Question 1

The mechanism by which testosterone alters cell function is by

Accepted Answer

A) binding to a receptor protein that enters the nucleus and activates specific genes. 
B) binding to a transmembrane signal receptor that activates cell-signaling pathways. 
C) acting as a steroid signal receptor that activates ion channel proteins. 
D) serving as a second messenger that activates cell-signaling pathways. 
A) binding to a receptor protein that enters the nucleus and activates specific genes. 
B) binding to a transmembrane signal receptor that activates cell-signaling pathways. 
C) acting as a steroid signal receptor that activates ion channel proteins. 
D) serving as a second messenger that activates cell-signaling pathways.

Question 2

Figure 5.2
-The solutions in the two arms of the U-tube shown in Figure 5.2 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 are equal,and the solution in side A is

Accepted Answer

A) hypotonic to the solution in side B. 
B) hypertonic to the solution in side B. 
C) isotonic to the solution in side B. 
A) hypotonic to the solution in side B. 
B) hypertonic to the solution in side B. 
C) isotonic to the solution in side B.

Question 3

The movement of the hydrophobic gas nitrous oxide (N2O)(laughing gas)into a cell is an example of

Accepted Answer

A) active transport across the lipid bilayer. 
B) facilitated diffusion through the lipid bilayer. 
C) diffusion through the lipid bilayer. 
D) osmosis through the lipid bilayer. 
E) cotransport across the lipid bilayer. 
A) active transport across the lipid bilayer. 
B) facilitated diffusion through the lipid bilayer. 
C) diffusion through the lipid bilayer. 
D) osmosis through the lipid bilayer. 
E) cotransport across the lipid bilayer.

Question 4

A major group of G protein-coupled receptors contains seven transmembrane α helices.The amino end of the protein lies at the exterior of the plasma membrane.Loops of amino acids connect the helices either at the exterior face or on the cytoplasmic face of the membrane.The loop on the cytoplasmic side between helices 5 and 6 is usually substantially longer than the other loops.The G protein activated by this receptor most likely interacts with the receptor

Accepted Answer

A) at the NH3 end. 
B) at the COO- end. 
C) along the exterior face of the membrane. 
D) at the loop between helices 5 and 6. 
A) at the NH3 end. 
B) at the COO- end. 
C) along the exterior face of the membrane. 
D) at the loop between helices 5 and 6.

Question 5

The difference between pinocytosis and receptor-mediated endocytosis is that

Accepted Answer

A) pinocytosis brings only water molecules into the cell,whereas receptor-mediated endocytosis brings in other molecules as well. 
B) pinocytosis increases the surface area of the plasma membrane,whereas receptor-mediated endocytosis decreases the plasma membrane surface area. 
C) pinocytosis is nonselective in the molecules it brings into the cell,whereas receptor-mediated endocytosis is highly selective. 
D) pinocytosis requires cellular energy,but receptor-mediated endocytosis does not. 
E) pinocytosis generally concentrates substances from the extracellular fluid,but receptor-mediated endocytosis does not. 
A) pinocytosis brings only water molecules into the cell,whereas receptor-mediated endocytosis brings in other molecules as well. 
B) pinocytosis increases the surface area of the plasma membrane,whereas receptor-mediated endocytosis decreases the plasma membrane surface area. 
C) pinocytosis is nonselective in the molecules it brings into the cell,whereas receptor-mediated endocytosis is highly selective. 
D) pinocytosis requires cellular energy,but receptor-mediated endocytosis does not. 
E) pinocytosis generally concentrates substances from the extracellular fluid,but receptor-mediated endocytosis does not.

Question 6

Figure 5.2
-The solutions in the two arms of the U-tube shown in Figure 5.2 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 are equal.After the system depicted in the figure reaches equilibrium,what changes are observed?

Accepted Answer

A) The concentrations of glucose and sucrose are unchanged. 
B) The water level is higher in side A than in side B. 
C) The water level is unchanged. 
D) The water level is higher in side B than in side A. 
A) The concentrations of glucose and sucrose are unchanged. 
B) The water level is higher in side A than in side B. 
C) The water level is unchanged. 
D) The water level is higher in side B than in side A.

Question 7

A protein that spans the phospholipid bilayer one or more times is

Accepted Answer

A) a transmembrane protein. 
B) a glycoprotein. 
C) a peripheral protein. 
D) an extracellular matrix protein. 
A) a transmembrane protein. 
B) a glycoprotein. 
C) a peripheral protein. 
D) an extracellular matrix protein.

Question 8

Figure 5.4
-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.Figure 5.4 illustrates the change in the mass of the bags over time.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 9

Transcription factors play a major role in regulating which of the following processes?

Accepted Answer

A) the conversion of ATP into cAMP 
B) DNA replication 
C) gene expression 
D) transmission of signals from steroid hormone receptors to intracellular G proteins 
A) the conversion of ATP into cAMP 
B) DNA replication 
C) gene expression 
D) transmission of signals from steroid hormone receptors to intracellular G proteins

Question 10

Which of the following molecules would you expect to diffuse through the lipid bilayer of a plasma membrane most slowly,if at all?

Accepted Answer

A) CH4 
B) an amino acid 
C) O2 
D) CO2 
E) water 
A) CH4 
B) an amino acid 
C) O2 
D) CO2 
E) water

Question 11

In receptor-mediated endocytosis,where are the receptors that bind specific molecules located immediately following endocytosis?

Accepted Answer

A) on the cytoplasmic surface of the cell membrane 
B) on the interior surface of a cytoplasmic vesicle 
C) on the exterior surface of a cytoplasmic vesicle 
D) on the interior surface of the Golgi apparatus 
E) on the interior surface of a lysosome membrane 
A) on the cytoplasmic surface of the cell membrane 
B) on the interior surface of a cytoplasmic vesicle 
C) on the exterior surface of a cytoplasmic vesicle 
D) on the interior surface of the Golgi apparatus 
E) on the interior surface of a lysosome membrane

Question 12

An integral membrane protein would have to be

Accepted Answer

A) hydrophilic. 
B) composed primarily of alpha helix structural domains. 
C) amphipathic,with at least one hydrophobic and one hydrophilic region. 
D) exposed to water on only one surface of the membrane. 
A) hydrophilic. 
B) composed primarily of alpha helix structural domains. 
C) amphipathic,with at least one hydrophobic and one hydrophilic region. 
D) exposed to water on only one surface of the membrane.

Question 13

In what way would the lack of receptors for local paracrine signal molecules affect animal cells?

Accepted Answer

A) The cells would not respond to growth factors from nearby cells. 
B) The cells would not respond to hormone signals delivered through the bloodstream. 
C) The cells would bind locally secreted growth factors,but signal transduction to alter gene expression would not occur. 
D) The cells would grow and divide normally. 
A) The cells would not respond to growth factors from nearby cells. 
B) The cells would not respond to hormone signals delivered through the bloodstream. 
C) The cells would bind locally secreted growth factors,but signal transduction to alter gene expression would not occur. 
D) The cells would grow and divide normally.

Question 14

Lipid-soluble signaling molecules,such as aldosterone,cross the membranes of all cells but affect only target cells because

Accepted Answer

A) only target cells retain the appropriate DNA segments. 
B) intracellular receptors are present only in target cells. 
C) only target cells have enzymes that break down aldosterone. 
D) only in target cells is aldosterone able to initiate a phosphorylation cascade that turns genes on. 
A) only target cells retain the appropriate DNA segments. 
B) intracellular receptors are present only in target cells. 
C) only target cells have enzymes that break down aldosterone. 
D) only in target cells is aldosterone able to initiate a phosphorylation cascade that turns genes on.

Question 15

Research on aging suggests that as cells age,their rate of cell division decreases until they ultimately no longer divide.Which of the following would provide evidence that the decreased rate of cell division is related to cell signaling?

Accepted Answer

A) decreased ATP production in aged cells 
B) decreased hormone production in aged cells 
C) decreased affinity of growth factor receptors for their respective ligands 
D) decreased numbers of cytoplasmic ribosomes 
A) decreased ATP production in aged cells 
B) decreased hormone production in aged cells 
C) decreased affinity of growth factor receptors for their respective ligands 
D) decreased numbers of cytoplasmic ribosomes

Question 16

Figure 5.4
-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.Figure 5.4 illustrates the change in the mass of the bags over time.Which line in the graph represents the bag that contained a 0.6 M solution at the beginning of the experiment?

Accepted Answer

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

Question 17

Figure 5.2
-The solutions in the two arms of the U-tube shown in Figure 5.2 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 are equal.After the system depicted in the figure reaches equilibrium,what changes are observed with respect to the concentrations of sugars?

Accepted Answer

A) The concentration of sucrose is equal in sides A and B,and the concentrations of glucose are unchanged. 
B) The concentrations of glucose and sucrose are equal in sides A and B. 
C) The concentration of glucose is equal in sides A and B,and the concentrations of sucrose are unchanged. 
D) The water levels change,but the concentrations of glucose and sucrose in sides A and B are unchanged. 
A) The concentration of sucrose is equal in sides A and B,and the concentrations of glucose are unchanged. 
B) The concentrations of glucose and sucrose are equal in sides A and B. 
C) The concentration of glucose is equal in sides A and B,and the concentrations of sucrose are unchanged. 
D) The water levels change,but the concentrations of glucose and sucrose in sides A and B are unchanged.

Question 18

A bacterium engulfed by a white blood cell through phagocytosis will be digested by enzymes contained in

Accepted Answer

A) peroxisomes. 
B) lysosomes. 
C) Golgi vesicles. 
D) vacuoles. 
E) secretory vesicles. 
A) peroxisomes. 
B) lysosomes. 
C) Golgi vesicles. 
D) vacuoles. 
E) secretory vesicles.

Question 19

Based on the figure below,which of these experimental treatments would increase the rate of sucrose transport into a plant cell?

Accepted Answer

A) decreasing extracellular sucrose concentration 
B) decreasing extracellular pH 
C) decreasing cytoplasmic pH 
D) 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 a substance that makes the membrane more permeable to hydrogen ions

Question 20

Proteins that allow the diffusion of ions across membranes in the direction of their concentration gradients are most likely

Accepted Answer

A) channel proteins. 
B) carrier proteins. 
C) aquaporins. 
D) active transport pumps. 
A) channel proteins. 
B) carrier proteins. 
C) aquaporins. 
D) active transport pumps.

Exam 5: Membrane Transport and Cell Signaling

The mechanism by which testosterone alters cell function is by

The movement of the hydrophobic gas nitrous oxide (N2O)(laughing gas)into a cell is an example of

The difference between pinocytosis and receptor-mediated endocytosis is that

A protein that spans the phospholipid bilayer one or more times is

Transcription factors play a major role in regulating which of the following processes?

Which of the following molecules would you expect to diffuse through the lipid bilayer of a plasma membrane most slowly,if at all?

In receptor-mediated endocytosis,where are the receptors that bind specific molecules located immediately following endocytosis?

An integral membrane protein would have to be

In what way would the lack of receptors for local paracrine signal molecules affect animal cells?

Lipid-soluble signaling molecules,such as aldosterone,cross the membranes of all cells but affect only target cells because

Research on aging suggests that as cells age,their rate of cell division decreases until they ultimately no longer divide.Which of the following would provide evidence that the decreased rate of cell division is related to cell signaling?

A bacterium engulfed by a white blood cell through phagocytosis will be digested by enzymes contained in

Based on the figure below,which of these experimental treatments would increase the rate of sucrose transport into a plant cell?

Proteins that allow the diffusion of ions across membranes in the direction of their concentration gradients are most likely

Introduction: Evolution and the Foundations of Biology

The Chemical Context of Life

Carbon and the Molecular Diversity of Life

A Tour of the Cell

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Development,stem Cells,and Cancer

Viruses

Genomes and Their Evolution

Descent With Modification

Phylogeny

The Evolution of Populations

The Origin of Species

Broad Patterns of Evolution

Early Life and the Diversification of Prokaryotes

The Origin and Diversification of Eukaryotes

The Colonization of Land by Plants and Fungi

The Rise of Animal Diversity

Plant Structure and Growth

Resource Acquisition,nutrition,and Transport in Vascular Plants

Reproduction and Domestication of Flowering Plants

Plant Responses to Internal and External Signals

Homeostasis and Endocrine Signaling

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Reproduction and Development

Neurons,synapses,and Signaling

Nervous and Sensory Systems

Motor Mechanisms and Behavior

Population Ecology and the Distribution of Organisms

Ecological Communities

Ecosystems and Energy

Conservation Biology and Global Change

Filters

The movement of the hydrophobic gas nitrous oxide (N₂O)(laughing gas)into a cell is an example of