Question 1

If the gene encoding the lac repressor is mutated so that the repressor can no longer bind the operator, will transcription of that operon occur?

Accepted Answer

A)  Yes, because the repressor transcriptionally activates the lac genes. 
B)  Yes, but only when lactose is present. 
C)  No, because RNA polymerase is needed to transcribe the genes. 
D)  Yes, because RNA polymerase will be able to bind the promoter and transcribe the operon. 
E)  No, because cAMP levels are low when the repressor is nonfunctional. 
A)  Yes, because the repressor transcriptionally activates the lac genes. 
B)  Yes, but only when lactose is present. 
C)  No, because RNA polymerase is needed to transcribe the genes. 
D)  Yes, because RNA polymerase will be able to bind the promoter and transcribe the operon. 
E)  No, because cAMP levels are low when the repressor is nonfunctional.

Question 2

A promoter is the region of

Accepted Answer

A)  a plasmid that binds the enzymes for replication. 
B)  the mRNA that binds to a ribosome. 
C)  DNA that binds RNA polymerase. 
D)  the mRNA that binds tRNAs. 
E)  None of the above 
A)  a plasmid that binds the enzymes for replication. 
B)  the mRNA that binds to a ribosome. 
C)  DNA that binds RNA polymerase. 
D)  the mRNA that binds tRNAs. 
E)  None of the above

Question 3

The promoter in the lac operon is

Accepted Answer

A)  the region that binds the repressor. 
B)  the region that binds RNA polymerase. 
C)  the gene that codes for the repressor. 
D)  a structural gene. 
E)  an operon. 
A)  the region that binds the repressor. 
B)  the region that binds RNA polymerase. 
C)  the gene that codes for the repressor. 
D)  a structural gene. 
E)  an operon.

Question 4

Viruses are

Accepted Answer

A)  cells containing DNA and protein. 
B)  larger than most bacteria. 
C)  acellular. 
D)  able to take in nutrients and expel wastes. 
E)  mutated forms of DNA. 
A)  cells containing DNA and protein. 
B)  larger than most bacteria. 
C)  acellular. 
D)  able to take in nutrients and expel wastes. 
E)  mutated forms of DNA.

Question 5

When an enhancer is bound, it

Accepted Answer

A)  increases the stability of a specific mRNA. 
B)  stimulates transcription of a specific gene. 
C)  stimulates transcription of all genes. 
D)  stimulates splicing of a specific mRNA. 
E)  stimulates splicing of all mRNAs. 
A)  increases the stability of a specific mRNA. 
B)  stimulates transcription of a specific gene. 
C)  stimulates transcription of all genes. 
D)  stimulates splicing of a specific mRNA. 
E)  stimulates splicing of all mRNAs.

Question 6

DNA methylation in eukaryotic chromosomes involves adding a methyl to the

Accepted Answer

A)  5´ position of G. 
B)  5´ position of C. 
C)  proteins bound to the DNA. 
D)  RNA molecules. 
E)  ribose. 
A)  5´ position of G. 
B)  5´ position of C. 
C)  proteins bound to the DNA. 
D)  RNA molecules. 
E)  ribose.

Question 7

Genes that produce single mRNAs containing information for more than one protein are called _______.

Accepted Answer

The answer of Genes that produce single mRNAs containing information...

Question 8

The process by which some phage may transfer DNA fragments from one bacterium to another is called

Accepted Answer

A)  transformation. 
B)  induction. 
C)  lysogeny. 
D)  transduction. 
E)  transfection. 
A)  transformation. 
B)  induction. 
C)  lysogeny. 
D)  transduction. 
E)  transfection.

Question 9

An operon is

Accepted Answer

A)  a molecule that can turn genes on and off. 
B)  an inducer bound to a repressor. 
C)  a series of regulatory sequences controlling transcription of protein-coding genes. 
D)  any long sequence of DNA. 
E)  a promoter, an operator, and a group of linked structural genes. 
A)  a molecule that can turn genes on and off. 
B)  an inducer bound to a repressor. 
C)  a series of regulatory sequences controlling transcription of protein-coding genes. 
D)  any long sequence of DNA. 
E)  a promoter, an operator, and a group of linked structural genes.

Question 10

A retrovirus

Accepted Answer

A)  has a double-stranded DNA genome. 
B)  has a single-stranded DNA genome. 
C)  has a double-stranded RNA genome. 
D)  encodes a reverse transcriptase. 
E)  integrates its genome directly into the host's genome. 
A)  has a double-stranded DNA genome. 
B)  has a single-stranded DNA genome. 
C)  has a double-stranded RNA genome. 
D)  encodes a reverse transcriptase. 
E)  integrates its genome directly into the host's genome.

Question 11

Several types of histone modification affect gene activation and repression. Cancer cells are characterized by a greater degree of

Accepted Answer

A)  methylation. 
B)  phosphorylation. 
C)  acetylation. 
D)  interference. 
E)  deacetylation. 
A)  methylation. 
B)  phosphorylation. 
C)  acetylation. 
D)  interference. 
E)  deacetylation.

Question 12

_______ acts as a co-repressor to block transcription of the tryptophan operon.

Accepted Answer

A)  cAMP 
B)  Lactose 
C)  Tryptophan 
D)  Methionine 
E)  CRP 
A)  cAMP 
B)  Lactose 
C)  Tryptophan 
D)  Methionine 
E)  CRP

Question 13

Which of the following statements about the lytic cycle is true?

Accepted Answer

A)  The phage DNA integrates into the bacterial chromosome. 
B)  Temperate viruses are formed. 
C)  Prophages are replicated. 
D)  The host cell lyses. 
E)  Immunity to a specific strain of phage may result. 
A)  The phage DNA integrates into the bacterial chromosome. 
B)  Temperate viruses are formed. 
C)  Prophages are replicated. 
D)  The host cell lyses. 
E)  Immunity to a specific strain of phage may result.

Question 14

The trp operon

Accepted Answer

A)  codes for proteins needed for tryptophan synthesis. 
B)  codes for proteins needed to metabolize tryptophan. 
C)  is activated by the presence of tryptophan. 
D)  is inducible. 
E)  All of the above 
A)  codes for proteins needed for tryptophan synthesis. 
B)  codes for proteins needed to metabolize tryptophan. 
C)  is activated by the presence of tryptophan. 
D)  is inducible. 
E)  All of the above

Question 15

The determination of whether a temperate phage undergoes a lytic or a lysogenic cycle depends on the

Accepted Answer

A)  presence or absence of protein CD4. 
B)  two viral regulatory proteins, cI and Cro. 
C)  presence or absence of plasmodesmata. 
D)  nucleotide sequences of the phage. 
E)  size of the genome. 
A)  presence or absence of protein CD4. 
B)  two viral regulatory proteins, cI and Cro. 
C)  presence or absence of plasmodesmata. 
D)  nucleotide sequences of the phage. 
E)  size of the genome.

Question 16

Control of gene expression in eukaryotes includes all of the following except

Accepted Answer

A)  alternative RNA splicing. 
B)  binding of proteins to DNA. 
C)  transcription factors. 
D)  stabilization of mRNA by miRNA. 
E)  DNA methylation. 
A)  alternative RNA splicing. 
B)  binding of proteins to DNA. 
C)  transcription factors. 
D)  stabilization of mRNA by miRNA. 
E)  DNA methylation.

Question 17

Catabolite repression refers to the

Accepted Answer

A)  increased transcription from many operons when glucose is present in the medium. 
B)  shutdown of transcription from many operons when glucose is present in the medium. 
C)  increased activity of inducers caused by glucose in the medium. 
D)  Both a and b 
E)  Both a and c 
A)  increased transcription from many operons when glucose is present in the medium. 
B)  shutdown of transcription from many operons when glucose is present in the medium. 
C)  increased activity of inducers caused by glucose in the medium. 
D)  Both a and b 
E)  Both a and c

Question 18

Beginning with a single bacterium, how many cells would be present after 4 hours of growth if they can double every 20 minutes?

Accepted Answer

A)  12 
B)  24 
C)  64 
D)  4,096 
E)  34,217,728 
A)  12 
B)  24 
C)  64 
D)  4,096 
E)  34,217,728

Question 19

DNA methylation

Accepted Answer

A)  is a mechanism of gene inactivation. 
B)  adds methyl groups to cytosine residues in certain genes. 
C)  inhibits transcription. 
D)  Both a and b 
E)  All of the above 
A)  is a mechanism of gene inactivation. 
B)  adds methyl groups to cytosine residues in certain genes. 
C)  inhibits transcription. 
D)  Both a and b 
E)  All of the above

Question 20

Viruses consist of

Accepted Answer

A)  a protein core and a nucleic acid capsid. 
B)  a cell wall surrounding nucleic acid. 
C)  RNA and DNA enclosed in a membrane. 
D)  a nucleic acid core surrounded by a protein capsid, and in some cases, a membrane. 
E)  a nucleic acid core surrounded by a cell membrane. 
A)  a protein core and a nucleic acid capsid. 
B)  a cell wall surrounding nucleic acid. 
C)  RNA and DNA enclosed in a membrane. 
D)  a nucleic acid core surrounded by a protein capsid, and in some cases, a membrane. 
E)  a nucleic acid core surrounded by a cell membrane.

Exam 16: Regulation of Gene Expression

If the gene encoding the lac repressor is mutated so that the repressor can no longer bind the operator, will transcription of that operon occur?

A promoter is the region of

The promoter in the lac operon is

Viruses are

When an enhancer is bound, it

DNA methylation in eukaryotic chromosomes involves adding a methyl to the

Genes that produce single mRNAs containing information for more than one protein are called _______.

The process by which some phage may transfer DNA fragments from one bacterium to another is called

An operon is

A retrovirus

Several types of histone modification affect gene activation and repression. Cancer cells are characterized by a greater degree of

_______ acts as a co-repressor to block transcription of the tryptophan operon.

Which of the following statements about the lytic cycle is true?

The trp operon

The determination of whether a temperate phage undergoes a lytic or a lysogenic cycle depends on the

Control of gene expression in eukaryotes includes all of the following except

Catabolite repression refers to the

Beginning with a single bacterium, how many cells would be present after 4 hours of growth if they can double every 20 minutes?

DNA methylation

Viruses consist of

Studying Life

Small Molecules and the Chemistry of Life

Proteins, Carbohydrates, and Lipids

Nucleic Acids and the Origin of Life

Cells: the Working Units of Life

Cell Membranes

Cell Signaling and Communication

Energy, Enzymes, and Metabolism

Pathways That Harvest Chemical Energy

Photosynthesis: Energy From Sunlight

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

Dna and Its Role in Heredity

From Dna to Protein: Gene Expression

Gene Mutation and Molecular Medicine

Genomes

Recombinent Dna and Biotechnology

Differential Gene Expression in Development

Development and Evolutionary Change

Evidence and Mechanisms of Evolution

Reconstructing and Using Phylogenies

Species and Their Formation

Evolution of Genes and Genomes

The History of Life on Earth

Bacteria and Archaea: the Prokaryotic Domains

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

Fungi: Recyclers, Pathogens, Parasites, and Plant Partners

Animal Origins and the Evolution of Body Plans

Protostome Animals

Deuterostome Animals

The Plant Body

Transport in Plants

Plant Nutrition

Regulation of Plant Growth

Reproduction in Flowering Plants

Plant Responses to Environmental Challenges

Physiology, Homeostasis, and Temperature Regulation

Animal Hormones

Immunology: Animal Defense Systems

Animal Reproduction

Animal Development

Neurons and Nervous Systems

Sensory Systems

The Mammalian Nervous System: Structure and Higher Function

Musculoskeletal Systems

Gas Exchange in Animals

Circulatory Systems

Nutrition, Digestion, and Absorption

Salt and Water Balance and Nitrogen

Animal Behavior

Ecology and the Distribution of Life

Population Ecology

Species Interaction and Coevolution

Community Ecology

Ecosystems and Global Ecology

Conservation Biology

Filters