Question 1

Naturally occurring fatty acids are typically

Accepted Answer

A) saturated. 
B) unsaturated. 
C) in the trans configuration. 
D) in the cis configuration. 
E) comprised of an odd number of carbon atoms. 
A) saturated. 
B) unsaturated. 
C) in the trans configuration. 
D) in the cis configuration. 
E) comprised of an odd number of carbon atoms. D

Question 2

Cholesterol

Accepted Answer

A) is found in abundance in prokaryotic cell membranes. 
B) intercalates between the fatty acid chains within the bilayer. 
C) increases permeability for small cations. 
D) destabilizes the cell membrane. 
E) is found only in plants. 
A) is found in abundance in prokaryotic cell membranes. 
B) intercalates between the fatty acid chains within the bilayer. 
C) increases permeability for small cations. 
D) destabilizes the cell membrane. 
E) is found only in plants. B

Question 3

With respect to the outer and inner faces of the lipid bilayer of the cell membrane,the composition of proteins is

Accepted Answer

A) asymmetrical. 
B) identical. 
C) not identical but symmetrical. 
D) highly random and varies throughout the cell. 
E) a mirror image. 
A) asymmetrical. 
B) identical. 
C) not identical but symmetrical. 
D) highly random and varies throughout the cell. 
E) a mirror image. A

Question 4

Which of the following disorders is the result of impaired glycosphingolipid metabolism?

Accepted Answer

A) leprosy 
B) glycosphingolipid anemia 
C) polydactyly 
D) tuberculosis 
E) Tay-Sachs disease 
A) leprosy 
B) glycosphingolipid anemia 
C) polydactyly 
D) tuberculosis 
E) Tay-Sachs disease

Question 5

Inactivation of a fluorescent dye in a very concentrated spot on a cell so that the fluidity of membranes can be visualized is called

Accepted Answer

A) liposome formation. 
B) SDS-PAGE. 
C) photobleaching. 
D) the freeze-fracture technique. 
E) ferritin-conjugated lectins. 
A) liposome formation. 
B) SDS-PAGE. 
C) photobleaching. 
D) the freeze-fracture technique. 
E) ferritin-conjugated lectins.

Question 6

Which of the following is a sterol-like lipid associated with the cell membrane of prokaryotes?

Accepted Answer

A) stearate 
B) phytosterol 
C) linoleate 
D) palmitate 
E) hopanoids 
A) stearate 
B) phytosterol 
C) linoleate 
D) palmitate 
E) hopanoids

Question 7

Of the following lipids,which would you expect to find associated with chloroplast membranes?

Accepted Answer

A) phosphatidylserine 
B) glycosphingolipid 
C) monogalactosyldiacylglycerol 
D) galactocerebroside 
E) hopanoids 
A) phosphatidylserine 
B) glycosphingolipid 
C) monogalactosyldiacylglycerol 
D) galactocerebroside 
E) hopanoids

Question 8

Recently,consumption of trans fatty acids has been reported to have a link to increased risk of coronary heart disease.What are trans fatty acids? Where are they found in nature? How and why have they been synthetically produced? What effect does their consumption have on humans,and how does that cause the problems associated with coronary heart disease?

Accepted Answer

In trans fatty acids,the hydrogen atoms

Question 9

Membranes contain several classes of lipids,such as phospholipids,sphingolipids,sterols,etc.In spite of their many differences,they all

Accepted Answer

A) are soluble in nonpolar solvents. 
B) can be easily hydrolyzed. 
C) are readily soluble in water at 37C. 
D) can be reduced by strong reducing agents such as sodium. 
E) easily react with bases but not with acids. 
A) are soluble in nonpolar solvents. 
B) can be easily hydrolyzed. 
C) are readily soluble in water at 37C. 
D) can be reduced by strong reducing agents such as sodium. 
E) easily react with bases but not with acids.

Question 10

Which is not a model for membrane structure?

Accepted Answer

A) Overton lipid coat 
B) Langmuir monolayer 
C) Gorter and Grendel bilayer 
D) Singer and Nicholson fluid mosaic 
E) Watson and Crick double helix 
A) Overton lipid coat 
B) Langmuir monolayer 
C) Gorter and Grendel bilayer 
D) Singer and Nicholson fluid mosaic 
E) Watson and Crick double helix

Question 11

Hopanoids

Accepted Answer

A) are found in eukaryotes only. 
B) are related to cholesterol. 
C) are a type of glycolipid. 
D) are a type of phospholipid. 
E) all of the above 
A) are found in eukaryotes only. 
B) are related to cholesterol. 
C) are a type of glycolipid. 
D) are a type of phospholipid. 
E) all of the above

Question 12

In E.coli the enzyme responsible for creating unsaturated bonds from saturated ones in the fatty acids of the cell membrane is ________.

Accepted Answer

The answer of In E.coli the enzyme responsible for creating...

Question 13

A prokaryotic organism is isolated from a glacier,where it was thriving.Based on your knowledge of the plasma membrane,you would expect to find a predominance of

Accepted Answer

A) largely saturated fatty acids. 
B) equal amounts of saturated and unsaturated fatty acids, as long as the chain was close to 12 carbons in length. 
C) cell wall to define the cell because the cell membrane would not be present. 
D) largely unsaturated fatty acids. 
E) none of the above 
A) largely saturated fatty acids. 
B) equal amounts of saturated and unsaturated fatty acids, as long as the chain was close to 12 carbons in length. 
C) cell wall to define the cell because the cell membrane would not be present. 
D) largely unsaturated fatty acids. 
E) none of the above

Question 14

The technique of transferring proteins from SDS-PAGE gels onto a membrane and using labeled antibodies to identify particular proteins is known as a(n)________.

Accepted Answer

The answer of The technique of transferring proteins from SDS-PAGE...

Question 15

The presence of trans fats in membranes ________ the transition temperature and ________ membrane fluidity.

Accepted Answer

increases;

Question 16

The ability of some organisms to alter their membrane lipid composition in response to temperature is known as ________.

Accepted Answer

homeovisco

Question 17

Lipid rafts have been associated with which of the following?

Accepted Answer

A) responses to extracellular signals 
B) transport of nutrients across cell membranes 
C) immune responses 
D) transport of cholera toxin into cells 
E) all of the above 
A) responses to extracellular signals 
B) transport of nutrients across cell membranes 
C) immune responses 
D) transport of cholera toxin into cells 
E) all of the above

Question 18

Acholeplasma laidlawii is a bacterium that cannot synthesize its own fatty acids and therefore is dependent upon the available fatty acids in its environment for assembling its own cell wall.Based upon your knowledge regarding the cell membrane,hypothesize the features of the cell membrane of A.laidlawii grown at 37°C under the following conditions: 50/50 mixture of saturated and unsaturated fatty acids,80/20 predominance of saturated fatty acids,80/20 predominance of unsaturated fatty acids,and a 50/50 mixture of saturated and specifically trans fatty acids.

Accepted Answer

Answers will vary.However,the membrane s

Question 19

You are a microbiologist working with a recently isolated species of bacteria.You start a culture of the bacterium growing at 15°C.In order to study the membrane composition of this species,you then increase the growth temperature to 37°C.If this bacterium were "typical," what would you expect to see with regard to the fatty acid composition of the membrane?

Accepted Answer

There would be an increase in the 18-car

Question 20

Cell-cell communication in plants takes place via specialized structures called

Accepted Answer

A) plasmodesmata. 
B) desmids. 
C) gap junctions. 
D) cell wall pores. 
E) connexons. 
A) plasmodesmata. 
B) desmids. 
C) gap junctions. 
D) cell wall pores. 
E) connexons.

Exam 7: Membranes: Their Structure, function, and Chemistry

Naturally occurring fatty acids are typically

Cholesterol

With respect to the outer and inner faces of the lipid bilayer of the cell membrane,the composition of proteins is

Which of the following disorders is the result of impaired glycosphingolipid metabolism?

Inactivation of a fluorescent dye in a very concentrated spot on a cell so that the fluidity of membranes can be visualized is called

Which of the following is a sterol-like lipid associated with the cell membrane of prokaryotes?

Of the following lipids,which would you expect to find associated with chloroplast membranes?

Membranes contain several classes of lipids,such as phospholipids,sphingolipids,sterols,etc.In spite of their many differences,they all

Which is not a model for membrane structure?

Hopanoids

In E.coli the enzyme responsible for creating unsaturated bonds from saturated ones in the fatty acids of the cell membrane is ________.

A prokaryotic organism is isolated from a glacier,where it was thriving.Based on your knowledge of the plasma membrane,you would expect to find a predominance of

The technique of transferring proteins from SDS-PAGE gels onto a membrane and using labeled antibodies to identify particular proteins is known as a(n)________.

The presence of trans fats in membranes ________ the transition temperature and ________ membrane fluidity.

The ability of some organisms to alter their membrane lipid composition in response to temperature is known as ________.

Lipid rafts have been associated with which of the following?

Cell-cell communication in plants takes place via specialized structures called

A Preview of the Cell

The Chemistry of the Cell

The Macromolecules of the Cell

Cells and Organelles

Bioenergetics: the Flow of Energy in the Cell

Enzymes: the Catalysts of Life

Transport Across Membranes: Overcoming the Permeability Barrier

Chemotrophic Energy Metabolism: Glycolysis and Fermentation

Chemotrophic Energy Metabolism: Aerobic Respiration

Phototrophic Energy Metabolism: Photosynthesis

The Endomembrane System and Peroxisomes

Signal Transduction Mechanisms: Ielectrical and Synaptic Signaling in Neurons

Signal Transduction Mechanisms: Iimessengers and Receptors

Cytoskeletal Systems

Cellular Movement: Motility and Contractility

Beyond the Cell: Cell Adhesions, cell Junctions, and Extracellular Structures

The Structural Basis of Cellular Information: DNA, chromosomes, and the Nucleus

The Cell Cycle, DNA Replication, and Mitosis

Sexual Reproduction, meiosis, and Genetic Recombination

Gene Expression: Ithe Genetic Code and Transcription

Gene Expression: Iiprotein Synthesis and Sorting

The Regulation of Gene Expression

Cancer Cells

Filters

The presence of trans fats in membranes the transition temperature and membrane fluidity.