Question 1

Why would flip-flop of membrane phospholipids as seen in the figure below be so rare?

Accepted Answer

For flip-flop to occur,it would be necessary for the hydrophilic head of a phospholipid to move through the hydrophobic part of the bilayer,an extremely unlikely event.

Question 2

A procedure in which the gene for an integral membrane protein is altered in such a way that the spatial relationships between some of the amino acids in the protein can be revealed is called ________.

Accepted Answer

A) site-directed mutagenesis 
B) site-directed amenuensis 
C) hydropathy plots 
D) electron paramagnetic resonance (EPR)spectroscopy 
E) infrared spectroscopy 
A) site-directed mutagenesis 
B) site-directed amenuensis 
C) hydropathy plots 
D) electron paramagnetic resonance (EPR)spectroscopy 
E) infrared spectroscopy A

Question 3

Which site in a neuron receives incoming information from external sources?

Accepted Answer

A) Dendrites 
B) Axon 
C) Axon hillock 
D) Terminal knob 
E) Cell body 
A) Dendrites 
B) Axon 
C) Axon hillock 
D) Terminal knob 
E) Cell body A

Question 4

Integral membrane proteins have been engineered to lack the portion that normally projects into the extracellular space.When the gene is inserted in cells,what happens to the mobility of this protein in the membrane?

Accepted Answer

A) They move at a much greater rate than the wild type protein. 
B) They move at a much smaller rate than the intact protein. 
C) They do not move at all. 
D) They are not inserted into the membrane so nothing can be learned about their mobility. 
E) They flip to the opposite leaflet. 
A) They move at a much greater rate than the wild type protein. 
B) They move at a much smaller rate than the intact protein. 
C) They do not move at all. 
D) They are not inserted into the membrane so nothing can be learned about their mobility. 
E) They flip to the opposite leaflet.

Question 5

The sodium-potassium pump makes the cell interior more ______ by pumping ____ sodium ions out of the cell for every ____ potassium ions pumped in.

Accepted Answer

A) negative,3,2 
B) negative,2,3 
C) positive,3,2 
D) positive,2,3 
E) negative,4,3 
A) negative,3,2 
B) negative,2,3 
C) positive,3,2 
D) positive,2,3 
E) negative,4,3

Question 6

You determine the transition temperatures for two membranes.The first has a transition temperature of 28°C,the second a transition temperature of 15°C.What can you conclude about the compositions of the two membranes?

Accepted Answer

The first probably has lipids

Question 7

On average,how many amino acids engaged in predominantly hydrophobic $\alpha$- helices does it take to cross the hydrophobic part of the membrane?

Accepted Answer

A) about 10 amino acids 
B) about 20 amino acids 
C) at least 40 amino acids 
D) about 2 - 3 amino acids 
E) None of these are correct. 
A) about 10 amino acids 
B) about 20 amino acids 
C) at least 40 amino acids 
D) about 2 - 3 amino acids 
E) None of these are correct.

Question 8

How might a liposome be prepared that could potentially be used in the treatment of a tumor whose cells have a protein called tumor cell antigen (TCA)in their membranes? This protein is missing from all normal cells.

Accepted Answer

Make an antibody to the TCA protein and

Question 9

In the figure below,what color should the fused mouse and human cell be 40 minutes after the fusion has occurred?

Accepted Answer

The fluorescent green and red antibodies

Question 10

In the 1950s,J.D.Robertson reported that any membrane that he observed in the electron microscope looked the same.This led to his proposal of the Unit Membrane model of membrane structure suggesting that all membranes were exactly alike.Why was this model eventually rejected?

Accepted Answer

It was eventually discovered that differ

Question 11

How was the asymmetry of membrane lipids discovered?

Accepted Answer

A) The lipid asymmetry was visualized in the electron microscope. 
B) The lipid asymmetry was observed with a special stain in the light microscope. 
C) Treatment of intact red blood cells with phospholipases. 
D) Treatment of intact red blood cells with trypsin. 
E) Treatment of liver cells with phospholipases. 
A) The lipid asymmetry was visualized in the electron microscope. 
B) The lipid asymmetry was observed with a special stain in the light microscope. 
C) Treatment of intact red blood cells with phospholipases. 
D) Treatment of intact red blood cells with trypsin. 
E) Treatment of liver cells with phospholipases.

Question 12

The temperature at which a lipid bilayer shifts from a fluid state to a crystalline gel is called the _____.

Accepted Answer

A) transition temperature 
B) temperature optimum 
C) transition series 
D) pH optimum 
E) gelation temperature 
A) transition temperature 
B) temperature optimum 
C) transition series 
D) pH optimum 
E) gelation temperature

Question 13

Phosphatidylethanolamine is concentrated in the inner leaflet of the plasma membrane and tends to promote the curvature of the membrane,which is important in _________.

Accepted Answer

A) membrane budding 
B) membrane fragmentation 
C) membrane fusion 
D) signal transduction 
E) both membrane budding and membrane fusion 
A) membrane budding 
B) membrane fragmentation 
C) membrane fusion 
D) signal transduction 
E) both membrane budding and membrane fusion

Question 14

Which of the following genetic diseases is characterized by fragile,abnormally shaped erythrocytes and has been traced to mutations in ankyrin or spectrin?

Accepted Answer

A) hemophilia 
B) sickle cell anemia 
C) hemolytic anemias 
D) leukemia 
E) erythroblastosis 
A) hemophilia 
B) sickle cell anemia 
C) hemolytic anemias 
D) leukemia 
E) erythroblastosis

Question 15

What word describes a molecule that contains both hydrophilic and hydrophobic portions?

Accepted Answer

A) amphoteric 
B) ambidextrous 
C) amphipathic 
D) rings 
E) straight 
A) amphoteric 
B) ambidextrous 
C) amphipathic 
D) rings 
E) straight

Question 16

What technique below is often used to identify transmembrane segments of integral proteins?

Accepted Answer

A) Lineweaver-Burk plot 
B) Michaelis-Menten plot 
C) hydrophilicity plot 
D) hydropathy plot 
E) titration plot 
A) Lineweaver-Burk plot 
B) Michaelis-Menten plot 
C) hydrophilicity plot 
D) hydropathy plot 
E) titration plot

Question 17

Which proteins move the farthest during SDS-polyacrylamide gel electrophoresis?

Accepted Answer

A) the largest 
B) the smallest 
C) the most negative 
D) the most positive 
E) both the largest and the most negative 
A) the largest 
B) the smallest 
C) the most negative 
D) the most positive 
E) both the largest and the most negative

Question 18

In the figure below,N- and O-glycosidic linkages are depicted.Why are these linkages called N- and O-glycosidic linkages?

Accepted Answer

N-glycosidic linkages are made through t

Question 19

Where cells are the most affected by CF? Describe two potential treatments for these symptoms.What are the advantages and disadvantages of lipid-based delivery of the normal CFTR gene?

Accepted Answer

Cells lining the airways are most affect

Question 20

How are the new "stealth liposomes" protected from immune system phagocytes?

Accepted Answer

A) They are kept cold before use. 
B) They are coated with carbohydrates. 
C) They are given a synthetic polymer coating that protects them from immune destruction. 
D) They are loaded with radioactive isotopes. 
E) They are colored red. 
A) They are kept cold before use. 
B) They are coated with carbohydrates. 
C) They are given a synthetic polymer coating that protects them from immune destruction. 
D) They are loaded with radioactive isotopes. 
E) They are colored red.

Why would flip-flop of membrane phospholipids as seen in the figure below be so rare?

A procedure in which the gene for an integral membrane protein is altered in such a way that the spatial relationships between some of the amino acids in the protein can be revealed is called ________.

Which site in a neuron receives incoming information from external sources?

Integral membrane proteins have been engineered to lack the portion that normally projects into the extracellular space.When the gene is inserted in cells,what happens to the mobility of this protein in the membrane?

The sodium-potassium pump makes the cell interior more __ by pumping sodium ions out of the cell for every potassium ions pumped in.

You determine the transition temperatures for two membranes.The first has a transition temperature of 28°C,the second a transition temperature of 15°C.What can you conclude about the compositions of the two membranes?

On average,how many amino acids engaged in predominantly hydrophobic $\alpha$ - helices does it take to cross the hydrophobic part of the membrane?

How might a liposome be prepared that could potentially be used in the treatment of a tumor whose cells have a protein called tumor cell antigen (TCA)in their membranes? This protein is missing from all normal cells.

In the figure below,what color should the fused mouse and human cell be 40 minutes after the fusion has occurred?

In the 1950s,J.D.Robertson reported that any membrane that he observed in the electron microscope looked the same.This led to his proposal of the Unit Membrane model of membrane structure suggesting that all membranes were exactly alike.Why was this model eventually rejected?

How was the asymmetry of membrane lipids discovered?

The temperature at which a lipid bilayer shifts from a fluid state to a crystalline gel is called the _____.

Phosphatidylethanolamine is concentrated in the inner leaflet of the plasma membrane and tends to promote the curvature of the membrane,which is important in _________.

Which of the following genetic diseases is characterized by fragile,abnormally shaped erythrocytes and has been traced to mutations in ankyrin or spectrin?

What word describes a molecule that contains both hydrophilic and hydrophobic portions?

What technique below is often used to identify transmembrane segments of integral proteins?

Which proteins move the farthest during SDS-polyacrylamide gel electrophoresis?

In the figure below,N- and O-glycosidic linkages are depicted.Why are these linkages called N- and O-glycosidic linkages?

Where cells are the most affected by CF? Describe two potential treatments for these symptoms.What are the advantages and disadvantages of lipid-based delivery of the normal CFTR gene?

How are the new "stealth liposomes" protected from immune system phagocytes?

Introduction to the Study of Cell and Molecular Biology

The Chemical Basis of Life

Bioenergetics,enzymes and Metabolism

Aerobic Respiration and the Mitochondrion

Photosynthesis and the Chloroplast

Interactions Between Cells and Their Environment

Cytoplasmic Membrane Systems: Structure, function, and Membrane Trafficking

The Cytoskeleton and Cell Motility

The Nature of the Gene and the Genome

Gene Expression: From Transcription to Translation

Control of Gene Expression

Dna Replication and Repair

Cellular Reproduction

Cell Signaling and Signal Transduction: Communication Between Cells

Cancer

The Immune Response

Techniques in Cell and Molecular Biology

Filters

Exam 4: The Structure and Function of the Plasma Membrane

Why would flip-flop of membrane phospholipids as seen in the figure below be so rare?

A procedure in which the gene for an integral membrane protein is altered in such a way that the spatial relationships between some of the amino acids in the protein can be revealed is called ________.

Which site in a neuron receives incoming information from external sources?

Integral membrane proteins have been engineered to lack the portion that normally projects into the extracellular space.When the gene is inserted in cells,what happens to the mobility of this protein in the membrane?

The sodium-potassium pump makes the cell interior more ______ by pumping ____ sodium ions out of the cell for every ____ potassium ions pumped in.

You determine the transition temperatures for two membranes.The first has a transition temperature of 28°C,the second a transition temperature of 15°C.What can you conclude about the compositions of the two membranes?

On average,how many amino acids engaged in predominantly hydrophobic α\alphaα - helices does it take to cross the hydrophobic part of the membrane?

How might a liposome be prepared that could potentially be used in the treatment of a tumor whose cells have a protein called tumor cell antigen (TCA)in their membranes? This protein is missing from all normal cells.

In the figure below,what color should the fused mouse and human cell be 40 minutes after the fusion has occurred?

In the 1950s,J.D.Robertson reported that any membrane that he observed in the electron microscope looked the same.This led to his proposal of the Unit Membrane model of membrane structure suggesting that all membranes were exactly alike.Why was this model eventually rejected?

How was the asymmetry of membrane lipids discovered?

The temperature at which a lipid bilayer shifts from a fluid state to a crystalline gel is called the _____.

Phosphatidylethanolamine is concentrated in the inner leaflet of the plasma membrane and tends to promote the curvature of the membrane,which is important in _________.

Which of the following genetic diseases is characterized by fragile,abnormally shaped erythrocytes and has been traced to mutations in ankyrin or spectrin?

What word describes a molecule that contains both hydrophilic and hydrophobic portions?

What technique below is often used to identify transmembrane segments of integral proteins?

Which proteins move the farthest during SDS-polyacrylamide gel electrophoresis?

In the figure below,N- and O-glycosidic linkages are depicted.Why are these linkages called N- and O-glycosidic linkages?

Where cells are the most affected by CF? Describe two potential treatments for these symptoms.What are the advantages and disadvantages of lipid-based delivery of the normal CFTR gene?

How are the new "stealth liposomes" protected from immune system phagocytes?

Introduction to the Study of Cell and Molecular Biology

The Chemical Basis of Life

Bioenergetics,enzymes and Metabolism

Aerobic Respiration and the Mitochondrion

Photosynthesis and the Chloroplast

Interactions Between Cells and Their Environment

Cytoplasmic Membrane Systems: Structure, function, and Membrane Trafficking

The Cytoskeleton and Cell Motility

The Nature of the Gene and the Genome

Gene Expression: From Transcription to Translation

Control of Gene Expression

Dna Replication and Repair

Cellular Reproduction

Cell Signaling and Signal Transduction: Communication Between Cells

Cancer

The Immune Response

Techniques in Cell and Molecular Biology

Filters

The sodium-potassium pump makes the cell interior more __ by pumping sodium ions out of the cell for every potassium ions pumped in.

On average,how many amino acids engaged in predominantly hydrophobic $\alpha$ - helices does it take to cross the hydrophobic part of the membrane?