CH20 DNA Tools and Biotechnology Questions

Genetically engineered plants _____. A) include transgenic rice plants that can grow in water of high salinity B) are used in research but not yet in commercial agricultural production C) are more difficult to develop than genetically engineered animals D) are banned throughout the world

A) include transgenic rice plants that can grow in water of high salinity

A laboratory might use dideoxyribonucleotides to _____. A) sequence a DNA fragment B) produce cDNA from mRNA C) visualize DNA expression D) separate DNA fragments

A) sequence a DNA fragment

Which of the following is required to make complementary DNA (cDNA) from RNA?

reverse transcriptase

What is the polymerase chain reaction (PCR)?

A method to amplify a fragment of DNA. PCR is an in vitro DNA synthesis reaction that produces many copies of a single DNA fragment.

Sequencing an entire genome, such as that of C. elegans, a nematode, is most important because _____. A) a sequence that is found to have a particular function in the nematode is likely to have a closely related function in vertebrates B) a sequence that is found to have no introns in the nematode genome is likely to have acquired the introns from higher organisms C) it allows research on a group of organisms we do not usually care much about D) it allows researchers to use the sequence to build a "better" nematode, which is resistant to disease

A) 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) abnormal gene regulation due to variant methylation B) use of pluripotent instead of totipotent stem cells C) use of nuclear DNA as well as mtDNA D) the indefinite replication of totipotent stem cells

A) abnormal gene regulation due to variant methylation

DNA microarrays have made a huge impact on genomic studies because they _____. A) allow the expression of many or even all of the genes in the genome to be compared at once B) can be used to eliminate the function of any gene in the genome C) allow physical maps of the genome to be assembled in a very short time D) can be used to introduce entire genomes into bacterial cells

A) 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) bacteria cannot remove eukaryotic introns B) prokaryotes use a different genetic code from that of eukaryotes C) bacteria translate only mRNAs that have multiple messages D) bacterial RNA polymerase cannot make RNA complementary to mammalian DNA

A) bacteria cannot remove eukaryotic introns

Transgenic mice are useful to human researchers because they _____. A) can be valuable animal models of human disease B) are now used in place of bacteria for cloning human genes C) were instrumental in pinpointing the location of the huntingtin gene D) are essential for mapping human genes

A) can be valuable animal models of human disease

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

Gene therapy requires _____. A) 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 B) the ability to express the introduced gene at the correct level, time, and tissue site within the patient C) the ability to introduce the normal allele into the patient D) knowledge and availability of the normal allele of the defective gene

A) 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

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) inability of the human digestive system to accept plant-derived protein D) use of plant cells to translate non-plant-derived mRNA

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) replication of the cloned gene using a bacterial plasmid C) use of a microarray to verify continued expression of the original gene D) transcription of the cloned gene using a BAC

A) recombination resulting in replacement of the wild type with the mutated gene (I don't know why)

A gene that contains introns can be made shorter (but remain functional) for genetic engineering purposes by using _____. A) reverse transcriptase to reconstruct the gene from its mRNA B) DNA polymerase to reconstruct the gene from its polypeptide product C) DNA ligase to put together fragments of the DNA that code for a particular polypeptide D) a restriction enzyme (endonuclease) to cut the gene into shorter pieces

A) reverse transcriptase to reconstruct the gene from its mRNA

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

ALL I, II, III

Which of the following is true of stem cells? They can be found in both embryonic and adult tissues. They can differentiate to produce many different kinds of specialized cells. Their use is highly controversial. They can reproduce indefinitely in culture. All of the above.

ALL OF THE ABOVE They can be found in both embryonic and adult tissues. They can differentiate to produce many different kinds of specialized cells. Their use is highly controversial. They can reproduce indefinitely in culture.

During which step in the PCR cycle do primers form bonds with a single-stranded template?

Annealing. Primers form hydrogen bonds with the single-stranded DNA template during the annealing step.

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) Cytoplasm from embryonic cells is injected into the adult cells. B) A retrovirus is used to introduce four specific regulatory genes. C) The adult stem cells must be fused with embryonic cells. D) The nucleus of an embryonic cell is used to replace the nucleus of an adult cell.

B) A retrovirus is used to introduce four specific regulatory genes.

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) Genetically engineer most crops to withstand very long droughts. B) Genetically engineer several genotypes within single crop types. C) Genetically engineer the fastest growing crops possible. D) Only plant crops that are genetically engineered.

B) Genetically engineer several genotypes within single crop types.

Organisms share many conserved core processes and features, including transcription and translation using a uniform genetic code. Scientists have used these shared processes and features in biotechnology. For example, for the process of some transformations, a plasmid is constructed when a eukaryotic gene of interest is added with an antibiotic resistant gene such beta-lactamase, which is used for ampicillin resistance. This plasmid is then inserted into a prokaryotic bacterial cell, such as E-coli, through a transformation process that leads to the production of the product protein from the eukaryotic organism. To culture the bacteria and obtain the protein product, the bacteria must grow. Select the appropriate condition to determine if the plasmid has entered the E-coli bacterial cell. A) Nutrient broth to which other resistant bacteria have been added. B) Nutrient broth to which ampicillin has been added. C) Nutrient broth to which no antibiotic has been added. D) Water to which ampicillin has been added.

B) Nutrient broth to which ampicillin has been added.

Bacterial cells protect their own DNA from restriction enzymes (endonucleases) by _____. A) forming "sticky ends" of bacterial DNA to prevent the enzyme (endonuclease) from attaching B) adding methyl groups to adenines and cytosines C) using DNA ligase to seal the bacterial DNA into a closed circle D) adding histones to protect the double-stranded DNA

B) adding methyl groups to adenines and cytosines

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) transcription and translation B) electroporation followed by recombination C) introducing a plasmid into the cell D) infecting the mouse cell with a Ti plasmid

B) electroporation followed by recombination

Which "ingredients" for PCR and for the dideoxy chain-termination method of DNA sequencing are the same? A) enucleated eggs, reverse transcriptase, free nucleotides B) free nucleotides, DNA polymerase, DNA primers C) template DNA, reverse transcriptase, DNA primers D) mRNA, reverse transcriptase, free nucleotides E) nucleic acid probes, DNA polymerase, DNA ligase

B) free nucleotides, DNA polymerase, DNA primers If DNA polymerase encounters a DNA template strand with a primer attached to it, and free nucleotides are available, DNA synthesis will proceed.

DNA technology has many medical applications. Which of the following is not done routinely at present? A) prenatal identification of genetic disease alleles B) introduction of genetically engineered genes into human gametes C) genetic testing for carriers of harmful alleles D) production of hormones for treating diabetes and dwarfism E) production of microbes that can metabolize toxins

B) introduction of genetically engineered genes into human gametes

Which of the following tools of recombinant DNA technology is incorrectly paired with its use? A) electrophoresis-separation of DNA fragments B) reverse transcriptase-production of cDNA from mRNA C) DNA ligase-cutting DNA, creating sticky ends of restriction fragments D) restriction enzyme-analysis of RFLPs E) DNA polymerase-polymerase chain reaction to amplify sections of DNA

C) DNA ligase-cutting DNA, creating sticky ends of restriction fragments

Silencing of selected genes is often done using RNA interference (RNAi). Which of the following question would NOT be answered with this process? A) What will happen in a particular insect's digestion if gene 173 is not able to be translated? B) 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? D) What is the function of gene 432 in a particular species of annelid?

C) Is gene HA292 expressed in individuals for a disorder in humans? (I don't know why)

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 generated during the sequencing reaction based on one-nucleotide differences in their size. D) It separates DNA fragments based on their charge.

C) It separates DNA fragments generated during the sequencing reaction based on one-nucleotide differences in their size.

Organisms share many conserved core processes and features, including transcription and translation using a uniform genetic code. Scientists have used these shared processes and features in biotechnology. For example, for the process of some transformations, a plasmid is constructed when a eukaryotic gene of interest is added with an antibiotic resistant gene such beta-lactamase, which is used for ampicillin resistance. This plasmid is then inserted into a prokaryotic bacterial cell, such as E-coli, through a transformation process that leads to the production of the product protein from the eukaryotic organism. To culture the bacteria and obtain the protein product, the bacteria must grow. Select the appropriate condition to determine if the plasmid has entered the E-coli bacterial cell. A) Nutrient broth to which no antibiotic has been added. B) Nutrient broth to which other resistant bacteria have been added. C) Nutrient broth to which ampicillin has been added. D) Water to which ampicillin has been added.

C) Nutrient broth to which ampicillin has been added.

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) Adult stem cells have more DNA nucleotides than their counterparts. B) The nonstem cells have fewer repressed genes. C) The cells from the two sources exhibit different patterns of DNA methylation. D) The two kinds of cells have virtually identical gene expression patterns in microarrays.

C) The cells from the two sources exhibit different patterns of DNA methylation.

You are a member of the jury for a murder case. The prosecution has presented DNA evidence linking the defendant to the crime scene. The defense claims that DNA evidence using STR analysis with 13 markers is not sufficient to reliably distinguish between people. What do you think? A) The prosecution will have to consult a genomic library to make sure their DNA evidence is valid. B) STR analysis is not sufficient. The defendant's entire genome should be sequenced. C) The prosecution is right. STR analysis with 13 markers gives a 1 in 10 billion or greater chance that two people will have the same pattern. This person was at the crime scene. D) The defense is right. STR analysis with 13 markers gives a 1 in 1 million chance of two people having the same pattern, leaving a reasonable doubt. E) DNA evidence is not generally accepted by legal experts.

C) The prosecution is right. STR analysis with 13 markers gives a 1 in 10 billion or greater chance that two people will have the same pattern. This person was at the crime scene.

Which of the following is true of embryonic stem cells but not of adult stem cells? A) One aim of using them is to provide cells for repair of diseased tissue. B) They can continue to reproduce for an indefinite period. C) They can give rise to all cell types in the organism. D) They normally differentiate into only eggs and sperm.

C) They can give rise to all cell types in the organism.

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 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 D) 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 (I don't know why)

In recombinant DNA methods, the term vector can refer to A) the enzyme that cuts DNA into restriction fragments. B) a DNA probe used to identify a particular gene. C) a plasmid used to transfer DNA into a living cell. D) a SNP marker. E) the sticky end of a DNA fragment.

C) a plasmid used to transfer DNA into a living cell.

Yeast cells are frequently used as hosts for cloning because they _____. A) easily form colonies B) do not have plasmids C) are eukaryotic cells E) can remove exons from mRNA

C) are eukaryotic cells

In 1997, Dolly the sheep was cloned. Which of the following processes was used? A) separation of an early stage sheep blastula into separate cells, one of which was incubated in a surrogate ewe B) replication and dedifferentiation of adult stem cells from sheep bone marrow 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

Using retroviral vectors for gene therapy might increase the patient's risk of developing cancer because they might _____. A) not express the genes that were introduced into a patient's cells B) introduce proteins from the virus C) integrate recombinant DNA into the genome in ways that misregulate the expression of genes at or near the site of integration D) not integrate their recombinant DNA into the patient's genome

C) integrate recombinant DNA into the genome in ways that misregulate the expression of genes at or near the site of integration

Which of the following is most like the formation of identical twins? A) therapeutic cloning B) use of adult stem cells C) organismal cloning D) cell cloning

C) organismal cloning

Many identical copies of genes cloned in bacteria are produced as a result of _____. A) transformation B) bacterial cell replication C) plasmid and bacterial cell replication D) plasmid replication

C) plasmid and bacterial cell replication

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 form a knockout organism that will not pass the deleted sequence to its progeny B) to destroy an unwanted allele in a homozygous individual C) to decrease the production from a harmful mutated gene D) to raise the concentration of a desired protein

C) to decrease the production from a harmful mutated gene

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 bone marrow B) treating a relative's cultured bone marrow cells with genetically engineered viruses and then injecting these cells into the patient's bone marrow C) injecting engineered viruses into the patient's bloodstream 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

If cells from a carrot are removed and placed in a culture medium, they can develop into a normal adult plant. This demonstrates that carrot cells _____. A) differentiate B) differ genetically at maturity C) differ as mature cells D) retain all the genes that were in the zygote that developed into the original plant E) are undifferentiated as adult cells

D) retain all the genes that were in the zygote that developed into the original plant

What is the most commonly used vector for introducing transgenes into plants? A) the bacterium Bacillus thuringiensis B) nuclear transplantation C) the flu virus D) the Ti plasmid E) beta-carotene

D) the Ti plasmid The Ti plasmid comes from Agrobacterium tumefaciens, and it is effective at integrating with the host cell's DNA.

What enzyme forms covalent bonds between restriction fragments?

DNA ligase catalyzes the formation of covalent bonds between restriction fragments.

Which of the following is in the correct order for one cycle of polymerase chain reaction (PCR)?

Denature DNA; anneal primers; extend primers.

Plants are more readily manipulated by genetic engineering than are animals because A) more vectors are available for transferring recombinant DNA into plant cells. B) genes can be inserted into plant cells by microinjection. C) plant genes do not contain introns. D) plant cells have larger nuclei. E) a somatic plant cell can often give rise to a complete plant.

E) a somatic plant cell can often give rise to a complete plant.

During which step in the PCR cycle are nucleotides used?

Extension. Nucleotides are used to synthesize the complementary strand to the DNA template during the extension step.

True or false? The Taq enzyme is a type of DNA polymerase that allows researchers to separate the DNA strands during the annealing step of the PCR cycle without destroying the polymerase.

FALSE Taq polymerase is derived from a species of bacteria living in hot springs, which makes it stable at the high temperature required for the denaturation step of PCR.

In recombinant DNA experiments, what is used to cut pieces of DNA and what joins the resulting fragments to form recombinant DNA?

Restriction enzymes cut DNA molecules at specific points; in most cases, the restriction fragments have sticky ends that can base-pair with complementary sticky ends. The joined segments are then covalently fused by DNA ligase.

True or false? Comparison of the sequences of the same gene across species can give some insight into the existence of a common ancestor with that gene.

TRUE DNA sequence comparisons are a powerful tool by which to estimate how closely related different species are along the evolutionary timeline.

What information is critical to the success of polymerase chain reaction (PCR) itself?

The DNA sequence of the ends of the DNA to be amplified must be known.

A paleontologist has recovered a bit of tissue from the 400-year-old preserved skin of an extinct dodo (a bird). To compare a specific region of the DNA from the sample with DNA from living birds, which of the following would be most useful for increasing the amount of dodo DNA available for testing? polymerase chain reaction (PCR) electroporation Southern blotting RFLP analysis gel electrophoresis

polymerase chain reaction (PCR)

The unpaired nucleotides produced by the action of restriction enzymes are referred to as _____.

sticky ends They are called sticky ends since they will "stick" to a complementary single-stranded sequence. The matching of sticky ends follows the rules of specific base pairing.

What information can not be obtained from the sequence of a gene? A) Whether the gene is methylated. B) Amino acid sequence of the protein. C) Effects of mutation on gene function. D) Relationship between two species.

A) Whether the gene is methylated. Although the gene's sequence may reveal the presence of methylation targets like cytosine (C), it does not give information about whether such bases have been methylated.

Which of the following is a concern expressed by opponents of the use of genetically modified (GM) food crops? 1. The protein products of transgenes in GM food crops might lead to allergic reactions in human consumers. 2. GM food crops might pass their new genes to human consumers. 3. GM food crops might pass their new genes to close relatives in nearby wild areas.

1. The protein products of transgenes in GM food crops might lead to allergic reactions in human consumers. 3. GM food crops might pass their new genes to close relatives in nearby wild areas.

What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium? 1. Transform bacteria with a recombinant DNA molecule. 2. Cut the plasmid DNA using restriction enzymes (endonucleases). 3. Extract plasmid DNA from bacterial cells. 4. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. 5. Use ligase to seal plasmid DNA to nonplasmid DNA.

3, 2, 4, 5, 1

Cold case detectives are investigating a homicide that took place 30 years ago. In reexamining the evidence, they find a tiny spot of blood on the victim's clothing that was likely left by the murderer. The DNA in the blood has partially degraded over time. What technique(s) would the blood lab technicians use in their examination of this tiny, degraded blood sample? 1. They would use reverse transcriptase-polymerase chain reaction (RT-PCR) to determine the genes expressed in this DNA. 2. They would use a restriction enzyme and DNA ligase to make recombinant DNA from this sample. 3. They would use PCR to amplify the DNA.

3. They would use PCR to amplify the DNA. PCR is impressive in the speed and specificity with which it amplifies DNA. Only minute amounts of DNA need be present in the starting material, and this DNA can be in a partially degraded state, as long as a few molecules contain the complete target sequence.

How many DNA molecules would there be after four rounds of PCR if the initial reaction mixture contained two molecules?

32 Thirty-two DNA molecules are produced if two molecules are doubled four times. (I don't know why)

Which of the following sequences is most likely to be cut by a restriction enzyme? A) AATATT TTATAA B) AATTCT TTAAGA C) ACTACT TGATGA D) AAAATT TTTTAA

A) AATATT TTATAA (I don't know why)

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) 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. B) Bacterial plasmids are circular DNAs; Ti plasmid DNA is linear. C) In bacteria, genes are stably expressed; in plants, gene expression is always lost quickly. D) Gene expression tends to decrease rapidly and unpredictably in bacteria; gene expression is much more stable in plants.

A) 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.

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) Cloning to produce embryonic stem cells may lead to great medical benefits for many. B) The use of adult stem cells is likely to produce more cell types than the use of embryonic stem cells. 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.

A) Cloning to produce embryonic stem cells may lead to great medical benefits for many.

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 is highly conserved and shows shared evolutionary ancestry. B) PAX-6 proteins are different for formation of different kinds of eyes. C) Pax-6 genes are identical in nucleotide sequence. D) PAX-6 proteins have identical amino acid sequences.

A) Pax-6 is highly conserved and shows shared evolutionary ancestry.

A researcher is preparing to insert a human gene of interest into a bacterial plasmid in order to clone the human gene. She has genetically engineered the plasmid to carry a gene amp R , which confers resistance to the antibiotic ampicillin. She will include ampicillin in the plating medium when she grows the recombinant bacteria. Why has she engineered the plasmid to include an antibiotic resistance gene? Choose the best answer. A) Recombinant bacteria that have taken up the plasmid can be recognized because they are able to survive in the presence of ampicillin. B) Recombinant bacteria that have taken up the plasmid can be recognized because the antibiotic resistance gene produces a blue color. C) Recombinant bacteria that have taken up the plasmid are vulnerable to infection and require antibiotic resistance.

A) Recombinant bacteria that have taken up the plasmid can be recognized because they are able to survive in the presence of ampicillin.

In large scale, genome-wide association studies in humans we look for _____. A) SNPs where one allele is found more often in persons with a particular disorder than in healthy controls B) lengthy sequences that might be shared by most members of a population C) SNPs where one allele is found in two or more adjacent genes D) SNPs where one allele is found in families with particular introns sequence

A) SNPs where one allele is found more often in persons with a particular disorder than in healthy controls

The vertebrate Pax-6 gene product (the PAX-6 protein) triggers a complex program of gene expression resulting in formation of the vertebrate eye, which has a single lens. The fly Pax-6 gene leads to formation of the compound fly eye. When scientists cloned a mouse Pax-6 gene and introduced it into a fly embryo, it led to formation of the compound eye of a fly. What did scientists induce from this? A) The Pax-6 genes of flies and mice arose from an ancestral gene in a common ancestor. B) Flies and mice have a more recent common ancestor than we originally thought. C) All genes controlling eye development are identical in flies and mice.

A) The Pax-6 genes of flies and mice arose from an ancestral gene in a common ancestor.

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) Every racial and ethnic group has inherited different short tandem repeats. C) The sequence of DNA that is repeated varies significantly from individual to individual. D) The sequence variation is acted upon differently by natural selection in different environments.

A) The number of repeats varies widely from person to person or animal to animal.

Which of the following is one of the technical reasons why gene therapy is problematic? A) Transferred genes may not have appropriately controlled activity. B) Most cells with an engineered gene do not produce gene product. C) mRNA from transferred genes cannot be translated. D) Cells with transferred genes are unlikely to replicate.

A) Transferred genes may not have appropriately controlled activity.

Gel electrophoresis separates DNA fragments on the basis of what characteristic?

length

Why is it so important to be able to amplify DNA fragments when studying genes? A) A clone requires multiple copies of each gene per clone. B) Restriction enzymes (endonucleases) cut DNA into fragments that are too small. C) Before amplification, DNA fragments are likely to bind to RNA and no longer be able to be analyzed. D) A gene may represent only a millionth of the cell's DNA.

D) A gene may represent only a millionth of the cell's DNA.

For applications in gene therapy, what is the most favorable characteristic of retroviruses? A) Retroviruses possess reverse transcriptase. B) Retroviruses have an RNA genome. C) Retroviruses mutate often. D) DNA copies of retroviral genomes become integrated into the genome of the infected cell.

D) DNA copies of retroviral genomes become integrated into the genome of the infected cell.

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) Next generation sequencing employs electrophoresis, but the chain termination method does not. B) 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. C) The chain termination method employs the polymerase chain reaction, but next generation sequencing does not. D) 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) 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.

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) Experiments involving HIV or other potentially dangerous viruses have been banned. B) Transgenic plants are engineered so that the plant genes cannot hybridize. C) Genetically modified organisms are not allowed to be part of our food supply. D) Microorganisms used in recombinant DNA experiments are genetically crippled to ensure that they cannot survive outside of the laboratory.

D) Microorganisms used in recombinant DNA experiments are genetically crippled to ensure that they cannot survive outside of the laboratory.

In animals, what is the difference between reproductive cloning and therapeutic cloning? A) Reproductive cloning uses totipotent cells, whereas therapeutic cloning does not. B) Therapeutic cloning uses nuclei of adult cells transplanted into enucleated nonfertilized eggs. C) Reproductive cloning uses embryonic stem cells, whereas therapeutic cloning does not. D) Therapeutic cloning supplies cells for repair of diseased or injured organs.

D) Therapeutic cloning supplies cells for repair of diseased or injured organs.

In an experiment, DNA from the linear form of the bacteriophage Lambda was cut into fragments using the restriction enzyme Hind III. Restriction enzymes are isolated from bacteria and cut DNA in specific locations. Hind III cuts the Lambda DNA between the adenine nucleotides on the complimentary strands in a specific sequence, as indicated in the diagram, producing eight different size fragments. These fragments are then separated with an electrical current based on size after the DNA fragments are placed in a porous gel, a process called gel electrophoresis. Cut site | | 5'-AAGCTT-3' 3'-TTCGAA-5' | | Cut Site Select an observation that best describes a correct aspect of the two processes of restriction digest and gel electrophoresis: A) If an electrical current is not used, eight separate DNA bands would be visible, but they would not be separated as much as when an electrical current is used. B) Only the restriction enzyme Hind III can be used to cut Lambda DNA since restriction enzymes are specific to the type of DNA they can cut. C) The sequence AAGCTT is found eight times in the Lambda genome and the restriction enzyme Hind III finds each location. D) When separated on a gel, the pattern of DNA bands will be characteristic of those cut with Hind III, different restriction enzymes will not produce these same fragments.

D) When separated on a gel, the pattern of DNA bands will be characteristic of those cut with Hind III, different restriction enzymes will not produce these same fragments

Which of the following is an example of "recombinant DNA technology?" A) alternate alleles assorting independently B) manipulating a meiotic crossing-over event C) combining alternate alleles of a gene in a single cell D) introducing a human gene into a bacterial plasmid E) cloning genes from homologous pairs of chromosomes

D) introducing a human gene into a bacterial plasmid

How are two or more of the same nucleotide (in a row) detected in the flow-gram?

They show up as a higher peak in the flow-gram. Because the height of the peak corresponds to the intensity of the light flash, it reflects the number added, consecutively, of a particular base. Some of these higher peaks are visible in the flow-gram shown, including in the example on the right side of the diagram.

Archaeologists unearthed a human skull with a small dried fragment of the scalp still attached. They extracted a tiny amount of DNA from the scalp tissue. How could they obtain sufficient DNA for an analysis of the ancient human's genes? Use the polymerase chain reaction. Subject the DNA to restriction enzymes. Use a nucleic acid probe. Subject the specimen to amniocentesis. Subject the DNA to electrophoresis.

Use the polymerase chain reaction. PCR is a method of DNA amplification.

In order to insert a human gene into a plasmid, both must _____

be cut by the same restriction enzyme Doing so will result in the formation of complementary sticky ends.

cDNA is synthesized from what molecule using an enzyme known as what?

mRNA ... reverse transcriptase Reverse transcriptase is a viral enzyme that can synthesize DNA from an RNA template.

Which of the following uses labeled probes to visualize the expression of genes in whole tissues and organisms?

in situ hybridization

The reason for using Taq polymerase for PCR is that _____.

it is heat stable and can withstand the heating step of PCR