How can we help?

You can also find more resources in our Help Center.

254 terms

Exam 2

STUDY
PLAY
What are the products of semiconservative replication for a double-stranded DNA molecule?

a. One double-stranded DNA molecule consisting of one parental strand and one daughter strand.
b. Two double-stranded DNA molecules, one consisting of two parental strands and the other consisting of two daughter strands.
c. Two double-stranded DNA molecules, each consisting of one parental strand and one daughter strand.
d. One double-stranded DNA molecule, consisting of two daughter strands.
c. Two double-stranded DNA molecules, each consisting of one parental strand and one daughter strand.
Why is DNA replication essential for a cell?

a. An organism must copy its DNA to pass genetic information to its offspring.
b. All organisms require two copies of DNA.
c. It allows the organism to repair any mistakes.
d. Because DNA is double-stranded.
a. An organism must copy its DNA to pass genetic information to its offspring.
What is the function of the parental DNA in replication?

a. It is passed into the offspring of the parent.
b. It gives the cell two complete copies of the DNA.
c. It allows for the DNA to be circular.
d. It serves as the template for DNA replication.
d. It serves as the template for DNA replication.
Which of the following is a DNA strand complementary to CGA ATC AGC?

a. GCT TAG TCG
b. CGA ATC AGC
c. GCU UAG UCG
d.TAG GCT GAT
a. GCT TAG TCG
Transcription produces which of the following?

a. mRNA
b. rRNA
c. tRNA
d. mRNA and tRNA
e. mRNA and rRNA
f. mRNA, tRNA, and rRNA are all produced by transcription.
f. mRNA, tRNA, and rRNA are all produced by transcription.
According to the animation, which of the following makes mRNA from the information stored in a DNA template?

a. DNA polymerase
b. tRNA
c. Ribosomes
d. RNA polymerase
d. RNA polymerase
Ribosomes contain which of the following?

a. mRNA, tRNA, and rRNA are all found as part of the ribosome.
b. rRNA
c. tRNA
d. mRNA
b. rRNA
Which of the following is involved in bringing amino acids to the ribosomes?

a. mRNA
b. mRNA, tRNA, and rRNA are all involved in transporting amino acids to the ribosomes.
c. rRNA
d. tRNA
d. tRNA
Which of the following can be translated into protein?

a. rRNA
b. mRNA, tRNA, and rRNA are all translated into protein.
c. mRNA
d. tRNA
c. mRNA
Which of the following statements concerning transcription is true?

a. Promoter sequences signal the end of a gene and mark the place where transcription stops.
b. During transcription, entire chromosomes are copied because the starting position of genes is unknown.
c. All types of RNA in the cell are synthesized by transcription, which uses a portion of DNA as a template for copying.
d. Transcription is the process whereby identical copies of DNA are made in preparation for cell division.
c. All types of RNA in the cell are synthesized by transcription, which uses a portion of DNA as a template for copying.
What results from the process of translation?

a. tRNA
b. mRNA
c. A polypeptide
d. Ribosomes
c. A polypeptide
How is bacterial translation different from eukaryotic translation?

a. mRNA is read 3' to 5'.
b. Bacteria can begin translation before transcription has terminated.
c. Bacterial translation does not involve ribosomes.
b. Bacteria can begin translation before transcription has terminated.
According to the animation, ribosomes move along the mRNA in which direction?

a. 5' to 3'
b. 3' to 5'
c. Either 5' to 3' or 3' to 5'
a. 5' to 3'
Which of the following best describes the flow of information in cells?

a. Ribosomes make proteins by randomly linking amino acids together.
b. DNA acts as a messenger. It binds to a ribosome and provides instructions for making protein.
c. DNA is converted to RNA, which is then converted to protein.
d. mRNA is made by copying specific regions of DNA called genes. Ribosomes use mRNA as instructions, which provide a code specifying the order of amino acids in a protein.
d. mRNA is made by copying specific regions of DNA called genes. Ribosomes use mRNA as instructions, which provide a code specifying the order of amino acids in a protein.
Which of the following genetic elements is transcribed into a single mRNA?

a. The inducer
b. The repressor
c. The promoter
d. The operator
e. The structural genes
e. The structural genes
Which operons are always transcribed unless deactivated?

a. Inducible operons
b. Repressible operons
c. Inducible and repressible operons
b. Repressible operons
Which operons are never transcribed unless activated?

a. Inducible operons
b. Repressible operons
c. Inducible and repressible operons
a. Inducible operons
According to the animation, where on the DNA strand does a repressor bind?

a. The inducer
b. The operator
c. The promoter
d. The structural genes
b. The operator
A recombinant cell

a. is the result of a cell dividing.
b. is a cell that receives DNA from an outside source and incorporates it into its own.
c. donates DNA into a new cell.
b. is a cell that receives DNA from an outside source and incorporates it into its own.
What is the hallmark of all horizontal gene transfers?

a. Transfer of DNA using a virus
b. Transfer of DNA between organisms of the same generation
c. Transfer of DNA from parent to offspring
d. The use of plasmids
b. Transfer of DNA between organisms of the same generation
Which of the following is an example of horizontal gene transfer in bacteria?

a. Conjugation
b. Transduction
c. Transduction, conjugation, and transformation
d. Transformation
e. Conjugation and transformation
c. Transduction, conjugation, and transformation
Bacterial conjugation is often referred to as bacterial sex. Why is this term inaccurate?

a. Bacteria are neither male nor female.
b. Sex is a phenomenon only seen in animals.
c. Conjugation does not result in the formation of new offspring.
d. It does not require two cells to occur.
c. Conjugation does not result in the formation of new offspring.
What must occur for bacterial conjugation to take place?

a. The cells must come into contact with each other.
b. Each cell must contain a plasmid.
c. One of the cells must be E. coli.
d. The cells must transfer RNA.
a. The cells must come into contact with each other.
Which statement about conjugation is false?

a. Conjugation is a process of bacterial reproduction.
b. E. coli is the model for bacterial conjugation.
c. After conjugation, each cell involved has a copy of the shared DNA.
a. Conjugation is a process of bacterial reproduction.
Based on the animation, what is transferred during bacterial conjugation?

a. RNA
b. A conjugation pilus
c. A bacterial plasmid
d. A bacterial chromosome
c. A bacterial plasmid
Competent cells are cells that

a. can take up DNA from their surrounding environment and integrate it into their own chromosomes by recombination.
b. are also considered "rough-strain" based on colony phenotype.
c. have the ability to produce capsules.
d. are killed by heat.
a. can take up DNA from their surrounding environment and integrate it into their own chromosomes by recombination.
Mice that are injected with only the R strain of Streptococcus pneumoniae

a. become sick for prolonged periods of time.
b. stay healthy, because their immune systems can kill this strain easily.
c. are killed, because R strain cells are deadly.
b. stay healthy, because their immune systems can kill this strain easily.
What characteristic of the S strain allows it to evade the immune system of the mice?

a. They are naturally competent.
b. The cells have a capsule.
c. They are resistant to heat.
d. They are genetically engineered to be resistant to killing.
b. The cells have a capsule.
What most likely explains the recovery of live S strain cells from a mouse injected with heat-killed S strain mixed with live R strain cells?

a. The S strain fused with the R strain, making it resistant.
b. The S strain was revived by the presence of the host's immune system.
c. The R strain cells picked up the capsules from the S strain cells.
d. The R strain picked up the S strain DNA, enabling it to produce a capsule.
d. The R strain picked up the S strain DNA, enabling it to produce a capsule.
Which finding is most surprising from Griffith's experiments?

a. R strain cells fail to produce a capsule.
b. S strains are able to escape phagocytosis.
c. S strain cells are isolated from the blood of mice infected with heat-killed S strains and live R strains.
d. S strain cells kill the mice.
c. S strain cells are isolated from the blood of mice infected with heat-killed S strains and live R strains.
What is unique about transduction compared to normal bacteriophage infection?

a. Transduction transfers DNA from the chromosome of one cell to another.
b. The bacteriophage does not erupt from an infected cell during transduction.
c. The bacteriophage takes fragments of the cell with it during transduction.
a. Transduction transfers DNA from the chromosome of one cell to another.
How is generalized transduction different from specialized transduction?

a. Generalized transduction is initiated by a lysogenic bacteriophage; specialized transduction is initiated by a lytic phage.
b. Only one specific host gene is transferred in both specialized transduction and generalized transduction.
c. Specialized transduction uses animal viruses instead of bacteriophage.
d. Generalized transduction is initiated during lytic cycle of a virulent bacteriophage; specialized transduction is initiated during the lysogenic cycle of a temperate bacteriophage.
d. Generalized transduction is initiated during lytic cycle of a virulent bacteriophage; specialized transduction is initiated during the lysogenic cycle of a temperate bacteriophage.
A transducing phage

a. cannot infect new host cells.
b. is a lysogenic bacteriophage.
c. contains fragments of the host chromosome instead of the viral genome.
d. has a viral coat made of host proteins.
c. contains fragments of the host chromosome instead of the viral genome.
When a transducing phage interacts with a new host cell,

a. the DNA from the previous host can recombine with the new host chromosome.
b. it will cause the new cell to produce more transducing phage.
c. the new host cell will be lysed.
a. the DNA from the previous host can recombine with the new host chromosome.
Which of the following is a method of vertical gene transmission?

a. conjugation
b. cell division
c. transformation
d. transduction
b. cell division
Frederick Griffith did experiments on genetic transformation. Which of the following statements about his experiments is accurate?

a. Griffith used only pathogenic bacteria in his experiments.
b. The combination of living nonencapsulated bacteria and heat-killed encapsulated bacteria did not cause disease.
c. Griffith used bacteria in which the nonpathogenic strain was encapsulated but the pathogenic strain was not.
d. Griffith found that DNA released from dead (virulent) bacteria entered live (avirulent) bacteria and changed them genetically, causing them to become virulent.
d. Griffith found that DNA released from dead (virulent) bacteria entered live (avirulent) bacteria and changed them genetically, causing them to become virulent.
Which of the following does NOT accurately apply to the Ames test?

a. The test uses bacteria as mutagen carcinogen indicators.
b. The Ames test is based on the observation that reversions CANNOT occur in mutant bacteria.
c. The Ames test measures the reversion of histidine auxotrophs of Salmonella.
d. The test can be used to qualitatively test potential mutagens.
b. The Ames test is based on the observation that reversions CANNOT occur in mutant bacteria.
What is considered to be the average natural mutation rate that occurs during DNA replication?

a. One in every million nucleotides replicated.
b. One in every trillion nucleotides replicated.
c. One in every billion nucleotides replicated.
d. One in every ten thousand nucleotides replicated.
c. One in every billion nucleotides replicated.
A mutation that affects the genotype of the organism but not the phenotype is called a

a. nonsense mutation.
b. missense mutation.
c. frameshift mutation.
d. silent mutation.
d. silent mutation.
A base insertion or deletion in the translated region of the gene may lead to

a. missense mutation.
b. frameshift mutation.
c. nonsense mutation.
d. silent mutation.
b. frameshift mutation.
A base substitution that changes a codon coding for an amino acid to a stop codon is called a

a. frameshift mutation.
b. missense mutation.
c. silent mutation.
d. nonsense mutation.
d. nonsense mutation.
How frequently do silent mutations occur?

a. One out of every billion mutations
b. One out of every three mutations
c. Half of all mutations
d. One out of every million mutations
b. One out of every three mutations
Which of the following build(s) new strands of DNA?

a. The leading strand
b. DNA polymerases
c. The lagging strand
d. Parental DNA
e. The origins of replication
b. DNA polymerases
Which statement about DNA replication is CORRECT?

a. The lagging strand is one of the strands of parental DNA.
b. DNA ligase helps assemble the leading strand.
c. The lagging strand is built continuously.
d. The leading strand is built continuously, and the lagging strand is built in pieces.
e. The leading strand is one of the strands of parental DNA.
d. The leading strand is built continuously, and the lagging strand is built in pieces.
During DNA replication, which nucleotide will bind to an A nucleotide in the parental DNA?

a. G
b. C
c. T
d. U
e. A
c. T
The molecule that seals the gaps between the pieces of DNA in the lagging strand is

a. RNA.
b. the replication fork.
c. the leading strand.
d. DNA polymerase.
e. DNA ligase.
e. DNA ligase.
Which statement about DNA replication is FALSE?

a. Because the two strands of parental DNA run in opposite directions, the new strands must be made in different ways.
b. The two strands of parental DNA are separated during DNA replication.
c. DNA polymerase builds a new strand by adding DNA nucleotides one at a time.
d. The lagging strand is made of a series of pieces that must be joined together to make a continuous strand.
e. DNA ligase adds nucleotides to the lagging strand.
e. DNA ligase adds nucleotides to the lagging strand.
Deleting or inserting one nucleotide pair in the middle of a gene is an example of which of the following?

a. base substitution
b. nonsense mutation
c. frameshift mutation
d. missense mutation
c. frameshift mutation
Transformation is the transfer of DNA from a donor to a recipient cell

a. by cell-to-cell contact.
b. as naked DNA in solution.
c. by a bacteriophage.
d. by sexual reproduction.
e. by crossing over.
b. as naked DNA in solution.
Genetic change in bacteria can be brought about by

a. transduction.
b. mutation.
c. conjugation.
d. transformation.
e. All of the answers are correct.
e. All of the answers are correct.
Which of the following statements regarding a bacterium that is R+ is false?

a. R+ can be transferred to a cell of the same species.
b. It possesses a plasmid.
c. It is F+.
d. It is resistant to certain drugs and heavy metals.
e. R+ can be transferred to a different species.
c. It is F+.
The necessary ingredients for DNA synthesis can be mixed together in a test tube. The DNA polymerase is from Thermus aquaticus, and the template is from a human cell. The DNA synthesized would be most similar to

a. human DNA.
b. T. aquaticus DNA.
c. a mixture of human and T. aquaticus DNA.
d. human RNA.
e. T. aquaticus RNA.
a. human DNA.
Based on the information in the table, prostate cancer is probably the result of which kind of mutation?

a. missense
b. nonsense
c. frameshift
d. analog
e. None of the answers is correct.
b. nonsense
If you knew the sequence of nucleotides within a gene, which one of the following could you determine with the most accuracy?

a. the primary structure of the protein
b. the secondary structure of the protein
c. the tertiary structure of the protein
d. the quaternary structure of the protein
e. The answer cannot be determined.
a. the primary structure of the protein
What is the end goal of PCR?

a. To increase the pool of different DNA sequences
b. To allow cells to make DNA faster, thereby growing faster
c. To quickly increase the number of copies of a specific DNA sequence
c. To quickly increase the number of copies of a specific DNA sequence
PCR stands for

a. polymerization copying rapidly.
b. polymerase chain reaction.
c. polymerase copy reaction.
b. polymerase chain reaction.
Which of the following is an application that uses PCR?

a. Sequencing a gene, diagnosing a disease, and providing enough DNA for cloning into another organism
b. Sequencing a gene
c. Providing enough DNA for cloning into another organism
d. Diagnosing a disease
a. Sequencing a gene, diagnosing a disease, and providing enough DNA for cloning into another organism
What is the function of the primers in PCR?

a. They are the monomer building blocks from which the DNA strand is synthesized.
b. They provide energy for the DNA polymerization reactions.
c. They polymerize free nucleotides to form the new DNA strands.
d. They provide a 3' end for the DNA polymerase.
d. They provide a 3' end for the DNA polymerase.
In which direction does DNA polymerase synthesize the new DNA strand?

a. 5' to 3'
b. 3' to 5'
c. Both 5' to 3' and 3' to 5'
a. 5' to 3'
What provides the energy for DNA polymerization in a PCR reaction?

a. DNA polymerase
b. Deoxyribonucleoside triphosphates
c. Primers
d. Template DNA
b. Deoxyribonucleoside triphosphates
Why is DNA polymerase from Thermus aquaticus ideal for PCR?

a. It can synthesize DNA 5' to 3' and 3' to 5'.
b. It does not require primers.
c. It can withstand the high temperatures associated with PCR.
d. It does not require energy to polymerize DNA.
c. It can withstand the high temperatures associated with PCR.
What is the temperature used for the extension step?

a. 72 °C
b. 60 °C
c. 94 °C
a. 72 °C
How do the strands separate during PCR?

a. The primers separate the strands during the annealing step.
b. The DNA polymerase breaks the hydrogen bonds between the two strands.
c. The cycling of the temperatures breaks the hydrogen bonds between the two strands.
d. The high heat of the denaturation step breaks the hydrogen bonds between the two strands.
d. The high heat of the denaturation step breaks the hydrogen bonds between the two strands.
What is a thermocycler?

a. The process of cycling through the different temperatures of a PCR reaction 30 times
b. The name for the DNA primers used in a PCR reaction
c. The machine that controls the heat of the reaction, cycling between the different temperatures of the different steps during PCR
d. The special DNA polymerase, used in a PCR reaction, that can tolerate the high temperatures
c. The machine that controls the heat of the reaction, cycling between the different temperatures of the different steps during PCR
What is the sequence of the temperatures of a typical PCR reaction?

a. 94 °C, 72 °C, 60 °C
b. 94 °C, 60 °C, 72 °C
c. 72 °C, 60 °C, 94 °C
d. 72 °C, 94 °C, 60 °C
e. 60 °C, 72 °C, 94 °C
b. 94 °C, 60 °C, 72 °C
If you used a broken thermocycler that could not heat above 75°C, which of the following problems could you expect?

a. You would get more amplification than with a "normal" thermocycler.
b. You would get some significant amplification, but less than if you used a "normal" thermocycler.
c. You would not get any amplification of DNA.
d. You would get the same amount of amplification as with a "normal" thermocycler.
b. You would get some significant amplification, but less than if you used a "normal" thermocycler.
Which of the following provides the specificity of the PCR reaction?

a. primers
b. separated DNA strands
c. heating to 94°C
d. Taq polymerase
a. primers
A new arrow labeled "lengthens" could be added between __________.

a. "target DNA" → "DNA strands"
b. "primers" → "DNA strands"
c. "Taq polymerase" → "primers"
d. "target DNA" → "primers"
c. "Taq polymerase" → "primers"
How do restriction enzymes cut DNA sequences?

a. They cut DNA at sequences that have lots of adenine bases.
b. They have the ability to cut DNA randomly.
c. They cut DNA at sites, called recognition sites, that have specific nucleotide sequences.
c. They cut DNA at sites, called recognition sites, that have specific nucleotide sequences.
In general, how might recombinant DNA technology be used to prevent a genetic disorder caused by a mutation in a single gene?

a. To insert a desirable gene, remove an undesirable gene, or replace a defective gene with a functioning gene
b. To remove an undesirable gene
c. To insert a desirable gene
d. To replace a defective gene with a working gene
a. To insert a desirable gene, remove an undesirable gene, or replace a defective gene with a functioning gene
Which of the following attaches the target gene to a desired location?

a. DNA ligase
b. Plasmids
c. Restriction enzymes
d. Chromosomal DNA
a. DNA ligase
Why would a recombinant DNA molecule be inserted into a host cell?

a. It can protect the recombinant DNA.
b. Restriction enzymes can only be used inside of a cell.
c. It can be copied, transcribed, and translated into a desired protein.
d. Plasmids cannot be isolated outside of a host cell.
c. It can be copied, transcribed, and translated into a desired protein.
Which statement best describes restriction enzymes?

a. They can cut only circular plasmid DNA.
b. They are important for cloning applications because they can be used to cut DNA at specific nucleotide sequences.
c. They randomly cut DNA molecules to generate numerous fragments.
d. They are necessary for the polymerase chain reaction (PCR) to occur.
b. They are important for cloning applications because they can be used to cut DNA at specific nucleotide sequences.
Which of the following pairings of recombinant DNA techniques and applications does NOT match?

a. genetic modification of yeast: production of purified insulin
b. gene therapy: replacing a defective gene
c. PCR: making many copies of a segment of DNA
d. gene silencing: production of subunit vaccines
d. gene silencing: production of subunit vaccines
Why is baker's yeast useful for expressing genetically engineered genes?

a. The yeast cells are best suited for making human products for medical use.
b. Yeast cells are eukaryotic and so would likely be successful in expressing eukaryotic genes.
c. Many inducible promoters from the yeast genome have been cloned, such as the lac operon.
d. The yeast cells do not secrete their protein products.
b. Yeast cells are eukaryotic and so would likely be successful in expressing eukaryotic genes.
Which of the following methods could be used to identify the source of an outbreak?

a. DNA fingerprinting
b. reverse genetics
c. production of a recombinant protein
d. artificial selection
a. DNA fingerprinting
Which of the following statements about recombinant DNA technology is FALSE?

a. It allows researchers to make many copies of a gene of interest.
b. It can be used to screen individuals for many different types of genetic diseases.
c. It has limited application because genes of interest cannot be moved from one type of cell to another.
d. It allows researchers to make protein products of a gene.
c. It has limited application because genes of interest cannot be moved from one type of cell to another.
Which of the following applications of recombinant DNA technology is NOT controversial?

a. genetic screening
b. biological weapons development
c. metagenomics
d. genetic food modification
c. metagenomics
Scientists like to use fluorescent proteins for various types of recombinant DNA procedures. You have a very small amount of the gene for a fluorescent protein. You'd like to make a fluorescent bacterium (!). Which of the following represents the correct sequence of procedures that you would use?


a. Transform the vector into the bacteria.
Amplify the gene using PCR.
Insert the gene into a plasmid vector.

b. Amplify the gene using PCR.
Transform the vector into the bacteria.
Insert the gene into a plasmid vector.

c. Amplify the gene using PCR.
Insert the gene into a plasmid vector.
Transform the vector into the bacteria.

d. Insert the gene into a plasmid vector.
Amplify the gene using PCR.
Transform the vector into the bacteria.
c. Amplify the gene using PCR.
Insert the gene into a plasmid vector.
Transform the vector into the bacteria.
Which statement regarding agricultural biotechnology is FALSE?

a. Scientists have created plants that produce an insect toxin originally found in bacteria.
b. Scientists have used gene silencing to create tomatoes with a longer shelf life.
c. Agricultural biotechnology is extremely limited because foreign genes cannot be inserted into plant cells.
d. Scientists have created plants that are resistant to herbicides by using a mutant enzyme gene from Salmonella.
c. Agricultural biotechnology is extremely limited because foreign genes cannot be inserted into plant cells.
The reaction catalyzed by reverse transcriptase is

a. DNA → mRNA.
b. mRNA → cDNA.
c. mRNA → protein.
d. DNA → DNA.
e. tRNA → mRNA.
b. mRNA → cDNA.
Which of the following is an advantage of using E. coli to make a human gene product?

a. Endotoxin may be in the product.
b. It does not secrete most proteins.
c. Its genes are well known.
d. It cannot process introns.
e. None of the answers is correct.
c. Its genes are well known.
Biotechnology involves the

a. use of microorganisms to make desired products.
b. use of animal cells to make vaccines.
c. development of disease-resistant crop plants.
d. use of microorganisms to make desired products and the use of animal cells to make vaccines.
e. use of microorganisms to make desired products, the use of animal cells to make vaccines, and the development of disease-resistanct crop plants.
e. use of microorganisms to make desired products, the use of animal cells to make vaccines, and the development of disease-resistanct crop plants.
The Human Genome Project, which was completed in 2003, was focused on

a. identifying all of the genes in the human genome.
b. determining the nucleotide sequence of the entire human genome.
c. determining all of the proteins encoded by the human genome.
d. finding a cure for all human genetic disorders.
e. cloning all of the genes of the human genome.
b. determining the nucleotide sequence of the entire human genome.
Place the following steps in the PCR procedure in the correct order:
1) Incubate at 94°C to denature DNA strands;
2) Incubate at 72°C for DNA synthesis;
3) Incubate at 60°C for primer hybridization.

a. 1 3 2
b. 3 2 1
c. 2 1 3
d. 3 1 2
e. 1 2 3
a. 1 3 2
A source of heat-stable DNA polymerase is

a. Thermus aquaticus.
b. Bacillus thuringiensis.
c. Agrobacterium tumefaciens.
d. Saccharomyces cerevisiae.
e. Pseudomonas.
a. Thermus aquaticus.
The Pap test for cervical cancer involves microscopic examination of cervical cells for cancerous cells. A new, rapid diagnostic test to detect human papilloma virus (HPV) DNA before cancer develops is done without microscopic exam. The steps involved in this FastHPV test are listed below. What is the second step?

a. Add an RNA probe for HPV DNA.
b. add enzyme substrate.
c. Add enzyme-linked antibodies against DNA-RNA.
d. Lyse human cells.
e. The order is unimportant.
a. Add an RNA probe for HPV DNA.
PCR can be used to identify an unknown bacterium because

a. the RNA primer is specific.
b. DNA polymerase will replicate DNA.
c. DNA can be electrophoresed.
d. all cells have DNA.
e. all cells have RNA.
a. the RNA primer is specific.
Restriction enzymes are

a. bacterial enzymes that splice DNA.
b. viral enzymes that destroy host DNA.
c. bacterial enzymes that destroy phage DNA.
d. animal enzymes that splice RNA.
c. bacterial enzymes that destroy phage DNA.
Why are archaea and bacteria—both collections of prokaryotic organisms—grouped into different domains while organisms like fungi and animals are in the same domain?

a. Bacteria and archaea differ significantly in their intracellular organization and structure, but fungi and animals have similar intracellular structure.
b. The DNA sequences of bacteria and archaea are more different than animals and fungi.
c. Fungi and animals look much more similar than bacteria and archaea.
d. Bacteria and archaea differ significantly in their rRNA sequences, but fungi and animals share some rRNA characteristics.
d. Bacteria and archaea differ significantly in their rRNA sequences, but fungi and animals share some rRNA characteristics.
While working with a broth culture of archaea in the laboratory, you accidentally spill some of the microorganisms on yourself. Do you need to be concerned about developing an infection? Why or why not?

a. No; archaea are not pathogenic.
b. Yes; certain archaea can be pathogenic, so an infection could occur.
c. Yes; all infectious prokaryotes are archaea.
d. No; archaea are prokaryotic, so they cannot cause infection.
a. No; archaea are not pathogenic.
Which of the following methods could be used to differentiate between a member of domain Bacteria and a member of domain Archaea?

a. You could look for the presence of mitochondria.
b. You could see if the organism produces rRNA.
c. You could see if the organism can survive in an extreme environment.
d. You could look for the presence of peptidoglycan.
e. All of the above would work.
f. None of the above would work.
d. You could look for the presence of peptidoglycan.
Why is visualization not sufficient to properly identify bacteria?

a. Identification is only needed in clinical specimens.
b. Not all bacteria can be seen with a light microscope.
c. Many unrelated bacteria can share the same shape.
d. Bacteria have a limited set of shapes.
e. Bacteria have a limited set of shapes and many unrelated bacteria share the same shape.
e. Bacteria have a limited set of shapes and many unrelated bacteria share the same shape.
What is the hallmark of dichotomous keys?

a. They are open-ended questions.
b. They only relate to biochemical processes of the cell.
c. They consist of a series of paired statements, in which only one statement of each pair applies to a given organism.
d. They only relate to the shape of the cell.
c. They consist of a series of paired statements, in which only one statement of each pair applies to a given organism.
Biochemical tests _________________.

a. are the main methods used to identify unknown bacteria
b. are visualized using microscopes
c. are used to determine rate of growth
d. are the most effective way to determine bacterial shape
a. are the main methods used to identify unknown bacteria
How many answers are there to a question in a dichotomous key flowchart?

a. Two
b. Any number of answers are possible.
c. Four
d. Three
a. Two
Why are flowcharts useful for dichotomous keys?

a. They allow the researcher to visualize relationships between different bacteria.
b. They allow the researcher to get the answer without having to do many tests.
c. They provide a map to the answer.
a. They allow the researcher to visualize relationships between different bacteria.
The first question in this dichotomous key addresses

a. oxygen tolerance.
b. bacterial morphology.
c. metabolic characteristics.
d. Gram stain differences.
d. Gram stain differences.
Why is the unknown in this example not Pseudomonas?

a. It is a rod-shaped cell.
b. It can tolerate oxygen.
c. It ferments lactose.
d. It is a Gram-negative cell.
c. It ferments lactose.
What test result indicates that the unknown can utilize citrate as its sole carbon source?

a. The medium turns pink.
b. The culture becomes turbid.
c. It turns the medium black.
d. The medium turns blue.
d. The medium turns blue.
How would the results be different if this organism was Salmonella?

a. It would be a rod.
b. It would not ferment lactose.
c. It would produce hydrogen sulfide.
d. It would not tolerate oxygen.
c. It would produce hydrogen sulfide.
How is fermentation of lactose detected?

a. The medium become turbid when exposed to air.
b. The acetoin produced turns the medium pink.
c. The drop in pH turns the indicator dye yellow.
d. The cells form a black precipitant.
c. The drop in pH turns the indicator dye yellow.
How many questions are needed in this dichotomous key to determine if the unknown is Bacteroides?

a. Four
b. Three
c. Five
d. Two
b. Three
How are negative stains different from other types of stains?

a. They stain the desired structure or specimen black.
b. They stain more than one type of specimen.
c. They stain the background, leaving the cells colorless.
c. They stain the background, leaving the cells colorless.
Which of the following is an example of a dye used in a simple stain?

a. Methylene blue
b. Carbolfuchsin
c. Nigrosin
d. Eosin
a. Methylene blue
How does the malachite green stain enter an endospore?

a. It is mixed with hydrochloric acid.
b. It is dissolved in alcohol.
c. It is heated.
d. It is mixed with the mordant tannic acid.
c. It is heated.
Following an endospore stain, how does one distinguish endospores from vegetative cells?

a. Vegetative cells are pink, endospores are green.
b. Vegetative cells are pink, endospores are purple.
c. Vegetative cells are purple, endospores are pink.
d. Vegetative cells are green, endospores are pink.
a. Vegetative cells are pink, endospores are green.
What is the fundamental purpose of staining in light microscopy?

a. To kill the specimen
b. To make the specimen appear larger in the microscope
c. To see the specimen without the aid of a microscope
d. To increase the contrast and visibility of the specimen
d. To increase the contrast and visibility of the specimen
Which statement regarding viral species is true?

a. Viral species are not classified as part of any of the three domains.
b. Viral species are taxonomically differentiated based upon their cell wall.
c. Viral species are classified within the Kingdom Plantae in the Domain Eukarya.
d. Viruses are classified as prokaryotes.
a. Viral species are not classified as part of any of the three domains.
Numerical identification methods rely on a series of which kind of test to identify microorganisms?

a. ELISA
b. DNA base composition
c. DNA fingerprinting
d. biochemical testing
d. biochemical testing
Consider a gram-negative human pathogen isolated from marine mammals. This pathogen is subjected to a series of tests and found to have the following characteristics: oxidase-positive; does not hydrolyze urea; produces indole; does not produce acetoin. Which of the following could it be?

a. Pasteurella multocida
b. Mannheimia haemolytica
c. Klebsiella pneumoniae
d. Yersinia enterocolitica
a. Pasteurella multocida
Which technique is often used to determine the identity and abundance of microorganisms in an environment? (This technique is particularly useful because it does not require culture.)

a. nucleic acid hybridization
b. ribotyping
c. fluorescent in situ hybridization (FISH)
d. DNA chips
c. fluorescent in situ hybridization (FISH)
Which of the following techniques could be used to identify antibodies produced by a patient?

a. Southern blotting
b. FAME
c. FISH
d. Western blotting
d. Western blotting
Members of the Domain Archaea are characterized by all of the following except:

a. Carry out unusual metabolic processes
b. Contain distinctive ribosomal RNA
c. Contain nuclei
d. Live in extreme environments
c. Contain nuclei
A unicellular, photosynthetic nucleated cell would belong to Domain:

a. Archaea
b. Bacteria
c. Eukarya
c. Eukarya
The first cells were formed approximately ___________ years ago.

a. 3 million years ago
b. 3 billion years ago
c. 2 billion years ago
b. 3 billion years ago
If two organisms have similar rRNA sequences, you can conclude that

a. they evolved from a common ancestor.
b. they will have different G-C ratios.
c. they will both ferment lactose.
d. they live in the same place.
e. they mated with each other.
a. they evolved from a common ancestor.
Which of the following is the best evidence for a three-domain system?

a. There are three distinctly different types of nuclei.
b. There are three distinctly different sets of metabolic reactions.
c. Nucleotide sequences in ribosomal RNA vary between all three domains.
d. Some bacteria live in extreme environments.
e. There are three distinctly different Gram reactions.
c. Nucleotide sequences in ribosomal RNA vary between all three domains.
Biochemical tests are used to determine

a. staining characteristics.
b. nucleic acid-base composition.
c. enzymatic activities.
d. amino acid sequences.
e. All of the answers are correct.
c. enzymatic activities.
Which of the following is NOT based on nucleic-acid hybridization?

a. Western blotting
b. Southern blotting
c. DNA chip
d. PCR
e. FISH
a. Western blotting
The phylogenetic classification of bacteria is based on

a. gram reaction.
b. rRNA sequences.
c. cell morphology.
d. habitat.
e. diseases.
b. rRNA sequences.
Which of the following statements is a reason for NOT classifying viruses in one of three
domains rather than in a fourth domain?

a. Viruses direct anabolic pathways of host cells.
b. Viruses are obligate parasites.
c. Some viruses can incorporate their genome into a host's genome.
d. Viruses are not composed of cells.
e. All of the answers are correct.
d. Viruses are not composed of cells.
Bacteria and Archaea are similar in which of the following?

a. sensitivity to antibiotics
b. considered prokaryotic cells
c. methionine as the start signal for protein synthesis
d. peptidoglycan cell walls
e. plasma membrane ester linkage
b. considered prokaryotic cells
Serological testing is based on the fact that

a. antibodies react specifically with an antigen.
b. bacteria clump together when mixed with any antibodies.
c. all bacteria have the same antigens.
d. the human body makes antibodies against bacteria.
e. antibodies cause the formation of antigens.
a. antibodies react specifically with an antigen.
Nucleic acid hybridization is based on the fact that

a. DNA is composed of genes.
b. the strands of DNA can be separated.
c. pairing between complementary bases occurs.
d. all cells have DNA.
e. a chromosome is composed of complementary strands.
c. pairing between complementary bases occurs.
Which of the following criteria is most useful in determining whether two organisms are related?

a. Both are aerobic.
b. Both are motile.
c. Both are gram-positive.
d. Both ferment lactose.
e. Each answer is equally important.
c. Both are gram-positive.
You discovered a unicellular organism that lacks a nucleus and peptidoglycan. You suspect the organism is in the group

a. Animalia.
b. Bacteria.
c. Plantae.
d. Archaea.
e. Fungi.
d. Archaea.
Into which group would you place a unicellular organism that has 70S ribosomes and a peptidoglycan cell wall?

a. Animalia
b. Fungi
c. Bacteria
d. Plantae
e. Protist
c. Bacteria
Which of the following characteristics indicates that two organisms are closely related?

a. Both of their DNA can hybridize.
b. Both are motile.
c. Both normally live in clams.
d. Both ferment lactose.
e. Both are cocci.
a. Both of their DNA can hybridize.
For which of the following would growth on blood agar be a good diagnostic tool?

a. streptococci
b. staphylococci
c. all Gram-positive cocci
d. enterococci
a. streptococci
Which of the following characteristics are shared by Enterococcus and Streptococcus?

a. found on/in healthy carriers
b. growth patterns on blood agar
c. cell arrangement
d. none of the above
c. cell arrangement
Which of the following techniques would allow you to easily differentiate between Staphylococcus and Enterococcus?

a. Gram stain
b. genetic testing
c. simple stain
d. all of the above
d. all of the above
Gram-positive organisms with low G + C content are commonly called __________.

a. proteobacteria
b. mycobacteria
c. Spirochaetes
d. Firmicutes
d. Firmicutes
Which gammaproteobacteria are facultatively anaerobic, gram-negative rods that inhabit the intestinal tracts of humans and other animals?

a. Pseudomonadales
b. Vibrionales
c. Enterobacteriales
d. Legionellales
c. Enterobacteriales
If a patient is diagnosed with a peptic ulcer, which genus of Proteobacteria is probably responsible?

a. Desulfovibrio
b. Campylobacter
c. Myxococcus
d. Helicobacter
d. Helicobacter
If a typhoid fever outbreak has occurred, which of the following statements is true?

a. Proteus colonies of Enterobacteriales are probably present.
b. Shigella species are present and may have been transmitted by cattle.
c. Salmonella is present, and the serovars may be differentiated by antigenic analysis.
d. Escherichia coli bacteria are present, probably passed on by infected human waste in the water supply.
c. Salmonella is present, and the serovars may be differentiated by antigenic analysis.
Regarding the order Rhizobiales of the class Alphaproteobacteria, which genus includes human pathogens?

a. Agrobacterium
b. Bradyrhizobium
c. Beijerinckia
d. Brucella
d. Brucella
You have isolated a gram-positive bacterium with low G + C content. It was a contaminant in unpasteurized milk. It infected a pregnant woman, and now you are worried that her child will be stillborn. What bacterium is it?

a. Anabaena
b. Listeria monocytogenes
c. Clostridium
d. Mycobacterium
b. Listeria monocytogenes
Which order or genus of Archaea are part of the microbiota of the human colon, vagina, and mouth?

a. Sulfolobales
b. Methanobacteriales
c. Halobacteriales
d. Pyrodictium
b. Methanobacteriales
Blood agar would be the culture medium of choice if one were testing a patient for which of the following?

a. tuberculosis
b. actinomycosis
c. scarlet fever
d. food poisoning
c. scarlet fever
Burkholderia was reclassified from the gammaproteobacteria to the betaproteobacteria because

a. it causes infections in cystic fibrosis patients.
b. it causes melioidosis.
c. it is a gram-negative rod.
d. it grows in disinfectants.
e. its rRNA sequence is similar to that of Neisseria.
e. its rRNA sequence is similar to that of Neisseria.
Thiobacillus oxidizes inorganic sulfur compounds and reduces CO2. This bacterium is a

a. chemoautotroph.
b. chemoheterotroph.
c. photoautotroph.
d. gammaproteobacteria.
e. photoheterotroph.
a. chemoautotroph.
Salmonella, Shigella, Yersinia, and Serratia are all

a. endospore-forming bacteria.
b. gram-negative facultatively anaerobic rods.
c. gram-positive aerobic cocci.
d. pathogens.
e. fermentative.
b. gram-negative facultatively anaerobic rods.
Which of the following statements about the causative agent of Rocky Mountain spotted fever is FALSE?

a. It is gram-negative.
b. It is found in soil and water.
c. It is an intracellular parasite.
d. It is in the genus Rickettsia.
e. It is transmitted by ticks.
b. It is found in soil and water.
Escherichia coli belongs to the

a. spirochetes.
b. proteobacteria.
c. green sulfur bacteria.
d. gram-positive bacteria.
e. actinomycetes.
b. proteobacteria.
You have isolated a bacterium that grows in a medium containing only inorganic nutrients. Ammonia is oxidized to a nitrate ion. This bacterium is

a. using anaerobic respiration.
b. a chemoautotroph.
c. a photoheterotroph.
d. gram-negative.
e. a photoautotroph
b. a chemoautotroph.
Requirements for X and V factors are used to identify

a. Pseudomonas.
b. Escherichia.
c. Neisseria.
d. Staphylococcus.
e. Haemophilus.
e. Haemophilus.
Rickettsias differ from chlamydias in that rickettsias

a. are enterics.
b. require an arthropod for transmission.
c. are intracellular parasites.
d. form elementary bodies.
e. are gram-negative.
b. require an arthropod for transmission.
Which of the following is NOT an enteric?

a. Enterobacter
b. Campylobacter
c. Shigella
d. Escherichia
e. Salmonella
b. Campylobacter
Which of the following are found primarily in the intestines of humans?

a. gram-negative aerobic rods and cocci
b. aerobic, helical bacteria
c. gram-positive cocci
d. endospore-forming rods
e. facultatively anaerobic gram-negative rods
e. facultatively anaerobic gram-negative rods
Mycoplasmas differ from other bacteria in that they

a. are acid-fast.
b. are gram-negative.
c. grow inside host cells.
d. are motile.
e. lack a cell wall.
e. lack a cell wall.
Which one of the following does NOT belong with the others?

a. Rickettsia
b. Ehrlichia
c. Coxiella
d. Staphylococcus
e. Wolbachia
d. Staphylococcus
You have isolated an aerobic gram-positive, endospore-forming bacterium that grows well on nutrient agar. To which of the following groups does it most likely belong?

a. deltaproteobacteria
b. phototrophic bacteria
c. gammaproteobacteria
d. bacillales
e. The answer cannot be determined based on the information provided.
d. bacillales
Actinomycetes differ from fungi in that actinomycetes

a. are decomposers.
b. cause disease.
c. require light.
d. lack a membrane-bounded nucleus.
e. are chemoheterotrophs.
d. lack a membrane-bounded nucleus.
Streptomyces differs from Actinomyces because Streptomyces

a. is a bacterium.
b. makes antibiotics.
c. produces conidia.
d. is a strict aerobe.
e. forms filaments.
d. is a strict aerobe.
Which of the following is the best reason to classify Streptococcus in the Lactobacillales?

a. rRNA sequences
b. found in dairy products
c. Gram reaction
d. fermentation of lactose
e. morphology
a. rRNA sequences
Which of the following bacteria are responsible for more infections and more different kinds of infections?

a. Neisseria
b. Salmonella
c. Pseudomonas
d. Staphylococcus
e. Streptococcus
e. Streptococcus
Which of the following bacteria is gram-positive?

a. Pseudomonas
b. Streptococcus
c. Salmonella
d. Rickettsia
e. Bacteroides
b. Streptococcus
Which of the following lacks a cell wall?

a. Mycoplasma
b. Borrelia
c. Clostridium
d. Mycobacterium
e. Nocardia
a. Mycoplasma
Staphylococcus and Streptococcus can be easily differentiated in a laboratory by which one of the following?

a. Gram stain reaction
b. growth in high salt concentrations
c. ability to cause disease
d. glucose fermentation
e. cell shape
b. growth in high salt concentrations
Of the following food products, which one was the most likely the source of Mr. Williams's infection?

a. cheese
b. raw milk
c. eggs
d. cream
b. raw milk
Why does Dr. Johnson order a PPD for Mr. Williams?

a. He wants to confirm the diagnosis of brucellosis.
b. He wants to confirm the diagnosis of Rickettsia infection.
c. He wants to rule out the possibility of bovine tuberculosis.
d. The PPD is a necessary component of the febrile antibodies panel.
c. He wants to rule out the possibility of bovine tuberculosis.
Which of the following Brucella species is most likely indicated in this case?

a. Brucella abortus
b. Brucella suis
c. Brucella melitensis
d. Brucella canis
a. Brucella abortus
Why are doxycycline and rifampin ideal agents for treating intracellular pathogens such as Brucella and Mycobacteria?

a. Both agents act synergistically in producing a bactericidal effect.
b. Both agents interfere with the protein synthesis of intracellular pathogens.
c. Both agents provide for good penetration of body tissues and reach therapeutic levels.
d. Both agents interfere with mRNA synthesis.
c. Both agents provide for good penetration of body tissues and reach therapeutic levels.
Considering that the digestive system is a major route of infection in most human cases of brucellosis, an investigator hypothesizes that the production of urease by the organism plays a key role as a virulence factor as well as in the organism's survival in the upper digestive tract. Indicate all of the following explanations that accurately describe the mechanism of action of the enzyme urease.
Select all that apply.

a. As a result of urea hydrolysis, there is an increase in pH due to the production of ammonia.
b. As a result of urea hydrolysis, there is a decrease in pH due to the production of ammonia.
c. The increased production of ammonia by urea hydrolysis serves to neutralize stomach acid, promoting survival of the organism.
d. The increased production of ammonia by urea hydrolysis serves to increase stomach acid, promoting survival of the organism.
a. As a result of urea hydrolysis, there is an increase in pH due to the production of ammonia.

c. The increased production of ammonia by urea hydrolysis serves to neutralize stomach acid, promoting survival of the organism.
Using a mouse model, the investigator orally inoculates mice with a mutated strain of Brucella lacking the gene for production of urease. Indicate which of the following would LEAST support the hypothesis that urease plays a role as a virulence factor in establishing Brucella infection.

a. Mice infected with mutated Brucella will NOT demonstrate inhibition of phagosome acidification by ammonia.
b. Mutant and nonmutant strains will demonstrate the ability to transition through intestinal mucosa.
c. Counts of viable mutant strains from the upper gastrointestinal (GI) tract will be significantly less than those of nonmutant strains.
d. Mice infected with nonmutated Brucella will demonstrate inhibition of phagosome acidification by ammonia.
b. Mutant and nonmutant strains will demonstrate the ability to transition through intestinal mucosa.
Which of the following pathogenic characteristics would best allow Brucella organisms to produce a chronic infection in a host?

a. weakened inflammatory response
b. resistance to complement
c. resistance to antibiotics
d. sequestering of organism within the endoplasmic reticulum
d. sequestering of organism within the endoplasmic reticulum
Which of the following statements concerning viruses is true?

a. Viruses possess enzymes for protein synthesis and ATP generation.
b. Viruses contain both DNA and RNA, and they undergo binary fusion.
c. Viruses are usually about the same size as bacteria.
d. The "host range" for a virus is determined by the presence or absence of particular components on the surface of a host cell that are required for the virus to attach.
d. The "host range" for a virus is determined by the presence or absence of particular components on the surface of a host cell that are required for the virus to attach.
Which statement concerning viral structure is true?

a. All viruses contain an envelope, which is made of lipid, carbohydrate, and protein.
b. The proteins in the envelope are capsomeres.
c. Animal viruses usually contain a tail sheath and spikes.
d. Spikes are found on some viruses. They are very consistent in structure and can be used for identification.
d. Spikes are found on some viruses. They are very consistent in structure and can be used for identification.
How does specialized transduction differ from regular lysogeny?

a. The resulting bacteriophage from specialized transduction cannot infect a new host cell.
b. The resulting bacteriophage from specialized transduction does not contain any viral DNA.
c. The prophage is not excised during specialized transduction.
d. The prophage in specialized transduction carries with it pieces of the host chromosomal DNA.
d. The prophage in specialized transduction carries with it pieces of the host chromosomal DNA.
What happens to the packaged DNA of a specialized transduced phage when it infects a new recipient cell?

a. The DNA is chewed up by enzymes found in the recipient cell.
b. The host DNA integrates, with the prophage, into the new recipient chromosome.
c. The DNA begins to replicate without integrating into the host chromosome.
b. The host DNA integrates, with the prophage, into the new recipient chromosome.
How can specialized transduction contribute to the transfer of antibiotic resistance genes in a bacterial population?

a. The prophage takes an antibiotic resistance gene with it and is packaged with the newly synthesized viral DNA.
b. The phage lyses the bacterium and releases resistance genes into the local environment, which can then be taken up by recipient cells.
c. The phage causes the destruction of any antibiotic present during the specialized transduction process.
a. The prophage takes an antibiotic resistance gene with it and is packaged with the newly synthesized viral DNA.
Which of the following is true concerning a lysogenic viral replication cycle?

a. During lysogeny, the viral DNA is present as a circular plasmid.
b. During lysogeny, the viral genome integrates into the host DNA, becoming a physical part of the chromosome.
c. Once the lysogenic portion of the cycle has begun, virus is never produced again.
d. Lysogenic infections are similar to persistent infections, in that virus is constantly produced.
b. During lysogeny, the viral genome integrates into the host DNA, becoming a physical part of the chromosome.
How are viruses different from cells?

a. They do not contain enzymes.
b. They do not contain genetic material.
c. They do not contain protein.
d. They require a host in order to reproduce.
d. They require a host in order to reproduce.
What is the function of the structural elements of a virus?

a. To provide a source of energy for the virus
b. To package and protect the viral genome
c. To use all of the cell proteins
b. To package and protect the viral genome
How do naked viruses differ from enveloped viruses in their attachment/penetration phase?

a. They uncoat after they enter the cell.
b. Their DNA attaches to receptors on the cell surface.
c. Their protein coat fuses to the cell membrane.
d. Their nucleic acids are injected into the cell.
d. Their nucleic acids are injected into the cell.
Which virus employs the use of an RNA-dependent RNA polymerase?

a. dsDNA viruses
b. Retroviruses
c. ssDNA viruses
d. +RNA viruses
d. +RNA viruses
Which of the following viruses is transcribed from RNA to DNA to RNA during the replication cycle?

a. dsDNA viruses
b. +RNA viruses
c. -RNA viruses
d. Retroviruses
d. Retroviruses
Which type of virus would produce viral glycoproteins to be expressed on the host cell membrane?

a. Naked viruses
b. Enveloped viruses
c. dsRNA viruses
d. +RNA viruses
b. Enveloped viruses
Which of the following can be used directly as messenger RNA?

a. -RNA
b. ssDNA
c. +RNA
c. +RNA
We sometimes are able to generate antibodies (immune system proteins) that bind to and cover up some of the proteins on the outermost portion of a virus while it is in the bloodstream. This renders the virus unable to reproduce. Which step of viral replication are antibodies directly preventing?

a. assembly
b. uncoating
c. synthesis
d. attachment
d. attachment
Enveloped viruses have a layer of lipids surrounding their capsid. This envelope is made mostly of host cell membrane. In which step does the virus acquire this envelope?

a. release
b. synthesis
c. attachment
d. assembly
a. release
What occurs during viral uncoating?

a. The capsid breaks apart, releasing the viral genome.
b. The nucleic acid breaks apart, allowing for translation.
c. The viral envelope is released.
d. The viral proteins are synthesized.
a. The capsid breaks apart, releasing the viral genome.
Which of the following statements regarding latent viral infections is true?

a. Latent viral infections are caused by the slow conversion of cellular glycoproteins from normal to infectious form.
b. Latent viral infections are almost always fatal.
c. During latent infections, small amounts of virus are produced, and virus numbers build up over time.
d. Latent infections can persist for years in an individual without causing any symptoms.
d. Latent infections can persist for years in an individual without causing any symptoms.
Which of the following is true regarding cultivation and isolation of animal viruses?

a. Diploid cell culture lines, developed from human embryos, are widely used for culturing viruses that require a human host.
b. The preferred and widely used method of viral isolation and growth is via growth in an embryonated egg.
c. Mouse models are available for virtually all human viral infections and can be routinely used for vaccine development.
d. Viruses can be easily grown in liquid culture without any other organisms present.
a. Diploid cell culture lines, developed from human embryos, are widely used for culturing viruses that require a human host.
From which phrase is the term "prions" derived?

a. Protein infections
b. Protein infection of the nervous system
c. Particles of infection
d. Proteinaceous infectious particles
d. Proteinaceous infectious particles
In what year did Stanley Prusiner discover prions?

a. 1928
b. 1979
c. 1997
d. 1982
d. 1982
Which disease did Stanley Prusiner first identify as being caused by prions?

a. Kuru
b. Mad cow disease
c. Fatal familial insomnia
d. Scrapie
d. Scrapie
How are prions different from other infectious agents?

a. They lack protein.
b. They cannot replicate.
c. They cause neurological disease.
d. They lack nucleic acid.
d. They lack nucleic acid.
The normal function of the PrP protein in mammals is believed to be:

a. assisting in normal membrane development and function.
b. assisting in normal synaptic development and function.
c. assisting proteins in forming beta-pleated sheets.
d. assisting proteins in forming alpha-helices.
b. assisting in normal synaptic development and function.
How do normal prion proteins (PrP) differ from the infectious prion proteins?

a. Normal PrP have alpha-helices; infectious PrP have beta-pleated sheets.
b. Normal PrP are found in all mammals; infectious PrP are found in only cows.
c. Normal PrP lack nucleic acid; infectious PrP have nucleic acid.
d. Normal PrP are found on mammals; infectious PrP are found on reptiles.
a. Normal PrP have alpha-helices; infectious PrP have beta-pleated sheets.
How does the number of infectious prions increase?

a. Prions reproduce by binary fission.
b. Prions transform normal proteins into the misfolded beta-pleated sheet configuration; therefore, prions multiply by conversion.
c. Prions form multimers which can then form more single copies of the prion protein.
d. Prions reproduce by mitosis.
b. Prions transform normal proteins into the misfolded beta-pleated sheet configuration; therefore, prions multiply by conversion.
Why are the beta-pleated multimers of PrP potentially pathogenic?

a. They are found on the surface of immune cells, resulting in damage to the immune system.
b. They are not detected by other organisms.
c. They repress the immune system.
d. The multimers are more stable and resistant to protease.
d. The multimers are more stable and resistant to protease.
Which of the following statements concerning prion diseases is true?

a. Normal host cellular prion proteins (PrPC) are converted into scrapie proteins (PrPSc).
b. Prion diseases affect humans but not other animals.
c. Prion diseases affect brain function but do not affect the morphology (overall appearance) of brain tissues.
d. Prion diseases are always inherited.
a. Normal host cellular prion proteins (PrPC) are converted into scrapie proteins (PrPSc).
Which of the following is true of viroids?

a. Viroids are typically extremely long and contain numerous genes.
b. There are similarities between the base sequences of viroids and exons, resulting in the hypothesis that viroids evolved from exons.
c. Viroid is the term for a virus that infects plants.
d. Viroids are short pieces of naked RNA.
d. Viroids are short pieces of naked RNA.
Viruses are the only known infectious agents that are obligatory intracellular parasites.

a. True
b. False
b. False
Which of the following statements about viruses is FALSE?

a. Viruses contain DNA or RNA but never both.
b. Viruses have genes.
c. Viruses use their own catabolic enzymes.
d. Viruses contain a protein coat.
e. Viruses use the anabolic machinery of the cell.
c. Viruses use their own catabolic enzymes.
Which of the following statements provides the most significant support for the idea that viruses are nonliving chemicals?

a. They cannot reproduce themselves outside a host.
b. They are chemically simple.
c. They cause diseases similar to those caused by chemicals.
d. They are filterable.
e. They are not composed of cells.
a. They cannot reproduce themselves outside a host.
How do all viruses differ from bacteria?

a. Viruses are obligate intracellular parasites.
b. Viruses are filterable.
c. Viruses are not composed of cells.
d. Viruses do not have any nucleic acid.
e. Viruses do not reproduce.
c. Viruses are not composed of cells.
A segmented genome can result in antigenic shift.

a. True
b. False
a. True
Helical and icosahedral are terms used to describe the shapes of a virus envelope.

a. True
b. False
b. False
What contributes to antigenic shift in influenza viruses?

a. worldwide distribution of the virus
b. a segmented genome
c. ease of virus transmission
d. attachment spikes
e. different virus subtypes
b. a segmented genome
Which of the following is NOT used as a criterion to classify viruses?

a. number of capsomeres
b. morphology
c. nucleic acid
d. biochemical tests
e. size
d. biochemical tests
Which of the following statements about viral spikes is FALSE?

a. They are used for attachment.
b. They are found only on nonenveloped viruses.
c. They bind to receptors on the host cell surface.
d. They may cause hemagglutination.
e. They are composed of carbohydrate-protein complexes.
b. They are found only on nonenveloped viruses.
Binomial nomenclature is used to name viruses.

a. True
b. False
b. False
DNA made from an RNA template will be incorporated into the virus capsid of

a. influenzavirus.
b. Retroviridae.
c. Herpesviridae.
d. Hepadnaviridae.
e. bacteriophage families.
d. Hepadnaviridae.
Viruses that utilize reverse transcriptase belong to the virus families

a. Hepadnaviridae and Retroviridae.
b. Herpesviridae and Poxviridae.
c. Rhabdoviridae and Herpesviridae.
d. Herpesviridae and Retroviridae.
e. Retroviridae and Picornaviridae.
a. Hepadnaviridae and Retroviridae.
A viral species is a group of viruses that

a. has the same genetic information and ecological niche.
b. has the same morphology and nucleic acid.
c. infects the same cells and cause the same disease.
d. cannot be defined.
a. has the same genetic information and ecological niche.
Continuous cell lines differ from primary cell lines in that

a. continuous cell lines are derived from primary cell lines.
b. continuous cell lines always have to be re-isolated from animal tissues.
c. continuous cell lines can be maintained through an indefinite number of generations.
d. viruses can be grown in continuous cell lines.
e. continuous cell lines are from human embryos.
c. continuous cell lines can be maintained through an indefinite number of generations.
A clear area against a confluent "lawn" of bacteria is called a

a. plaque.
b. phage.
c. rash.
d. cell lysis.
e. pock.
a. plaque.
Which of the following is NOT utilized to culture viruses?

a. culture media
b. laboratory animals
c. embryonated eggs
d. bacterial cultures
e. animal cell cultures
a. culture media
Most drugs that interfere with viral multiplication also interfere with host cell function.

a. True
b. False
a. True
Positive sense RNA strands of viruses are treated like mRNA inside the host cell.

a. True
b. False
a. True
Most RNA viruses carry which of the following enzymes?

a. lysozyme
b. DNA-dependent DNA polymerase
c. ATP synthase
d. reverse transcriptase
e. RNA-dependent RNA polymerase
e. RNA-dependent RNA polymerase
Which one of the following steps does NOT occur during multiplication of a picornavirus?

a. synthesis of DNA
b. synthesis of - strands of RNA
c. synthesis of + strands of RNA
d. synthesis of viral proteins
e. None of the answers is correct.
a. synthesis of DNA
The following steps occur during multiplication of retroviruses. Which is the fourth step?

a. penetration
b. attachment
c. uncoating
d. synthesis of double-stranded DNA
e. synthesis of +RNA
d. synthesis of double-stranded DNA
Which of the following places these items in the correct order for DNA-virus replication?
1. Maturation
2. DNA synthesis
3. Transcription
4. Translation


a. 2; 3; 4; 1
b. 1; 2; 3; 4
c. 4; 1; 2; 3
d. 3; 4; 1; 2
e. 4; 3; 2; 1
a. 2; 3; 4; 1
Generally, in an infection caused by a DNA-containing virus, the host animal cell supplies all of the following EXCEPT

a. RNA polymerase.
b. nucleotides.
c. tRNA.
d. DNA polymerase.
e. None of the answers are correct; all of these are supplied by the host animal cell.
d. DNA polymerase.
Bacteriophage replication differs from animal virus replication because only bacteriophage replication involves

a. adsorption to specific receptors.
b. replication of viral nucleic acid.
c. assembly of viral components.
d. injection of naked nucleic acid into the host cell.
e. lysis of the host cell.
d. injection of naked nucleic acid into the host cell.
Bacteriophages derive all of the following from the host cell EXCEPT

a. nucleotides.
b. ATP.
c. tRNA.
d. lysozyme.
e. amino acids.
d. lysozyme.
The mechanism whereby an enveloped virus leaves a host cell is called

a. lysogeny.
b. penetration.
c. abduction.
d. transduction.
e. budding.
e. budding.
Assume you have isolated an unknown virus. This virus has a single, positive sense strand of RNA, and possesses an envelope. To which group does it most likely belong?

a. papovavirus
b. herpesvirus
c. picornavirus
d. retrovirus
e. togavirus
e. togavirus
A viruss ability to infect an animal cell depends primarily upon the

a. presence of receptor sites on the cell membrane.
b. enzymatic activity of a host cell.
c. host cells ability to phagocytize viral particles.
d. presence of pili on the host cell wall.
e. type of viral nucleic acid.
a. presence of receptor sites on the cell membrane.
It causes lysis of host cells.

a. It can give infected pathogens the genetic information for toxin production.
b. It is a "silent" infection; the virus does not replicate.
c. Prophage is inserted into the host genome.
d. Lytic cycle may follow lysogeny.
a. It can give infected pathogens the genetic information for toxin production.
An envelope is acquired during which of the following steps?

a. release
b. biosynthesis
c. penetration
d. adsorption
e. uncoating
a. release
Which of the following would be the first step in biosynthesis of a virus with a - (minus) strand of RNA?

a. transcription of mRNA from DNA
b. synthesis of DNA from a DNA template
c. synthesis of double-stranded RNA from a DNA template
d. synthesis of double-stranded RNA from an RNA template
e. synthesis of DNA from an RNA template
d. synthesis of double-stranded RNA from an RNA template
Lysogeny can result in all of the following EXCEPT

a. specialized transduction.
b. acquisition of new characteristics by the host cell.
c. immunity to reinfection by the same phage.
d. immunity to reinfection by any phage.
e. phage conversion.
d. immunity to reinfection by any phage.
Which of the following statements is FALSE?

a. A prophage may result in new properties of the host cell.
b. A prophage is phage DNA inserted into a bacterial chromosome.
c. A prophage can "pop" out of the chromosome.
d. Prophage genes are repressed by a repressor protein coded for by the prophage.
e. The prophage makes the host cell immune to infection by other phages.
e. The prophage makes the host cell immune to infection by other phages.
The definition of lysogeny is

a. when the burst time takes an unusually long time.
b. phage DNA is incorporated into host cell DNA.
c. the period during replication when virions are not present.
d. lysis of the host cell due to a phage.
e. attachment of a phage to a cell.
b. phage DNA is incorporated into host cell DNA.
In which stage is the viral DNA introduced into the cell?

a. Release
b. Penetration
c. Biosynthesis
d. Assembly
e. Attachment
b. Penetration
In which stage does formation of mature viruses occur?

a. Release
b. Penetration
c. Attachment
d. Biosynthesis
e. Assembly
e. Assembly
The host DNA is usually degraded during which stage?

a. Biosynthesis
b. Assembly
c. Penetration
d. Release
e. Attachment
a. Biosynthesis
What would be the fate of a lytic bacteriophage if the host cell died prior to the assembly stage?

a. The cell could still be revived by the virus.
b. The virus would infect new hosts.
c. The virus would not be able to infect new hosts.
c. The virus would not be able to infect new hosts.
Lysogenic viral DNA integrating into the host genome is referred to as

a. lysogeny.
b. induction.
c. a prophage.
d. lytic.
c. a prophage.
Which of the following events might trigger induction of a temperate bacteriophage?

a. Bacterial conjugation
b. Exposure to UV light
c. An infected cell entering the logarithmic phase of growth
d. Normal cell division of an infected cell
b. Exposure to UV light
How is the lytic cycle different from the lysogenic cycle with respect to the infected host cell?

a. The host cell is allowed to live during the lytic stage.
b. The host cell can only divide during the lytic stage.
c. The host cell dies during the lytic stage.
d. The viral DNA may integrate into the host genome during the lytic stage.
c. The host cell dies during the lytic stage.
What is the fate of the prophage during the lysogenic stage?

a. It is released from the cell by lysing the cell.
b. It is copied every time the host DNA replicates.
c. It is packaged into viral proteins and maintained until the host is exposed to an environmental stress.
d. It is degraded by the activity of host defense enzymes.
b. It is copied every time the host DNA replicates.
Oncogenic viruses

a. have no effect on the host cell.
b. cause tumors to develop.
c. are lytic viruses that kill the host cell.
d. are genetically unstable.
e. cause acute infections.
b. cause tumors to develop.
The most conclusive evidence that viruses cause cancers is provided by

a. treating cancer with antibodies.
b. finding oncogenes in viruses.
c. cancer following injection of cell-free filtrates.
d. the presence of antibodies against viruses in cancer patients.
e. some liver cancer patients having had hepatitis.
c. cancer following injection of cell-free filtrates.
Some viruses, such as human herpesvirus 1, infect a cell without causing symptoms. These are called

a. latent viruses.
b. slow viruses.
c. phages.
d. lytic viruses.
e. unconventional viruses.
a. latent viruses.
A lytic virus has infected a patient. Which of the following would best describe what is happening inside the patient?

a. The virus is incorporating its nucleic acid with that of the patients cells.
b. The virus is causing the death of the infected cells in the patient.
c. The virus is slowly killing the patients cells.
d. The virus is infecting cells and then releasing only small amounts of virus.
e. The virus is not killing any cells in the host.
b. The virus is causing the death of the infected cells in the patient.
An example of a latent viral infection is

a. cold sores.
b. mumps.
c. influenza.
d. subacute sclerosing panencephalitis.
e. smallpox.
a. cold sores.
A persistent infection is one in which

a. host cells are gradually lysed.
b. the virus remains in equilibrium with the host without causing a disease.
c. host cells are transformed.
d. viral replication is unusually slow.
e. the disease process occurs gradually over a long period.
e. the disease process occurs gradually over a long period.
An infectious protein is a

a. retrovirus.
b. papovavirus.
c. bacteriophage.
d. viroid.
e. prion.
e. prion.
Which of the following is necessary for replication of a prion?

a. lysozyme
b. DNA
c. PrPSc
d. RNA
e. DNA polymerase
c. PrPSc
Which of the following prion diseases is found in deer and elk?

a. Chronic wasting disease
b. Scrapie
c. Variant Creutzfeldt-Jakob disease
d. Bovine spongiform encephalopathy
a. Chronic wasting disease
Which of the following prion diseases was also known as laughing disease?

a. Gerstmann-Straussler-Scheinker syndrome
b. Bovine spongiform encephalopathy
c. Kuru
d. Creutzfeldt-Jakob disease
c. Kuru
Which of the following conditions in humans is linked to bovine spongiform encephalopathy?

a. Variant Creutzfeldt-Jakob disease
b. Kuru
c. Gerstmann-Straussler-Scheinker syndrome
d. Fatal familial insomnia
a. Variant Creutzfeldt-Jakob disease
What part of the nervous system is most affected by fatal familial insomnia?

a. Thalamus
b. Cerebellum
c. The spinal cord
d. Cerebrum
a. Thalamus
Where does the name "scrapie" come from?

a. The prion disorder causes infected sheep to scrape against objects until their skin is raw.
b. The prions cause amyloid plaques to scrape against each other.
c. The disease results in the animal wasting away, sending them to the "scrap heap."
a. The prion disorder causes infected sheep to scrape against objects until their skin is raw.
Which of the following is most likely a product of an early gene?

a. lysozyme
b. DNA polymerase
c. spike proteins
d. capsid proteins
e. envelope proteins
b. DNA polymerase
Which virus is NOT associated with cancer?

a. hepatitis B virus (HBV)
b. human papillomavirus (HPV)
c. coronavirus
d. Epstein-Barr virus (EBV)
c. coronavirus
Which statement is CORRECT concerning animal viruses?

a. Enveloped viruses are surrounded by a lipid and carbohydrate coat, which is made from the host cell's mitochondria.
b. The genome of animal viruses is always single-stranded.
c. Capsid proteins are produced in the nucleus.
d. Retroviruses use an enzyme called reverse transcriptase, which synthesizes DNA by copying RNA.
d. Retroviruses use an enzyme called reverse transcriptase, which synthesizes DNA by copying RNA.
Which of the following is a human disease caused by prions?

a. shingles
b. Creutzfeldt-Jakob disease (CJD)
c. chickenpox (varicella)
d. subacute sclerosing panencephalitis (SSPE)
b. Creutzfeldt-Jakob disease (CJD)