Question 1

A rise in extracellular glucose results in which of the following changes at the lac operon?

Accepted Answer

A)  RNA polymerase binds the lac promoter with greater affinity 
B)  cAMP receptor protein (CRP) detaches from the lac promoter 
C)  lac repressor is allosterically inactivated 
D)  lac operator binds inducer with greater affinity 
A)  RNA polymerase binds the lac promoter with greater affinity 
B)  cAMP receptor protein (CRP) detaches from the lac promoter 
C)  lac repressor is allosterically inactivated 
D)  lac operator binds inducer with greater affinity

Question 2

If a mutation alters a maternal effect gene in a female Drosophila zygote, which of the following is most likely to occur?

Accepted Answer

A)  She will not develop past the early embryonic stage. 
B)  All of her offspring will show the mutant phenotype, regardless of their genotype. 
C)  Only her male offspring will show the mutant phenotype. 
D)  Only her female offspring will show the mutant phenotype. 
A)  She will not develop past the early embryonic stage. 
B)  All of her offspring will show the mutant phenotype, regardless of their genotype. 
C)  Only her male offspring will show the mutant phenotype. 
D)  Only her female offspring will show the mutant phenotype.

Question 3

Forms of the Ras protein found in tumors usually cause which of the following events to occur?

Accepted Answer

A)  DNA replication to stop 
B)  decreased cell-to-cell adhesion 
C)  cell division to cease 
D)  excessive cell division 
A)  DNA replication to stop 
B)  decreased cell-to-cell adhesion 
C)  cell division to cease 
D)  excessive cell division

Question 4

In colorectal cancer, several genes must be mutated for a cell to develop into a cancer cell. Which of the following kinds of genes would you expect to be mutated?

Accepted Answer

A)  genes coding enzymes that act in the colon 
B)  genes involved in control of the cell cycle 
C)  genes that are especially susceptible to mutation 
D)  genes regulating cell division in colon bacteria 
A)  genes coding enzymes that act in the colon 
B)  genes involved in control of the cell cycle 
C)  genes that are especially susceptible to mutation 
D)  genes regulating cell division in colon bacteria

Question 5

What would occur if the repressor of an inducible operon were mutated so it could not bind the operator?

Accepted Answer

A)  irreversible binding of the repressor to the promoter 
B)  reduced transcription of the operon's genes 
C)  buildup of a substrate for the pathway controlled by the operon 
D)  continuous transcription of the operon's genes 
A)  irreversible binding of the repressor to the promoter 
B)  reduced transcription of the operon's genes 
C)  buildup of a substrate for the pathway controlled by the operon 
D)  continuous transcription of the operon's genes

Question 6

A researcher introduced many copies of a double-stranded RNA into a culture of mammalian cells and used a fluorescent probe to follow it. Later she finds that the introduced strands separate into single-stranded RNAs and she hypothesizes that the molecules is acting as an miRNA. Which of the following pieces of evidence would support her claim?

Accepted Answer

A)  The degradation rate of the single strand is slower than that of other cellular mRNA's. 
B)  The rate of accumulation of the polypeptide encoded by the target mRNA is reduced. 
C)  The amount of the RNA she introduced increases due to transcription. 
D)  After separating the strands she introduced shut down all translation. 
A)  The degradation rate of the single strand is slower than that of other cellular mRNA's. 
B)  The rate of accumulation of the polypeptide encoded by the target mRNA is reduced. 
C)  The amount of the RNA she introduced increases due to transcription. 
D)  After separating the strands she introduced shut down all translation.

Question 7

A researcher introduced many copies of a double-stranded RNA into a culture of mammalian cells and used a fluorescent probe to follow it. She found that the introduced strands separated; one strand degraded and the other single-stranded RNA remained. The remaining strand is able to do which of the following?

Accepted Answer

A)  attach to histones in the chromatin 
B)  bind to complementary regions of target mRNAs 
C)  activate other siRNAs in the cell 
D)  act as a template for transcription 
A)  attach to histones in the chromatin 
B)  bind to complementary regions of target mRNAs 
C)  activate other siRNAs in the cell 
D)  act as a template for transcription

Question 8

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 
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

Question 9

If the DNA of a mammalian promoter region experiences increased methylation on cytosine (C) which of the following results is most likely to occur?

Accepted Answer

A)  decreased chromatin condensation 
B)  activation of histone tails for enzymatic function 
C)  higher levels of transcription of certain genes 
D)  inactivation of the gene 
A)  decreased chromatin condensation 
B)  activation of histone tails for enzymatic function 
C)  higher levels of transcription of certain genes 
D)  inactivation of the gene

Question 10

In wildtype Drosophila embryos, the bicoid mRNA is localized to the anterior end of the embryo. If bicoid mRNA was injected into the embryo's posterior end as well, which of the following developmental events would occur?

Accepted Answer

A)  The embryo would grow extra wings and legs. 
B)  The embryo would have altered segmentation. 
C)  The embryo would show anterior structures at both ends of the embryo. 
D)  The embryo would develop normally. 
A)  The embryo would grow extra wings and legs. 
B)  The embryo would have altered segmentation. 
C)  The embryo would show anterior structures at both ends of the embryo. 
D)  The embryo would develop normally.

Question 11

Which of the following types of RNA is responsible for helping to reestablish methylation patterns during gamete formation?

Accepted Answer

A)  miRNA 
B)  piRNA 
C)  lncRNA 
D)  siRNA 
A)  miRNA 
B)  piRNA 
C)  lncRNA 
D)  siRNA

Question 12

Gene expression is often assayed by measuring the level of mRNA produced from a gene. Which of the following levels of the control of gene expression can by analyzed by this type of assay?

Accepted Answer

A)  replication control 
B)  transcriptional control 
C)  alternative splicing 
D)  translational control 
A)  replication control 
B)  transcriptional control 
C)  alternative splicing 
D)  translational control

Question 13

Which of the following explains why introducing the MyoD protein into a fat cell causes that cell to become a muscle cell but adding it to a neuron will have no effect?

Accepted Answer

A)  Fat cells are undifferentiated, the MyoD protein causes them to differentiate. 
B)  Neurons are a differentiation step after muscle cells, they cannot go "backwards." 
C)  Muscle-specific gene expression requires a protein that neurons do not make. 
D)  MyoD is causes positive feedback of MyoD expression in fats cells but not neurons. 
A)  Fat cells are undifferentiated, the MyoD protein causes them to differentiate. 
B)  Neurons are a differentiation step after muscle cells, they cannot go "backwards." 
C)  Muscle-specific gene expression requires a protein that neurons do not make. 
D)  MyoD is causes positive feedback of MyoD expression in fats cells but not neurons.

Question 14

Which of the following predictions about the survival of a lactose intolerant E. coli cell is most likely correct?

Accepted Answer

A)  The cell will survive if the environment has sufficient glucose. 
B)  The cell will survive if the cell has high levels of lacI expression. 
C)  The cell will not survive because E. coli require lactose as a nutrient source for life. 
D)  The cell will not survive because inducible operons must be stimulated for the cell to survive. 
A)  The cell will survive if the environment has sufficient glucose. 
B)  The cell will survive if the cell has high levels of lacI expression. 
C)  The cell will not survive because E. coli require lactose as a nutrient source for life. 
D)  The cell will not survive because inducible operons must be stimulated for the cell to survive.

Question 15

Which of the following statements correctly describes a characteristic of tumor-suppressor genes?

Accepted Answer

A)  They are frequently overexpressed in cancerous cells. 
B)  They are cancer-causing genes introduced into cells by viruses. 
C)  They encode proteins that help prevent uncontrolled cell growth. 
D)  They often encode proteins that stimulate the cell cycle. 
A)  They are frequently overexpressed in cancerous cells. 
B)  They are cancer-causing genes introduced into cells by viruses. 
C)  They encode proteins that help prevent uncontrolled cell growth. 
D)  They often encode proteins that stimulate the cell cycle.

Question 16

Muscle cells differ from nerve cells mainly because they ________.

Accepted Answer

A)  express different genes 
B)  contain different genes 
C)  use different genetic codes 
D)  have unique ribosomes 
A)  express different genes 
B)  contain different genes 
C)  use different genetic codes 
D)  have unique ribosomes

Question 17

DNA methylation and histone acetylation are examples of which of the following processes?

Accepted Answer

A)  genetic mutation 
B)  chromosomal rearrangements 
C)  epigenetic phenomena 
D)  translocation 
A)  genetic mutation 
B)  chromosomal rearrangements 
C)  epigenetic phenomena 
D)  translocation

Question 18

If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then ________.

Accepted Answer

A)  the amino acid inactivates the repressor 
B)  the repressor is active in the absence of the amino acid 
C)  the amino acid acts as a corepressor 
D)  the amino acid turns on transcription of the operon 
A)  the amino acid inactivates the repressor 
B)  the repressor is active in the absence of the amino acid 
C)  the amino acid acts as a corepressor 
D)  the amino acid turns on transcription of the operon

Question 19

Which of the following describes the normal function of the p53 gene product?

Accepted Answer

A)  It inhibits the cell cycle. 
B)  It slows down the rate of DNA replication by interfering with the binding of DNA polymerase. 
C)  It causes cells to reduce expression of genes involved in DNA repair. 
D)  It allows cells to pass on mutations due to DNA damage. 
A)  It inhibits the cell cycle. 
B)  It slows down the rate of DNA replication by interfering with the binding of DNA polymerase. 
C)  It causes cells to reduce expression of genes involved in DNA repair. 
D)  It allows cells to pass on mutations due to DNA damage.

Question 20

Which of the following statements correctly describes the primary difference between enhancers and proximal control elements?

Accepted Answer

A)  Enhancers are transcription factors; proximal control elements are DNA sequences. 
B)  Enhancers improve transcription; proximal control elements inhibit transcription. 
C)  Enhancers are located considerable distances from the promoter; proximal control elements are close to the promoter. 
D)  Enhancers are long regions of DNA; proximal control elements are shorter RNA molecules that stand in for DNA. 
A)  Enhancers are transcription factors; proximal control elements are DNA sequences. 
B)  Enhancers improve transcription; proximal control elements inhibit transcription. 
C)  Enhancers are located considerable distances from the promoter; proximal control elements are close to the promoter. 
D)  Enhancers are long regions of DNA; proximal control elements are shorter RNA molecules that stand in for DNA.

Exam 18: Control of Gene Expression

A rise in extracellular glucose results in which of the following changes at the lac operon?

If a mutation alters a maternal effect gene in a female Drosophila zygote, which of the following is most likely to occur?

Forms of the Ras protein found in tumors usually cause which of the following events to occur?

In colorectal cancer, several genes must be mutated for a cell to develop into a cancer cell. Which of the following kinds of genes would you expect to be mutated?

What would occur if the repressor of an inducible operon were mutated so it could not bind the operator?

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

If the DNA of a mammalian promoter region experiences increased methylation on cytosine (C) which of the following results is most likely to occur?

In wildtype Drosophila embryos, the bicoid mRNA is localized to the anterior end of the embryo. If bicoid mRNA was injected into the embryo's posterior end as well, which of the following developmental events would occur?

Which of the following types of RNA is responsible for helping to reestablish methylation patterns during gamete formation?

Gene expression is often assayed by measuring the level of mRNA produced from a gene. Which of the following levels of the control of gene expression can by analyzed by this type of assay?

Which of the following explains why introducing the MyoD protein into a fat cell causes that cell to become a muscle cell but adding it to a neuron will have no effect?

Which of the following predictions about the survival of a lactose intolerant E. coli cell is most likely correct?

Which of the following statements correctly describes a characteristic of tumor-suppressor genes?

Muscle cells differ from nerve cells mainly because they ________.

DNA methylation and histone acetylation are examples of which of the following processes?

If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then ________.

Which of the following describes the normal function of the p53 gene product?

Which of the following statements correctly describes the primary difference between enhancers and proximal control elements?

Biology and Its Themes

Atoms and Molecules

The Chemistry of Water

Carbon: the Basis of Molecular Diversity

Biological Macromolecules and Lipids

Energy and Life

Cell Structure and Function

Cell Membranes

Cellular Signaling

Cell Respiration

Photosynthetic Processes

Mitosis

Sexual Life Cycles and Meiosis

Mendelian Genetics

Linkage and Chromosomes

Nucleic Acids and Inheritance

Expression of Genes

Dna Technology

The Evolution of Genomes

How Evolution Works

Phylogenetic Reconstruction

Microevolution

Species and Speciation

Macroevolution

Introduction to Viruses

Prokaryotes

The Origin and Evolution of Eukaryotes

Nonvascular and Seedless Vascular Plants

Seed Plants

Introduction to Fungi

An Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure and Growth

Transport in Vascular Plants

Plant Nutrition

Reproduction of Flowering Plants

Plant Signals and Behavior

The Animal Body

Chemical Signals in Animals

Animal Digestive Systems

Animal Transport Systems

Animal Excretory Systems

Animal Reproductive Systems

Development in Animals

Animal Defenses Against Infection

Electrical Signals in Animals

Neural Regulation in Animals

Sensation and Movement in Animals

An Overview of Ecology

Behavioral Ecology

Populations and Life History Traits

Biodiversity and Communities

Energy Flow and Chemical Cycling in Ecosystems

Conservation and Global Ecology

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