Question 1

Which of the following processes includes all others?

Accepted Answer

A) osmosis 
B) diffusion of a solute across a membrane 
C) facilitated diffusion 
D) passive transport 
E) transport of an ion down its electrochemical gradient 
A) osmosis 
B) diffusion of a solute across a membrane 
C) facilitated diffusion 
D) passive transport 
E) transport of an ion down its electrochemical gradient

Question 2

Use the following information to answer the questions below.
Human immunodeficiency virus (HIV)infects cells that have both CD4 and CCR5 cell surface molecules.The viral nucleic acid molecules are enclosed in a protein capsid,and the protein capsid is itself contained inside an envelope consisting of a lipid bilayer membrane and viral glycoproteins.One hypothesis for viral entry into cells is that binding of HIV membrane glycoproteins to CD4 and CCR5 initiates fusion of the HIV membrane with the plasma membrane,releasing the viral capsid into the cytoplasm.An alternative hypothesis is that HIV gains entry into the cell via receptor-mediated endocytosis,and membrane fusion occurs in the endocytotic vesicle.To test these alternative hypotheses for HIV entry,researchers labelled the lipids on the HIV membrane with a red fluorescent dye.
  
-In an HIV-infected cell producing HIV virus particles,the viral glycoprotein is expressed on the plasma membrane.How do the viral glycoproteins get to the plasma membrane?

Accepted Answer

A) They are synthesized on ribosomes on the plasma membrane. 
B) They are synthesized by ribosomes in the rough ER, and arrive at the plasma membrane in the membrane of secretory vesicles. 
C) They are synthesized on free cytoplasmic ribosomes, and then inserted into the plasma membrane. 
D) They are synthesized by ribosomes in the rough ER, secreted from the cell, and inserted into the plasma membrane from the outside. 
E) They are synthesized by ribosomes on the HIV viral membrane, which fuses with the plasma membrane from inside the cell. 
A) They are synthesized on ribosomes on the plasma membrane. 
B) They are synthesized by ribosomes in the rough ER, and arrive at the plasma membrane in the membrane of secretory vesicles. 
C) They are synthesized on free cytoplasmic ribosomes, and then inserted into the plasma membrane. 
D) They are synthesized by ribosomes in the rough ER, secreted from the cell, and inserted into the plasma membrane from the outside. 
E) They are synthesized by ribosomes on the HIV viral membrane, which fuses with the plasma membrane from inside the cell.

Question 3

A patient has had a serious accident and lost a lot of blood.In an attempt to replenish body fluids,distilled water-equal to the volume of blood lost-is transferred directly into one of his veins.What will be the most probable result of this transfusion?

Accepted Answer

A) It will have no unfavourable effect as long as the water is free of viruses and bacteria. 
B) The patient's red blood cells will shrivel up because the blood fluid has become hypotonic compared to the cells. 
C) The patient's red blood cells will swell because the blood fluid has become hypotonic compared to the cells. 
D) The patient's red blood cells will shrivel up because the blood fluid has become hypertonic compared to the cells. 
E) The patient's red blood cells will burst because the blood fluid has become hypertonic compared to the cells. 
A) It will have no unfavourable effect as long as the water is free of viruses and bacteria. 
B) The patient's red blood cells will shrivel up because the blood fluid has become hypotonic compared to the cells. 
C) The patient's red blood cells will swell because the blood fluid has become hypotonic compared to the cells. 
D) The patient's red blood cells will shrivel up because the blood fluid has become hypertonic compared to the cells. 
E) The patient's red blood cells will burst because the blood fluid has become hypertonic compared to the cells.

Question 4

Ions diffuse across membranes through specific ion channels

Accepted Answer

A) down their chemical gradients. 
B) down their concentration gradients. 
C) down the electrical gradients. 
D) down their electrochemical gradients. 
E) down the osmotic potential gradients. 
A) down their chemical gradients. 
B) down their concentration gradients. 
C) down the electrical gradients. 
D) down their electrochemical gradients. 
E) down the osmotic potential gradients.

Question 5

Use the following information to answer the questions below.
Five dialysis bags,constructed from a semipermeable 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 in the graph represent(s)bags that contain a solution that is hypertonic at 50 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 6

An organism with a cell wall would most likely be unable to take in materials through

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 7

The phosphate transport system in bacteria imports phosphate into the cell even when the concentration of phosphate outside the cell is much lower than the cytoplasmic phosphate concentration.Phosphate import depends on a pH gradient across the membrane-more acidic outside the cell than inside the cell.Phosphate transport is an example of

Accepted Answer

A) passive diffusion. 
B) facilitated diffusion. 
C) active transport. 
D) osmosis. 
E) cotransport. 
A) passive diffusion. 
B) facilitated diffusion. 
C) active transport. 
D) osmosis. 
E) cotransport.

Question 8

The cell membranes of Arctic ice fish might have which of the following adaptations?

Accepted Answer

A) very long chain fatty acids 
B) branched isoprenoid lipids 
C) a high percentage of polyunsaturated fatty acids 
D) a higher percentage of trans-fatty acids 
E) no cholesterol 
A) very long chain fatty acids 
B) branched isoprenoid lipids 
C) a high percentage of polyunsaturated fatty acids 
D) a higher percentage of trans-fatty acids 
E) no cholesterol

Question 9

Familial hypercholesterolemia is characterized by which of the following?

Accepted Answer

A) defective low-density lipoprotein 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 low-density lipoprotein 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 10

Which of the following is true of osmosis?

Accepted Answer

A) Osmosis only occurs in red blood cells. 
B) Osmosis is an energy-demanding or "active" process. 
C) In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration. 
D) In osmosis, solutes move across a membrane from areas of lower water concentration to areas of higher water concentration. 
E) Osmosis only occurs in eukaryotes 
A) Osmosis only occurs in red blood cells. 
B) Osmosis is an energy-demanding or "active" process. 
C) In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration. 
D) In osmosis, solutes move across a membrane from areas of lower water concentration to areas of higher water concentration. 
E) Osmosis only occurs in eukaryotes

Question 11

What does a ribbon diagram show?

Accepted Answer

A) nucleic acid backbone 
B) protein backbone 
C) carbohydrate backbone 
D) lipid backbone 
E) hydrocarbon backbone 
A) nucleic acid backbone 
B) protein backbone 
C) carbohydrate backbone 
D) lipid backbone 
E) hydrocarbon backbone

Question 12

Use the following information to answer the questions below.
Human immunodeficiency virus (HIV)infects cells that have both CD4 and CCR5 cell surface molecules.The viral nucleic acid molecules are enclosed in a protein capsid,and the protein capsid is itself contained inside an envelope consisting of a lipid bilayer membrane and viral glycoproteins.One hypothesis for viral entry into cells is that binding of HIV membrane glycoproteins to CD4 and CCR5 initiates fusion of the HIV membrane with the plasma membrane,releasing the viral capsid into the cytoplasm.An alternative hypothesis is that HIV gains entry into the cell via receptor-mediated endocytosis,and membrane fusion occurs in the endocytotic vesicle.To test these alternative hypotheses for HIV entry,researchers labelled the lipids on the HIV membrane with a red fluorescent dye.
  
-Using live-cell fluorescence microscopy,researchers observed that a red fluorescent spot moved from the plasma membrane into the interior of target cells when red fluorescent dye-labelled HIV was added to the cells.What is the best conclusion from these observations?

Accepted Answer

A) The hypothesis that HIV enters the cell via fusion with the target cell plasma membrane is proved. 
B) The hypothesis that HIV enters the cell via fusion with the target cell plasma membrane is not supported. 
C) The hypothesis that HIV enters the cell via endocytosis is proved. 
D) The hypothesis that HIV enters the cell via endocytosis is not supported. 
E) Neither hypothesis is supported by these results. 
A) The hypothesis that HIV enters the cell via fusion with the target cell plasma membrane is proved. 
B) The hypothesis that HIV enters the cell via fusion with the target cell plasma membrane is not supported. 
C) The hypothesis that HIV enters the cell via endocytosis is proved. 
D) The hypothesis that HIV enters the cell via endocytosis is not supported. 
E) Neither hypothesis is supported by these results.

Question 13

Use the following information to answer the questions below.
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 14

You are working on a team that is designing a new drug.In order for this drug to work,it must enter the cytoplasm of specific target cells.Which of the following would be a factor that determines whether the molecule selectively enters the target cells?

Accepted Answer

A) blood or tissue type of the patient 
B) hydrophobicity of the drug molecule 
C) lack of charge on the drug molecule 
D) similarity of the drug molecule to other molecules transported by the target cells 
E) lipid composition of the target cells' plasma membrane 
A) blood or tissue type of the patient 
B) hydrophobicity of the drug molecule 
C) lack of charge on the drug molecule 
D) similarity of the drug molecule to other molecules transported by the target cells 
E) lipid composition of the target cells' plasma membrane

Question 15

The movement of potassium into an animal cell requires

Accepted Answer

A) low cellular concentrations of sodium. 
B) high cellular concentrations of potassium. 
C) an energy source such as ATP. 
D) a cotransport protein. 
E) a potassium channel protein. 
A) low cellular concentrations of sodium. 
B) high cellular concentrations of potassium. 
C) an energy source such as ATP. 
D) a cotransport protein. 
E) a potassium channel protein.

Question 16

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.Refer to the figure to answer the following questions.
  
-At the beginning of the experiment,

Accepted Answer

A) side A is hypertonic to side B. 
B) side A is hypotonic to side B. 
C) side A is isotonic to side B. 
D) side A is hypertonic to side B with respect to glucose. 
E) side A is hypotonic to side B with respect to sodium chloride. 
A) side A is hypertonic to side B. 
B) side A is hypotonic to side B. 
C) side A is isotonic to side B. 
D) side A is hypertonic to side B with respect to glucose. 
E) side A is hypotonic to side B with respect to sodium chloride.

Question 17

Use the following information to answer the questions below.
Five dialysis bags,constructed from a semipermeable 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 in the graph represents the bag with the highest initial concentration of sucrose?

Accepted Answer

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

Question 18

What do contractile vacuoles in Paramecium assist with?

Accepted Answer

A) osmoregulation 
B) selective uptake 
C) endocytosis 
D) digestion 
E) water storage 
A) osmoregulation 
B) selective uptake 
C) endocytosis 
D) digestion 
E) water storage

Question 19

Which of the following would increase the electrochemical potential across a membrane?

Accepted Answer

A) a chloride channel 
B) a sucrose-proton cotransporter 
C) a proton pump 
D) a potassium channel 
E) both a proton pump and a potassium channel 
A) a chloride channel 
B) a sucrose-proton cotransporter 
C) a proton pump 
D) a potassium channel 
E) both a proton pump and a potassium channel

Question 20

What kinds of molecules pass through a cell membrane most easily?

Accepted Answer

A) large and hydrophobic 
B) small and hydrophobic 
C) large polar 
D) ionic 
E) monosaccharides such as glucose 
A) large and hydrophobic 
B) small and hydrophobic 
C) large polar 
D) ionic 
E) monosaccharides such as glucose

Exam 7: Membrane Structure and Function

Which of the following processes includes all others?

A patient has had a serious accident and lost a lot of blood.In an attempt to replenish body fluids,distilled water-equal to the volume of blood lost-is transferred directly into one of his veins.What will be the most probable result of this transfusion?

Ions diffuse across membranes through specific ion channels

An organism with a cell wall would most likely be unable to take in materials through

The cell membranes of Arctic ice fish might have which of the following adaptations?

Familial hypercholesterolemia is characterized by which of the following?

Which of the following is true of osmosis?

What does a ribbon diagram show?

You are working on a team that is designing a new drug.In order for this drug to work,it must enter the cytoplasm of specific target cells.Which of the following would be a factor that determines whether the molecule selectively enters the target cells?

The movement of potassium into an animal cell requires

What do contractile vacuoles in Paramecium assist with?

Which of the following would increase the electrochemical potential across a membrane?

What kinds of molecules pass through a cell membrane most easily?

Introduction: Evolution and Themes of Biology

The Chemical Context of Life

Water and Life

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 and Fermentation

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

Regulation of Gene Expression

Viruses

DNA Tools and 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 Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure,Growth,and Development

Resource Acquisition and 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 Signalling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behaviour

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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