Question 1

Phosphatides may contain glycerol in ester linkage to two fatty acids, and in phosphodiester linkage with which of the following alcohols?

Accepted Answer

A)   choline, serine, ethanolamine
B)   choline, sphingosine, serine
C)   serine, cholesterol, choline
D)   All of the above.
E)   None of the above.F) A) and E)
G) D) and E)

Question 2

To what superfamily of transporters do the P-glycoproteins belong?

Accepted Answer

A)   ABC (ATP-binding cassette) 
B)   Calmodulin-associated
C)   Glyceroaquaporins
D)   Ionophores
E)   Secondary activeF) B) and D)
G) D) and E)

Question 3

The observation that plasma membrane components mix after fusion of two different cells provides evidence for

Accepted Answer

A)   bilayer structure of biological membranes.
B)   lateral mobility of membrane proteins.
C)   relative asymmetry of membrane lipids.
D)   rotational movement of membrane proteins.
E)   transbilayer movement of membrane lipids.F) B) and D)
G) A) and C)

Question 4

A new transport protein is found to undergo a cycle of phosphorylation-dephosphorylation during the movement of selenium ion into cells. To which of the following would you expect the sequence of this protein to be related ?

Accepted Answer

A)   the anion transport protein
B)   the Ca2+- ATPase
C)   the glucose transport protein
D)   an amino acid cotransporter
E)   the mitochondrial coupling factorF) B) and C)
G) A) and B)

Question 5

A structural feature common to all membrane forming lipids is

Accepted Answer

A)   charged groups.
B)   fatty acyl groups.
C)   hydroxyl groups.
D)   amphipathic character.
E)   detergent property.F) C) and E)
G) All of the above

Question 6

Chloride transport through the CFTR protein is

Accepted Answer

A)   gated by the binding of guanine nucleotides.
B)   linked to a cotransport (antiport)  of phosphate.
C)   localized to the endoplasmic reticulum of normal epithelial cells.
D)   regulated by phosphorylation and dephosphorylation of Ser residues.E) None of the above
F) A) and B)

Question 7

In biological membranes the PREDOMINANT interaction between the proteins and phospholipids is probably

Accepted Answer

A)   hydrogen bonding.
B)   hydrophobic interaction.
C)   ionic interactions.
D)   covalent linkages.E) A) and C)
F) A) and B)

Question 8

The movement of glucose across the erythrocyte membrane is an example of

Accepted Answer

A)   non-mediated transport.
B)   passive mediated transport.
C)   direct active mediated transport.
D)   indirect active mediated transport.
E)   altered molecule mediated transport (group translocation) .F) A) and C)
G) B) and D)

Question 9

Which of the following characteristics is typical of the fluid Mosaic model of membrane structure?

Accepted Answer

A)   The proteins are all spread in a sheet over the surface of the lipid bilayer.
B)   The proteins are all attached as spherical molecules to the surface of the membrane.
C)   Some proteins have polypeptides consisting predominantly of nonpolar residues in the interior of the membrane.
D)   All proteins are loosely attached to the exterior and interior surfaces of the lipid bilayer.
E)   None of the above is true.F) A) and B)
G) None of the above

Question 10

The lateral diffusion of an integral membrane protein is

Accepted Answer

A)   decreased by interactions with peripheral proteins.
B)   increased as the fatty acyl residues of membrane phospholipids become more saturated.
C)   decreased relative to that of a phospholipid because of the large difference in molecular size.
D)   increased as a consequence of fluorescence recovery after photobleaching.E) A) and B)
F) A) and C)

Question 11

The major lipid class found in mammalian membranes is

Accepted Answer

A)   cholesterol.
B)   cholesteryl esters.
C)   phospholipids.
D)   sphingolipids.
E)   triacylglycerols.F) All of the above
G) A) and B)

Question 12

Phosphorylation of the Na+ - K+ ATPase promotes a conformational change in which:

Accepted Answer

A)   The phosphorylated conformation has a low binding affinity for Na+.
B)   The phosphorylated conformation has a high binding affinity for K+.
C)   Both
D)   NeitherE) B) and C)
F) B) and D)

Question 13

Which one of the following membranes contains the highest percentage of lipid?

Accepted Answer

A)   Endoplasmic reticulum
B)   Erythrocyte plasma membrane
C)   Myelin sheath
D)   Inner mitochondrial membrane
E)   Outer mitochondrial membraneF) B) and E)
G) C) and D)

Question 14

Cholesterol, phosphatidylserine, and palmitate have in common

Accepted Answer

A)   a phosphate group.
B)   a hydrophobic unit.
C)   an acyl chain.
D)   a carboxylate group.
E)   a free hydroxyl group.F) None of the above
G) C) and E)

Question 15

Membranes will have their greatest fluidity when which one of the following is present in the phospholipids?

Accepted Answer

A)   palmitic acid
B)   stearic acid
C)   arachidonic acid
D)   linoleic acid
E)   oleic acidF) All of the above
G) A) and E)

Question 16

A membrane lipid which is found covalently attached to certain proteins, and anchors the protein to the lipid bilayer is

Accepted Answer

A)   sphingomyelin
B)   cholesterol
C)   phosphatidyl inositol
D)   phosphatidyl choline
E)   cerebrosideF) B) and E)
G) A) and E)

Question 17

Bilayer-forming glycerophospholipids

Accepted Answer

A)   are found exclusively in the plasma membrane.
B)   exhibit rapid transverse diffusion across the membrane.
C)   have two fatty acyl groups.
D)   rarely participate in non-covalent bonds with proteins.
E)   readily assemble in water into micelles.F) D) and E)
G) A) and D)

Question 18

The protein that is defective in cystic fibrosis normally functions as

Accepted Answer

A)   a chloride transporter protein.
B)   a G-protein.
C)   a receptor for insulin.
D)   a sodium, potassium ATPase.
E)   an endoplasmic reticulum calcium pump.F) A) and B)
G) A) and C)

Question 19

Differences in bilayer fluidity among human cell membranes are due to

Accepted Answer

A)   changes in membrane potential resulting from ATP-driven ion pumps.
B)   fluctuations in body temperature.
C)   interactions between phosphatidylethanolamine and divalent cations.
D)   the level of monoacylglycerol.
E)   the ratio of cholesterol to phospholipids.F) All of the above
G) D) and E)

Question 20

Which of the following pairs of compounds are components of a phospholipid?

Accepted Answer

A)   CDP and inositol
B)   monoglyceride and choline
C)   phosphatidic acid and CDP
D)   phosphatidic acid and ethanolamine
E)   sphingosine and lecithinF) A) and C)
G) A) and E)

Exam 12: Biological Membranes: Structure and Membrane Transport

Which one of the following membranes contains the highest percentage of lipid?

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The observation that plasma membrane components mix after fusion of two different cells provides evidence for

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Which of the following characteristics is typical of the fluid Mosaic model of membrane structure?

Correct AnswerverifiedShow Answer

A membrane lipid which is found covalently attached to certain proteins, and anchors the protein to the lipid bilayer is

Correct AnswerverifiedShow Answer

Phosphorylation of the Na+ - K+ ATPase promotes a conformational change in which:

Correct AnswerverifiedShow Answer

The lateral diffusion of an integral membrane protein is

Correct AnswerverifiedShow Answer

The major lipid class found in mammalian membranes is

Correct AnswerverifiedShow Answer

Phosphatides may contain glycerol in ester linkage to two fatty acids, and in phosphodiester linkage with which of the following alcohols?

Correct AnswerverifiedShow Answer

Cholesterol, phosphatidylserine, and palmitate have in common

Correct AnswerverifiedShow Answer

To what superfamily of transporters do the P-glycoproteins belong?

Correct AnswerverifiedShow Answer

Differences in bilayer fluidity among human cell membranes are due to

Correct AnswerverifiedShow Answer

The movement of glucose across the erythrocyte membrane is an example of

Correct AnswerverifiedShow Answer

Chloride transport through the CFTR protein is

Correct AnswerverifiedShow Answer

The protein that is defective in cystic fibrosis normally functions as

Correct AnswerverifiedShow Answer

In biological membranes the PREDOMINANT interaction between the proteins and phospholipids is probably

Correct AnswerverifiedShow Answer

Bilayer-forming glycerophospholipids

Correct AnswerverifiedShow Answer

Membranes will have their greatest fluidity when which one of the following is present in the phospholipids?

Correct AnswerverifiedShow Answer

A structural feature common to all membrane forming lipids is

Correct AnswerverifiedShow Answer

A new transport protein is found to undergo a cycle of phosphorylation-dephosphorylation during the movement of selenium ion into cells. To which of the following would you expect the sequence of this protein to be related ?

Correct AnswerverifiedShow Answer

Which of the following pairs of compounds are components of a phospholipid?

Correct AnswerverifiedShow Answer

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Phosphorylation of the Na⁺ - K⁺ ATPase promotes a conformational change in which:

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