Deck 19: Analyzing and Engineering Genes

Question 1

Plasmids are used as cloning vectors in genetic engineering.This means that plasmids allow for _____.

A)carrying of DNA into a cell and DNA replication
B)DNA to mutate within the gene of interest
C)DNA replication outside rather than inside cells
D)carrying of RNA into a cell and RNA replication

Answer 1

A

Question 2

Imagine that you've isolated the complete human growth hormone gene directly from the human genome.After running through all the steps described in Chapter 19 for cloning and gene expression in bacteria,you find that no human growth hormone is expressed.What is the most likely explanation?

A)Human DNA cannot be cloned in a bacterium.
B)Human DNA can be maintained in cloned form only for brief periods in bacteria.
C)Bacteria cannot translate human mRNA coding sequences.
D)Bacteria cannot carry out splicing.
E)Bacteria lack a nucleus for proper transcription of eukaryotic genes.

Answer 2

D

Question 3

The final step in a 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.

Answer 3

D

Question 4

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

Question 5

In a single PCR cycle consisting of 15 seconds at 94°C,30 seconds at 50°C,and 1 min at 72°C,what is happening in the step run at 50°C?

A)The DNA to be amplified is being denatured.
B)Primers are being denatured.
C)DNA polymerase is extending new DNA from the primers.
D)Primers are annealing to the DNA to be amplified.
E)DNA polymerase is being inactivated.

Question 6

In early forensic applications of DNA fingerprinting,DNA was extracted from crime scene material,digested with restriction enzymes,and then used to prepare a Southern blot.Today,PCR is used in the early steps of forensic DNA analysis.What advantage does PCR provide over the former method?

A)PCR produces many more bands for fingerprint analysis,making it a more informative technique.
B)PCR can cut DNA at many more sites than can restriction enzymes.
C)PCR requires much less DNA for analysis.
D)PCR can analyze DNA,proteins,and carbohydrates,whereas restriction enzyme analysis is limited to DNA.

Question 7

If a scientist needs to put new DNA into a bacteria,she must _____ the bacteria.

A)transform
B)ligate
C)make a library of the genes of
D)make a cDNA library of
E)make a vector of

Question 8

The restriction enzymes BamHI and BclI cut at the points indicated by arrows:

If one sample of DNA was cut with BamHI and another with BclI,and these two samples were mixed and treated with DNA ligase,what would occur?

A)No DNAs would be ligated (joined together).
B)Only the BamHI-cut DNA would be ligated.
C)Only the BclI-cut DNA would be ligated.
D)Both BamHI-cut and BclI-cut DNAs would be ligated,but only to DNA fragments cut with the same enzyme (e.g. ,BamHI fragments would be ligated only to other BamHI fragments).
E)Both BamHI-cut and BclI-cut DNAs would be ligated with no preference for which fragment is ligated to which other.

Question 9

Which of the following sequences is most likely to be cut by a restriction enzyme?

A)AATCGT TTACGA
B)AATTCT TTAAGA
C)AATATT TTATAA
D)AAAATT TTTTAA
E)ACTACT TGATGA

Question 10

What information is critical to the success of 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.

Question 11

When constructing a cDNA library from a particular organism,the choice of tissue is _____,whereas when constructing a genomic DNA library from the same organism,the choice of tissue is _____.

A)critical;critical
B)immaterial;immaterial
C)immaterial;critical
D)critical;immaterial

Question 12

How can an amino acid sequence be used to design a gene-specific hybridization probe?

A)A portion of a polypeptide chain can be synthesized based on the amino acid sequence of the full protein.
B)A protein can be purified,digested with proteases that cleave it at specific sites,and one of the peptide fragments can be used as a probe.
C)All possible nucleotide sequences that could encode a portion of the polypeptide can be synthesized and used as probes.

Question 13

Which of the following is in the correct order for one cycle of PCR?

A)Denature DNA;add fresh enzyme;anneal primers;add dNTPs;extend primers.
B)Add fresh enzyme;denature DNA;anneal primers;add dNTPs;extend primers.
C)Anneal primers;denature DNA;extend primers.
D)Extend primers;anneal primers;denature DNA.
E)Denature DNA;anneal primers;extend primers.

Question 14

Imagine that you've prepared a Southern blot and probed it using a single probe.You observe eight different bands after autoradiography,with one band being very dark and the other seven being significantly lighter.What is suggested by these results?

A)The gene recognized by the probe has been cut into eight different fragments by the restriction enzyme.
B)The probe has been cut into eight different fragments by the restriction enzyme.
C)There are eight similar genes in the genome.
D)The DNA did not transfer from the gel to the nylon filter.
E)The DNA remained double stranded on the blot.

Question 15

The answer set for this question shows a series of short amino acid sequences obtained from a protein.If you were faced with choosing one of these to design a probe for a particular gene,which would provide the simplest probe or probe set? (To answer this question,consult the codon table shown in the figure above. )

A)leucine-leucine-serine-leucine
B)leucine-serine-proline-proline
C)proline-methionine-proline-leucine
D)tryptophan-methionine-tryptophan-tryptophan

Question 16

A gene library from a particular human's retinal cell would be?

A)a collection of DNAs cut by a restriction enzyme
B)a collection of plasmids cut by a restriction enzyme
C)a collection of different DNA fragments ligated into plasmids
D)a collection of genes that have been sequenced from a particular organism
E)a collection of PCR-amplified DNAs

Question 17

Scientists have begun discussing the possibility of putting an entire human genome (including that arising from endosymbiosis)into a cow egg cell without a genome.The next generation of cells from the cow egg would have _____.

A)human genome only
B)cow genome only
C)a mix of cow and human genomes
D)recombinant DNA

Question 18

What is a primary difference between PCR and traditional cloning procedures such as those used to clone the human growth hormone gene?

A)PCR and traditional cloning make use of different types of bacteria.
B)PCR and traditional cloning make use of different types of vectors.
C)PCR uses plasmid vectors,whereas traditional cloning uses bacteria.
D)PCR eliminates the need for restriction enzymes,vectors,and cells.
E)PCR is more time-consuming,but the purity of the obtained DNA clone is much higher than in traditional cloning.

Question 19

If mRNAs could be ligated and replicated within plasmids,what enzyme commonly used in recombinant DNA technology would no longer be needed?

A)restriction enzymes
B)DNA polymerase
C)RNA polymerase
D)reverse transcriptase
E)Taq polymerase

Question 20

Which of the following is a correct difference between a gene library and a gene clone?

A)A gene library contains many different cloned DNA sequences;a gene clone contains one type of DNA sequence.
B)A gene library contains one type of cloned DNA sequence;a gene clone contains many different DNA sequences.
C)A gene library is a much longer DNA sequence than a gene clone.
D)A gene library is a much shorter DNA sequence than a gene clone.
E)A gene library is sequence information stored in a computerized database;a gene clone is an actual sequence of DNA.

Question 21

Which type of disorder is most difficult to correct by gene therapy?

A)a dominant disorder
B)an incompletely dominant disorder
C)a recessive disorder
D)Disorders showing all these forms of dominance present equal challenges.

Question 22

To create a viral vector for delivery of genes into mammalian cells,the virus must be engineered to _____.

A)remove viral coat proteins
B)remove all viral genes,replacing them with the mammalian genes to be delivered
C)remove viral genes involved with virus replication and add mammalian genes to be delivered
D)remove the viral genome and coat proteins and replace them with recombinant plasmids carrying the mammalian genes to be delivered

Question 23

The genes needed for β-carotene synthesis are not normally expressed in endosperm.In the creation of golden rice,how did researchers ensure that these genes were expressed in rice endosperm?

A)The genes were injected only in the endosperm of rice grains.
B)Agrobacterium cells were added only to rice grains,not to any other part of the plant.
C)The protein-coding sequence of each gene was linked to a regulatory region of DNA that directed transcription in endosperm.
D)The wild-type genes were mutated and new mutant alleles that are expressed only in endosperm were selected.

Question 24

One example of an innovation from an unexpected source comes from studies of tumor-like plant growths.What information did the study of plant tumors provide that was critical for plant genetic engineering?

A)understanding the role of plant hormones in growth promotion
B)knowledge of plant tumor suppressor and proto-oncogenes
C)learning that metastasis is critical for tumor progression
D)learning the biosynthetic pathway to β-carotene
E)discovery of a plasmid that could be modified to introduce genes into plants

Question 25

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

Question 26

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.

Question 27

Plasmids are used as vectors in both 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 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.
E)Bacterial plasmids typically do not modify the growth of the host cells;Ti plasmids modified for genetic engineering always produce plant galls.

Question 28

The areas that have received the greatest attention in genetically modified plants are _____.

A)improved product quality and increased pest and herbicide resistance
B)improved product quality,more rapid growth rate through plant hormone production,and decreased herbicide resistance
C)more rapid growth rate through plant hormone production,pharmaceutical production,and increased antibiotic resistance
D)pharmaceutical production,production of useful compounds not normally found in nature (xenobiotics),and the ability to remove or neutralize toxic compounds from the environment (bioremediation)

Question 29

If you are a human geneticist looking for an ideal population in which to map disease genes,which of the following characteristics would help the mapping study?

A)small family sizes with well-known genealogies
B)all members of the population have the disease
C)large family sizes with poorly known genealogies
D)large family sizes with well-known genealogies

Question 30

In the current form of dideoxy DNA sequencing,the primer is unlabeled and each dideoxynucleotide is labeled with a different fluorescent marker.This method _____.

A)eliminates the need to run sequencing reaction products on a gel
B)allows a DNA sequence to be determined from four separate sequencing reactions,each run on a separate lane of a gel
C)allows a DNA sequence to be determined from one sequencing reaction that is run on a single lane of a gel
D)eliminates the need for sophisticated machines to read the output of each sequencing reaction

Question 31

Use the following information when answering the corresponding question(s).
In Chapter 19 you read about the amplification and sequencing of 30,000-year-old Neanderthal DNA to learn that it's unlikely Neanderthals and modern humans interbred.Let's take a closer look at this early work with ancient DNA (M.Krings,A.Stone,R.W.Schmitz,H.Krainitzki,M.Stoneking,and S.Pääbo.1997.Neanderthal DNA sequences and the origin of modern humans.Cell 90:19-30).
Here is part of the lead paragraph in the "Methods" section of the Krings et al.paper:
Protective clothing was worn throughout the sampling procedure.Instruments used were treated with 1 M HCl followed by extensive rinsing in distilled water.After removal,the sample was immediately put into a sterile tube for transport to Munich.All subsequent manipulations of the sample,and experimental procedures prior to cycling of PCR reactions,were carried out in laboratories solely dedicated to the analysis of archaeological specimens,where protective clothing,separate equipment and reagents,UV irradiation,and other measures to...
A concluding paragraph of the Krings et al.paper states:
It must be emphasized that the above conclusions are based on a single individual sequence;the retrieval and analysis of mtDNA sequences from additional Neanderthal specimens is obviously desirable.If this proves possible,then the potential exists to address several questions concerning Neanderthals that hitherto could be studied exclusively by morphological and archaeological approaches.For example,the genetic relationship between Neanderthal populations in Europe and in western Asia could be explored,as could the demographic history of Neanderthal populations.
Refer to the paragraph on Krings et al.How could the "demographic history of Neanderthal populations" be explored if mitochondrial DNA from other Neanderthal samples could be PCR amplified?

A)These Neanderthal sequences could be compared to those of modern humans to learn if they are closely related.
B)These Neanderthal sequences could be compared to those of modern humans;the more they differ,the more distant the time of divergence between the Neanderthal and modern human lineages.
C)These Neanderthal sequences could be compared to each other to see how much they differ;the more they differ,the greater the divergence between these populations.
D)In the attempt to amplify other Neanderthal DNAs,those that amplify must be from more modern populations and those that don't are from more ancient populations.

Question 32

Why is it essential that genetic markers used in mapping disease genes be polymorphic?

A)If the marker isn't polymorphic,its position cannot be known.
B)If the marker isn't polymorphic,it cannot be physically linked to a gene associated with human disease.
C)If the marker isn't polymorphic,then it will not be inherited in any predictable manner.
D)If the marker isn't polymorphic,then it's impossible to use genetic mapping techniques to establish an association between the marker and the disease gene.

Question 33

Since dideoxy sequencing is based on the chain termination,why are normal deoxynucleotides also included in the reaction?

A)to enhance the chain termination ability of the deoxynucleotides
B)to provide a substrate for DNA polymerase
C)to produce a range of DNA synthesis products that terminate at every occurrence of a particular base
D)to create DNA synthesis products long enough to allow running a gel

Question 34

Use the following information when answering the corresponding question(s).
In Chapter 19 you read about the amplification and sequencing of 30,000-year-old Neanderthal DNA to learn that it's unlikely Neanderthals and modern humans interbred.Let's take a closer look at this early work with ancient DNA (M.Krings,A.Stone,R.W.Schmitz,H.Krainitzki,M.Stoneking,and S.Pääbo.1997.Neanderthal DNA sequences and the origin of modern humans.Cell 90:19-30).
Here is part of the lead paragraph in the "Methods" section of the Krings et al.paper:
Protective clothing was worn throughout the sampling procedure.Instruments used were treated with 1 M HCl followed by extensive rinsing in distilled water.After removal,the sample was immediately put into a sterile tube for transport to Munich.All subsequent manipulations of the sample,and experimental procedures prior to cycling of PCR reactions,were carried out in laboratories solely dedicated to the analysis of archaeological specimens,where protective clothing,separate equipment and reagents,UV irradiation,and other measures to...
A concluding paragraph of the Krings et al.paper states:
It must be emphasized that the above conclusions are based on a single individual sequence;the retrieval and analysis of mtDNA sequences from additional Neanderthal specimens is obviously desirable.If this proves possible,then the potential exists to address several questions concerning Neanderthals that hitherto could be studied exclusively by morphological and archaeological approaches.For example,the genetic relationship between Neanderthal populations in Europe and in western Asia could be explored,as could the demographic history of Neanderthal populations.
Refer to the paragraph on Krings et al.Why did the researchers wear protective clothing and note so emphatically that they did so?

A)They needed to be certain there were no ancient pathogens on the sample that modern humans hadn't been exposed to.
B)They needed to be sure not to harm the precious sample with oils from skin or moisture from their breath.
C)They needed to minimize the chance of introducing their own mitochondrial DNA to the sample.
D)Because the work was done in Germany,they needed to follow stringent,standard German laboratory procedures and document their compliance.

Question 35

Gene therapy requires _____.

A)knowledge and availability of the wild-type allele of the defective gene
B)an ability to introduce the wild-type allele into the patient
C)an ability to express the introduced gene at the correct level,time,and site within the patient
D)the knowledge and availability of the wild-type allele of the defective gene and the ability to introduce the allele into the patient
E)knowledge and availability of the wild-type allele of the defective gene;an ability to introduce the wild-type allele into the patient;and an ability to express the introduced gene at the correct level,time,and site within the patient

Question 36

Why might retroviral vectors for gene therapy increase the patient's risk of developing cancer?

A)They might introduce proteins from the virus.
B)They might not express the genes that were introduced into a patient's cells.
C)They might not integrate their recombinant DNA into the patient's genome.
D)They might integrate recombinant DNA into the genome in ways that misregulate the expression of genes at or near the site of integration.

Question 37

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)protect against disease
E)none of the above

Question 38

Imagine that you are searching for the gene associated with nail-patella syndrome,a dominant genetic disorder that causes developmental abnormalities.In a large pedigree you discover an association between nail-patella syndrome and a genetic marker that occurs in two different alleles,A and B.Fifteen individuals within this pedigree have nail-patella syndrome and are A/B heterozygotes for the marker.Thirty individuals within this pedigree don't suffer from nail-patella syndrome and are homozygous for the A marker allele.One individual within this pedigree has nail-patella syndrome and is also homozygous for the A marker allele.The most likely explanation for this exceptional individual is _____.

A)a new mutation converted the disease-causing allele to the wild-type form
B)a new mutation converted the B allele of the marker to the A form
C)the exceptional nail-patella individual is haploid
D)recombination occurred between the nail-patella gene and marker gene in one of the parents of the exceptional individual

Question 39

In the form of gene therapy used successfully for severe combined immunodeficiency syndrome (SCID)-X1,the genetic engineering of human cells is done _____.

A)by injecting engineered viruses into the patient's bloodstream
B)by injecting engineered viruses into the patient's bone marrow
C)by treating a relative's cultured bone marrow cells with genetically engineered viruses and then injecting these cells into the patient's bone marrow
D)by isolating the patient's bone marrow cells,infecting them with genetically engineered viruses,and injecting them back into the patient's bone marrow

Question 40

Animal rights activists often say that all animals are not useful for research purposes.Why might transgenic mice be useful to human researchers?

A)often provide 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