Question 1

In eukaryotes, general transcription factors

Accepted Answer

A)  are required for the expression of specific protein-encoding genes. 
B)  bind to other proteins or to a sequence element within the promoter called the TATA box. 
C)  inhibit RNA polymerase binding to the promoter and begin transcribing. 
D)  usually lead to a high level of transcription even without additional specific transcription factors. 
E)  bind to sequences just after the start site of transcription. 
A)  are required for the expression of specific protein-encoding genes. 
B)  bind to other proteins or to a sequence element within the promoter called the TATA box. 
C)  inhibit RNA polymerase binding to the promoter and begin transcribing. 
D)  usually lead to a high level of transcription even without additional specific transcription factors. 
E)  bind to sequences just after the start site of transcription. B

Question 2

Please use the following information to answer the question(s) below.
Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome.
-If she moves the operator to the far end of the operon, past the transacetylase (lacA) gene, which of the following would likely occur when the cell is exposed to lactose?

Accepted Answer

A)  The inducer will no longer bind to the repressor. 
B)  The repressor will no longer bind to the operator. 
C)  The operon will never be transcribed. 
D)  The three genes of the operon will be transcribed continuously. 
E)  The repressor protein will no longer be produced. 
A)  The inducer will no longer bind to the repressor. 
B)  The repressor will no longer bind to the operator. 
C)  The operon will never be transcribed. 
D)  The three genes of the operon will be transcribed continuously. 
E)  The repressor protein will no longer be produced. D

Question 3

Since Watson and Crick described DNA in 1953, which of the following statements might best explain why the function of small RNAs is still being explained?

Accepted Answer

A)  As RNAs have evolved since that time, they have taken on new functions. 
B)  Watson and Crick described DNA but did not predict any function for RNA. 
C)  The functions of small RNAs could not be approached until the entire human genome was sequenced. 
D)  Ethical considerations prevented scientists from exploring this material until recently. 
E)  Changes in technology as well as our ability to determine how much of the DNA is expressed have now made this possible. 
A)  As RNAs have evolved since that time, they have taken on new functions. 
B)  Watson and Crick described DNA but did not predict any function for RNA. 
C)  The functions of small RNAs could not be approached until the entire human genome was sequenced. 
D)  Ethical considerations prevented scientists from exploring this material until recently. 
E)  Changes in technology as well as our ability to determine how much of the DNA is expressed have now made this possible. E

Question 4

Please use the following information to answer the question(s) below.
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 (lacZ) gene and the permease (lacY) gene, which of the following would be likely?

Accepted Answer

A)  The three genes will be expressed normally. 
B)  RNA polymerase will no longer transcribe permease. 
C)  The operon will no longer be inducible. 
D)  Beta galactosidase will not be produced. 
E)  The cell will continue to metabolize but more slowly. 
A)  The three genes will be expressed normally. 
B)  RNA polymerase will no longer transcribe permease. 
C)  The operon will no longer be inducible. 
D)  Beta galactosidase will not be produced. 
E)  The cell will continue to metabolize but more slowly.

Question 5

For a repressible operon to be transcribed, which of the following must occur?

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 6

What is the role of a molecule that controls a repressible operon?

Accepted Answer

A)  bind to the promoter region and decrease the affinity of RNA polymerase for the promoter 
B)  bind to the operator region and block the attachment of RNA polymerase to the promoter 
C)  increase the production of inactive repressor proteins 
D)  bind to the repressor protein and deactivate it 
E)  bind to the repressor protein and activate it 
A)  bind to the promoter region and decrease the affinity of RNA polymerase for the promoter 
B)  bind to the operator region and block the attachment of RNA polymerase to the promoter 
C)  increase the production of inactive repressor proteins 
D)  bind to the repressor protein and deactivate it 
E)  bind to the repressor protein and activate it

Question 7

In response to chemical signals, prokaryotes can carry out which of the following activities?

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 8

Steroid hormones produce their effects in cells by

Accepted Answer

A)  activating key enzymes in metabolic pathways. 
B)  activating translation of certain mRNAs. 
C)  promoting the breakdown of specific mRNAs. 
D)  binding to receptors inside the cell and promoting transcription of specific genes. 
A)  activating key enzymes in metabolic pathways. 
B)  activating translation of certain mRNAs. 
C)  promoting the breakdown of specific mRNAs. 
D)  binding to receptors inside the cell and promoting transcription of specific genes.

Question 9

Researchers are looking for better treatments for breast cancer. For a particular DNA microarray assay (DNA chip), cDNA has been made from the mRNAs of a dozen patients' breast tumor biopsies. What would the researchers be looking for in this type of assay?

Accepted Answer

A)  a particular gene that is amplified in all or most of the patient samples 
B)  a pattern of fluorescence that indicates which cells are overproliferating 
C)  a pattern shared among some or all of the samples that indicates gene expression differing from control samples 
D)  a group of cDNAs that act differently from those on the rest of the grid 
E)  a group of cDNAs that match those in non-breast-cancer control samples from the same population 
A)  a particular gene that is amplified in all or most of the patient samples 
B)  a pattern of fluorescence that indicates which cells are overproliferating 
C)  a pattern shared among some or all of the samples that indicates gene expression differing from control samples 
D)  a group of cDNAs that act differently from those on the rest of the grid 
E)  a group of cDNAs that match those in non-breast-cancer control samples from the same population

Question 10

If you were to observe the activity of methylated DNA, you would expect it to

Accepted Answer

A)  be replicating nearly continuously. 
B)  be unwinding in preparation for protein synthesis. 
C)  be transcriptionally inactive. 
D)  be very actively transcribed and translated. 
E)  induce protein synthesis by not allowing repressors to bind to it. 
A)  be replicating nearly continuously. 
B)  be unwinding in preparation for protein synthesis. 
C)  be transcriptionally inactive. 
D)  be very actively transcribed and translated. 
E)  induce protein synthesis by not allowing repressors to bind to it.

Question 11

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. 
E)  Methylated DNA is copied in the cytoplasm, and unmethylated DNA is copied in the nucleus. 
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. 
E)  Methylated DNA is copied in the cytoplasm, and unmethylated DNA is copied in the nucleus.

Question 12

Gene expression can be blocked by small RNA molecules called siRNAs. What is this process called?

Accepted Answer

A)  RNA interference 
B)  RNA blocking 
C)  RNA targeting 
D)  RNA disposal 
A)  RNA interference 
B)  RNA blocking 
C)  RNA targeting 
D)  RNA disposal

Question 13

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 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 14

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)  the binding of RNA polymerase to transcription factors 
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)  the binding of RNA polymerase to transcription factors

Question 15

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

Question 16

Altering patterns of gene expression in prokaryotes would most likely contribute to the organism's survival in which of the following ways?

Accepted Answer

A)  organizing gene expression so that genes are expressed in a given order 
B)  allowing each gene to be expressed an equal number of times 
C)  allowing the organism to adjust to changes in environmental conditions 
D)  allowing young organisms to respond differently than more mature organisms 
A)  organizing gene expression so that genes are expressed in a given order 
B)  allowing each gene to be expressed an equal number of times 
C)  allowing the organism to adjust to changes in environmental conditions 
D)  allowing young organisms to respond differently than more mature organisms

Question 17

One way scientists hope to use the recent knowledge gained about noncoding RNAs lies with the possibilities for their use in medicine. Of the following scenarios for future research, which would you expect to gain most from RNAs?

Accepted Answer

A)  exploring a way to turn on the expression of introns 
B)  targeting siRNAs to disable the expression of an allele associated with an autosomal recessive disease 
C)  targeting siRNAs to disable the expression of an allele associated with an autosomal dominant disease 
D)  creating knockout organisms that can be useful for pharmaceutical drug design 
E)  looking for a way to prevent viral DNA from causing infection in humans 
A)  exploring a way to turn on the expression of introns 
B)  targeting siRNAs to disable the expression of an allele associated with an autosomal recessive disease 
C)  targeting siRNAs to disable the expression of an allele associated with an autosomal dominant disease 
D)  creating knockout organisms that can be useful for pharmaceutical drug design 
E)  looking for a way to prevent viral DNA from causing infection in humans

Question 18

In positive control of several sugar-metabolism-related operons, the cAMP receptor protein (CRP) binds to DNA to stimulate transcription. What causes an increase in CRP?

Accepted Answer

A)  increase in glucose and increase in cAMP 
B)  decrease in glucose and increase in cAMP 
C)  increase in glucose and decrease in cAMP 
D)  decrease in glucose and increase in repressor 
E)  decrease in glucose and decrease in repressor 
A)  increase in glucose and increase in cAMP 
B)  decrease in glucose and increase in cAMP 
C)  increase in glucose and decrease in cAMP 
D)  decrease in glucose and increase in repressor 
E)  decrease in glucose and decrease in repressor

Question 19

Which of the following 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

The tryptophan operon in some bacteria is a repressible operon that is

Accepted Answer

A)  permanently turned on. 
B)  turned on only when tryptophan is present in the growth medium. 
C)  turned off only when glucose is present in the growth medium. 
D)  turned on only when glucose is present in the growth medium. 
E)  turned off whenever tryptophan is added to the growth medium. 
A)  permanently turned on. 
B)  turned on only when tryptophan is present in the growth medium. 
C)  turned off only when glucose is present in the growth medium. 
D)  turned on only when glucose is present in the growth medium. 
E)  turned off whenever tryptophan is added to the growth medium.

Exam 15: Regulation of Gene Expression

In eukaryotes, general transcription factors

Since Watson and Crick described DNA in 1953, which of the following statements might best explain why the function of small RNAs is still being explained?

For a repressible operon to be transcribed, which of the following must occur?

What is the role of a molecule that controls a repressible operon?

In response to chemical signals, prokaryotes can carry out which of the following activities?

Steroid hormones produce their effects in cells by

Researchers are looking for better treatments for breast cancer. For a particular DNA microarray assay (DNA chip), cDNA has been made from the mRNAs of a dozen patients' breast tumor biopsies. What would the researchers be looking for in this type of assay?

If you were to observe the activity of methylated DNA, you would expect it to

Which of the following events occurs during DNA replication?

Gene expression can be blocked by small RNA molecules called siRNAs. What is this process called?

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 occurs when the lactose enters the cell?

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

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

Altering patterns of gene expression in prokaryotes would most likely contribute to the organism's survival in which of the following ways?

One way scientists hope to use the recent knowledge gained about noncoding RNAs lies with the possibilities for their use in medicine. Of the following scenarios for future research, which would you expect to gain most from RNAs?

In positive control of several sugar-metabolism-related operons, the cAMP receptor protein (CRP) binds to DNA to stimulate transcription. What causes an increase in CRP?

Which of the following best describes siRNA?

The tryptophan operon in some bacteria is a repressible operon that is

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

Species Interactions

Ecosystems and Energy

Global Ecology and Conservation Biology

Filters