Question 1

Which of the following is most likely true of a protein that cotransports glucose and sodium ions into the intestinal cells of an animal?

Accepted Answer

A)  Sodium and glucose compete for the same binding site in the cotransporter. 
B)  Glucose entering the cell down its concentration gradient provides energy for uptake of sodium ions against the electrochemical gradient. 
C)  Sodium ions can move down their electrochemical gradient through the cotransporter whether or not glucose is present outside the cell. 
D)  The cotransporter can also transport potassium ions. 
E)  A substance that blocks sodium ions from binding to the cotransport protein will also block the transport of glucose. 
A)  Sodium and glucose compete for the same binding site in the cotransporter. 
B)  Glucose entering the cell down its concentration gradient provides energy for uptake of sodium ions against the electrochemical gradient. 
C)  Sodium ions can move down their electrochemical gradient through the cotransporter whether or not glucose is present outside the cell. 
D)  The cotransporter can also transport potassium ions. 
E)  A substance that blocks sodium ions from binding to the cotransport protein will also block the transport of glucose.

Question 2

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

Question 3

Figure 5.5
The following questions are based on Figure 5.5.
-In Figure 5.5, the dots in the space between the two structures represent which of the following?

Accepted Answer

A)  receptor molecules 
B)  signal transducers 
C)  neurotransmitters 
D)  hormones 
E)  pheromones 
A)  receptor molecules 
B)  signal transducers 
C)  neurotransmitters 
D)  hormones 
E)  pheromones

Question 4

Figure 5.1
For the following questions, match the labeled component of the cell membrane in Figure 5.1 with its description.
-Which component is a glycolipid?

Accepted Answer

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

Question 5

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

Accepted Answer

A)  a transmembrane protein. 
B)  an integral protein. 
C)  a peripheral protein. 
D)  an integrin. 
E)  a glycoprotein. 
A)  a transmembrane protein. 
B)  an integral protein. 
C)  a peripheral protein. 
D)  an integrin. 
E)  a glycoprotein.

Question 6

Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a 0.15 M salt solution become limp and soft. From this we can deduce that

Accepted Answer

A)  the fresh water and the salt solution are both hypertonic to the cells of the celery stalks. 
B)  the fresh water and the salt solution are both hypotonic to the cells of the celery stalks. 
C)  the fresh water is hypotonic and the salt solution is hypertonic to the cells of the celery stalks. 
D)  the fresh water is hypertonic and the salt solution is hypotonic to the cells of the celery stalks. 
E)  the fresh water is isotonic and the salt solution is hypertonic to the cells of the celery stalks. 
A)  the fresh water and the salt solution are both hypertonic to the cells of the celery stalks. 
B)  the fresh water and the salt solution are both hypotonic to the cells of the celery stalks. 
C)  the fresh water is hypotonic and the salt solution is hypertonic to the cells of the celery stalks. 
D)  the fresh water is hypertonic and the salt solution is hypotonic to the cells of the celery stalks. 
E)  the fresh water is isotonic and the salt solution is hypertonic to the cells of the celery stalks.

Question 7

The difference between pinocytosis and receptor-mediated endocytosis is that

Accepted Answer

A)  pinocytosis brings only water molecules into the cell, but 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 offers more selectivity. 
D)  pinocytosis requires cellular energy, but receptor-mediated endocytosis does not. 
E)  pinocytosis can concentrate substances from the extracellular fluid, but receptor-mediated endocytosis cannot. 
A)  pinocytosis brings only water molecules into the cell, but 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 offers more selectivity. 
D)  pinocytosis requires cellular energy, but receptor-mediated endocytosis does not. 
E)  pinocytosis can concentrate substances from the extracellular fluid, but receptor-mediated endocytosis cannot.

Question 8

Figure 5.5
The following questions are based on Figure 5.5.
-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 9

At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogens and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects?

Accepted Answer

A)  Estrogen is produced in very large concentration and therefore diffuses widely. 
B)  Estrogen has specific receptors inside several cell types, but each cell responds in the same way to its binding. 
C)  Estrogen is kept away from the surface of any cells not able to bind it at the surface. 
D)  Estrogen binds to specific receptors inside many kinds of cells, each of which have different responses to its binding. 
E)  The subcomponents of estrogen, when metabolized, can influence cell response. 
A)  Estrogen is produced in very large concentration and therefore diffuses widely. 
B)  Estrogen has specific receptors inside several cell types, but each cell responds in the same way to its binding. 
C)  Estrogen is kept away from the surface of any cells not able to bind it at the surface. 
D)  Estrogen binds to specific receptors inside many kinds of cells, each of which have different responses to its binding. 
E)  The subcomponents of estrogen, when metabolized, can influence cell response.

Question 10

Figure 5.5
The following questions are based on Figure 5.5.
-Which of the following types of signaling is represented in Figure 5.5?

Accepted Answer

A)  autocrine 
B)  paracrine 
C)  hormonal 
D)  synaptic 
E)  long distance 
A)  autocrine 
B)  paracrine 
C)  hormonal 
D)  synaptic 
E)  long distance

Question 11

Figure 5.3
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, side A

Accepted Answer

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

Question 12

Which of the following is true for the evolution of cell membranes?

Accepted Answer

A)  The fluid mosaic nature of cell membranes provides the explanation for the evolution of cell membranes. 
B)  Membrane proteins are the sole component responsible for the evolution of cell membranes. 
C)  The evolution of cell membranes is driven by the evolution of glycoproteins and glycolipids. 
D)  All components of membranes evolve as a result of natural selection. 
E)  An individual organism selects its preferred type of cell membrane for particular functions. 
A)  The fluid mosaic nature of cell membranes provides the explanation for the evolution of cell membranes. 
B)  Membrane proteins are the sole component responsible for the evolution of cell membranes. 
C)  The evolution of cell membranes is driven by the evolution of glycoproteins and glycolipids. 
D)  All components of membranes evolve as a result of natural selection. 
E)  An individual organism selects its preferred type of cell membrane for particular functions.

Question 13

Figure 5.1
For the following questions, match the labeled component of the cell membrane in Figure 5.1 with its description.
-Which component is the peripheral protein?

Accepted Answer

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

Question 14

When protein membrane receptors are activated, what usually happens?

Accepted Answer

A)  A change occurs in intracellular ion concentration. 
B)  The receptors open and close in response to protein signals. 
C)  A change occurs on only one membrane surface: exterior or interior. 
D)  The receptor preferentially binds with lipid or glycolipid signal molecules. 
E)  The receptor changes conformation after binding with signal polypeptides. 
A)  A change occurs in intracellular ion concentration. 
B)  The receptors open and close in response to protein signals. 
C)  A change occurs on only one membrane surface: exterior or interior. 
D)  The receptor preferentially binds with lipid or glycolipid signal molecules. 
E)  The receptor changes conformation after binding with signal polypeptides.

Question 15

According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids?

Accepted Answer

A)  They can move laterally along the plane of the membrane. 
B)  They frequently flip-flop from one side of the membrane to the other. 
C)  They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane. 
D)  They are free to depart from the membrane and dissolve in the surrounding solution. 
E)  They have hydrophilic tails in the interior of the membrane. 
A)  They can move laterally along the plane of the membrane. 
B)  They frequently flip-flop from one side of the membrane to the other. 
C)  They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane. 
D)  They are free to depart from the membrane and dissolve in the surrounding solution. 
E)  They have hydrophilic tails in the interior of the membrane.

Question 16

Which of the following is true of transcription factors?

Accepted Answer

A)  They regulate the synthesis of DNA in response to a signal. 
B)  They transcribe ATP into cAMP. 
C)  They initiate the epinephrine response in animal cells. 
D)  They control gene expression. 
E)  They regulate the synthesis of lipids in the cytoplasm. 
A)  They regulate the synthesis of DNA in response to a signal. 
B)  They transcribe ATP into cAMP. 
C)  They initiate the epinephrine response in animal cells. 
D)  They control gene expression. 
E)  They regulate the synthesis of lipids in the cytoplasm.

Question 17

In which of the following ways could signal transduction most probably be explored in research to treat cancer?

Accepted Answer

A)  removal of serine/threonine phosphate acceptors from transduction pathways in colon pre-cancerous growths 
B)  alteration of protein kinases in cell cycle regulation in order to slow cancer growth 
C)  increase in calcium ion uptake into the cytoplasm in order to modulate the effects of environmental carcinogens 
D)  expansion of the role of transduction inhibitors in the cells before they give rise to cancer 
E)  increase in the concentration of phosphodiesterases in order to produce more AMP 
A)  removal of serine/threonine phosphate acceptors from transduction pathways in colon pre-cancerous growths 
B)  alteration of protein kinases in cell cycle regulation in order to slow cancer growth 
C)  increase in calcium ion uptake into the cytoplasm in order to modulate the effects of environmental carcinogens 
D)  expansion of the role of transduction inhibitors in the cells before they give rise to cancer 
E)  increase in the concentration of phosphodiesterases in order to produce more AMP

Question 18

A drug designed to inhibit the response of cells to testosterone would almost certainly result in which of the following?

Accepted Answer

A)  lower cytoplasmic levels of cAMP 
B)  an increase in receptor tyrosine kinase activity 
C)  a decrease in transcriptional activity of certain genes 
D)  an increase in cytosolic calcium concentration 
E)  a decrease in G-protein activity 
A)  lower cytoplasmic levels of cAMP 
B)  an increase in receptor tyrosine kinase activity 
C)  a decrease in transcriptional activity of certain genes 
D)  an increase in cytosolic calcium concentration 
E)  a decrease in G-protein activity

Question 19

In general, a signal transmitted via phosphorylation of a series of proteins

Accepted Answer

A)  brings a conformational change to each protein. 
B)  requires binding of a hormone to a cytosol receptor. 
C)  cannot occur in yeasts because they lack protein phosphatases. 
D)  requires phosphorylase activity. 
E)  allows target cells to change their shape and therefore their activity. 
A)  brings a conformational change to each protein. 
B)  requires binding of a hormone to a cytosol receptor. 
C)  cannot occur in yeasts because they lack protein phosphatases. 
D)  requires phosphorylase activity. 
E)  allows target cells to change their shape and therefore their activity.

Question 20

The formulation of a model for a structure or for a process serves which of the following purposes?

Accepted Answer

A)  It asks a scientific question. 
B)  It functions as a testable hypothesis. 
C)  It records observations. 
D)  It serves as a data point among results. 
E)  It can only be arrived at after years of experimentation. 
A)  It asks a scientific question. 
B)  It functions as a testable hypothesis. 
C)  It records observations. 
D)  It serves as a data point among results. 
E)  It can only be arrived at after years of experimentation.

Exam 5: Membrane Transport and Cell Signaling

Which of the following is most likely true of a protein that cotransports glucose and sodium ions into the intestinal cells of an animal?

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

Figure 5.5 The following questions are based on Figure 5.5. -In Figure 5.5, the dots in the space between the two structures represent which of the following?

Figure 5.1 For the following questions, match the labeled component of the cell membrane in Figure 5.1 with its description. -Which component is a glycolipid?

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

Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a 0.15 M salt solution become limp and soft. From this we can deduce that

The difference between pinocytosis and receptor-mediated endocytosis is that

At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogens and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects?

Figure 5.5 The following questions are based on Figure 5.5. -Which of the following types of signaling is represented in Figure 5.5?

Which of the following is true for the evolution of cell membranes?

Figure 5.1 For the following questions, match the labeled component of the cell membrane in Figure 5.1 with its description. -Which component is the peripheral protein?

When protein membrane receptors are activated, what usually happens?

According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids?

Which of the following is true of transcription factors?

In which of the following ways could signal transduction most probably be explored in research to treat cancer?

A drug designed to inhibit the response of cells to testosterone would almost certainly result in which of the following?

In general, a signal transmitted via phosphorylation of a series of proteins

The formulation of a model for a structure or for a process serves which of the following purposes?

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

Species Interactions

Ecosystems and Energy

Global Ecology and Conservation Biology

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