Question 1

Which of the following is a correct association?

Accepted Answer

A)  kinase activity and the addition of a tyrosine 
B)  phosphodiesterase activity and the removal of phosphate groups 
C)  GTPase activity and hydrolysis of GTP to GDP 
D)  phosphorylase activity and the catabolism of glucose 
E)  adenylyl cyclase activity and the conversion of cAMP to AMP 
A)  kinase activity and the addition of a tyrosine 
B)  phosphodiesterase activity and the removal of phosphate groups 
C)  GTPase activity and hydrolysis of GTP to GDP 
D)  phosphorylase activity and the catabolism of glucose 
E)  adenylyl cyclase activity and the conversion of cAMP to AMP C

Question 2

In research on aging (both cellular aging and organismal aging), it has been found that aged cells do not progress through the cell cycle as they had previously. Which of the following would provide evidence that this is related to cell signaling?

Accepted Answer

A)  Growth factor ligands do not bind as efficiently to receptors. 
B)  Their lower hormone concentrations elicit a lesser response. 
C)  cAMP levels change very frequently. 
D)  Enzymatic activity declines. 
E)  ATP production decreases. 
A)  Growth factor ligands do not bind as efficiently to receptors. 
B)  Their lower hormone concentrations elicit a lesser response. 
C)  cAMP levels change very frequently. 
D)  Enzymatic activity declines. 
E)  ATP production decreases. A

Question 3

Use this description to answer the following question.
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 cytosol face of the membrane. The loop on the cytosol side between helices 5 and 6 is usually substantially longer than the others.
-In what way do the membranes of a eukaryotic cell vary?

Accepted Answer

A)  Phospholipids are found only in certain membranes. 
B)  Certain proteins are unique to each kind of membrane. 
C)  Only certain membranes of the cell are selectively permeable. 
D)  Only certain membranes are constructed from amphipathic molecules. 
E)  Some membranes have hydrophobic surfaces exposed to the cytoplasm, while others have hydrophilic surfaces facing the cytoplasm. 
A)  Phospholipids are found only in certain membranes. 
B)  Certain proteins are unique to each kind of membrane. 
C)  Only certain membranes of the cell are selectively permeable. 
D)  Only certain membranes are constructed from amphipathic molecules. 
E)  Some membranes have hydrophobic surfaces exposed to the cytoplasm, while others have hydrophilic surfaces facing the cytoplasm. B

Question 4

Which of the following statements is true of signal molecules?

Accepted Answer

A)  When signal molecules first bind to receptor tyrosine kinases, the receptors phosphorylate a number of nearby molecules. 
B)  In response to some G-protein-mediated signals, a special type of lipid molecule associated with the plasma membrane is cleaved to form IP3 and calcium. 
C)  In most cases, signal molecules interact with the cell at the plasma membrane and then enter the cell and eventually the nucleus. 
D)  Toxins such as those that cause botulism and cholera interfere with the ability of activated G proteins to hydrolyze GTP to GDP, resulting in phosphodiesterase activity in the absence of an appropriate signal molecule. 
E)  Protein kinase A activation is one possible result of signal molecules binding to G-protein-coupled receptors. 
A)  When signal molecules first bind to receptor tyrosine kinases, the receptors phosphorylate a number of nearby molecules. 
B)  In response to some G-protein-mediated signals, a special type of lipid molecule associated with the plasma membrane is cleaved to form IP3 and calcium. 
C)  In most cases, signal molecules interact with the cell at the plasma membrane and then enter the cell and eventually the nucleus. 
D)  Toxins such as those that cause botulism and cholera interfere with the ability of activated G proteins to hydrolyze GTP to GDP, resulting in phosphodiesterase activity in the absence of an appropriate signal molecule. 
E)  Protein kinase A activation is one possible result of signal molecules binding to G-protein-coupled receptors.

Question 5

Sutherland discovered that the signaling molecule epinephrine

Accepted Answer

A)  brings about a decrease in levels of cAMP as a result of bypassing the plasma membrane. 
B)  causes lower blood glucose by binding to liver cells. 
C)  interacts with insulin inside muscle cells. 
D)  interacts directly with glycogen phosphorylase. 
E)  elevates cytosolic concentrations of cyclic AMP. 
A)  brings about a decrease in levels of cAMP as a result of bypassing the plasma membrane. 
B)  causes lower blood glucose by binding to liver cells. 
C)  interacts with insulin inside muscle cells. 
D)  interacts directly with glycogen phosphorylase. 
E)  elevates cytosolic concentrations of cyclic AMP.

Question 6

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 7

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 8

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

Which of the following most likely would be an immediate result of a growth factor binding to its receptor?

Accepted Answer

A)  protein kinase activity 
B)  adenylyl cyclase activity 
C)  GTPase activity 
D)  protein phosphatase activity 
E)  phosphorylase activity 
A)  protein kinase activity 
B)  adenylyl cyclase activity 
C)  GTPase activity 
D)  protein phosphatase activity 
E)  phosphorylase activity

Question 10

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 11

When a plant cell, such as one from a peony stem, is submerged in a very hypotonic solution, what is likely to occur?

Accepted Answer

A)  The cell will burst. 
B)  The cell membrane will lyse. 
C)  Plasmolysis will shrink the interior. 
D)  The cell will become flaccid. 
E)  The cell will become turgid. 
A)  The cell will burst. 
B)  The cell membrane will lyse. 
C)  Plasmolysis will shrink the interior. 
D)  The cell will become flaccid. 
E)  The cell will become turgid.

Question 12

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 fiber of the extracellular matrix?

Accepted Answer

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

Question 13

Over the years, the fluid mosaic model has been refined based on recent experimental findings. 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 in the membrane. 
C)  Unsaturated lipids are excluded from the membranes and do not contribute to membrane fluidity. 
D)  The concentration of protein molecules appears to be much higher. 
E)  Membrane proteins are made of only acidic amino acids. 
A)  The membrane is only fluid across a very narrow temperature range. 
B)  Proteins rarely move in the membrane. 
C)  Unsaturated lipids are excluded from the membranes and do not contribute to membrane fluidity. 
D)  The concentration of protein molecules appears to be much higher. 
E)  Membrane proteins are made of only acidic amino acids.

Question 14

Use this description to answer the following question.
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 cytosol face of the membrane. The loop on the cytosol side between helices 5 and 6 is usually substantially longer than the others.
-Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because

Accepted Answer

A)  they are species specific. 
B)  they always lead to the same cellular response. 
C)  they amplify the original signal manifold. 
D)  they counter the harmful effects of phosphatases. 
E)  the number of molecules used is small and fixed. 
A)  they are species specific. 
B)  they always lead to the same cellular response. 
C)  they amplify the original signal manifold. 
D)  they counter the harmful effects of phosphatases. 
E)  the number of molecules used is small and fixed.

Question 15

What is the voltage across a membrane called?

Accepted Answer

A)  water potential 
B)  chemical gradient 
C)  membrane potential 
D)  osmotic potential 
E)  electrochemical gradient 
A)  water potential 
B)  chemical gradient 
C)  membrane potential 
D)  osmotic potential 
E)  electrochemical gradient

Question 16

Which of the following is one of the ways that the membranes of winter wheat are able to remain fluid when it is extremely cold?

Accepted Answer

A)  by increasing the percentage of unsaturated phospholipids in the membrane 
B)  by increasing the percentage of cholesterol molecules in the membrane 
C)  by decreasing the number of hydrophobic proteins in the membrane 
D)  by cotransport of glucose and hydrogen 
E)  by using active transport 
A)  by increasing the percentage of unsaturated phospholipids in the membrane 
B)  by increasing the percentage of cholesterol molecules in the membrane 
C)  by decreasing the number of hydrophobic proteins in the membrane 
D)  by cotransport of glucose and hydrogen 
E)  by using active transport

Question 17

Testosterone functions inside a cell by

Accepted Answer

A)  acting as a signal receptor that activates tyrosine kinases. 
B)  binding with a receptor protein that enters the nucleus and activates specific genes. 
C)  acting as a steroid signal receptor that activates ion channel proteins. 
D)  becoming a second messenger that inhibits nitric oxide. 
E)  coordinating a phosphorylation cascade that increases spermatogenesis. 
A)  acting as a signal receptor that activates tyrosine kinases. 
B)  binding with a receptor protein that enters the nucleus and activates specific genes. 
C)  acting as a steroid signal receptor that activates ion channel proteins. 
D)  becoming a second messenger that inhibits nitric oxide. 
E)  coordinating a phosphorylation cascade that increases spermatogenesis.

Question 18

Which of the following is true of integral membrane proteins?

Accepted Answer

A)  They lack tertiary structure. 
B)  They are loosely bound to the surface of the bilayer. 
C)  They are usually transmembrane proteins. 
D)  They are not mobile within the bilayer. 
E)  They serve only a structural role in membranes. 
A)  They lack tertiary structure. 
B)  They are loosely bound to the surface of the bilayer. 
C)  They are usually transmembrane proteins. 
D)  They are not mobile within the bilayer. 
E)  They serve only a structural role in membranes.

Question 19

Which of the following is characterized by a cell releasing a signal molecule into the environment, followed by a number of cells in the immediate vicinity responding?

Accepted Answer

A)  hormonal signaling 
B)  autocrine signaling 
C)  paracrine signaling 
D)  endocrine signaling 
E)  synaptic signaling 
A)  hormonal signaling 
B)  autocrine signaling 
C)  paracrine signaling 
D)  endocrine signaling 
E)  synaptic signaling

Question 20

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.

Exam 5: Membrane Transport and Cell Signaling

Which of the following is a correct association?

In research on aging (both cellular aging and organismal aging), it has been found that aged cells do not progress through the cell cycle as they had previously. Which of the following would provide evidence that this is related to cell signaling?

Which of the following statements is true of signal molecules?

Sutherland discovered that the signaling molecule epinephrine

Familial hypercholesterolemia is characterized by which of the following?

Which of the following most likely would be an immediate result of a growth factor binding to its receptor?

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

When a plant cell, such as one from a peony stem, is submerged in a very hypotonic solution, what is likely to occur?

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 fiber of the extracellular matrix?

Over the years, the fluid mosaic model has been refined based on recent experimental findings. 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?

What is the voltage across a membrane called?

Which of the following is one of the ways that the membranes of winter wheat are able to remain fluid when it is extremely cold?

Testosterone functions inside a cell by

Which of the following is true of integral membrane proteins?

Which of the following is characterized by a cell releasing a signal molecule into the environment, followed by a number of cells in the immediate vicinity responding?

The movement of potassium into an animal cell requires

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

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Motor Mechanisms and Behavior

Population Ecology and the Distribution of Organisms

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Ecosystems and Energy

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