Question 1

Who proposed that membranes are a phospholipid bilayer between two layers of hydrophilic proteins?

Accepted Answer

A) H. Davson and J. Danielli 
B) I. Langmuir 
C) C. Overton 
D) S. Singer and G. Nicolson 
E) E. Gorter and F. Grendel 
A) H. Davson and J. Danielli 
B) I. Langmuir 
C) C. Overton 
D) S. Singer and G. Nicolson 
E) E. Gorter and F. Grendel A

Question 2

Which of these often serve as receptors or cell recognition molecules on cell surfaces?

Accepted Answer

A) transmembrane proteins 
B) integral proteins 
C) peripheral proteins 
D) integrins 
E) glycoproteins 
A) transmembrane proteins 
B) integral proteins 
C) peripheral proteins 
D) integrins 
E) glycoproteins E

Question 3

For the following questions, match the labeled component of the cell membrane (Figure 7.1) with its description.

-glycolipid

Accepted Answer

B

Question 4

Familial hypercholesterolemia is characterized by which of the following?

Accepted Answer

A) defective LDL receptors on the cell membranes 
B) poor attachment of the cholesterol to the extracellular matrix of cells 
C) a poorly formed lipid bilayer that cannot incorporate cholesterol into cell membranes 
D) inhibition of the cholesterol active transport system in red blood cells 
E) a general lack of glycolipids in the blood cell membranes 
A) defective LDL receptors on the cell membranes 
B) poor attachment of the cholesterol to the extracellular matrix of cells 
C) a poorly formed lipid bilayer that cannot incorporate cholesterol into cell membranes 
D) inhibition of the cholesterol active transport system in red blood cells 
E) a general lack of glycolipids in the blood cell membranes

Question 5

The sodium-potassium pump in animal cells requires cytoplasmic ATP to pump ions across the plasma membrane. When the proteins of the pump are first synthesized in the rough ER, what side of the ER membrane will the ATP binding site be on?

Accepted Answer

A) It will be on the cytoplasmic side of the ER. 
B) It will be on the side facing the interior of the ER. 
C) It could be facing in either direction because the orientation of proteins is scrambled in the Golgi apparatus. 
D) It doesn't matter, because the pump is not active in the ER. 
A) It will be on the cytoplasmic side of the ER. 
B) It will be on the side facing the interior of the ER. 
C) It could be facing in either direction because the orientation of proteins is scrambled in the Golgi apparatus. 
D) It doesn't matter, because the pump is not active in the ER.

Question 6

Refer to Figure 7.3 to answer the following questions.
The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same.

-Which of the following statements correctly describes the normal tonicity conditions for typical plant and animal cells?

Accepted Answer

A) The animal cell is in a hypotonic solution, and the plant cell is in an isotonic solution. 
B) The animal cell is in an isotonic solution, and the plant cell is in a hypertonic solution. 
C) The animal cell is in a hypertonic solution, and the plant cell is in an isotonic solution. 
D) The animal cell is in an isotonic solution, and the plant cell is in a hypotonic solution. 
E) The animal cell is in a hypertonic solution, and the plant cell is in a hypotonic solution. 
A) The animal cell is in a hypotonic solution, and the plant cell is in an isotonic solution. 
B) The animal cell is in an isotonic solution, and the plant cell is in a hypertonic solution. 
C) The animal cell is in a hypertonic solution, and the plant cell is in an isotonic solution. 
D) The animal cell is in an isotonic solution, and the plant cell is in a hypotonic solution. 
E) The animal cell is in a hypertonic solution, and the plant cell is in a hypotonic solution.

Question 7

Who proposed that the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids?

Accepted Answer

A) H. Davson and J. Danielli 
B) I. Langmuir 
C) C. Overton 
D) S. Singer and G. Nicolson 
E) E. Gorter and F. Grendel 
A) H. Davson and J. Danielli 
B) I. Langmuir 
C) C. Overton 
D) S. Singer and G. Nicolson 
E) E. Gorter and F. Grendel

Question 8

In order for a protein to be an integral membrane protein it would have to be which of the following?

Accepted Answer

A) hydrophilic 
B) hydrophobic 
C) amphipathic 
D) completely covered with phospholipids 
E) exposed on only one surface of the membrane 
A) hydrophilic 
B) hydrophobic 
C) amphipathic 
D) completely covered with phospholipids 
E) exposed on only one surface of the membrane

Question 9

Use the diagram of the U-tube in Figure 7.2 to answer the questions that follow.
The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half filled with a solution of 2 M sucrose and 1 M glucose. Side B is half filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels on both sides are equal.

-Initially, in terms of tonicity, the solution in side A with respect to that in side B is

Accepted Answer

A) hypotonic. 
B) plasmolyzed. 
C) isotonic. 
D) saturated. 
E) hypertonic. 
A) hypotonic. 
B) plasmolyzed. 
C) isotonic. 
D) saturated. 
E) hypertonic.

Question 10

When a membrane is freeze-fractured, the bilayer splits down the middle between the two layers of phospholipids. In an electron micrograph of a freeze-fractured membrane, the bumps seen on the fractured surface of the membrane are

Accepted Answer

A) peripheral proteins. 
B) phospholipids. 
C) carbohydrates. 
D) integral proteins. 
E) cholesterol molecules. 
A) peripheral proteins. 
B) phospholipids. 
C) carbohydrates. 
D) integral proteins. 
E) cholesterol molecules.

Question 11

Read the following information and refer to Figure 7.4 to answer the following questions.
Five dialysis bags, constructed from a semi-permeable membrane that is impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed.

-Which line represents the bag with the highest initial concentration of sucrose?

Accepted Answer

The answer of Read the following information and refer to...

Question 12

In the years since the proposal of the fluid mosaic model of the cell membrane, which of the following observations has been added to the model?

Accepted Answer

A) The membrane is only fluid across a very narrow temperature range. 
B) Proteins rarely move, even though they possibly can do so. 
C) Unsaturated lipids are excluded from the membranes. 
D) The concentration of protein molecules is now known to be much higher. 
E) The proteins are known to be made of only acidic amino acids. 
A) The membrane is only fluid across a very narrow temperature range. 
B) Proteins rarely move, even though they possibly can do so. 
C) Unsaturated lipids are excluded from the membranes. 
D) The concentration of protein molecules is now known to be much higher. 
E) The proteins are known to be made of only acidic amino acids.

Question 13

Which of the following span the phospholipids bilayer, usually a number of times?

Accepted Answer

A) transmembrane proteins 
B) integral proteins 
C) peripheral proteins 
D) integrins 
E) glycoproteins 
A) transmembrane proteins 
B) integral proteins 
C) peripheral proteins 
D) integrins 
E) glycoproteins

Question 14

An organism with a cell wall would have the most difficulty doing which process?

Accepted Answer

A) diffusion 
B) osmosis 
C) active transport 
D) phagocytosis 
E) facilitated diffusion 
A) diffusion 
B) osmosis 
C) active transport 
D) phagocytosis 
E) facilitated diffusion

Question 15

After a membrane freezes and then thaws, it often becomes leaky to solutes. The most reasonable explanation for this is that

Accepted Answer

A) transport proteins become nonfunctional during freezing. 
B) the lipid bilayer loses its fluidity when it freezes. 
C) aquaporins can no longer function after freezing. 
D) the integrity of the lipid bilayer is broken when the membrane freezes. 
E) the solubility of most solutes in the cytoplasm decreases on freezing. 
A) transport proteins become nonfunctional during freezing. 
B) the lipid bilayer loses its fluidity when it freezes. 
C) aquaporins can no longer function after freezing. 
D) the integrity of the lipid bilayer is broken when the membrane freezes. 
E) the solubility of most solutes in the cytoplasm decreases on freezing.

Question 16

Several seriously epidemic viral diseases of earlier centuries were then incurable because they resulted in severe dehydration due to vomiting and diarrhea. Today they are usually not fatal because we have developed which of the following?

Accepted Answer

A) antiviral medications that are efficient and work well with all viruses 
B) antibiotics against the viruses in question 
C) intravenous feeding techniques 
D) medication to prevent blood loss 
E) hydrating drinks that include high concentrations of salts and glucose 
A) antiviral medications that are efficient and work well with all viruses 
B) antibiotics against the viruses in question 
C) intravenous feeding techniques 
D) medication to prevent blood loss 
E) hydrating drinks that include high concentrations of salts and glucose

Question 17

Read the following information and refer to Figure 7.4 to answer the following questions.
Five dialysis bags, constructed from a semi-permeable membrane that is impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed.

-Which line or lines represent(s)bags that contain a solution that is hypertonic at the end of 60 minutes?

Accepted Answer

A) A and B 
B) B 
C) C 
D) D 
E) D and E 
A) A and B 
B) B 
C) C 
D) D 
E) D and E

Question 18

Based on Figure 7.19 in your textbook, which of these experimental treatments would increase the rate of sucrose transport into the cell?

Accepted Answer

A) decreasing extracellular sucrose concentration 
B) decreasing extracellular pH 
C) decreasing cytoplasmic pH 
D) adding an inhibitor that blocks the regeneration of ATP 
E) adding a substance that makes the membrane more permeable to hydrogen ions 
A) decreasing extracellular sucrose concentration 
B) decreasing extracellular pH 
C) decreasing cytoplasmic pH 
D) adding an inhibitor that blocks the regeneration of ATP 
E) adding a substance that makes the membrane more permeable to hydrogen ions

Question 19

What mechanisms do plants use to load sucrose produced by photosynthesis into specialized cells in the veins of leaves?

Accepted Answer

A) an electrogenic pump 
B) a proton pump 
C) a contransport protein 
D) A and C only 
E) A, B, and C 
A) an electrogenic pump 
B) a proton pump 
C) a contransport protein 
D) A and C only 
E) A, B, and C

Question 20

The following information should be used to answer the following questions.
Cystic fibrosis is a genetic disease in humans in which chloride ion channels in cell membranes are missing or nonfunctional.
-If a young male child has cystic fibrosis, which of the following would affect his fertility?

Accepted Answer

A) inability to make sperm 
B) incomplete maturation of the testes 
C) failure to form genital structures appropriately 
D) incorrect concentrations of ions in semen 
E) abnormal pH in seminal fluid 
A) inability to make sperm 
B) incomplete maturation of the testes 
C) failure to form genital structures appropriately 
D) incorrect concentrations of ions in semen 
E) abnormal pH in seminal fluid

Exam 7: Membrane Structure and Function

Who proposed that membranes are a phospholipid bilayer between two layers of hydrophilic proteins?

Which of these often serve as receptors or cell recognition molecules on cell surfaces?

For the following questions, match the labeled component of the cell membrane (Figure 7.1) with its description. -glycolipid

Familial hypercholesterolemia is characterized by which of the following?

The sodium-potassium pump in animal cells requires cytoplasmic ATP to pump ions across the plasma membrane. When the proteins of the pump are first synthesized in the rough ER, what side of the ER membrane will the ATP binding site be on?

Who proposed that the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids?

In order for a protein to be an integral membrane protein it would have to be which of the following?

When a membrane is freeze-fractured, the bilayer splits down the middle between the two layers of phospholipids. In an electron micrograph of a freeze-fractured membrane, the bumps seen on the fractured surface of the membrane are

In the years since the proposal of the fluid mosaic model of the cell membrane, which of the following observations has been added to the model?

Which of the following span the phospholipids bilayer, usually a number of times?

An organism with a cell wall would have the most difficulty doing which process?

After a membrane freezes and then thaws, it often becomes leaky to solutes. The most reasonable explanation for this is that

Several seriously epidemic viral diseases of earlier centuries were then incurable because they resulted in severe dehydration due to vomiting and diarrhea. Today they are usually not fatal because we have developed which of the following?

Based on Figure 7.19 in your textbook, which of these experimental treatments would increase the rate of sucrose transport into the cell?

What mechanisms do plants use to load sucrose produced by photosynthesis into specialized cells in the veins of leaves?

The following information should be used to answer the following questions. Cystic fibrosis is a genetic disease in humans in which chloride ion channels in cell membranes are missing or nonfunctional. -If a young male child has cystic fibrosis, which of the following would affect his fertility?

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and the Fitness of the Environment

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

An Introduction to Metabolism

Cellular Respiration: Harvesting Chemical Energy

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Control of Gene Expression

Viruses

Biotechnology

Genomes and Their Evolution

Descent With Modification: a Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity Ii: the Evolution of Seed Plants

Fungi

An Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure, Growth, and Development

Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems

Conservation Biology and Restoration Ecology

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