mbio 305 week 5 practice problems

genetic recombination.

Bacteria that have properties of both the donor and recipient cells are the result of SOS repair. antibiotic resistance. UV light. genetic recombination. frame shift mutations.

histidine AND streptomycin

Cells that are His-, StrR could be isolated from a mixed sample by using a medium containing histidine AND streptomycin glucose AND streptomycin penicillin AND streptomycin streptomycin histidine AND glucose

hydrogen bonding properties of the nucleobase.

Chemical mutagens often act by altering the nucleobase sequence. number of binding sites on the nucleobase. alkyl groups of the nucleobase. hydrogen bonding properties of the nucleobase. nucleobases.

base analogs.

Chemical mutagens that mimic the naturally occurring bases are called nitrous oxide. base analogs. nitrogen mustards. alkylating agents. nucleobase copiers.

phenotypic change.

Colonies of the bacterium Serratia marcescens are red when incubated at 22°C but white when incubated at 37°C. This is an example of mutation. selective media. antigenic variation. genotypic change. phenotypic change.

viruses AND plasmids.

Common vectors used for cloning genes are nucleotides. bacteria. viruses AND plasmids. plasmids. viruses.

are able to take up naked DNA, occur naturally, AND can be created in the laboratory.

Competent cells are able to take up naked DNA, can be created in the laboratory, AND are always antibiotic resistant. are always antibiotic resistant, are always auxotrophs, AND occur naturally. can be made in the laboratory, are always antibiotic resistant, AND are always auxotrophs. are able to take up naked DNA, occur naturally, AND are always antibiotic resistant. are able to take up naked DNA, occur naturally, AND can be created in the laboratory.

are mutagens.

The Ames test is useful as a rapid screening test to identify those compounds that respond to the deletion of DNAses. will protect an organism from cancer. are mutagens. will respond to chemical agents. will respond to chemical agents AND will protect an organism from cancer.

the sex pilus.

The F plasmid carries the information for bacterial flagella. the Y chromosome. recipient cell DNA replication. antibiotic resistance. the sex pilus.

Agrobacterium.

The Ti plasmid is naturally found in Pseudomonas. Escherichia. Staphylococcus. E. coli AND Staphylococcus. Agrobacterium.

plant cells.

The Ti plasmid is used as a vector to transfer DNA into viruses. protozoa. plant cells. bacteria. animal cells.

separates DNA fragments by size.

The agarose used in electrophoresis selectively sorts recombinant DNA from host DNA. denatures DNA/RNA. separates DNA fragments by size. chemically binds to the DNA. interacts electrically with the DNA.

E. coli.

The gene for human insulin has been successfully cloned in pig cells. rhinovirus. human cells. E. coli. S. aureus.

alkylating agents.

The largest group of chemical mutagens consists of intercalating agents. base analogs. radiation. nitrous acid. alkylating agents.

Avery, MacLeod, and McCarty.

The material responsible for transformation was shown to be DNA by Watson and Crick. Beadle and Tatum. Stanley. Avery, MacLeod, and McCarty. Lederberg.

transduction.

The mechanism by which genes are transferred into bacteria via viruses is called transduction. conjugation. ellipsis. transformation. replica plating.

DNA ligase.

The molecule(s) that act as molecular glue to bind DNA fragments together is/are ligandase. DNAse AND ligandase. polymerase. DNA ligase. DNAse.

restriction enzymes.

The molecules used to cut target DNA in genetic engineering are proteases. DNA ligases. restriction enzymes. exonucleases. RNA polymerases.

DNA.

The polymerase chain reaction is used to duplicate small sections of RNA. DNA. lipopolysaccharides. proteins. lipids.

phenotype.

The properties of a cell that are determined by its DNA composition are its metabolism. genotype. nucleoid. phenotype. plasmids.

It doesn't matter—human cells don't have the enzymes needed for photorepair of thymine dimers.

To maximize the number of thymine dimer mutations following UV exposure, should you keep human cells in tissue culture in the dark, in the light, or does it matter at all? The light—it's important to keep on producing the thymine dimers by keeping the plate exposed to light as much as possible. Alternating light and dark every 24 hours to increase the chances that thymine dimers will form. The dark—light will activate the photorepair systems that can break thymine dimers induced by UV light. It doesn't matter—human cells don't have the enzymes needed for photorepair of thymine dimers. Alternating light and dark every hour to increase the chances that thymine dimers will form, but prevent photorepair systems from correcting them as they are formed.

Core genome; accessory genome; unique genes

What comprises the pan-genome of a given species? Core genome; unique genes Core genome; accessory genome; unique genes; genomic islands Core genome; accessory genome Core genome; accessory genome; unique genes; pathogenicity islands Core genome; accessory genome; unique genes

They were first recognized in fungi.

Which of the following about transposons is not true? They are informally known as jumping genes. They may cause insertion mutations. They may cause knockout mutations. They were first recognized in fungi. All of the statements are true.

Transcription

Which of the following does not introduce DNA into a bacterial cell? All of these introduce DNA into a cell. Transduction Transformation Transcription Conjugation

Agrobacterium

Which of the following genera has proved useful for manipulating plant cells? Escherichia Pseudomonas Rhizobium Agrobacterium Bacillus

The bacterial host DNA is protected from restriction enzyme degradation by phosphorylation.

A bacterial strain is resistant to infection by a bacteriophage. Which statement is FALSE? If the phage DNA was methylated, it would be protected from restriction enzyme degradation. The bacteria make restriction enzymes that degrade the virus genome. The bacterial host DNA is protected from restriction enzyme degradation by phosphorylation. The statements are ALL false. The bacterial host DNA is protected from restriction enzyme degradation by methylation.

replica plating.

A clever technique that streamlines the identification of auxotrophic mutants is reversion. gas chromatography. intercalation. direct selection. replica plating.

probe.

A common way to identify the E. coli that carries the desired recombinant DNA is by using a(n) vector. probe. antibiotic. plasmid. host.

the outer membrane is toxic to humans.

A danger in using E. coli in cloning is that E. coli could cause disease. the outer membrane is toxic to humans. working with E. coli requires a BSL3 laboratory. the exons may invert the introns. the human cells may reject the insertion.

BamHI to cut both sides—since this enzyme cuts asymmetrically, it'll leave the sticky, cohesive single-strand DNA ends that will make it easier to ligate into a BamHI-cut plasmid DNA sequence.

A graduate student wants to clone a particular gene into a plasmid. The sequence includes AluI and BamHI sites on both sides of the desired fragment. AluI cuts symmetrically directly between the G and C nucleotides in a palindromic 5' AGCT 3' sequence. BamHI cuts asymmetrically directly between the G and G nucleotides in a palindromic 5' GGATCC 3' sequence. Which of the two restriction endonucleases should the graduate student choose, and why? AluI to cut both sides—it's always easier to ligate together blunt ends of DNA. She should also use AluI on the plasmid she wants to put the fragment into. BamHI to cut both sides—since this enzyme cuts asymmetrically, it'll leave the sticky, cohesive single-strand DNA ends that will make it easier to ligate into a BamHI-cut plasmid DNA sequence. Neither of these endonucleases will really be useful; she should look for a single enzyme that creates either blunt ends or sticky ends, depending on the plasmid that she is using as a vector. BamHI on the fragment, and AluI on the plasmid—this will give her the matching sequences to anneal/ligate together on the fragment/plasmid combination. BamHI on one side of the fragment, and AluI on the other side—this would keep the fragment from sticking right back to where it was cut out from in the original DNA.

Yes—the loss of the restriction endonucleases would leave the recipient E. coli unable to break down "invading" viral DNA from the transducing phage, AND the loss of the modification enzymes would leave the recipient E. coli unable to tag its own DNA as "self," leaving the viral DNA untagged and recognizable as "foreign," and targeted for destruction. Together, these would lead to higher rates of successful transduction.

A mutation in E. coli results in the loss of both restriction endonucleases and modification enzymes. Would you expect any difference in the frequency of gene transfer via transduction FROM Salmonella INTO this E. coli strain? No—since the Salmonella strain is normal, the rate of production of transducing virus particles would still be the same, resulting in the same frequency of gene transfer. Yes—the loss of the modification enzymes would leave the recipient E. coli unable to tag its own DNA as "self," leaving the viral DNA untagged and recognizable as "foreign," and targeted for destruction. This would lead to higher rates of successful transduction. Yes—the loss of the restriction endonucleases would leave the recipient E. coli unable to break down "invading"' viral DNA from the transducing phage. This would lead to higher rates of successful transduction. No—transduction efficiency isn't affected by either restriction endonucleases or modification enzymes, so there'd be no effect on the overall rate. Yes—the loss of the restriction endonucleases would leave the recipient E. coli unable to break down "invading" viral DNA from the transducing phage, AND the loss of the modification enzymes would leave the recipient E. coli unable to tag its own DNA as "self," leaving the viral DNA untagged and recognizable as "foreign," and targeted for destruction. Together, these would lead to higher rates of successful transduction.

Ames.

A quick microbiological test for potential carcinogens was developed by Ames. Fleming. McClintock. Lederberg. Crick.

size.

Agarose gel electrophoresis separates nucleic acid fragments according to nucleobase sequence. shape. size. type of 5C sugar. density.

the use of biotechnology in cancer and disease diagnostics.

All of the following are concerns about biotechnology EXCEPT using biotechnology to generate products such as insulin. the possibility of using it for treating a genetic disease. the possibility that microbes are modified for use in bioterrorism. the use of biotechnology in cancer and disease diagnostics. the risk of GMOs having an unintended negative environmental impact.

creating a recombinant DNA molecule.

All of the following are examples of gene function studies using dCas9 EXCEPT blocking transcription of a particular gene. creating a recombinant DNA molecule. methylation of DNA to study effects of DNA modification. tagging DNA with a detectable marker. delivery of an activator that turns on gene expression.

are usually tagged dsRNA.

All of the following are true about DNA probes EXCEPT they may be obtained from similar genes from another organism. may be synthesized usually using information based on the protein sequence. may be tagged with a fluorescent dye. are usually tagged dsRNA. may be obtained from denatured tagged dsDNA.

involve haploid chromosomes AND involve antibiotic resistance.

Among the easiest of the mutations to isolate are those which allow populations to be measured AND use an indirect method for measurement. use an indirect method for measurement AND involve antibiotic resistance. involve antibiotic resistance AND allow populations to be measured. involve polyploid chromosomes AND allow populations to be measured. involve haploid chromosomes AND involve antibiotic resistance.

provide an environment in which preexisting mutants survive.

Antibiotics increase the rate of spontaneous mutation. may act as alkylating mutagens. cause mutations to occur. provide an environment in which preexisting mutants survive. destroy all mutant bacteria.

methylated.

DNA is protected from restriction enzymes by being made into double-stranded RNA. methylated. turned into RNA. phosphorylated. sequestered in a lysosome.

in both eukaryotes and prokaryotes.

DNA repair mechanisms occur None of the answer choices is correct. in neither eukaryotes nor prokaryotes. only in eukaryotes. in both eukaryotes and prokaryotes. only in prokaryotes.

the mutant but not the parental cell type will grow.

Direct selection involves inoculating cells onto growth media on/in which the mutagen is present. the nutrients necessary for mutation to occur are present. the mutant but not the parental cell type will grow. histidine has been added. the mutation will be reversed.

high temperature AND high pH.

Double-stranded DNA will separate into two strands when exposed to high temperature AND high pH. high pH AND low salt low salt AND low pH high temperature AND low pH low temperature AND high salt

Both the forward primer and the reverse primer.

During PCR, which primer anneals to template DNA at its 3' end? Both the forward primer and the reverse primer. The forward primer only. Primers don't bind to template DNA. The reverse primer only. Either the forward primer or the reverse primer.

the selectable marker is still functional but the second genetic marker is not functional.

During generation of a DNA library, once a DNA fragment has been successfully joined with a vector either the selectable marker nor the second genetic marker is still functional. the selectable marker is still functional but the second genetic marker is not functional. both the selectable marker and the second genetic marker are still functional. the multiple cloning site is substituted with a selectable marker gene. the selectable marker is no longer functional but the second genetic marker is functional.

act during DNA synthesis AND often result in frameshift mutations.

Intercalating agents act during RNA synthesis AND change the hydrogen bonding properties of nucleotides. change the hydrogen bonding properties of nucleotides AND always result in nonsense mutations. act during DNA synthesis AND always result in nonsense mutations. act during DNA synthesis AND often result in frameshift mutations. act during RNA synthesis AND often result in frameshift mutations.

Proofreading by DNA polymerase, glycosylase enzyme activities, excision repair, SOS repair

Every 24 hours, every genome in every cell of the human body is damaged 10,000 times or more. Given the possible DNA repair mechanisms, which order listed below would be most effective at repairing these as quickly as possible in order to prevent mutations from being carried forward in DNA replication? Proofreading by DNA polymerase, SOS repair, glycosylase enzyme activities, excision repair SOS repair, excision repair, glycosylase enzyme activities, proofreading by DNA polymerase Glycosylase enzyme activities, SOS repair, proofreading by DNA polymerase, excision repair SOS repair, proofreading by DNA polymerase, glycosylase enzyme activities, excision repair Proofreading by DNA polymerase, glycosylase enzyme activities, excision repair, SOS repair

uses a labeled probe, is useful in microbial ecology, AND allows identification of particular bacterial groups in mixed samples.

Fluorescence in situ hybridization (FISH) is useful in microbial ecology, allows identification of particular bacterial groups in mixed samples AND uses virus hosts. uses a labeled probe, is useful in microbial ecology, AND allows identification of particular bacterial groups in mixed samples. uses virus hosts, uses a labeled probe, AND is useful in microbial ecology. uses a labeled probe, allows identification of particular bacterial groups in mixed samples, AND uses virus hosts. is useful in microbial ecology, allows identification of particular bacterial groups in mixed samples AND depends on electron microscopy.

conjugation.

Gene transfer that requires cell-to-cell contact is transduction. competency. transformation. conjugation. functional genomics.

allows the use of bacteria as production factories for a number of molecules AND relies on recombinant DNA technology.

Genetic engineering allows the use of bacteria as production factories for a number of molecules AND is dependent on RNA enzymes. relies on recombinant DNA technology AND relies completely on conjugation. allows the use of bacteria as production factories for a number of molecules AND relies completely on conjugation. allows the use of bacteria as production factories for a number of molecules AND relies on recombinant DNA technology. is dependent on RNA enzymes AND relies on recombinant DNA technology.

All of the answer choices are correct.

Genetic engineering of plants has so far produced pest-resistant plants. plants that are herbicide resistant. plants with increased nutritional value. All of the answer choices are correct. None of the answer choices is correct.

the modified DNA may transfer to other organisms.

Genetically modified food has raised some concerns because it contains very dangerous allergens. it contains radioactive nucleic acids. All of the choices are valid concerns. it releases radioactivity into the environment. the modified DNA may transfer to other organisms.

a protein, many copies of the gene to be used as a probe, AND many copies of the gene for sequencing.

Goal(s) of gene cloning may be to produce many copies of the gene to be used as a probe. many copies of the gene for sequencing. a protein. a protein, many copies of the gene to be used as a probe, AND many copies of the gene for sequencing. more copies of the host cell.

vector.

Host cells containing recombinant DNA can be selected on the basis of the properties of the virus. ribosomes. introns. vector. enzymes.

bacterial DNA cut with restriction enzyme A.

Human DNA cut with restriction enzyme A can be joined to uncut human DNA. bacterial DNA cut with a human restriction enzyme. bacterial DNA cut with restriction enzyme H. bacterial DNA cut with restriction enzyme A. uncut bacterial DNA.

3; 1; 2

Identify the correct sequence in which the steps below occur during a single PCR cycle. 1. Complementary base pairing between primers and target DNA. 2. Addition of DNA nucleotides by Taq DNA polymerase. 3. Heat separation of strands of target DNA. 3; 1; 2 2; 3; 1 1; 3; 2 1; 2; 3 2; 1; 3

One strand of the DNA molecule is cut.

Identify the statement about digestion of DNA by restriction enzymes that is NOT true. It produces sticky ends. It produces blunt ends. One strand of the DNA molecule is cut. It generates restriction fragments. Both strands of the DNA molecule are cut.

Prototrophs and auxotrophs would both be killed by the penicillin; only PenR mutants would grow and you would not enrich for auxotrophs.

If you were carrying out a penicillin enrichment culture and you forgot to add penicillinase before plating the sample onto nutrient agar, what would happen? The auxotrophs would be able to grow on the agar plates but the prototrophs would not. The prototrophs would be able to grow on the agar plates but the auxotrophs would not. You would get the same results whether you add this enzyme of not because penicillin naturally rapidly degrades in agar. Prototroph and auxotroph colonies would change color from cream to red in the presence of the penicillin. Prototrophs and auxotrophs would both be killed by the penicillin; only PenR mutants would grow and you would not enrich for auxotrophs.

You would get false-positive results in different areas where the probe hadn't actually bound, but it was still sitting there and lighting up.

In a FISH experiment, what would happen if unbound probe was not washed off? You would get false-positive results in different areas where the probe hadn't actually bound, but it was still sitting there and lighting up. Nothing—the target nucleotide sequences are labeled, not the probe. Therefore, excess unbound probe wouldn't matter for the experiment. Your FISH would be floating at the top of the tank due to the toxicity of the probe building up within them. Nothing—it's not necessary to wash off the unbound probe and doing so just adds an extra step to the procedure. You would get an intermediate color on the array because of the presence of both bound and unbound probes that fluoresce at different temperatures.

an F plasmid.

In conjugation the donor cell is recognized by the presence of an F plasmid AND diploid chromosomes. diploid chromosomes. a Y chromosome. an F plasmid. an SOS response.

from the same species of bacteria.

In conjugation, transformation, or transduction, the recipient bacteria is most likely to accept donor DNA from any species of bacteria. from any source AND only through plasmids. only through plasmids. from the same species of bacteria. from any source.

RNA-seq.

In late 2019, a novel coronavirus, SARS-CoV-2 was reported in China. The virus, which has an RNA genome, spread rapidly around the globe, starting a pandemic that is still ongoing. Within weeks of identifying the virus, scientists published its complete genome sequence, using proteomics. DNA cloning. pan genomics. gel electrophoresis. RNA-seq.

within the gene in question.

In order for insertional inactivation to occur, the transposon must be placed in an intron. downstream from the gene in question. within the gene in question. randomly in the genome. upstream from the gene in question.

generate cDNA from mRNA.

In order to get around the lack of ability of prokaryotes to remove introns from precursor RNA, it may be necessary to use different promoters. turn cDNA into mRNA. use the DNA directly. generate cDNA from mRNA. use the DNA after it has been processed.

is necessary to isolate auxotrophic mutants.

Indirect selection uses media upon which neither the parental cell type nor mutant grows. uses media that reverses the mutation. is necessary to isolate auxotrophic mutants. uses media on which the mutant but not the parental cell type will grow. is necessary to isolate his+ prototrophs.

are the simplest type of transposon, code for a transposase enzyme, AND are characterized by an inverted repeat.

Insertion sequences are the simplest type of transposon, code for a transposase enzyme AND can produce pili. code for a transposase enzyme AND are characterized by an inverted repeat. can produce pili AND are the simplest type of transposon. are the simplest type of transposon, code for a transposase enzyme, AND are characterized by an inverted repeat. are characterized by an inverted repeat AND can produce pili.

thymine dimers.

Irradiation of cells with ultraviolet light may cause adenine complementary base pairing with cytosine. the addition of uracil. cytosine trimers. four nucleotides to covalently bind together. thymine dimers.

No. If the antibiotics are given sequentially, there is a chance that resistance to either one may arise through mutation. When antibiotics are given simultaneously, the chance of resistance to two different antibiotics occurring is extremely low.

Is it as effective to take two antibiotics sequentially for an infection as it is to take them simultaneously, as long as the total length of time of the treatment is the same? Yes. As long as the length of time is the same, the two treatments should be essentially the same in terms of effectively eliminating the infection. No. Taken sequentially, the first antibiotic will select for the small portion of the population that will spontaneously mutate toward resistance. Then, the second antibiotic will do the exact same thing—selecting for resistance to the second drug from the few bacterial cells that remained from the first drug treatment. No. If the antibiotics are given sequentially, there is a chance that resistance to either one may arise through mutation. When antibiotics are given simultaneously, the chance of resistance to two different antibiotics occurring is extremely low. No. There's always one specific antibiotic that will be the most effective, and that is the only antibiotic that should be used to treat a particular infection. Yes. Each antibiotic will kill all the cells that are sensitive to it, no matter if the drugs are taken simultaneously or sequentially. The important thing is to take the medication for as few days as possible.

8 additional pieces of dsDNA.

Starting with a single piece of dsDNA, after 3 PCR cycles there are 16 additional pieces of dsDNA. 4 additional pieces of dsDNA. 1 additional piece of dsDNA. 8 additional pieces of dsDNA. 2 additional pieces of dsDNA.

identifying genetic alterations associated with disease, studying evolutionary relationships, AND determining protein sequences.

Knowing the sequence of a genome is useful in identifying genetic alterations associated with disease AND studying evolutionary relationships. studying evolutionary relationships AND determining protein sequences. determining protein sequences AND identifying genetic alterations associated with disease. determining protein sequences BUT not identifying genetic changes. identifying genetic alterations associated with disease, studying evolutionary relationships, AND determining protein sequences.

can be used to identify related people.

Mitochondrial DNA (mtDNA) in humans can be isolated only from intact embryos. is linear, single-stranded DNA. can be used to establish paternity. is always donated to the offspring from both parents. can be used to identify related people.

AATTAGTTC

On which of the following DNA strands would UV radiation have the most effect? AATTAGTTC TATATACG AND AATTAGTTC TATATACG AACCGGG AUAUCGAU

All of the answer choices are correct.

PCR is particularly useful in detecting viable yet non-culturable organisms. assessing impure (multiple types of bacteria present) samples. dealing with very small numbers of bacteria.relatively quickly producing results. All of the answer choices are correct.

DNA fragments of a particular size.

PCR produces DNA fragments that are three nucleotides smaller than the previous fragment. DNA fragments of all possible sizes. DNA fragments that are one nucleotide larger than the next fragment. protein fragments of all possible sizes. DNA fragments of a particular size.

intercalating agents.

Planar molecules used as chemical mutagens are called base analogs. intercalating agents. acids. alkylating agents. nitrous oxide.

All known bacteria contain plasmids of some kind.

Plasmids work well for insertion of foreign DNA into a cell. Which statement is FALSE? Plasmids have an origin of replication. All known bacteria contain plasmids of some kind. Plasmids usually contain a selectable marker such as antibiotic resistance. Plasmids are relatively small compared with a chromosome. Plasmids can replicate independent of the chromosome.

A missense mutation is also called a synonymous mutation, meaning no change in the amino acid encoded.

Please select the INCORRECT statement regarding mutation. Insertional inactivation is the disruption of a gene's function due to a DNA segment inserted into the gene. A missense mutation is also called a synonymous mutation, meaning no change in the amino acid encoded. A base substitution is a mutation in which the wrong nucleotide has been incorporated. A reversion is a mutation that corrects a defect caused by an earlier mutation.Spontaneous mutations are those that occur during the normal processes of a cell.

The restriction enzyme identifies and cuts a short nucleotide sequence in the bacterial genome.

Please select the INCORRECT statement regarding restriction-modification systems. A restriction enzyme will not degrade DNA that has been methylated. The modification enzyme may add methyl groups to viral DNA. The modification enzyme adds methyl groups to bacterial nucleobases recognized by the restriction enzyme. The restriction enzyme identifies and cuts a short nucleotide sequence in the bacterial genome. The restriction enzyme identifies and cuts a short nucleotide sequence in the virus genome.

Good and bad—they're very good at killing cancer cells, but they could also be dangerous to non-cancerous cells.

Strong chemical mutagens may be used to treat cancer cells. Is this a good or bad idea? Good—kill those cancer cells as quickly as possible to cure the patient! Good and bad—they're very good at killing cancer cells, but they could also be dangerous to non-cancerous cells. Bad—these mutagens will also affect the non-cancerous cells, possibly leading to new cancerous states! Bad—the medications are toxic and will cause healthy normal microbiots to become cancerous. Bad—the cancer cells are already mutated. We don't want to mutate them more and make them more cancerous!

No—dideoxynucleotide sequencing depends on different length fragments being formed and then separated based on size. This can take place with only a specific forward OR a specific reverse primer.

Polymerase chain reaction (PCR) can be used to perform DNA sequencing reactions. In this case, are two primers (a forward and a reverse) necessary? No—dideoxynucleotide sequencing depends on different length fragments being formed and then separated based on size. This can take place with only a specific forward OR a specific reverse primer. No—you actually need a primer pair for each round of DNA amplification ... so you'll need many, many primer pairs, depending how many rounds you plan to do. Yes—and it will be important to make sure that the primer pairs are made with dideoxynucleotides that are labeled with fluorescent dyes. Otherwise, you won't be able to detect the fragments that are made in the PCR process. Yes—if you only have one primer, you will only be able to determine the dideoxynucleotide sequence of RNA, which is a single-stranded molecule. Yes—you can't perform PCR without two specific primers to amplify the region in question in the DNA.

Due to the presence of introns/exons, and splicing of RNA after transcription, the DNA sequence doesn't necessarily tell us the exact number/type of proteins that will eventually be made from it.

Possessing the entire sequence of a particular human genome may not be as useful as we think. Why not? Due to the presence of introns/exons, and pre-transcriptional modification, the protein profile varies considerably among people, so it would be better to determine that. Due to the presence of introns/exons, and splicing of RNA after transcription, the DNA sequence doesn't necessarily tell us the exact number/type of proteins that will eventually be made from it. The amount of "junk DNA" present in the human genome masks any useful genetic information that we'd like to obtain. It's not the DNA sequence that matters—we need to know the mRNA sequence of the human genome. Every human genome is different enough that knowing ONE human's DNA sequence can't tell us almost anything about ALL humans.

is useful for identifying auxotrophs AND uses media on which the mutant will not grow but the parental cell type will.

Replica plating is useful for direct selection of antibiotic resistance AND is useful for identifying auxotrophs. is useful for direct selection of antibiotic resistance AND is useful for identifying prototrophs. is useful for identifying auxotrophs AND uses media on which the mutant will not grow but the parental cell type will. uses media on which the mutant will grow but the parental cell type will not AND is useful for identifying prototrophs. is useful for identifying auxotrophs AND uses media on which the mutant will grow but the parental cell type will not.

they cut at defined sites AND the sticky ends make it very easy to allow recombination of any type of DNA.

Restriction enzymes have proved so useful in manipulating DNA because they protect eukaryotes against virus attack AND they cut both RNA and DNA. they protect eukaryotes against virus attack AND the sticky ends make it very easy to allow recombination of DNA with RNA. they cut at random sites AND the sticky ends make it very easy to allow recombination of any type of DNA. they cut at defined sites AND the sticky ends make it very easy to allow recombination of any type of DNA. they cut at defined sites AND the sticky ends make it very easy to allow recombination of DNA with RNA.

A bacteriophage

Scientists have cloned the human insulin gene into E. coli. Which of the following would NOT have been used in the procedure? DNA ligase A plasmid A bacteriophage Competent bacteria A restriction enzyme

transposons.

Segments of DNA capable of moving from one area in the DNA to another are called mutagens. inverted repeats. base analogs. intercalating agents. transposons.

a heat-stable DNA polymerase from Thermus aquaticus.

Taq polymerase is a heat-stable DNA polymerase from Thermus aquaticus. an enzyme from Escherichia coli. an RNA polymerase AND an enzyme from Escherichia coli. a reverse transcriptase. an RNA polymerase.

Genomic islands are large DNA segments in a cell's genome that originated in other species; pathogenicity islands are genomic islands that code for factors that allow an organism to cause disease.

Select the CORRECT statement regarding genomic islands. Genomic islands are large DNA segments in a cell's genome that originated in other species; pathogenicity islands are genomic islands that code for factors that protect an organism from disease. Genomic islands are large DNA segments in a cell's genome that move from one place to another; pathogenicity islands are genomic islands that code for factors that allow an organism to cause disease. Genomic islands code for factors that allow an organism to cause disease; pathogenicity islands are large DNA segments in a cell's genome that originated in other species. Genomic islands are large DNA segments in a cell's genome that originated in other species; pathogenicity islands are genomic islands that code for factors that allow an organism to cause disease. Genomic islands are large DNA segments in a cell's genome that originated in other species; pathogenicity islands are genomic islands that confer antibiotic resistance on an organism.

gRNA contains guanisine in place of uracil.

Select the INCORRECT statement regarding CRISPR-Cas technology. RNA contains guanisine in place of uracil. Cas9 nucleases cut DNA at a target site. dCas9 binds to but does not cut target DNA. gRNA directs Cas9 nucleases to target sites. dCas9 is used for studying gene function.

identifying organisms that have taken up recombinant DNA.

Selecting for transformants involves identifying organisms that have taken up recombinant DNA. identifying organisms that have taken up recombinant RNA. identifying organisms that are producing DNA. identifying organisms that are producing antibiotics. identifying organisms that are producing proteins.

are useful in identifying specific individuals.

Short tandem repeats (STRs) are DNA fragments generated during PCR. are generally found in exons. are useful in identifying specific individuals. are important sites in vectors where foreign DNA can be integrated. are errors that can arise during DNA sequencing.

They may simply have a higher proportion of T nucleotides next to each other in their DNA than other bacteria, leading to more possible dimers being formed AND they may have a weaker expression of photoreactivation enzymes, leading to formation of more thymine dimers.

Some bacteria have a higher incidence rate of thymine dimer mutations following exposure to UV light than others. What might be going on here to lead to this outcome? They may simply have a higher proportion of T nucleotides next to each other in their DNA than other bacteria, leading to more possible dimers being formed AND they may have a weaker expression of photoreactivation enzymes, leading to formation of more thymine dimers. They may have a stronger expression of photoreactivation enzymes, leading to more thymine dimers being formed and retained. They may have a weaker expression of photoreactivation enzymes, leading to more thymine dimers being formed and retained. They may simply have a higher proportion of T nucleotides next to each other in their DNA sequences than other bacteria, leading to more possible dimers being formed. They may simply have a higher proportion of T nucleotides next to each other in their DNA sequences than other bacteria, leading to more possible dimers being formed AND they may have a stronger expression of photoreactivation enzymes, leading to formation of more thymine dimers.

integrate fragments from the phage DNA in their own chromosomes and target for destruction any DNA that contains the same fragments in the future.

The clustered, regularly interspaced short palindromic repeats (CRISPR) system in bacterial cells has been called the "immune" system of bacteria. CRISPR protect bacteria from a repeat infection from the same phage because bacterial cells integrate fragments from the phage DNA in their own chromosomes and target for destruction any DNA that contains the same fragments in the future. recognize proteins on the surface of the phage and secrete proteins that block the binding of the phage. recognize proteins on the surface of the phage and secrete enzymes that digest the phage. integrate fragments from the phage RNA in their own chromosomes and target for destruction any RNA that contains the same fragments in the future. modify the attachment sites for the phages so that new infections cannot take place.

the genotype of bacteria that lack a functional gene for histidine synthesis AND bacteria that are auxotrophic for histidine.

The designation his- refers to the genotype of bacteria that have a functional gene for histidine synthesis AND bacteria that are auxotrophic for histidine. the genotype of bacteria that have a functional gene for histidine synthesis AND bacteria that require addition of histidine to the growth medium. the genotype of bacteria that lack a functional gene for histidine synthesis AND bacteria that have a hers gene. the genotype of bacteria that lack a functional gene for histidine synthesis AND bacteria that are auxotrophic for histidine. the genotype of bacteria that lack a functional gene for histidine synthesis AND bacteria that do not require addition of histidine to the growth medium.

the matching chromosome may carry the correct version of the gene.

The diploid character of eukaryotic cells may mask the appearance of a mutation since All answer choices are correct. the matching chromosome may carry the correct version of the gene. the mutation may create inverted repeats. the matching chromosome may repair the mutated gene. the mutation is usually reversible.

electricity.

The energy to separate fragments during agarose gel electrophoresis is supplied by agarosis. active transport. buffers. electricity. gravity.

DNA library.

The entire set of cloned fragments of the complete human genome is termed a recombinant gene. book of genes. DNA library. genetic set. restructured genome.

UV radiation.

The formation of a covalent bond between two adjacent thymines is caused by heat. X-rays. microwave radiation. UV radiation. alkylating agents.

TACCAT; ATGGTA

The sequence of cDNA synthesized from an mRNA template with the sequence AUGGUA would be ______. This cDNA probe would hybridize to gene chip DNA with the sequence ______. UACCAU; ATGGTA AUGGUA; AUGGUA TACCAT; AUGGUA TACCAT; ATGGTA AUGGUA; TACCAT

the location to which the primers anneal.

The size of the amplified DNA fragment generated during PCR is determined by the size of the template DNA.how many cycles are performed. the location to which the primers anneal. the time for each cycle. how much Taq polymerase is used.

mutation.

The source of variation among microorganisms that were once identical is mutant. sigma factors. antibiotic resistance. mutation. virulence factors.

a bacterial plasmid promoter that was similar to plant promoters.

The study of the crown gall tumor found an R plasmid in plant cells. incorporation of the plant chromosome into the bacteria. a bacterial plasmid promoter that was similar to plant terminators. incorporation of the bacterial chromosome into the plant. a bacterial plasmid promoter that was similar to plant promoters.

conjugation AND transposons.

The transfer of vancomycin resistance from Enterococcus faecalis to Staphylococcus aureus is thought to have involved conjugation AND transposons. transduction AND transposons. transformation AND transposons. transformation AND transduction. conjugation AND transformation.

DNA fragments are cloned into the plasmid using DNA polymerase.

These are all steps in creating a DNA library EXCEPT A plasmid with selectable markers is cut using the same restriction enzyme. Recombinant plasmids are introduced into competent bacteria. DNA fragments are cloned into the plasmid using DNA polymerase. Transformed bacteria are grown on differential/ selective medium. Total cellular DNA is extracted and cut into fragments using restriction enzymes.

SOS repair, photoreactivation repair, AND excision repair.

Thymine dimers are removed by photoreactivation repair AND excision repair. SOS repair, photoreactivation repair, AND excision repair. cold-activated repair mechanisms. SOS repair AND photoreactivation repair. SOS repair AND excision repair.

ground-up rat liver.

To increase the chance of detecting carcinogens in the Ames test, the test substance is treated with ground-up rat liver. penicillin AND heat. reverse transcriptase. heat. penicillin.

penicillin enrichment.

To increase the proportion of auxotrophic mutants in a population of bacteria, one may use penicillin enrichment. replica plating. individual transfer. direct selection. mutant reversion.

It's highly likely that the two genes are located next to each other in the host cell chromosome. Since transduction results from a packaging error or an excision error that occurs during the infection cycle of the bacteriophage, the genes must lie close to each other to be transduced into a new cell simultaneously.

Two bacterial genes are transduced simultaneously. What does this suggest about their proximity to each other within the original host genome? It's highly likely that one gene was on the chromosome but the other was actually on a plasmid; if those two elements are in one cell, genes can be transferred simultaneously. They must be within five gene lengths of each other, but not necessarily immediately adjacent. If they were immediately adjacent, the transposons that facilitate the transfer of genetic information between the two cells wouldn't be able to "jump" into them. It's highly likely that the two genes are located next to each other in the host cell chromosome. Since transduction results from a packaging error or an excision error that occurs during the infection cycle of the bacteriophage, the genes must lie close to each other to be transduced into a new cell simultaneously. It doesn't mean anything. Transduction relies on the ability of a cell to take up foreign DNA. It's possible here that the cell has simply taken up two separate bits of DNA at the same time from the surrounding environment. Nothing. It's highly likely that two separate virus particles were carrying each gene, and that they coinfected the new target cell at the same time. This could mean the two original genes might not even be from the same original host cell!

It can be cultured on a selective medium containing histidine and penicillin.

What do you know about a bacterium that is His-/Trp+/StrS/PenR? It can be cultured on a selective medium containing tryptophan and streptomycin. It cannot be cultured on a selective medium containing histidine and tryptophan. It can be cultured anaerobically on a selective medium containing histidine and penicillin. It can be cultured on a selective medium containing streptomycin and penicillin. It can be cultured on a selective medium containing histidine and penicillin.

Reverse transcriptase

What enzyme is used to generate cDNA from pre-mRNA? DNA polymerase DNA ligase RNA polymerase ATP synthase Reverse transcriptase

A collection of clones that together contain the entire genome of an organism.

What is a DNA library? A collection of clones that together contain the entire genome of an organism. A place where DNA can be studied in depth. A collection of clones that together contain all of the exons and proteins of an organism. A collection of clones that together contain all of the introns of an organism. A repository in which samples of DNA from all organisms can be found.

DNA synthesized from an mRNA template (copy DNA). It does not contain introns.

What is cDNA? DNA synthesized from an mRNA template (copy DNA). It does not contain introns. Clonal DNA obtained from a selection of highly related microorganisms. DNA synthesized from a chloroplast mRNA template (copy DNA). It does not contain introns. DNA synthesized from an mRNA template (copy DNA). It does not contain exons.DNA synthesized from a chloroplast mRNA template (copy DNA). It does not contain exons.

The sum total of genes encoded by the various strains of a given species.

What is the pan-genome? DNA sequences found in all strains of Escherichia coli. DNA sequences found in all strains of a particular species. The sum total of genes encoded by the various strains of Escherichia coli. The sum total of genes encoded by the various strains of a given species. Segments of DNA that can move from one DNA molecule to another.

The cell would not recognize and destroy invading viral DNA.

What would be the outcome if a bacterial cell failed to make a Cas nuclease-crRNA complex? The cell would not be able to make a Cas nuclease. The cell would be unable to generate a CRISPR array. The bacterial cell would die. The cell would be unable to transcribe the CRISPR array. The cell would not recognize and destroy invading viral DNA.

white colonies.

When a vector that uses the lacZ gene as a second marker is used in a cloning experiment, bacteria that contain the recombinant DNA will give rise to red colonies. white colonies. blue colonies. cream colonies. All of the answer choices are correct.

It results from the incorporation of bacterial plasmid DNA into the plant chromosome.

Which is TRUE about a crown gall tumor? It is a unique viral infection of plants. It results from the transfer of a transposon to the plant. It results from an Agrogallerium infection of the plant. It results from the incorporation of bacterial plasmid DNA into the plant chromosome. It results from the incorporation of plant plasmid DNA into the bacterial chromosome.

It removes both strands in the mismatch area.

Which is not true about mismatch repair? It uses methylation of the DNA to differentiate between strands. It fixes errors missed by the proofreading of DNA polymerase. It requires DNA polymerase and DNA ligase. It uses an endonuclease. It removes both strands in the mismatch area.

It relies on visual detection of the labeled probes after hybridization.

Which of the following about DNA microarray technology is NOT true? It involves the use of fluorescently labeled singe-stranded cDNA. It involves attaching nucleotides to a solid support such as a glass slide. It relies on visual detection of the labeled probes after hybridization. It uses nucleic acid hybridization. It may use many DNA fragments that function like probes.

Development of antibiotic resistance in bacteria.

Which of the following is NOT an application molecular cloning? Development of antibiotic resistance in bacteria. Determining the function of a particular gene by silencing it. Determining the nucleotide sequence of a bacterial genome. Production of human insulin by bacterial cells. Production of a vaccine such as the hepatitis B vaccine.

A vector contains an RNA primer.

Which of the following is NOT true about an ideal vector? A vector contains an origin of replication. A vector contains a selectable marker. A vector may be a plasmid or bacteriophage. A vector contains an RNA primer. A vector has a restriction enzyme recognition site.

E. coli is fastidious but can usually be grown in the lab.

Which of the following is NOT true about laboratory strains of E. coli being desirable hosts for genetic engineering? E. coli is fastidious but can usually be grown in the lab. The genetics of E. coli is very well known. E. coli is especially able to express foreign genes. E. coli has known phenotypic characteristics. All of the answer choices are correct.

Some of them generate "sticky ends" when they cut, making it easy to join DNA fragments.

Which of the following is a reason that restriction enzymes are useful in biotechnology? Bacteria can use them for genome replication in cells lacking polymerase. They are bacterial enzymes, so they are useful for bacterial engineering. They produce fragments of regular size, essential for genetic engineering. Some of them generate "sticky ends" when they cut, making it easy to join DNA fragments. They can generate a DNA copy of an RNA fragment for cloning.

Editing a mutated gene in an organism.

Which of the following is not a direct application of sequencing? Editing a mutated gene in an organism. Determining evolutionary relatedness of microbes. Gaining insights into protein function. Studying gene expression in an organism. Tracking pathogens in an outbreak.

Risk that genetically modified foods contain DNA.

Which of the following is not a reasonable concern regarding biotechnology? Risk that genetically modified foods contain DNA. Risk that GMOs may impact the environment. Risk that genes from a GMO may get into a different species. Risk that GM food may contain unexpected allergens. Risk that CRISPR-Cas technology may be used unethically.

Interferon alpha

Which of the following recombinant proteins may be used to treat a microbial infection? Interferon alpha Tissue plasminogen activator Insulin Platelet derived growth factor Factor VIII

If the mutation rate to antibiotic A is 10-9 per cell division, and to antibiotic B is 10-6 per cell division, the probability of the cell being resistant to both medications is 10-15.

Which of the following statements about spontaneous mutation is TRUE? A frameshift mutation in which three nucleotides are added is less likely to impact a cell that a frameshift mutation in which two nucleotides are deleted. If the mutation rate to antibiotic A is 10-9 per cell division, and to antibiotic B is 10-6 per cell division, the probability of the cell being resistant to both medications is 10-15. If the mutation rate to antibiotic A is 10-9 per cell division, and to antibiotic B is 10-6 per cell division, the probability of the cell being resistant to both medications is 10-54. A single mutation is common but a double mutation is very rare. A transposon may insertionally inactivate a gene when it jumps from one place in a genome to another.

initiating pathogenic outbreaks.

Whole genome sequencing has been used for all of the following EXCEPT: understanding the role of certain proteins. determining evolutionary relatedness among organisms. initiating pathogenic outbreaks. identifying cancer genes. tracking pathogens around the globe.

All food contains DNA; every cell has DNA in it.

Why is the concern that genetically modified foods contain DNA an unfounded one? All food contains DNA; every cell has DNA in it. Genetic modification techniques involve RNA, not DNA. Even if the food has DNA in it, cooking removes the DNA. Genetically modified food doesn't have any DNA in it; it's food. Genetically modified foods are not real, so there's no problem.

Ions in the buffer conduct the electric current needed to move the DNA fragments in the gel matrix.

Why must an agarose gel be placed in a buffer solution for DNA gel electrophoresis? Even distilled, autoclaved water has a high number of DNases in it that would destroy the DNA. DNA cannot be detected unless buffer is added to the system; the buffer colors the DNA fragments for visualization.Ions in the buffer conduct the electric current needed to move the DNA fragments in the gel matrix. The buffer contains phosphates, and the DNA fragments must be phosphorylated before they move in agarose. The DNA fragments will disintegrate unless there is a buffer present to prevent this from happening.

cause breaks in DNA molecules.

X-rays destroy lipopolysaccharide. make the DNA radioactive. cause thymine trimers. cause breaks in DNA molecules. have no effect on DNA.

The original piece of DNA has seven EcoRI restriction sites.

You are examining the DNA profile of an unknown pathogen. The pathogen's DNA has been digested with EcoRI restriction enzyme. There are 7 bands on DNA on the gel. Which of the following is NOT true? The original piece of DNA has seven EcoRI restriction sites. The restriction enzyme has been denatured. The original piece of DNA has six EcoRI restriction sites. The restriction enzyme EcoRI was isolated from E. coli. The DNA has not been completely restricted.

The prototrophs are resistant to penicillin but the auxotrophs are sensitive to this antibiotic.

You make two agar plates: one is a nutrient agar plate (plate A) that contains histidine and penicillin. The other is a glucose salts agar (plate B) that also contains penicillin. You inoculate a sample onto both plates using replica plating technique, incubate the plates, and compare the growth after 48 hours. There are 12 colonies on the nutrient agar plate and 11 colonies on the glucose salts medium. Which of the following statements is INCORRECT? This experiment describes indirect selection of a mutant. Prototrophs and auxotrophs in this experiment are resistant to penicillin. The colony that is missing from plate B is an auxotroph that cannot synthesize histidine. Approximately 92% of the bacteria in the original sample are prototrophs. The prototrophs are resistant to penicillin but the auxotrophs are sensitive to this antibiotic.

The bacteria in the colonies are His+, Val+, Trp+, Leu+.

You mix two bacterial stains in a tube of glucose-salts agar. One strain is His−, Val−, while the other strain is Trp−, Leu−. You previously showed that neither strain grows on glucose-salts agar. After incubating the tube, you plate a sample onto a new glucose-salts agar plate. Several colonies grow. What do you know is TRUE about these colonies? The bacteria in the colonies are His−, Val−, Trp+, Leu+. The bacteria in the colonies are His−, Val+, Trp+, Leu+. The bacteria in the colonies are His+, Val+, Trp+, Leu+, PenR. The bacteria in the colonies are His−, Val−, Trp−, Leu−. The bacteria in the colonies are His+, Val+, Trp+, Leu+.