Question 1

Describe a hydropathy plot for a hypothetical integral membrane protein with 3 transmembrane segments and containing 190 amino acids.

Accepted Answer

A hydropathy plot is a graph that shows ...

Question 2

Which structure describes an integral membrane protein containing a  β\betaβ barrel?

Accepted Answer

A)   maltoporin
B)   aquaporin
C)   E. coli OmpF
D)   both maltoporin and E. coli OmpF
E)   both maltoporin and aquaporin

Question 3

Which statement is TRUE for passive transport across a biological membrane?

Accepted Answer

A)   Passive transport is driven by a solute electrochemical gradient.
B)   Passive transport is driven by ATP.
C)   Passive transport is irreversible.
D)   Passive transport is driven by both a solute electrochemical gradient ATP.
E)   Passive transport is driven by a solute electrochemical gradient and is irreversible.

Question 4

An integral membrane protein can be extracted with:

Accepted Answer

A)   a buffer of alkaline or acid pH.
B)   a chelating agent that removes divalent cations.
C)   a solution containing detergent.
D)   a solution of high ionic strength.
E)   hot water.

Question 5

Which transporter will move lipids from the cytosolic leaflet to the outer leaflet of a plasma membrane?

Accepted Answer

A)   a flippase
B)   a floppase
C)   a scramblase
D)   both a flippase and a floppase
E)   both a floppase and a scramblase

Question 6

Describe two different ways a plant can adjust the components of its cell membranes to keep them as fluid as possible on a cold winter morning.

Accepted Answer

One way a plant can adjust the component...

Question 7

Which statement is TRUE concerning the chloride-bicarbonate exchanger?

Accepted Answer

A)   This transporter is electrogenic.
B)   The exchanger is a passive antiporter.
C)   This protein is involved in carbon dioxide transport in the blood stream.
D)   The exchanger is a passive antiporter, and this protein is involved in carbon dioxide transport in the blood stream.
E)   This transporter is electrogenic, and the exchanger is a passive antiporter.

Question 8

Which statement is NOT true about the chloride-bicarbonate exchanger (AE) ?

Accepted Answer

A)   The AE protein increases the rate of bicarbonate transport across the membrane.
B)   The AE protein uses ATP as an energy source to drive bicarbonate transport.
C)   The AE protein transports chloride ions across the membrane.
D)   The AE protein is classified as an anti-porter.
E)   The AE protein spans the membrane at least 12 times.

Question 9

The inner (plasma)  membrane of E. coli is about 75% lipid and 25% protein by weight. How many molecules of membrane lipid are there for each molecule of protein? (Assume that the average protein is Mr 50,000 and the average lipid is 750.)

Accepted Answer

A)   1
B)   50
C)   200
D)   10,000
E)   50,000

Question 10

Which statement about the composition of membranes is TRUE?

Accepted Answer

A)   All biological membranes contain cholesterol.
B)   Free fatty acids are major components of all membranes.
C)   The inner and outer membranes of mitochondria have different protein compositions.
D)   The lipid composition of all membranes of eukaryotic cells is essentially the same.
E)   The lipid:protein ratio varies from about 1:4 to 4:1.

Question 11

Which transporter will move lipids from the outer leaflet to the cytosolic leaflet of a plasma membrane?

Accepted Answer

A)   a flippase
B)   a floppase
C)   a scramblase
D)   both a flippase and a floppase
E)   both a flippase and a scramblase

Question 12

Which enzymes are NOT involved in moving phospholipids from one leaflet to another?

Accepted Answer

A)   flippases that move phosphatidylethanolamine and phosphatidylserine
B)   floppases that move phospholipids from the cytosolic leaflet to the extracellular leaflet
C)   flip-floppases that allow phospholipids to move back and forth between the inner and outer leaflets
D)   scramblases that allow phospholipids to move down their concentration gradient
E)   phosphatidylinositol transfer proteins that play a role in lipid signaling

Question 13

The bacterium E. coli can grow at 20 °C or at 40 °C. At which growth temperature would you expect the membrane phospholipids to have a higher ratio of saturated to unsaturated fatty acids, and why?

Accepted Answer

At 20 °C, you would expect the membrane ...

Question 14

Integrins are:

Accepted Answer

A)   membrane proteins that are involved in ion transport.
B)   membrane proteins that are involved in sugar transport.
C)   membrane proteins that mediate cell adhesion.
D)   proteins of the extracellular matrix that bind to cell surface proteins.
E)   proteins that are found at the membrane-cytoplasm interface.

Question 15

Which statement is generally TRUE of integral membrane proteins?

Accepted Answer

A)   The secondary structure in the transmembrane region consists solely of  α\alphaα  helices or  β\betaβ sheets.
B)   The domains that protrude on the cytoplasmic face of the plasma membrane nearly always have covalently attached oligosaccharides.
C)   They are unusually susceptible to degradation by trypsin.
D)   They can be removed from the membrane with high salt or mild denaturing agents.
E)   They undergo constant rotational motion that moves a given domain from the outer face of a membrane to the inner face and then back to the outer.

Question 16

Which process does NOT require a protein facilitator?

Accepted Answer

A)   simple diffusion
B)   ionophore-mediated diffusion
C)   a primary active uniport
D)   a passive antiporter
E)   both simple diffusion and ionophore-mediated diffusion

Question 17

(a) What kinds of forces or bonds anchor an integral membrane protein in a biological membrane? (b) What forces hold a peripheral membrane protein to the membrane? (c) What might one do to solubilize each of the two types of membrane proteins?

Accepted Answer

(a) Integral membrane proteins are ancho...

Question 18

A protein is found to extend all the way through the membrane of a cell. Describe this protein in terms of the location of particular types of amino acid side chains in its structure and its ability to move within the membrane.

Accepted Answer

The protein that extends all the way thr...

Question 19

A plant breeder has developed a new frost-resistant variety of tomato that contains higher levels of unsaturated fatty acids in membrane lipids than those found in standard tomato varieties. However, when temperatures climb above 95 °F, this frost-resistant variety dies, whereas the standard variety continues to grow. Provide a likely explanation of the biochemical basis of increased tolerance to cold and increased susceptibility to heat of this new tomato variety.

Accepted Answer

The likely explanation for the biochemic...

Question 20

What are the similarities and differences between integrins, cadherins, and selectins?

Accepted Answer

Integrins, cadherins, and selectins are ...

Exam 11: Biological Membranes and Transport

Which statement is TRUE concerning the chloride-bicarbonate exchanger?

Correct Answer
verified

Which transporter will move lipids from the cytosolic leaflet to the outer leaflet of a plasma membrane?

Correct Answer
verified

Which statement about the composition of membranes is TRUE?

Correct Answer
verified

Which statement is generally TRUE of integral membrane proteins?

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
The likely explanation for the biochemic...
View Answer

Integrins are:

Correct Answer
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Which process does NOT require a protein facilitator?

Correct Answer
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(a) What kinds of forces or bonds anchor an integral membrane protein in a biological membrane? (b) What forces hold a peripheral membrane protein to the membrane? (c) What might one do to solubilize each of the two types of membrane proteins?

Correct Answer
Answered by ExamLex AI
(a) Integral membrane proteins are ancho...
View Answer

Which enzymes are NOT involved in moving phospholipids from one leaflet to another?

Correct Answer
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Which structure describes an integral membrane protein containing a $\beta$ barrel?

Correct Answer
verified

Describe two different ways a plant can adjust the components of its cell membranes to keep them as fluid as possible on a cold winter morning.

Correct Answer
Answered by ExamLex AI
One way a plant can adjust the component...
View Answer

Which transporter will move lipids from the outer leaflet to the cytosolic leaflet of a plasma membrane?

Correct Answer
verified

Which statement is NOT true about the chloride-bicarbonate exchanger (AE) ?

Correct Answer
verified

Describe a hydropathy plot for a hypothetical integral membrane protein with 3 transmembrane segments and containing 190 amino acids.

Correct Answer
Answered by ExamLex AI
A hydropathy plot is a graph that shows ...
View Answer

Which statement is TRUE for passive transport across a biological membrane?

Correct Answer
verified

An integral membrane protein can be extracted with:

Correct Answer
verified

A protein is found to extend all the way through the membrane of a cell. Describe this protein in terms of the location of particular types of amino acid side chains in its structure and its ability to move within the membrane.

Correct Answer
Answered by ExamLex AI
The protein that extends all the way thr...
View Answer

What are the similarities and differences between integrins, cadherins, and selectins?

Correct Answer
Answered by ExamLex AI
Integrins, cadherins, and selectins are ...
View Answer

The bacterium E. coli can grow at 20 °C or at 40 °C. At which growth temperature would you expect the membrane phospholipids to have a higher ratio of saturated to unsaturated fatty acids, and why?

Correct Answer
Answered by ExamLex AI
At 20 °C, you would expect the membrane ...
View Answer

The inner (plasma) membrane of E. coli is about 75% lipid and 25% protein by weight. How many molecules of membrane lipid are there for each molecule of protein? (Assume that the average protein is M_r 50,000 and the average lipid is 750.)

Correct Answer
verified

Exam 11: Biological Membranes and Transport

Which statement is TRUE concerning the chloride-bicarbonate exchanger?

Correct AnswerverifiedShow Answer

Which transporter will move lipids from the cytosolic leaflet to the outer leaflet of a plasma membrane?

Correct AnswerverifiedShow Answer

Which statement about the composition of membranes is TRUE?

Correct AnswerverifiedShow Answer

Which statement is generally TRUE of integral membrane proteins?

Correct AnswerverifiedShow Answer

Correct AnswerAnswered by ExamLex AIThe likely explanation for the biochemic...View AnswerShow Answer

Integrins are:

Correct AnswerverifiedShow Answer

Which process does NOT require a protein facilitator?

Correct AnswerverifiedShow Answer

(a) What kinds of forces or bonds anchor an integral membrane protein in a biological membrane? (b) What forces hold a peripheral membrane protein to the membrane? (c) What might one do to solubilize each of the two types of membrane proteins?

Correct AnswerAnswered by ExamLex AI(a) Integral membrane proteins are ancho...View AnswerShow Answer

Which enzymes are NOT involved in moving phospholipids from one leaflet to another?

Correct AnswerverifiedShow Answer

Which structure describes an integral membrane protein containing a β\betaβ barrel?

Correct AnswerverifiedShow Answer

Describe two different ways a plant can adjust the components of its cell membranes to keep them as fluid as possible on a cold winter morning.

Correct AnswerAnswered by ExamLex AIOne way a plant can adjust the component...View AnswerShow Answer

Which transporter will move lipids from the outer leaflet to the cytosolic leaflet of a plasma membrane?

Correct AnswerverifiedShow Answer

Which statement is NOT true about the chloride-bicarbonate exchanger (AE) ?

Correct AnswerverifiedShow Answer

Describe a hydropathy plot for a hypothetical integral membrane protein with 3 transmembrane segments and containing 190 amino acids.

Correct AnswerAnswered by ExamLex AIA hydropathy plot is a graph that shows ...View AnswerShow Answer

Which statement is TRUE for passive transport across a biological membrane?

Correct AnswerverifiedShow Answer

An integral membrane protein can be extracted with:

Correct AnswerverifiedShow Answer

A protein is found to extend all the way through the membrane of a cell. Describe this protein in terms of the location of particular types of amino acid side chains in its structure and its ability to move within the membrane.

Correct AnswerAnswered by ExamLex AIThe protein that extends all the way thr...View AnswerShow Answer

What are the similarities and differences between integrins, cadherins, and selectins?

Correct AnswerAnswered by ExamLex AIIntegrins, cadherins, and selectins are ...View AnswerShow Answer

The bacterium E. coli can grow at 20 °C or at 40 °C. At which growth temperature would you expect the membrane phospholipids to have a higher ratio of saturated to unsaturated fatty acids, and why?

Correct AnswerAnswered by ExamLex AIAt 20 °C, you would expect the membrane ...View AnswerShow Answer

The inner (plasma) membrane of E. coli is about 75% lipid and 25% protein by weight. How many molecules of membrane lipid are there for each molecule of protein? (Assume that the average protein is Mr 50,000 and the average lipid is 750.)

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
The likely explanation for the biochemic...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
(a) Integral membrane proteins are ancho...
View Answer

Correct Answer
verified

Which structure describes an integral membrane protein containing a $\beta$ barrel?

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
One way a plant can adjust the component...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
A hydropathy plot is a graph that shows ...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
The protein that extends all the way thr...
View Answer

Correct Answer
Answered by ExamLex AI
Integrins, cadherins, and selectins are ...
View Answer

Correct Answer
Answered by ExamLex AI
At 20 °C, you would expect the membrane ...
View Answer

The inner (plasma) membrane of E. coli is about 75% lipid and 25% protein by weight. How many molecules of membrane lipid are there for each molecule of protein? (Assume that the average protein is M_r 50,000 and the average lipid is 750.)

Correct Answer
verified