Question 1

Houseplants adapted to indoor temperatures may die if they are left outdoors, because in a cold environment their

Accepted Answer

A)  DNA cannot function. 
B)  membranes lack adequate fluidity. 
C)  photosynthesis is impaired. 
D)  chloroplasts malfunction. 
E)  membranes need more cholesterol. 
A)  DNA cannot function. 
B)  membranes lack adequate fluidity. 
C)  photosynthesis is impaired. 
D)  chloroplasts malfunction. 
E)  membranes need more cholesterol.

Question 2

Which of the following statements about membrane proteins is false?

Accepted Answer

A)  Hydrophilic regions of integral membrane proteins are in contact with the interior of the bilayer. 
B)  Peripheral membrane proteins may be associated with the phospholipid head groups. 
C)  Integral membrane proteins can move in the plane of the membrane. 
D)  Some membrane proteins may have oligosaccharides attached to them. 
E)  None of the above 
A)  Hydrophilic regions of integral membrane proteins are in contact with the interior of the bilayer. 
B)  Peripheral membrane proteins may be associated with the phospholipid head groups. 
C)  Integral membrane proteins can move in the plane of the membrane. 
D)  Some membrane proteins may have oligosaccharides attached to them. 
E)  None of the above

Question 3

The biochemical reactions of biological membranes are carried out by _______ that may be either in contact with the interior of the bilayer (_______ to the membrane) or arranged on either side of the bilayer (_______ to the membrane).

Accepted Answer

A)  polysaccharides; intrinsic; exterior 
B)  proteins; integral; peripheral 
C)  lipids; integral; attached 
D)  proteins; peripheral; integral 
E)  lipids; integral; peripheral 
A)  polysaccharides; intrinsic; exterior 
B)  proteins; integral; peripheral 
C)  lipids; integral; attached 
D)  proteins; peripheral; integral 
E)  lipids; integral; peripheral

Question 4

A concentration gradient of glucose across a membrane means that

Accepted Answer

A)  there are more moles of glucose on one side of the membrane than on the other. 
B)  glucose molecules are more crowded on one side of the membrane than on the other. 
C)  there is less water on one side of the membrane than on the other. 
D)  the glucose molecules are chemically more tightly bonded on one side than on the other. 
E)  there are more glucose molecules within the membrane than outside the membrane. 
A)  there are more moles of glucose on one side of the membrane than on the other. 
B)  glucose molecules are more crowded on one side of the membrane than on the other. 
C)  there is less water on one side of the membrane than on the other. 
D)  the glucose molecules are chemically more tightly bonded on one side than on the other. 
E)  there are more glucose molecules within the membrane than outside the membrane.

Question 5

Structures that contain networks of keratin fibers and provide mechanical stability to epithelial tissues are called

Accepted Answer

A)  extracellular matrices. 
B)  glycoproteins. 
C)  gap junctions. 
D)  desmosomes. 
E)  phospholipid bilayers. 
A)  extracellular matrices. 
B)  glycoproteins. 
C)  gap junctions. 
D)  desmosomes. 
E)  phospholipid bilayers.

Question 6

Protein movement within a membrane may be restricted by

Accepted Answer

A)  glycolipids and glycoproteins. 
B)  closure of gated channels. 
C)  the cytoskeleton. 
D)  cell adhesion. 
E)  tight junctions and desmosomes. 
A)  glycolipids and glycoproteins. 
B)  closure of gated channels. 
C)  the cytoskeleton. 
D)  cell adhesion. 
E)  tight junctions and desmosomes.

Question 7

Which statement about membrane phospholipids is not true?

Accepted Answer

A)  They associate to form bilayers. 
B)  They have hydrophobic "tails." 
C)  They have hydrophilic "heads." 
D)  They give the membrane fluidity. 
E)  They flip-flop readily from one side of the membrane to the other. 
A)  They associate to form bilayers. 
B)  They have hydrophobic "tails." 
C)  They have hydrophilic "heads." 
D)  They give the membrane fluidity. 
E)  They flip-flop readily from one side of the membrane to the other.

Question 8

Which of the following is not one of the functional roles of membrane proteins?

Accepted Answer

A)  Allowing movement of molecules that otherwise would be excluded by the lipid components of the membrane 
B)  Transferring signals from outside the cell to inside the cell 
C)  Maintaining the shape of the cell 
D)  Facilitating the transport of macromolecules across the membrane 
E)  Stabilizing the lipid bilayer 
A)  Allowing movement of molecules that otherwise would be excluded by the lipid components of the membrane 
B)  Transferring signals from outside the cell to inside the cell 
C)  Maintaining the shape of the cell 
D)  Facilitating the transport of macromolecules across the membrane 
E)  Stabilizing the lipid bilayer

Question 9

Which of the following is not involved in secondary active transport?

Accepted Answer

A)  The direct use of ATP 
B)  Coupling to another transport system 
C)  Use of an existing concentration gradient 
D)  The plasma membrane 
E)  The ability to concentrate the transported molecule 
A)  The direct use of ATP 
B)  Coupling to another transport system 
C)  Use of an existing concentration gradient 
D)  The plasma membrane 
E)  The ability to concentrate the transported molecule

Question 10

Water crosses the plasma membrane at a rate faster than expected for simple diffusion because of

Accepted Answer

A)  the hydration of the ions as they pass through. 
B)  water channels called aquaporins. 
C)  gated channels. 
D)  Both a and b 
E)  All of the above 
A)  the hydration of the ions as they pass through. 
B)  water channels called aquaporins. 
C)  gated channels. 
D)  Both a and b 
E)  All of the above

Question 11

Compare and contrast active and passive transport.

Accepted Answer

The main difference between active and p

Question 12

How does an ion channel exert its specificity for one ion and not another?

Accepted Answer

A)  It is a simple matter of charge and ionic size. 
B)  The ion channel hydrates ions as they pass through. 
C)  The ion channel makes use of aquaporins. 
D)  There are recognition sites in the ion channel. 
E)  The ion lets go of its water and is attracted to a channel pore protein. 
A)  It is a simple matter of charge and ionic size. 
B)  The ion channel hydrates ions as they pass through. 
C)  The ion channel makes use of aquaporins. 
D)  There are recognition sites in the ion channel. 
E)  The ion lets go of its water and is attracted to a channel pore protein.

Question 13

The cells of the intestinal epithelium are linked together in order to prevent substances from passing between them. The type of cell junction linking these cells is called a _______.

Accepted Answer

The answer of The cells of the intestinal epithelium are...

Question 14

The speed and direction of ions as they move into and out of the cell are determined by the

Accepted Answer

A)  ability of the ion to let go of its water. 
B)  concentration gradient and electrochemical imbalances. 
C)  number of channel proteins present. 
D)  size and charge of the ion. 
E)  presence of specific stimuli to open gated channel proteins. 
A)  ability of the ion to let go of its water. 
B)  concentration gradient and electrochemical imbalances. 
C)  number of channel proteins present. 
D)  size and charge of the ion. 
E)  presence of specific stimuli to open gated channel proteins.

Question 15

A comparison of the properties of the plasma membrane to those of the membrane of lysosomes would reveal that

Accepted Answer

A)  only the plasma membrane has a lipid bilayer. 
B)  the two membranes contain the same proteins. 
C)  the two membranes have the same lipids. 
D)  all of the proteins in the two membranes are extrinsic to the membrane. 
E)  the two membranes have different proteins and lipids. 
A)  only the plasma membrane has a lipid bilayer. 
B)  the two membranes contain the same proteins. 
C)  the two membranes have the same lipids. 
D)  all of the proteins in the two membranes are extrinsic to the membrane. 
E)  the two membranes have different proteins and lipids.

Question 16

A group of transmembrane proteins involved in maintaining cell structure via their interactions with the cytoskeletion are being studied to determine their role in the spread of cancer. These proteins are known as

Accepted Answer

A)  integrins. 
B)  desmosomes. 
C)  seal tissues. 
D)  connexins. 
E)  keratins. 
A)  integrins. 
B)  desmosomes. 
C)  seal tissues. 
D)  connexins. 
E)  keratins.

Exam 6: Cell Membranes

Houseplants adapted to indoor temperatures may die if they are left outdoors, because in a cold environment their

Which of the following statements about membrane proteins is false?

The biochemical reactions of biological membranes are carried out by _______ that may be either in contact with the interior of the bilayer (_______ to the membrane) or arranged on either side of the bilayer (_______ to the membrane).

A concentration gradient of glucose across a membrane means that

Structures that contain networks of keratin fibers and provide mechanical stability to epithelial tissues are called

Protein movement within a membrane may be restricted by

Which statement about membrane phospholipids is not true?

Which of the following is not one of the functional roles of membrane proteins?

Which of the following is not involved in secondary active transport?

Water crosses the plasma membrane at a rate faster than expected for simple diffusion because of

Compare and contrast active and passive transport.

How does an ion channel exert its specificity for one ion and not another?

The cells of the intestinal epithelium are linked together in order to prevent substances from passing between them. The type of cell junction linking these cells is called a _______.

The speed and direction of ions as they move into and out of the cell are determined by the

A comparison of the properties of the plasma membrane to those of the membrane of lysosomes would reveal that

A group of transmembrane proteins involved in maintaining cell structure via their interactions with the cytoskeletion are being studied to determine their role in the spread of cancer. These proteins are known as

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The biochemical reactions of biological membranes are carried out by ___ that may be either in contact with the interior of the bilayer (_ to the membrane) or arranged on either side of the bilayer (_____ to the membrane).