Question 1

The product of the bicoid gene in Drosophila provides essential information about

Accepted Answer

A)  lethal genes. 
B)  the dorsal-ventral axis. 
C)  the left-right axis. 
D)  segmentation. 
E)  the anterior-posterior axis. 
A)  lethal genes. 
B)  the dorsal-ventral axis. 
C)  the left-right axis. 
D)  segmentation. 
E)  the anterior-posterior axis.

Question 2

Which of the following, when taken up by the cell, binds to the repressor so that the repressor no longer binds to the operator?

Accepted Answer

A)  ubiquitin 
B)  inducer 
C)  promoter 
D)  repressor 
E)  corepressor 
A)  ubiquitin 
B)  inducer 
C)  promoter 
D)  repressor 
E)  corepressor

Question 3

Which of the following genes map out the basic subdivisions along the anterior-posterior axis of the Drosophila embryo?

Accepted Answer

A)  homeotic genes 
B)  segmentation genes 
C)  egg-polarity genes 
D)  morphogens 
E)  inducers 
A)  homeotic genes 
B)  segmentation genes 
C)  egg-polarity genes 
D)  morphogens 
E)  inducers

Question 4

Your brother has just purchased a new plastic model airplane. He places all the parts on the table in approximately the positions in which they will be located when the model is complete. His actions are analogous to which process in development?

Accepted Answer

A)  morphogenesis 
B)  determination 
C)  induction 
D)  differentiation 
E)  pattern formation 
A)  morphogenesis 
B)  determination 
C)  induction 
D)  differentiation 
E)  pattern formation

Question 5

A researcher has arrived at a method to prevent gene expression from Drosophila embryonic genes. The following questions assume that he is using this method.
-The researcher continues to study the reactions of the embryo to these new proteins and you hypothesize that he is most likely to see which of the following (while embryonic genes are still not being expressed)?

Accepted Answer

A)  The cells begin to differentiate. 
B)  The proteins are evenly distributed throughout the embryo. 
C)  Larval features begin to make their appearance. 
D)  Spatial axes (anterior → posterior, etc.) begin to be determined. 
E)  The embryo begins to lose cells due to apoptosis from no further gene expression. 
A)  The cells begin to differentiate. 
B)  The proteins are evenly distributed throughout the embryo. 
C)  Larval features begin to make their appearance. 
D)  Spatial axes (anterior → posterior, etc.) begin to be determined. 
E)  The embryo begins to lose cells due to apoptosis from no further gene expression.

Question 6

A few decades ago, Knudsen and colleagues proposed a theory that, for a normal cell to become a cancer cell, a minimum of two genetic changes had to occur in that cell. Knudsen was studying retinoblastoma, a childhood cancer of the eye.
-In colorectal cancer, several genes must be mutated in order to make a cell a cancer cell, supporting Knudsen's hypothesis. Which of the following kinds of genes would you expect to be mutated?

Accepted Answer

A)  genes coding for enzymes that act in the colon 
B)  genes involved in control of the cell cycle 
C)  genes that are especially susceptible to mutation 
D)  the same genes that Knudsen identified as associated with retinoblastoma 
E)  the genes of the bacteria that are abundant in the colon 
A)  genes coding for enzymes that act in the colon 
B)  genes involved in control of the cell cycle 
C)  genes that are especially susceptible to mutation 
D)  the same genes that Knudsen identified as associated with retinoblastoma 
E)  the genes of the bacteria that are abundant in the colon

Question 7

Epstein Bar Virus (EBV) causes most of us to have an episode of sore throat and swollen glands during early childhood. If we first become exposed to the virus during our teen years, however, EBV causes the syndrome we know as mononucleosis. However, in special circumstances, the same virus can be carcinogenic.
-In areas of the world in which malaria is endemic, notably in sub-Saharan Africa, EBV can cause Burkitt's lymphoma in children, which is usually associated with large tumors of the jaw. Which of the following is consistent with these findings?

Accepted Answer

A)  EBV infection makes the malarial parasite able to produce lymphoma. 
B)  Malaria's strain on the immune system makes EBV infection worse. 
C)  Malaria occurs more frequently in those infected with EBV. 
D)  Malarial response of the immune system prevents an individual from making EBV antibodies. 
E)  A cell infected with the malarial parasite is more resistant to the virus. 
A)  EBV infection makes the malarial parasite able to produce lymphoma. 
B)  Malaria's strain on the immune system makes EBV infection worse. 
C)  Malaria occurs more frequently in those infected with EBV. 
D)  Malarial response of the immune system prevents an individual from making EBV antibodies. 
E)  A cell infected with the malarial parasite is more resistant to the virus.

Question 8

A geneticist introduces a transgene into yeast cells and isolates five independent cell lines in which the transgene has integrated into the yeast genome. In four of the lines, the transgene is expressed strongly, but in the fifth there is no expression at all.
-Which of the following is a likely explanation for the lack of transgene expression in the fifth cell line?

Accepted Answer

A)  A transgene integrated into a heterochromatic region of the genome. 
B)  A transgene integrated into a euchromatic region of the genome. 
C)  The transgene was mutated during the process of integration into the host cell genome. 
D)  The host cell lacks the enzymes necessary to express the transgene. 
E)  A transgene integrated into a region of the genome characterized by high histone acetylation. 
A)  A transgene integrated into a heterochromatic region of the genome. 
B)  A transgene integrated into a euchromatic region of the genome. 
C)  The transgene was mutated during the process of integration into the host cell genome. 
D)  The host cell lacks the enzymes necessary to express the transgene. 
E)  A transgene integrated into a region of the genome characterized by high histone acetylation.

Question 9

A researcher has arrived at a method to prevent gene expression from Drosophila embryonic genes. The following questions assume that he is using this method.
-The researcher in question measures the amount of new polypeptide production in embryos from 2-8 hours following fertilization and the results show a steady and significant rise in polypeptide concentration over that time. The researcher concludes that

Accepted Answer

A)  his measurement skills must be faulty. 
B)  the results are due to building new cell membranes to compartmentalize dividing nuclei. 
C)  the resulting new polypeptides are due to translation of maternal mRNAs. 
D)  the new polypeptides were inactive and not measurable until fertilization. 
E)  polypeptides were attached to egg membranes until this time. 
A)  his measurement skills must be faulty. 
B)  the results are due to building new cell membranes to compartmentalize dividing nuclei. 
C)  the resulting new polypeptides are due to translation of maternal mRNAs. 
D)  the new polypeptides were inactive and not measurable until fertilization. 
E)  polypeptides were attached to egg membranes until this time.

Question 10

The lactose operon is likely to be transcribed when

Accepted Answer

A)  there is more glucose in the cell than lactose. 
B)  the cyclic AMP levels are low. 
C)  there is glucose but no lactose in the cell. 
D)  the cyclic AMP and lactose levels are both high within the cell. 
E)  the cAMP level is high and the lactose level is low. 
A)  there is more glucose in the cell than lactose. 
B)  the cyclic AMP levels are low. 
C)  there is glucose but no lactose in the cell. 
D)  the cyclic AMP and lactose levels are both high within the cell. 
E)  the cAMP level is high and the lactose level is low.

Question 11

There is a mutation in the repressor that results in a molecule known as a super-repressor because it represses the lac operon permanently. Which of these would characterize such a mutant?

Accepted Answer

A)  It cannot bind to the operator. 
B)  It cannot make a functional repressor. 
C)  It cannot bind to the inducer. 
D)  It makes molecules that bind to one another. 
E)  It makes a repressor that binds CAP. 
A)  It cannot bind to the operator. 
B)  It cannot make a functional repressor. 
C)  It cannot bind to the inducer. 
D)  It makes molecules that bind to one another. 
E)  It makes a repressor that binds CAP.

Question 12

Which of the following is an example of post-transcriptional control of gene expression?

Accepted Answer

A)  the addition of methyl groups to cytosine bases of DNA 
B)  the binding of transcription factors to a promoter 
C)  the removal of introns and alternative splicing of exons 
D)  gene amplification contributing to cancer 
E)  the folding of DNA to form heterochromatin 
A)  the addition of methyl groups to cytosine bases of DNA 
B)  the binding of transcription factors to a promoter 
C)  the removal of introns and alternative splicing of exons 
D)  gene amplification contributing to cancer 
E)  the folding of DNA to form heterochromatin

Question 13

A researcher introduces double-stranded RNA into a culture of mammalian cells, and can identify its location or that of its smaller subsections experimentally, using a fluorescent probe.
-Some time later, she finds that the introduced strand separates into single-stranded RNAs, one of which is degraded. What does this enable the remaining strand to do?

Accepted Answer

A)  attach to histones in the chromatin 
B)  bind to complementary regions of target mRNAs 
C)  bind to Dicer enzymes to destroy other RNAs 
D)  activate other siRNAs in the cell 
E)  bind to noncomplementary RNA sequences 
A)  attach to histones in the chromatin 
B)  bind to complementary regions of target mRNAs 
C)  bind to Dicer enzymes to destroy other RNAs 
D)  activate other siRNAs in the cell 
E)  bind to noncomplementary RNA sequences

Question 14

Transcription of the structural genes in an inducible operon

Accepted Answer

A)  occurs continuously in the cell. 
B)  starts when the pathway's substrate is present. 
C)  starts when the pathway's product is present. 
D)  stops when the pathway's product is present. 
E)  does not result in the production of enzymes. 
A)  occurs continuously in the cell. 
B)  starts when the pathway's substrate is present. 
C)  starts when the pathway's product is present. 
D)  stops when the pathway's product is present. 
E)  does not result in the production of enzymes.

Question 15

Use the following information to answer the following questions.
In Drosophila after ~100 minutes postfertilization, the embryo looks like the following diagram, with all nuclei having moved to the periphery and, subsequently, four of the nuclei being sequestered at the posterior end.
   
Drosophila embryo after about 2 hours.
-The developmental stages described for Drosophila illustrate

Accepted Answer

A)  a hierarchy of gene expression. 
B)  homeotic developmental control. 
C)  the blockage of cell-to-cell communication. 
D)  homeotic developmental control and the blockage of cell-to-cell communication. 
E)  a hierarchy of gene expression and the blockage of cell-to-cell communication. 
A)  a hierarchy of gene expression. 
B)  homeotic developmental control. 
C)  the blockage of cell-to-cell communication. 
D)  homeotic developmental control and the blockage of cell-to-cell communication. 
E)  a hierarchy of gene expression and the blockage of cell-to-cell communication.

Question 16

Which of the following mechanisms is (are)used to coordinate the expression of multiple, related genes in eukaryotic cells?

Accepted Answer

A)  Genes are organized into clusters, with local chromatin structures influencing the expression of all the genes at once. 
B)  The genes share a common intragenic sequence, and allow several activators to turn on their transcription, regardless of location. 
C)  The genes are organized into large operons, allowing them to be transcribed as a single unit. 
D)  A single repressor is able to turn off several related genes. 
E)  Environmental signals enter the cell and bind directly to promoters. 
A)  Genes are organized into clusters, with local chromatin structures influencing the expression of all the genes at once. 
B)  The genes share a common intragenic sequence, and allow several activators to turn on their transcription, regardless of location. 
C)  The genes are organized into large operons, allowing them to be transcribed as a single unit. 
D)  A single repressor is able to turn off several related genes. 
E)  Environmental signals enter the cell and bind directly to promoters.

Question 17

Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome.
-If she moves the promoter for the lac operon to the region between the beta galactosidase gene and the permease gene, which of the following would be likely?

Accepted Answer

A)  Three structural genes will no longer be expressed. 
B)  RNA polymerase will no longer transcribe permease. 
C)  The operon will no longer be inducible. 
D)  Beta galactosidase will be produced. 
E)  The cell will continue to metabolize but more slowly. 
A)  Three structural genes will no longer be expressed. 
B)  RNA polymerase will no longer transcribe permease. 
C)  The operon will no longer be inducible. 
D)  Beta galactosidase will be produced. 
E)  The cell will continue to metabolize but more slowly.

Question 18

In response to chemical signals, prokaryotes can do which of the following?

Accepted Answer

A)  turn off translation of their mRNA 
B)  alter the level of production of various enzymes 
C)  increase the number and responsiveness of their ribosomes 
D)  inactivate their mRNA molecules 
E)  alter the sequence of amino acids in certain proteins 
A)  turn off translation of their mRNA 
B)  alter the level of production of various enzymes 
C)  increase the number and responsiveness of their ribosomes 
D)  inactivate their mRNA molecules 
E)  alter the sequence of amino acids in certain proteins

Question 19

A few decades ago, Knudsen and colleagues proposed a theory that, for a normal cell to become a cancer cell, a minimum of two genetic changes had to occur in that cell. Knudsen was studying retinoblastoma, a childhood cancer of the eye.
-One of the human leukemias, called CML (chronic myelogenous leukemia), is associated with a chromosomal translocation between chromosomes 9 and 22 in somatic cells of bone marrow. Which of the following allows CML to provide further evidence of this multistep nature of cancer?

Accepted Answer

A)  CML usually occurs in more elderly persons (late age of onset). 
B)  The resulting chromosome 22 is abnormally short; it is then known as the Philadelphia chromosome. 
C)  The translocation requires breaks in both chromosomes 9 and 22, followed by fusion between the reciprocal pieces. 
D)  CML involves a proto-oncogene known as abl. 
E)  CML can usually be treated by chemotherapy. 
A)  CML usually occurs in more elderly persons (late age of onset). 
B)  The resulting chromosome 22 is abnormally short; it is then known as the Philadelphia chromosome. 
C)  The translocation requires breaks in both chromosomes 9 and 22, followed by fusion between the reciprocal pieces. 
D)  CML involves a proto-oncogene known as abl. 
E)  CML can usually be treated by chemotherapy.

Question 20

One hereditary disease in humans, called xeroderma pigmentosum (XP), makes homozygous individuals exceptionally susceptible to UV-induced mutation damage in the cells of exposed tissue, especially skin. Without extraordinary avoidance of sunlight exposure, patients soon succumb to numerous skin cancers.
-Which of the following best describes this phenomenon?

Accepted Answer

A)  inherited cancer taking a few years to be expressed 
B)  embryonic or fetal cancer 
C)  inherited predisposition to mutation 
D)  inherited inability to repair UV-induced mutation 
E)  susceptibility to chemical carcinogens 
A)  inherited cancer taking a few years to be expressed 
B)  embryonic or fetal cancer 
C)  inherited predisposition to mutation 
D)  inherited inability to repair UV-induced mutation 
E)  susceptibility to chemical carcinogens

Exam 18: Regulation of Gene Expression

The product of the bicoid gene in Drosophila provides essential information about

Which of the following, when taken up by the cell, binds to the repressor so that the repressor no longer binds to the operator?

Which of the following genes map out the basic subdivisions along the anterior-posterior axis of the Drosophila embryo?

Your brother has just purchased a new plastic model airplane. He places all the parts on the table in approximately the positions in which they will be located when the model is complete. His actions are analogous to which process in development?

The lactose operon is likely to be transcribed when

There is a mutation in the repressor that results in a molecule known as a super-repressor because it represses the lac operon permanently. Which of these would characterize such a mutant?

Which of the following is an example of post-transcriptional control of gene expression?

Transcription of the structural genes in an inducible operon

Which of the following mechanisms is (are)used to coordinate the expression of multiple, related genes in eukaryotic cells?

Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. -If she moves the promoter for the lac operon to the region between the beta galactosidase gene and the permease gene, which of the following would be likely?

In response to chemical signals, prokaryotes can do which of the following?

Introduction: Themes in the Study of Life

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

Membrane Structure and Function

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

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 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 Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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