Question 1

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

Accepted Answer

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

Question 2

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

Accepted Answer

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

Question 3

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?

Accepted Answer

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. 
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. C

Question 4

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?

Accepted Answer

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. 
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 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?

Accepted Answer

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. 
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

-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. )

Accepted Answer

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

Question 7

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

Accepted Answer

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) 
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 8

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?

Accepted Answer

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. 
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 9

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

Accepted Answer

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 
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 10

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

Accepted Answer

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. 
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 11

What information is critical to the success of PCR itself?

Accepted Answer

A) The DNA sequence of the ends of the DNA to be amplified must be known. 
B) The complete DNA sequence of the DNA to be amplified must be known. 
C) The sequence of restriction enzyme recognition sites in the DNA to be amplified must be known. 
D) The sequence of restriction enzyme recognition sites in the DNA to be amplified and in the plasmid where the amplified DNA fragment will be cloned must be known. 
A) The DNA sequence of the ends of the DNA to be amplified must be known. 
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 12

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?

Accepted Answer

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 
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 13

For applications in gene therapy,what is the most favorable characteristic of retroviruses?

Accepted Answer

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. 
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 14

The final step in a DNA sequencing reaction is to run the DNA fragments on a gel.What purpose does this serve?

Accepted Answer

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. 
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.

Question 15

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 _____.

Accepted Answer

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

Question 16

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

Accepted Answer

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 
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

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

Accepted Answer

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 
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 18

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

Accepted Answer

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 
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

Question 19

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?

Accepted Answer

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. 
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 20

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?

Accepted Answer

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. 
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.

Exam 19: Analyzing and Engineering Genes

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

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

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?

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?

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?

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

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

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

What information is critical to the success of PCR itself?

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?

For applications in gene therapy,what is the most favorable characteristic of retroviruses?

The final step in a DNA sequencing reaction is to run the DNA fragments on a gel.What purpose does this serve?

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

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

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

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?

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?

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Lipids, membranes, and the First Cells

Inside the Cell

Cell-Cell Interactions

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

Genomics

Principles of Development

An Introduction to Animal Development

An Introduction to Plant Development

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, signals, and Responses

Plant Reproduction

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Electrical Signals in Animals

Animal Sensory Systems and Movement

Chemical Signals in Animals

Animal Reproduction

The Immune System in Animals

An Introduction to Ecology

Behavioral Ecology

Population Ecology

Community Ecology

Ecosystems

Biodiversity and Conservation Biology

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