Question 1

Which of the following is a protein product of a regulatory gene?

Accepted Answer

A) operon 
B) inducer 
C) promoter 
D) repressor 
A) operon 
B) inducer 
C) promoter 
D) repressor D

Question 2

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

Accepted Answer

A) A specific combination of control elements in each gene's enhancer coordinates the simultaneous activation of the genes. 
B) The genes share a single common enhancer,which allows appropriate activators to turn on their transcription at the same time. 
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. 
A) A specific combination of control elements in each gene's enhancer coordinates the simultaneous activation of the genes. 
B) The genes share a single common enhancer,which allows appropriate activators to turn on their transcription at the same time. 
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. A

Question 3

Which statement about DNA in one of your brain cells is true?

Accepted Answer

A) Most of the DNA codes for protein. 
B) The majority of genes are likely to be transcribed. 
C) It is the same as the DNA in one of your liver cells. 
D) Many genes are grouped into operon-like clusters. 
A) Most of the DNA codes for protein. 
B) The majority of genes are likely to be transcribed. 
C) It is the same as the DNA in one of your liver cells. 
D) Many genes are grouped into operon-like clusters. C

Question 4

The functioning of enhancers is an example of

Accepted Answer

A) a eukaryotic equivalent of prokaryotic promoter functioning. 
B) transcriptional control of gene expression. 
C) the stimulation of translation by initiation factors. 
D) post-translational control that activates certain proteins. 
A) a eukaryotic equivalent of prokaryotic promoter functioning. 
B) transcriptional control of gene expression. 
C) the stimulation of translation by initiation factors. 
D) post-translational control that activates certain proteins.

Question 5

When the substrate of a metabolic pathway is present in a bacterial cell,which of the following processes will occur?

Accepted Answer

A) transcription of the genes in a repressible operon 
B) deactivation of the promoter for an operon 
C) transcription of the genes in an inducible operon 
D) allosteric regulation of an inducer 
A) transcription of the genes in a repressible operon 
B) deactivation of the promoter for an operon 
C) transcription of the genes in an inducible operon 
D) allosteric regulation of an inducer

Question 6

Which of the following activities can prokaryotes carry out in response to certain chemical signals?

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 
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

Question 7

Allolactose,an isomer of lactose,is formed in small amounts from lactose.An E.coli cell is presented for the first time with the sugar lactose (containing allolactose)as a potential food source.Which of the following processes occurs when the lactose enters the cell?

Accepted Answer

A) The repressor protein attaches to the regulator. 
B) Allolactose binds to the repressor protein. 
C) Allolactose binds to the operator. 
D) The repressor protein and allolactose bind to RNA polymerase. 
E) Allolactose binds to the inducer. 
A) The repressor protein attaches to the regulator. 
B) Allolactose binds to the repressor protein. 
C) Allolactose binds to the operator. 
D) The repressor protein and allolactose bind to RNA polymerase. 
E) Allolactose binds to the inducer.

Question 8

What would be the result of a mutation that deactivates the regulatory gene of a repressible operon in an Escherichia coli cell?

Accepted Answer

A) continuous transcription of the enzyme-coding gene controlled by that regulator 
B) complete inhibition of transcription of the enzyme-coding gene controlled by that regulator 
C) irreversible binding of the repressor to the operator 
D) inactivation of RNA polymerase by alteration of its active site 
A) continuous transcription of the enzyme-coding gene controlled by that regulator 
B) complete inhibition of transcription of the enzyme-coding gene controlled by that regulator 
C) irreversible binding of the repressor to the operator 
D) inactivation of RNA polymerase by alteration of its active site

Question 9

At the beginning of this century there was a general announcement regarding the sequencing of the human genome and the genomes of many other multicellular eukaryotes.There was surprise expressed by many that the number of protein-coding sequences in the human genome was much smaller than had been expected.Which of the following statements would describe most of the rest of the DNA in the human genome?

Accepted Answer

A) "junk" DNA that serves no possible purpose 
B) rRNA and tRNA coding sequences 
C) DNA that is translated directly without being transcribed 
D) non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function 
A) "junk" DNA that serves no possible purpose 
B) rRNA and tRNA coding sequences 
C) DNA that is translated directly without being transcribed 
D) non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function

Question 10

Which of the following events occurs during DNA replication?

Accepted Answer

A) All methylation of the DNA is lost at the first round of replication. 
B) DNA polymerase is blocked by methyl groups,and methylated regions of the genome are therefore left uncopied. 
C) Methylation of the DNA is maintained because methylation enzymes act at DNA sites where one strand is already methylated and thus correctly methylate daughter strands after replication. 
D) Methylation of the DNA is maintained because DNA polymerase directly incorporates methylated nucleotides into the new strand opposite any methylated nucleotides in the template. 
A) All methylation of the DNA is lost at the first round of replication. 
B) DNA polymerase is blocked by methyl groups,and methylated regions of the genome are therefore left uncopied. 
C) Methylation of the DNA is maintained because methylation enzymes act at DNA sites where one strand is already methylated and thus correctly methylate daughter strands after replication. 
D) Methylation of the DNA is maintained because DNA polymerase directly incorporates methylated nucleotides into the new strand opposite any methylated nucleotides in the template.

Question 11

A researcher introduces double-stranded RNA into a culture of mammalian cells.The double-stranded RNA corresponds to a region of a protein-coding gene of interest.How may the introduced RNA affect gene expression in these cells?

Accepted Answer

A) The overall rate of translation in the cell may be significantly reduced. 
B) The overall rate of transcription in the cell may be significantly reduced. 
C) The overall rate of transcription in the cell may be significantly increased. 
D) The amount of protein produced by the target gene may be significantly reduced. 
A) The overall rate of translation in the cell may be significantly reduced. 
B) The overall rate of transcription in the cell may be significantly reduced. 
C) The overall rate of transcription in the cell may be significantly increased. 
D) The amount of protein produced by the target gene may be significantly reduced.

Question 12

Most repressor proteins exhibit allosteric properties.Which of the following molecules binds with the repressor to alter its structure?

Accepted Answer

A) inducer 
B) promoter 
C) RNA polymerase 
D) transcription factor 
A) inducer 
B) promoter 
C) RNA polymerase 
D) transcription factor

Question 13

In a genome-wide expression study using a DNA microarray assay,what is each spot used to detect?

Accepted Answer

A) the fate of proteins produced by a cell 
B) the location of a protein produced by a cell 
C) the location of a gene within a cell 
D) the expression of a specific gene by a cell 
A) the fate of proteins produced by a cell 
B) the location of a protein produced by a cell 
C) the location of a gene within a cell 
D) the expression of a specific gene by a cell

Question 14

Which of the following techniques involves reverse transcriptase,PCR amplification,and gel electrophoresis?

Accepted Answer

A) DNA microarray assays 
B) RT-PCR 
C) in situ hybridization 
D) nucleic acid hybridization 
A) DNA microarray assays 
B) RT-PCR 
C) in situ hybridization 
D) nucleic acid hybridization

Question 15

Which of the following statements correctly describes the role of a molecule that controls a repressible operon?

Accepted Answer

A) The molecule binds to the promoter region and decreases the affinity of RNA polymerase for the promoter. 
B) The molecule binds to the operator region and blocks the attachment of RNA polymerase to the promoter. 
C) The molecule increases the production of inactive repressor proteins. 
D) The molecule binds to the repressor protein and activates it. 
A) The molecule binds to the promoter region and decreases the affinity of RNA polymerase for the promoter. 
B) The molecule binds to the operator region and blocks the attachment of RNA polymerase to the promoter. 
C) The molecule increases the production of inactive repressor proteins. 
D) The molecule binds to the repressor protein and activates it.

Question 16

The tryptophan operon in some bacteria is a repressible operon.Which of the following statements correctly describes this operon?

Accepted Answer

A) It is permanently active. 
B) It is activated only when tryptophan is present in the growth medium. 
C) It is activated only when glucose is present in the growth medium. 
D) It is deactivated whenever tryptophan is added to the growth medium. 
A) It is permanently active. 
B) It is activated only when tryptophan is present in the growth medium. 
C) It is activated only when glucose is present in the growth medium. 
D) It is deactivated whenever tryptophan is added to the growth medium.

Question 17

Among the newly discovered small noncoding RNAs,one type reestablishes methylation patterns during gamete formation and blocks expression of some transposons.
What are these types of RNA called?

Accepted Answer

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

Question 18

Which of the following must occur in order for a repressible operon to be transcribed?

Accepted Answer

A) A corepressor must be present. 
B) RNA polymerase and the active repressor must be present. 
C) RNA polymerase must bind to the promoter,and the repressor must be inactive. 
D) RNA polymerase cannot be present,and the repressor must be inactive. 
A) A corepressor must be present. 
B) RNA polymerase and the active repressor must be present. 
C) RNA polymerase must bind to the promoter,and the repressor must be inactive. 
D) RNA polymerase cannot be present,and the repressor must be inactive.

Question 19

Which of the following statements best describes siRNA?

Accepted Answer

A) a short double-stranded RNA,one of whose strands can block gene expression 
B) a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor 
C) a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits 
D) an RNA sequence that can block the expression of some transposons 
A) a short double-stranded RNA,one of whose strands can block gene expression 
B) a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor 
C) a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits 
D) an RNA sequence that can block the expression of some transposons

Question 20

A lack of which of the following molecules would result in the cell's inability to "turn off" genes?

Accepted Answer

A) operon 
B) inducer 
C) promoter 
D) corepressor 
A) operon 
B) inducer 
C) promoter 
D) corepressor

Exam 15: Regulation of Gene Expression

Which of the following is a protein product of a regulatory gene?

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

Which statement about DNA in one of your brain cells is true?

The functioning of enhancers is an example of

When the substrate of a metabolic pathway is present in a bacterial cell,which of the following processes will occur?

Which of the following activities can prokaryotes carry out in response to certain chemical signals?

Allolactose,an isomer of lactose,is formed in small amounts from lactose.An E.coli cell is presented for the first time with the sugar lactose (containing allolactose)as a potential food source.Which of the following processes occurs when the lactose enters the cell?

What would be the result of a mutation that deactivates the regulatory gene of a repressible operon in an Escherichia coli cell?

Which of the following events occurs during DNA replication?

A researcher introduces double-stranded RNA into a culture of mammalian cells.The double-stranded RNA corresponds to a region of a protein-coding gene of interest.How may the introduced RNA affect gene expression in these cells?

Most repressor proteins exhibit allosteric properties.Which of the following molecules binds with the repressor to alter its structure?

In a genome-wide expression study using a DNA microarray assay,what is each spot used to detect?

Which of the following techniques involves reverse transcriptase,PCR amplification,and gel electrophoresis?

Which of the following statements correctly describes the role of a molecule that controls a repressible operon?

The tryptophan operon in some bacteria is a repressible operon.Which of the following statements correctly describes this operon?

Among the newly discovered small noncoding RNAs,one type reestablishes methylation patterns during gamete formation and blocks expression of some transposons. What are these types of RNA called?

Which of the following must occur in order for a repressible operon to be transcribed?

Which of the following statements best describes siRNA?

A lack of which of the following molecules would result in the cell's inability to "turn off" genes?

Introduction: Evolution and the Foundations of Biology

The Chemical Context of Life

Carbon and the Molecular Diversity of Life

A Tour of the Cell

Membrane Transport and Cell Signaling

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

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

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