CH 19, 20, 21
In recent times, it has been shown that adult cells can be induced to become pluripotent stem cells (iPS). To make this conversion, what has been done to the adult cells? A) A retrovirus is used to introduce four specific regulatory genes. B) The adult stem cells must be fused with embryonic cells. C) Cytoplasm from embryonic cells is injected into the adult cells. D) The nucleus of an embryonic cell is used to replace the nucleus of an adult cell.
A) A retrovirus is used to introduce four specific regulatory genes.
Why is it so important to be able to amplify DNA fragments when studying genes? A) Before amplification, DNA fragments are likely to bind to RNA and no longer be able to be analyzed. B) A gene may represent only a millionth of the cell's DNA. C) Restriction enzymes (endonucleases) cut DNA into fragments that are too small. D) A clone requires multiple copies of each gene per clone.
A) Before amplification, DNA fragments are likely to bind to RNA and no longer be able to be analyzed.
What is the function of reverse transcriptase in retroviruses? A) It uses viral RNA as a template for DNA synthesis. B) It converts host cell RNA into viral DNA. C) It translates viral RNA into proteins. D) It uses viral RNA as a template for making complementary RNA strands.
A) It uses viral RNA as a template for DNA synthesis.
Scientists developed a set of guidelines to address the safety of DNA technology. Which of the following is one of the adopted safety measures? A) Microorganisms used in recombinant DNA experiments are genetically crippled to ensure that they cannot survive outside of the laboratory. B) Genetically modified organisms are not allowed to be part of our food supply. C) Transgenic plants are engineered so that the plant genes cannot hybridize. D) Experiments involving HIV or other potentially dangerous viruses have been banned.
A) Microorganisms used in recombinant DNA experiments are genetically crippled to ensure that they cannot survive outside of the laboratory.
Will treating a viral infection with antibiotics affect the course of the infection? A) No; antibiotics work by inhibiting enzymes specific to bacteria. Antibiotics have no effect on eukaryotic or virally encoded enzymes. B) No; antibiotics do not kill viruses because viruses do not have DNA or RNA. C) Yes; antibiotics activate the immune system, and this decreases the severity of the infection. D) Yes; antibiotics can prevent viral entry into the cell by binding to host-receptor proteins.
A) No; antibiotics work by inhibiting enzymes specific to bacteria. Antibiotics have no effect on eukaryotic or virally encoded enzymes.
What information is critical to the success of polymerase chain reaction (PCR) itself? A) The DNA sequence of the ends of the DNA to be amplified must be known. B) The complete DNA sequence of the DNA to be amplified must be known. C) The sequence of restriction-enzyme recognition sites in the DNA to be amplified must be known. D) The sequence of restriction-enzyme recognition sites in the DNA to be amplified and in the plasmid where the amplified DNA fragment will be cloned must be known.
A) The DNA sequence of the ends of the DNA to be amplified must be known.
A researcher is using adult stem cells and comparing them to other adult cells from the same tissue. Which of the following is a likely finding? A) The cells from the two sources exhibit different patterns of DNA methylation. B) Adult stem cells have more DNA nucleotides than their counterparts. C) The two kinds of cells have virtually identical gene expression patterns in microarrays. D) The nonstem cells have fewer repressed genes.
A) The cells from the two sources exhibit different patterns of DNA methylation.
What characteristic of short tandem repeats (STRs) DNA makes it useful for DNA fingerprinting? A) The number of repeats varies widely from person to person or animal to animal. B) The sequence of DNA that is repeated varies significantly from individual to individual. C) The sequence variation is acted upon differently by natural selection in different environments. D) Every racial and ethnic group has inherited different short tandem repeats.
A) The number of repeats varies widely from person to person or animal to animal.
If a viral host cell has a mutation that interferes with the addition of carbohydrates to proteins in the Golgi, which of the following could likely result? A) The viral envelope proteins would not be glycosylated and might not arrive at the host plasma membrane. B) The viral capsid proteins would not be glycosylated and might not arrive at the host plasma membrane. C) The viral core proteins would not be glycosylated and might not arrive at the host plasma membrane. D) The virus would be unable to reproduce within the host cell.
A) The viral envelope proteins would not be glycosylated and might not arrive at the host plasma membrane.
Which of the following supports the argument that viruses are nonliving? A) They are not cellular. B) Their DNA does not encode proteins. C) They have RNA rather than DNA. D) They do not evolve.
A) They are not cellular.
Bacterial cells protect their own DNA from restriction enzymes (endonucleases) by _____. A) adding methyl groups to adenines and cytosines B) using DNA ligase to seal the bacterial DNA into a closed circle C) adding histones to protect the double-stranded DNA D) forming "sticky ends" of bacterial DNA to prevent the enzyme (endonuclease) from attaching
A) adding methyl groups to adenines and cytosines
An early step in shotgun sequencing is to ____. A) break genomic DNA at random sites B) map the position of cloned DNA fragments C) randomly select DNA primers and hybridize these to random positions of chromosomes in preparation for sequencing
A) break genomic DNA at random sites
Transgenic mice are useful to human researchers because they ____. A) can be valuable animal models of human disease B) are essential for mapping human genes C) are now used in place of bacteria for cloning human genes D) were instrumental in pinpointing the location of the huntingtin gene
A) can be valuable animal models of human disease
A person is most likely to recover from a viral infection if the infected cells ____. A) can undergo normal cell division B) can carry on translation, at least for a few hours C) produce and release viral protein D) transcribe viral mRNA
A) can undergo normal cell division
Imagine that you compare two DNA sequences found in the same location on homologous chromosomes. On one of the homologs, the sequence is AACTACGA. On the other homolog, the sequence is AACTTCGA. Within a population, you discover that each of these sequences is common. These sequences ____. A) contain an SNP that may be useful for genetic mapping B) identify a protein-coding region of a gene C) cause disease D) do none of the listed actions
A) contain an SNP that may be useful for genetic mapping
To introduce a particular piece of DNA into an animal cell, such as that of a mouse, you would most likely be successful with which of the following methods? A) electroporation followed by recombination B) introducing a plasmid into the cell C) infecting the mouse cell with a Ti plasmid D) transcription and translation
A) electroporation followed by recombination
Effective antiviral drugs are usually associated with which of the following properties? A) interference with viral replication B) prevention of the host from becoming infected C) removal of viral proteins D) removal of viral mRNAs
A) interference with viral replication
The reason for using Taq polymerase for PCR is that ____. A) it is heat stable and can withstand the heating step of PCR B) only minute amounts are needed for each cycle of PCR C) it binds more readily than other polymerases to the primers D) it has regions that are complementary to the primers
A) it is heat stable and can withstand the heating step of PCR
One possible use of transgenic plants is in the production of human proteins, such as vaccines. Which of the following is a possible hindrance that must be overcome? A) prevention of transmission of plant allergens to the vaccine recipients B) prevention of vaccine-containing plants being consumed by insects C) use of plant cells to translate non-plant-derived mRNA D) inability of the human digestive system to accept plant-derived protein
A) prevention of transmission of plant allergens to the vaccine recipients
A researcher has used in vitro mutagenesis to mutate a cloned gene and then has reinserted the mutated gene into a cell. To have the mutated sequence disable the function of the gene, what must then occur? A) recombination resulting in replacement of the wild type with the mutated gene B) use of a microarray to verify continued expression of the original gene C) replication of the cloned gene using a bacterial plasmid D) transcription of the cloned gene using a BAC
A) recombination resulting in replacement of the wild type with the mutated gene
Which of the following could use reverse transcriptase to transcribe its genome? A) ssRNA B) dsRNA C) ssDNA D) dsDNA
A) ssRNA
A population of viruses with similar characteristics is called a ____. A) strain B) species C) type D) genome
A) strain
RNAi methodology uses double-stranded pieces of RNA to trigger breakdown of a specific mRNA or inhibit its translation. For which of the following might this technique be useful? A) to decrease the production from a harmful mutated gene B) to destroy an unwanted allele in a homozygous individual C) to form a knockout organism that will not pass the deleted sequence to its progeny D) to raise the concentration of a desired protein
A) to decrease the production from a harmful mutated gene
The difference between vertical and horizontal transmission of plant viruses is that vertical transmission is ____. A) transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant B) the spread of viruses from upper leaves to lower leaves of the plant, and horizontal transmission is the spread of a virus among leaves at the same general level C) the spread of viruses from trees and tall plants to bushes and other smaller plants, and horizontal transmission is the spread of viruses among plants of similar size D) the transfer of DNA from a plant of one species to a plant of a different species, and horizontal transmission is the spread of viruses among plants of the same species
A) transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant
Which of the following sequences is most likely to be cut by a restriction enzyme? A) AATTCT TTAAGA B) AATATT TTATAA C) AAAATT TTTTAA D) ACTACT TGATGA
B) AATATT TTATAA
Which of the following human diseases is caused by a virus that requires reverse transcriptase to transcribe its genome inside the host cell? A) herpes B) AIDS C) smallpox D) influenza
B) AIDS
What is difference between an epidemic and a pandemic? A) An epidemic is a disease; a pandemic is a treatment. B) An epidemic is restricted to a local region; a pandemic is global. C) An epidemic has low mortality; a pandemic has higher mortality. D) An epidemic is caused by a bacterial infection; a pandemic is caused by a viral infection.
B) An epidemic is restricted to a local region; a pandemic is global.
The segment of DNA shown in the figure above has restriction sites I and II, which create restriction fragments A, B, and C. Which of the gels produced by electrophoresis shown below best represents the separation and identity of these fragments?
B) C large space AB
Reproductive cloning of human embryos is generally considered unethical. However, on the subject of therapeutic cloning there is a wider divergence of opinion. Which of the following is a likely explanation? A) The use of adult stem cells is likely to produce more cell types than the use of embryonic stem cells. B) Cloning to produce embryonic stem cells may lead to great medical benefits for many. C) Cloning to produce stem cells relies on a different initial procedure than reproductive cloning. D) A clone that lives until the blastocyst stage does not yet have human DNA.
B) Cloning to produce embryonic stem cells may lead to great medical benefits for many.
What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium? I. Transform bacteria with a recombinant DNA molecule. II. Cut the plasmid DNA using restriction enzymes (endonucleases). III. Extract plasmid DNA from bacterial cells. IV. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. V. Use ligase to seal plasmid DNA to nonplasmid DNA. A) II, III, V, IV, I B) III, II, IV, V, I C) III, IV, V, I, II D) IV, V, I, II, III
B) III, II, IV, V, I
Why do RNA viruses appear to have higher rates of mutation? A) RNA nucleotides are more unstable than DNA nucleotides. B) Replication of their genomes does not involve proofreading. C) RNA viruses can incorporate a variety of nonstandard bases. D) RNA viruses are more sensitive to mutagens.
B) Replication of their genomes does not involve proofreading.
In large scale, genome-wide association studies in humans we look for _____. A) lengthy sequences that might be shared by most members of a population B) SNPs where one allele is found more often in persons with a particular disorder than in healthy controls C) SNPs where one allele is found in families with particular introns sequence D) SNPs where one allele is found in two or more adjacent genes
B) SNPs where one allele is found more often in persons with a particular disorder than in healthy controls
Poliovirus is an RNA virus of the picornavirus group, which uses its RNA as mRNA. At its 5' end, the RNA genome has a viral protein (VPg) instead of a 5' cap. This is followed by a nontranslated leader sequence, and then a single long protein-coding region (~7000 nucleotides), followed by a poly-A tail. Observations were made that used radioactive amino acid analogues. Short period use of the radioactive amino acids result in labeling of only very long proteins, while longer periods of labeling result in several different short polypeptides. What conclusion is most consistent with the results of the radioactive labeling experiment? A) Host cell ribosomes only translate the viral code into short polypeptides. B) The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones. C) The RNA is translated into short polypeptides, which are subsequently assembled into large ones. D) The large radioactive polypeptides are coded by the host, whereas the short ones are coded for by the virus.
B) The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones.
HIV is inactivated in the laboratory after a few minutes of sitting at room temperature, but the flu virus is still active after sitting for several hours. What are the practical consequences of these findings? A) HIV can be transmitted more easily from person to person than the flu virus B) The flu virus can be transmitted more easily from person to person than HIV C) This property of HIV makes it more likely to be a pandemic than the flu virus D) Disinfecting surfaces is more important to reduce the spread of HIV than the flu
B) The flu virus can be transmitted more easily from person to person than HIV
Viruses use the host's machinery to make copies of themselves. However, some human viruses require a type of replication that humans do not normally have. For example, humans normally do not have the ability to convert RNA into DNA. How can these types of viruses infect humans, when human cells cannot perform a particular role that the virus requires? A) The virus causes mutations in the human cells, resulting in the formation of new enzymes that are capable of performing these roles. B) The viral genome codes for specialized enzymes not in the host. C) The virus infects only those cells and species that can perform all the replication roles necessary. D) Viruses can stay in a quiescent state until the host cell evolves this ability.
B) The viral genome codes for specialized enzymes not in the host.
Which of the following is true of embryonic stem cells but not of adult stem cells? A) They normally differentiate into only eggs and sperm. B) They can give rise to all cell types in the organism. C) They can continue to reproduce for an indefinite period. D) One aim of using them is to provide cells for repair of diseased tissue.
B) They can give rise to all cell types in the organism.
Which of the following represents a difference between viruses and viroids? A) Viruses infect many types of cells, whereas viroids infect only prokaryotic cells. B) Viruses have capsids composed of protein, whereas viroids have no capsids. C) Viruses have genomes composed of RNA, whereas viroids have genomes composed of DNA. D) Viruses cannot pass through plasmodesmata, whereas viroids can.
B) Viruses have capsids composed of protein, whereas viroids have no capsids.
Which enzyme was used to produce the molecule in the figure above? A) ligase B) a restriction enzyme (endonuclease) C) RNA polymerase D) DNA polymerase
B) a restriction enzyme (endonuclease)
Which of the following viruses would most likely have reverse transcriptase? A) an RNA-based lytic virus B) an RNA-based lysogenic virus C) a DNA-based lytic virus D) a DNA-based lysogenic virus
B) an RNA-based lysogenic virus
Viral infections in plants ____. A) can be controlled with antibiotics B) can spread within a plant via plasmodesmata C) have little effect on plant growth D) are not spread by animals
B) can spread within a plant via plasmodesmata
A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV). The cell contents are left in a covered test tube overnight. The next day this mixture is sprayed on tobacco plants. We expect that the plants would ____. A) develop some but not all of the symptoms of the TMV infection B) develop the typical symptoms of TMV infection C) not show any disease symptoms D) become infected, but the sap from these plants would be unable to infect other plants
B) develop the typical symptoms of TMV infection
Which of the following can be effective in preventing the onset of viral infection in humans? A) taking vitamins B) getting vaccinated C) taking antibiotics D) taking drugs that inhibit transcription
B) getting vaccinated
Which of the following uses labeled probes to visualize the expression of genes in whole tissues and organisms? A) RT-PCR B) in situ hybridization C) DNA microarrays D) RNA interference
B) in situ hybridization
Genetically engineered plants ____. A) are more difficult to develop than genetically engineered animals B) include transgenic rice plants that can grow in water of high salinity C) are used in research but not yet in commercial agricultural production D) are banned throughout the world
B) include transgenic rice plants that can grow in water of high salinity
If scientists are trying to use what they know about HSV to devise a means of protecting other people from being infected, which of the following would have the best chance of lowering the number of new cases of infection? A) vaccinate of all persons with preexisting cases of HSV B) interfere with new viral replication in preexisting cases of HSV C) treat HSV lesions to shorten the breakout D) educate people about avoiding sources of infection
B) interfere with new viral replication in preexisting cases of HSV
To make a vaccine against mumps, measles, or rabies, which type of viruses would be useful? A) dsDNA viruses B) negative-sense ssRNA viruses C) positive-sense ssRNA viruses D) dsRNA viruses
B) negative-sense ssRNA viruses
A virus consisting of a single strand of RNA, which is transcribed into complementary DNA, is a ____. A) protease B) retrovirus C) RNA replicase virus D) nonenveloped virus
B) retrovirus
A gene that contains introns can be made shorter (but remain functional) for genetic engineering purposes by using _____. A) a restriction enzyme (endonuclease) to cut the gene into shorter pieces B) reverse transcriptase to reconstruct the gene from its mRNA C) DNA polymerase to reconstruct the gene from its polypeptide product D) DNA ligase to put together fragments of the DNA that code for a particular polypeptide
B) reverse transcriptase to reconstruct the gene from its mRNA
Viruses ____. A) manufacture their own ATP, proteins, and nucleic acids B) use the host cell to copy themselves and make viral proteins C) use the host cell to copy themselves and then viruses synthesize their own proteins D) metabolize food and produce their own ATP
B) use the host cell to copy themselves and make viral proteins
Using the data in the figure above, how long does it take for virus A to go through one lytic cycle? A) 15 minutes B) 30 minutes C) 45 minutes D) 90 minutes
C) 45 minutes
Which of the following is characteristic of the lytic cycle? A) Viral DNA is incorporated into the host genome. B) The viral genome replicates without destroying the host. C) A large number of phages are released at a time. D) The virus—host relationship usually lasts for generations.
C) A large number of phages are released at a time.
For applications in gene therapy, what is the most favorable characteristic of retroviruses? A) Retroviruses have an RNA genome. B) Retroviruses possess reverse transcriptase. C) DNA copies of retroviral genomes become integrated into the genome of the infected cell. D) Retroviruses mutate often.
C) DNA copies of retroviral genomes become integrated into the genome of the infected cell
What is the main structural difference between enveloped and nonenveloped viruses? A) Enveloped viruses have their genetic material enclosed by a layer made only of protein. B) Nonenveloped viruses have only a phospholipid membrane, while enveloped viruses have two membranes, the other one being a protein capsid. C) Enveloped viruses have a phospholipid membrane outside their capsid, whereas nonenveloped viruses do not have a phospholipid membrane. D) Both types of viruses have a capsid and phospholipid membrane; but in the nonenveloped virus the genetic material is between these two membranes, while in the enveloped virus the genetic material is inside both membranes.
C) Enveloped viruses have a phospholipid membrane outside their capsid, whereas nonenveloped viruses do not have a phospholipid membrane.
One predicted aspect of climate change is that climates, including precipitation and temperature, over most of the Earth will become more variable. Which of the following is a good crop genetic engineering strategy if this is true? A) Only plant crops that are genetically engineered. B) Genetically engineer most crops to withstand very long droughts. C) Genetically engineer several genotypes within single crop types. D) Genetically engineer the fastest growing crops possible.
C) Genetically engineer several genotypes within single crop types.
Why do scientists consider HIV to be an emerging virus? A) HIV infected humans long before the 1980s, but it has now mutated to a more deadly form. B) HIV mutates rapidly making the virus very different from HIV in the early 1980s. C) HIV suddenly became apparent and widespread in the 1980s. D) HIV is now starting to cause diseases other than AIDS, such as rare types of cancers and pneumonias.
C) HIV suddenly became apparent and widespread in the 1980s.
If you already know that the infectious agent was either bacterial or viral, which method(s) listed above would allow you to distinguish between these two possibilities? A) I B) II C) II or III D) IV
C) II or III
DNA sequencing has transformed our understanding of genes, genomes and evolution. Which of the following statements comparing two common sequencing techniques, the chain termination method and next generation sequencing is TRUE? A) The chain termination method is faster and more efficient, so it is used to generate large-scale sequences, while next generation synthesis is used for routine, small-scale jobs. B) The chain termination method employs the polymerase chain reaction, but next generation sequencing does not. C) In the chain termination method, the order of bases is detected by fluorescently labeling each dideoxy-nucleotide in a different color, while next generation sequencing determines the order of bases by detecting the release of PPi during the formation of the phosphodiester bond. D) Next generation sequencing employs electrophoresis, but the chain termination method does not.
C) In the chain termination method, the order of bases is detected by fluorescently labeling each dideoxy-nucleotide in a different color, while next generation sequencing determines the order of bases by detecting the release of PPi during the formation of the phosphodiester bond.
Silencing of selected genes is often done using RNA interference (RNAi). Which of the following questions would NOT be answered with this process? A) What is the function of gene 432 in a particular species of annelid? B) What will happen in a particular insect's digestion if gene 173 is not able to be translated? C) Is gene HA292 expressed in individuals for a disorder in humans? D) Will the disabling of this gene in Drosophila and in a mouse cause similar results?
C) Is gene HA292 expressed in individuals for a disorder in humans?
Pax-6 is a gene that is involved in eye formation in many invertebrates, such as Drosophila. Pax-6 is also found in vertebrates. A Pax-6 gene from a mouse can be expressed in a fly and the protein (PAX-6) leads to a compound fly eye. This information suggests which of the following? A) Pax-6 genes are identical in nucleotide sequence. B) PAX-6 proteins have identical amino acid sequences. C) Pax-6 is highly conserved and shows shared evolutionary ancestry. D) PAX-6 proteins are different for formation of different kinds of eyes.
C) Pax-6 is highly conserved and shows shared evolutionary ancestry.
Which of the following statements describes the lysogenic cycle of lambda (λ) phage? A) After infection, the viral genes immediately turn the host cell into a lambda-producing factory, and the host cell then lyses. B) Most of the prophage genes are activated by the product of a particular prophage gene. C) The phage genome replicates along with the host genome. D) The phage DNA is copied and exits the cell as a phage.
C) The phage genome replicates along with the host genome.
Which of the following is one of the technical reasons why gene therapy is problematic? A) Most cells with an engineered gene do not produce gene product. B) Cells with transferred genes are unlikely to replicate. C) Transferred genes may not have appropriately controlled activity. D) mRNA from transferred genes cannot be translated.
C) Transferred genes may not have appropriately controlled activity.
For a particular microarray assay (DNA chip), cDNA has been made from the mRNAs of a dozen patients' breast tumor biopsies. The researchers will be looking for _____. 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 over proliferating 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 match those in non-breast cancer control samples from the same population
C) a pattern shared among some or all of the samples that indicates gene expression differing from control samples
Sequencing an entire genome, such as that of C. elegans, a nematode, is most important because _____. A) it allows researchers to use the sequence to build a "better" nematode, which is resistant to disease B) it allows research on a group of organisms we do not usually care much about C) a sequence that is found to have a particular function in the nematode is likely to have a closely related function in vertebrates D) a sequence that is found to have no introns in the nematode genome is likely to have acquired the introns from higher organisms
C) a sequence that is found to have a particular function in the nematode is likely to have a closely related function in vertebrates
Which of the following problems with animal cloning might result in premature death of the clones? A) use of pluripotent instead of totipotent stem cells B) use of nuclear DNA as well as mtDNA C) abnormal gene regulation due to variant methylation D) the indefinite replication of totipotent stem cells
C) abnormal gene regulation due to variant methylation
DNA microarrays have made a huge impact on genomic studies because they _____. A) can be used to eliminate the function of any gene in the genome B) can be used to introduce entire genomes into bacterial cells C) allow the expression of many or even all of the genes in the genome to be compared at once D) allow physical maps of the genome to be assembled in a very short time
C) allow the expression of many or even all of the genes in the genome to be compared at once
A principal problem with inserting an unmodified mammalian gene into a plasmid and then getting that gene expressed in bacteria is that ____. A) prokaryotes use a different genetic code from that of eukaryotes B) bacteria translate only mRNAs that have multiple messages C) bacteria cannot remove eukaryotic introns D) bacterial RNA polymerase cannot make RNA complementary to mammalian DNA
C) bacteria cannot remove eukaryotic introns
The first class of drugs developed to treat AIDS, such as AZT, were known as reverse transcriptase inhibitors. They worked because they ____. A) targeted and destroyed the viral genome before it could be reverse transcribed into DNA B) bonded to the dsDNA genome of the virus in such a way that it could not separate for replication to occur C) bonded to the viral reverse transcriptase enzyme, thus preventing the virus from making a DNA copy of its RNA genome D) prevented host cells from producing the enzymes used by the virus to replicate its genome
C) bonded to the viral reverse transcriptase enzyme, thus preventing the virus from making a DNA copy of its RNA genome
In many ways, the regulation of the genes of a particular group of viruses will be similar to the regulation of the host genes. Therefore, which of the following would you expect of the genes of a bacteriophage? A) regulation via acetylation of histones B) positive control mechanisms rather than negative C) control of more than one gene in an operon D) reliance on transcription activators
C) control of more than one gene in an operon
Which of the following accounts for someone who has had regular herpesvirus-mediated cold sore or genital sore flare-ups? A) re-infection by a closely related herpesvirus of a different strain B) re-infection by the same herpesvirus strain C) copies of the herpesvirus genome permanently maintained in host nuclei D) copies of the herpesvirus genome permanently maintained in host cell cytoplasm
C) copies of the herpesvirus genome permanently maintained in host nuclei
In 1997, Dolly the sheep was cloned. Which of the following processes was used? A) replication and dedifferentiation of adult stem cells from sheep bone marrow B) separation of an early stage sheep blastula into separate cells, one of which was incubated in a surrogate ewe C) fusion of an adult cell's nucleus with an enucleated sheep egg, followed by incubation in a surrogate D) isolation of stem cells from a lamb embryo and production of a zygote equivalent
C) fusion of an adult cell's nucleus with an enucleated sheep egg, followed by incubation in a surrogate
In the figure, at the arrow marked II, what enzyme(s) are being utilized? A) reverse transcriptase B) viral DNA polymerase C) host cell DNA polymerase D) host cell RNA polymerase
C) host cell DNA polymerase
A laboratory might use dideoxyribonucleotides to ____. A) separate DNA fragments B) produce cDNA from mRNA C) sequence a DNA fragment D) visualize DNA expression
C) sequence a DNA fragment
The virus genome and viral proteins are assembled into virions (virus particles) during ____. A) the lytic cycle and the lysogenic cycle in all known host organisms B) the lysogenic cycle only C) the lytic cycle only D) the lytic cycle in all host organisms but the lysogenic cycle only in bacteria
C) the lytic cycle only
If the yellow mottle virus begins its infection of a cell by using its genome as mRNA, which of the following would you expect to be able to measure? A) replication rate B) transcription rate C) translation rate D) formation of new transcription factors
C) translation rate
Using the data in the figure above, how long does it take for virus B to go through one lytic cycle? A) 15 minutes B) 30 minutes C) 45 minutes D) 60 minutes
D) 60 minutes
Which of the following best reflects what we know about how the flu virus moves between species? A) The flu virus in a pig is mutated and replicated in alternate arrangements so that humans who eat the pig products can be infected. B) A flu virus from a human epidemic or pandemic infects birds; the birds replicate the virus differently and then pass it back to humans. C) An influenza virus gains new sequences of DNA from another virus, such as a herpesvirus; this enables it to be transmitted to a human host. D) An animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates, the virus is passed to a new species such as a bird, and the virus mutates again and can now be transmitted to humans.
D) An animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates, the virus is passed to a new species such as a bird, and the virus mutates again and can now be transmitted to humans.
Plasmids are used as vectors in plant and bacterial genetic engineering. However, there is a major difference in the fate of genes introduced into bacteria on most bacterial plasmids and into plants on tumor-inducing (Ti) plasmids. What is this difference? A) In bacteria, genes are stably expressed; in plants, gene expression is always lost quickly. B) Gene expression tends to decrease rapidly and unpredictably in bacteria; gene expression is much more stable in plants. C) Bacterial plasmids are circular DNAs; Ti plasmid DNA is linear. D) Bacterial plasmids and the genes they carry usually are not integrated into the chromosome; Ti plasmids and the genes they carry are integrated into the chromosome.
D) Bacterial plasmids and the genes they carry usually are not integrated into the chromosome; Ti plasmids and the genes they carry are integrated into the chromosome.
Which of the following is in the correct order for one cycle of polymerase chain reaction (PCR)? A) Denature DNA; add fresh enzyme; anneal primers; add dNTPs; extend primers. B) Anneal primers; denature DNA; extend primers. C) Extend primers; anneal primers; denature DNA. D) Denature DNA; anneal primers; extend primers.
D) Denature DNA; anneal primers; extend primers.
Which of the three types of viruses shown above would you expect to include glycoproteins? A) I only B) II only C) III only D) I and II only
D) I and II only
Let us suppose that someone is successful at producing induced pluripotent stem cells (iPS) for replacement of pancreatic insulin-producing cells for people with type 1 diabetes. Which of the following could still be problems? I. the possibility that, once introduced into the patient, the iPS cells produce nonpancreatic cells II. the failure of the iPS cells to take up residence in the pancreas III. the inability of the iPS cells to respond to appropriate regulatory signals A) I only B) II only C) III only D) I, II, and III
D) I, II, and III
Which of the three types of viruses shown above would you expect to include a capsid(s)? A) I only B) II only C) III only D) I, II, and III
D) I, II, and III
The final step in a Sanger DNA sequencing reaction is to run the DNA fragments on a gel. What purpose does this serve? A) It adds ddNTP to the end of each DNA fragment. B) It changes the length of the DNA fragments. C) It separates DNA fragments based on their charge. D) It separates DNA fragments generated during the sequencing reaction based on one- nucleotide differences in their size.
D) It separates DNA fragments generated during the sequencing reaction based on one- nucleotide differences in their size.
In electron micrographs of HSV infection, it can be seen that the intact virus initially reacts with cell surface proteoglycans, then with specific receptors. This is later followed by viral capsids docking with nuclear pores. Afterward, the capsids go from being full to being "empty." Which of the following best fits these observations? A) Viral capsids are needed for the cell to become infected; only the capsids enter the nucleus. B) The viral envelope is not required for infectivity, since the envelope does not enter the nucleus. C) Only the genetic material of the virus is involved in the cell's infectivity, and is injected like the genome of a phage. D) The viral envelope mediates entry into the cell, the capsid mediates entry into the nuclear membrane, and the genome is all that enters the nucleus.
D) The viral envelope mediates entry into the cell, the capsid mediates entry into the nuclear membrane, and the genome is all that enters the nucleus.
In animals, what is the difference between reproductive cloning and therapeutic cloning? A) Reproductive cloning uses totipotent cells, whereas therapeutic cloning does not. B) Reproductive cloning uses embryonic stem cells, whereas therapeutic cloning does not. C) Therapeutic cloning uses nuclei of adult cells transplanted into enucleated nonfertilized eggs. D) Therapeutic cloning supplies cells for repair of diseased or injured organs.
D) Therapeutic cloning supplies cells for repair of diseased or injured organs.
The first cloned cat, called Carbon Copy, was a calico, but she looked significantly different from her female parent because _____. A) the cloning was done poorly and it was likely that some contaminating cat DNA became part of Carbon Copy's genome B) fur color genes in cats is determined by differential acetylation patterns C) cloned animals have been found to have a higher frequency of transposon activation D) X inactivation in the embryo is random and produces different patterns
D) X inactivation in the embryo is random and produces different patterns
Yeast cells are frequently used as hosts for cloning because they ____. A) easily form colonies B) can remove exons from mRNA C) do not have plasmids D) are eukaryotic cells
D) are eukaryotic cells
If you already know that the infectious agent was either a viroid or a prion, which method(s) listed above would allow you to distinguish between these two possibilities? A) I only B) II only C) IV only D) either I or IV
D) either I or IV
Using retroviral vectors for gene therapy might increase the patient's risk of developing cancer because they might _____. A) introduce proteins from the virus B) not express the genes that were introduced into a patient's cells C) not integrate their recombinant DNA into the patient's genome D) integrate recombinant DNA into the genome in ways that misregulate the expression of genes at or near the site of integration
D) integrate recombinant DNA into the genome in ways that misregulate the expression of genes at or near the site of integration
In the form of gene therapy used successfully for severe combined immunodeficiency syndrome (SCID)-X1, the genetic engineering of human cells is done by _____. A) injecting engineered viruses into the patient's bloodstream B) injecting engineered viruses into the patient's bone marrow C) treating a relative's cultured bone marrow cells with genetically engineered viruses and then injecting these cells into the patient's bone marrow D) isolating the patient's bone marrow cells, infecting them with genetically engineered viruses, and injecting them back into the patient's bone marrow
D) isolating the patient's bone marrow cells, infecting them with genetically engineered viruses, and injecting them back into the patient's bone marrow
Gene therapy requires _____. A) knowledge and availability of the normal allele of the defective gene B) the ability to introduce the normal allele into the patient C) the ability to express the introduced gene at the correct level, time, and tissue site within the patient D) knowledge and availability of the normal allele of the defective gene, an ability to introduce the normal allele into the patient, and an ability to express the introduced gene at the correct level, and time, and tissue site within the patient
D) knowledge and availability of the normal allele of the defective gene, an ability to introduce the normal allele into the patient, and an ability to express the introduced gene at the correct level, and time, and tissue site within the patient
What are prions? A) mobile segments of DNA B) tiny circular molecules of RNA that can infect plants C) viral DNA that attaches itself to the host genome and causes disease D) misfolded versions of normal protein that can cause disease
D) misfolded versions of normal protein that can cause disease
In the figure, when new viruses are being assembled at the point marked IV, what mediates the assembly? A) host cell chaperones B) assembly proteins coded for by the host nucleus C) assembly proteins coded for by the viral genes D) nothing; they self-assemble
D) nothing; they self-assemble
Which of the following is most like the formation of identical twins? A) cell cloning B) therapeutic cloning C) use of adult stem cells D) organismal cloning
D) organismal cloning
Many identical copies of genes cloned in bacteria are produced as a result of ____. A) plasmid replication B) bacterial cell replication C) transformation D) plasmid and bacterial cell replication
D) plasmid and bacterial cell replication
Which viruses have single-stranded RNA that acts as a template for DNA synthesis? A) proviruses B) viroids C) bacteriophages D) retroviruses
D) retroviruses
Which of the following is required to make complementary DNA (cDNA) from RNA? A) restriction enzymes (endonucleases) B) gene cloning C) DNA ligase D) reverse transcriptase
D) reverse transcriptase
What is metagenomics? A) genomics as applied to a species that most typifies the average phenotype of its genus B) the sequencing of one or two representative genes from several species C) the sequencing of only the most highly conserved genes in a lineage D) sequencing DNA from a group of species from the same ecosystem
D) sequencing DNA from a group of species from the same ecosystem
The host range of a virus is determined by ____. A) the enzymes carried by the virus B) whether its nucleic acid is DNA or RNA C) the proteins in the host's cytoplasm D) the proteins on its surface and that of the host
D) the proteins on its surface and that of the host
Proteomics is defined as the ____ a. linkage of each gene to a particular protein b. study of the full protein set encoded by a genome c. totality of the functional possibilities of a single protein d. study of how amino acids are ordered in a protein
b. study of the full protein set encoded by a genome
Using modern techniques of sequencing by synthesis and the shotgun approach, sequences are assembled into chromosomes by ____ a. placing them on previously generated genetic maps b. cloning them into plasmid vectors c. computer analysis looking for sequence overlaps d. cloning them into plasmid vectors, placing them on previously generated genetic maps, followed by computer analysis looking for sequence overlaps
c. computer analysis looking for sequence overlaps
