.Which component of the cell membrane might contribute to maintaining the fluidity of plasma membranes under freezing conditions?

Accepted Answer

A)  Peripheral proteins
B)  High levels of long fatty acyl tails within the lipid bilayer
C)  High levels of unsaturated fatty acyl tails within the lipid bilayer
D)  Absence of cholesterol
E)  High levels of saturated fatty acyl tails within the lipid bilayerF) B) and E)
G) B) and D)

Question 8

What process best characterizes Ca2+ movement from the cytosol (low Ca2+ concentration) into the endoplasmic reticulum (high Ca2+ concentration) ?

Accepted Answer

A)  Calcium movement is spontaneous.
B)  Calcium movement involves active transport.
C)  Calcium movement occurs by facilitated diffusion using a transporter protein.
D)  Calcium movement does not require energy.
E)  Calcium movement occurs by passive diffusion.F) C) and E)
G) A) and B)

Question 9

The process that most involves the selective uptake of a specific cargo molecule into the cell through receptor binding and aggregation is

Accepted Answer

A)  pinocytosis.
B)  receptor-mediated endocytosis.
C)  autophagocytosis.
D)  phagocytosis.
E)  receptor-mediated exocytosis.F) A) and D)
G) All of the above

Question 10

Cell surface molecules are labeled with a fluorescent tag and then a portion of them are bleached with a laser beam.What would one observe after the cell is incubated for a few minutes?

Accepted Answer

A)  The bleached molecules would disappear into the cell.
B)  The bleached molecules would diffuse laterally through the membrane and intermix with unbleached molecules.
C)  The bleached molecules would remain in the spot where bleaching occurred.
D)  All the bleached molecules would flip-flop across the cell membrane.
E)  The bleached molecules would be released from the cell.F) C) and D)
G) None of the above

Exam 5: Membrane Structure, Transport, and Cell Junctions

Scientists unearth a Wooly Mammoth from the Siberian Ice Sheath and discover that a eukaryotic "amoeba"-like cell is still alive.Which component of the cell membrane might contribute to maintaining the fluidity of plasma membranes under freezing conditions?

Correct Answer
verified

Water diffuses through certain organs such as the kidneys and bladder much faster than would occur by passive diffusion through a lipid bilayer alone.What accounts for this more rapid rate of water transport in these organs?

Correct Answer
verified

One can inject dyes of different sizes into a liver cell and determine those molecules that can readily pass through gap junctions.What sized molecules can pass through gap junctions?

Correct Answer
verified

Diffusion is the movement of a molecule from an area of high to low concentration.

Correct Answer
verified

What process best characterizes Ca²⁺ movement from the cytosol (low Ca²⁺ concentration) into the endoplasmic reticulum (high Ca²⁺ concentration) ?

Correct Answer
verified

Ion gradients across the membrane drive numerous cellular functions.

Correct Answer
verified

The release of the protein insulin from pancreatic cells occurs by

Correct Answer
verified

Cell surface molecules are labeled with a fluorescent tag and then a portion of them are bleached with a laser beam.What would one observe after the cell is incubated for a few minutes?

Correct Answer
verified

The process that most involves the selective uptake of a specific cargo molecule into the cell through receptor binding and aggregation is

Correct Answer
verified

In order to study a cell at lower temperatures,a researcher must artificially increase its membrane fluidity.What would be a reasonable strategy for increasing plasma membrane fluidity at low temperatures?

Correct Answer
verified

Exam 5: Membrane Structure, Transport, and Cell Junctions

Scientists unearth a Wooly Mammoth from the Siberian Ice Sheath and discover that a eukaryotic "amoeba"-like cell is still alive.Which component of the cell membrane might contribute to maintaining the fluidity of plasma membranes under freezing conditions?

Correct AnswerverifiedShow Answer

Water diffuses through certain organs such as the kidneys and bladder much faster than would occur by passive diffusion through a lipid bilayer alone.What accounts for this more rapid rate of water transport in these organs?

Correct AnswerverifiedShow Answer

One can inject dyes of different sizes into a liver cell and determine those molecules that can readily pass through gap junctions.What sized molecules can pass through gap junctions?

Correct AnswerverifiedShow Answer

Diffusion is the movement of a molecule from an area of high to low concentration.

Correct AnswerverifiedShow Answer

What process best characterizes Ca2+ movement from the cytosol (low Ca2+ concentration) into the endoplasmic reticulum (high Ca2+ concentration) ?

Correct AnswerverifiedShow Answer

Ion gradients across the membrane drive numerous cellular functions.

Correct AnswerverifiedShow Answer

The release of the protein insulin from pancreatic cells occurs by

Correct AnswerverifiedShow Answer

Cell surface molecules are labeled with a fluorescent tag and then a portion of them are bleached with a laser beam.What would one observe after the cell is incubated for a few minutes?

Correct AnswerverifiedShow Answer

The process that most involves the selective uptake of a specific cargo molecule into the cell through receptor binding and aggregation is

Correct AnswerverifiedShow Answer

In order to study a cell at lower temperatures,a researcher must artificially increase its membrane fluidity.What would be a reasonable strategy for increasing plasma membrane fluidity at low temperatures?

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

What process best characterizes Ca²⁺ movement from the cytosol (low Ca²⁺ concentration) into the endoplasmic reticulum (high Ca²⁺ concentration) ?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified