Deck 13: Nucleic Acid Biotechnology Techniques

Question 1

The application of gel electrophoresis (PAGE) in DNA sequencing

A) is nonexistent because DNA fragments differ widely in charge.
B) depends on separation of similar charge/mass ratio on the basis of size.
C) depends on separation of identical size on the basis of charge/mass ratio.
D) is nonexistent because DNA fragments have no net charge.

Answer 1

B

Question 2

Fluorescence works because the fluorescent molecule

A) absorbs light at one wavelength and emits light at a longer wavelength.
B) absorbs light at one wavelength and emits light at a shorter wavelength.
C) absorbs light at one wavelength and emits light at the same wavelength.
D) absorbs light at many wavelengths and emits light at many wavelengths.

Answer 2

A

Question 3

Which of the following statements concerning restriction endonucleases is true?

A) They attack RNA, not DNA.
B) They can produce "sticky ends".
C) They attack single-stranded sequences only.
D) They do not display sequence specificity in their site of attack.

Answer 3

B

Question 4

Fluorescence and other luminescent methods of visualizing bands offer these advantages over methods dependent on radioactivity.

A) They can detect smaller amounts of material (they are more sensitive).
B) Fluorescent molecules like ethidium bromide offer no health hazard, while radioisotopes do.
C) Special licenses are required to work with radioisotopes.
D) These methods are both more sensitive and require no special license.
E) All of these are advantages.

Question 5

Which of the following best describes electrophoretic gels used for DNA?

A) Most separations are done horizontally, while sequencing gels are typically run vertically.
B) Most separations are done vertically, while sequencing gels are typically run horizontally.
C) Most electrophoretic gels are run horizontally, whether for separation or sequencing.
D) Most electrophoretic gels are run vertically, whether for separation or sequencing.

Question 6

Fluorescent techniques can detect concentrations as low as

A) molar (10¹ M).
B) micromolar (10^-6 M).
C) picomolar (10^-12 M).
D) attamolar (10^-18 M).

Question 7

Restriction enzymes are especially useful for genetic recombination work for all of the following reasons,except:

A) They cut DNA in the middle of specific sequences.
B) They cut DNA independent of the source of the DNA.
C) They often generate single stranded tails or "sticky ends".
D) There are a large variety of them commercially available.
E) All of these traits make restriction enzymes useful.

Question 8

A plasmid is

A) a virus that infects bacteria.
B) a piece of DNA derived from two or more sources.
C) a small circular DNA that is not part of a bacterial chromosome.
D) an artificially created cytoplasm.

Question 9

Which of the following parameters affects the distance DNA molecules migrate during electrophoresis,at pH = 8?

A) The mass of the DNA
B) The total ionic charge on the DNA molecule
C) The fact that each nucleotide contributes one negative charge at this pH.
D) The concentration of agarose or polyacrylamide in the gel.
E) All of these features control the distance the DNA migrates.

Question 10

A highly useful method for determining the presence of hydrolyzed fragments of DNA separated by electrophoresis is

A) autoradiography.
B) x-ray crystallography.
C) analytical ultracentrifugation.
D) all of the above

Question 11

SyBr green and SyBr gold were developed because

A) ethidium bromide is not sensitive enough for modern research
B) they allow faster electrophoretic separations of DNA
C) they fluoresce with RNA as well as DNA, while ethidium bromide does not
D) ethidium bromide is carcinogenic

Question 12

Enzymes that seal nicks in DNA are called

A) restriction enzymes.
B) bacteriophages.
C) ligases.
D) exonucleases.

Question 13

An isoschizomer is a(n)

A) a DNA sequence that is identical to one in a different organsim
B) a DNA sequence from a virus that mimics a sequence in bacteria
C) enzyme that cuts DNA from the 3' end
D) a restriction enzyme that has the same sequence specificity as another restriction enzyme from a different organism
E) none of these is correct

Question 14

Which of the following are methods used to determine where the DNA bands are located on an electrophoresis gel?

A) Radioactivity
B) Fluorescence
C) Dyes which bind to DNA
D) Luminescence
E) All of these can visualize the DNA

Question 15

When fluorescence detection methods are used in biotechnology they

A) have limitations due to low sensitivity
B) can be used for only one substance at a time
C) are not used in DNA sequencing
D) do not present the hazards associated with radioactivity

Question 16

The "natural" function of restriction endonucleases is to

A) protect bacterial cells from invasion by viruses (bacteriophages).
B) help bacteriophages infect cells.
C) regulate gene expression from specific promoters.
D) remove chromatin from histones.

Question 17

Ethidium bromide slips between the bases of DNA giving it fluorescent properties that differ from those observed when it is free in solution.

Question 18

Migration of DNA during electrophoresis is based

A) mostly on the size of the molecule, since the ratio of charge to mass is approximately the same, no matter how large the DNA is.
B) mostly on the charge of the molecule, since the ratio of charge to mass is approximately the same, no matter how large the DNA is.
C) mostly on the charge-to-mass ratio since this can vary greatly among pieces of DNA.
D) on parameters not understood well.

Question 19

A single clone of interest can be distinguished from others in a mixture of clones by

A) testing the clones for antibiotic resistance.
B) mobility of the clones in gel electrophoresis.
C) a specific probe, usually a labeled complementary DNA.
D) resistance to damage by ultraviolet light.

Question 20

A palindrome is

A) a DNA sequence that contains only one kind of base
B) a DNA sequence that contains only two kinds of bases
C) a sequence that reads the same from left to right or from right to left
D) none of the above

Question 21

Cells that contain a "blue/white screening" plasmid that has an added gene are recognized by the method:

A) Ability to grow on ampicillin.
B) Inability to grow on ampicillin.
C) The colonies have a blue color.
D) The colonies lack a blue color.
E) More than one of these choices indicates that the plasmid contains recombined DNA.

Question 22

Exhibit 13A This is a map of the pBR322 plasmid,numbers on the map refer to the base where the site is located.

Refer to Exhibit 13A.If the region between the 2 sites for HgiEII were deleted,the resulting plasmid

A) would be useless as it would lack an origin of replication.
B) would work well for cloning.
C) would be about 2.6 kb in length.
D) would confer resistance to ampicillin but not tetracycline.

Question 23

The presence of bacterial or viral clones is detected experimentally by

A) the presence of colonies or plaques on a suitably prepared Petri dish.
B) gel electrophoresis.
C) analytical ultracentrifugation.
D) x-ray crystallography.

Question 24

A multiple clonic site is also known as:

A) a polylinker
B) an origin of replication
C) a restriction enzyme site
D) a selectable marker

Question 25

Exhibit 13A This is a map of the pBR322 plasmid,numbers on the map refer to the base where the site is located.
Refer to Exhibit 13A.If a recombinant plasmid were obtained inserting DNA into the AflIII site,the recombinant plasmid would lack which of the following properties?

A) It can replicate autonomously.
B) It will be resistant to the antibiotic tetracycline.
C) It will be resistant to the antibiotic ampicillin.
D) It will possess at lest two promoter sites.
E) All of these are true for the recombined plasmid.

Question 26

During the simplest type of genetic recombination,there is a ____ chance that the gene will be inserted in the correct direction.

A) 10%
B) 25%
C) 50%
D) 75%
E) 100%

Question 27

Which of the following is not required in order for a plasmid to be used in genetic recombination?

A) An "ori" site.
B) A gene to allow for easy screening an isolation of cells which contain the plasmid.
C) A poly-cloning site or multi-cloning site for gene insertion.
D) At least one site for a restriction enzyme to cut.
E) All of these are essential in a plasmid for DNA recombination.

Question 28

Suitable vectors for cloning of recombinant DNA can be

A) bacteriophages.
B) bacterial plasmids.
C) both of these.
D) neither of these.

Question 29

Recombinant DNA molecules contain covalently linked segments derived from two or more sources.

Question 30

Exhibit 13A This is a map of the pBR322 plasmid,numbers on the map refer to the base where the site is located.
Refer to Exhibit 13A.If the plasmid were completely digested with the two restriction enzymes BamHI and HgiEII,the resulting fragments would be this large:

A) 1920, 1305, 761, and 377 base pairs long.
B) 1920, 1682 and 761 base pairs long.
C) 1920, 1680 and 761 base pairs long.
D) 3056, 2295 and 375 base pairs long.
E) The sizes cannot be determined from the data given.

Question 31

Multi-cloning sites ("poly-linkers") in most commercially available plasmids offer all the following advantages over the earlier plasmids used in genetic recombination except:

A) They can be used with a wide variety of restriction enzymes.
B) They assure that only the desired DNA will be inserted into the plasmid.
C) They enable easy control of the direction of insertion of the gene of interest.
D) They are usually adjacent to any necessary promoters for gene expression.
E) All of these are advantages.

Question 32

Exhibit 13A This is a map of the pBR322 plasmid,numbers on the map refer to the base where the site is located.
Refer to Exhibit 13A.If a recombinant plasmid was obtained inserting DNA into the BamHI site,screening for the recombinant plasmid can be done by the following technique.

A) Plate on nutrient agar plates that contain ampicillin.
B) Plate on nutrient agar plates that contain tetracycline.
C) Plate on nutrient agar plates that contain both ampicillin and tetracycline.
D) Plate on nutrient agar plates that contain ampicillin, followed by replica plating on tetracycline.
E) Plate on nutrient agar plates that contain tetracycline, followed by replica plating on ampicillin.

Question 33

The following steps are all involved in genetic recombination: 1.Screening for cells that contain the recombined gene.
2)Cutting the vector with restriction enzyme.
3)Mixing the gene of interest with the vector.
4)Isolating the gene of interest from its original source.
5)Ligating the gene of interest and the vector together.
The following sequence of these five steps would be typical:

A) 1 2 3 4 5
B) 2 3 5 1 4
C) 5 4 3 2 1
D) 4 2 3 5 1
E) 2 3 5 4 1

Question 34

In recombinant DNA technology

A) vectors are used as carriers for recombinant genes.
B) it is possible to insert eukaryotic genes into prokaryotic DNA.
C) foreign DNA is frequently inserted into a bacterial plasmid.
D) all of these

Question 35

Which of the following are methods by which bacteria can be induced to take up recombinant DNA molecules?

A) Heat shock.
B) DNA "guns" which spray the DNA at very high speeds.
C) Electroporation
D) Phage or virus infection.
E) All of these are used to transform bacteria.

Question 36

Antibiotic-resistance genes in vectors are often used as selectable markers.

Question 37

Exhibit 13A This is a map of the pBR322 plasmid,numbers on the map refer to the base where the site is located.
Refer to Exhibit 13A.If a recombinant plasmid were obtained inserting DNA into the BamHI site,the recombinant plasmid would lack which of the following properties?

A) It would replicate autonomously.
B) It would be resistant to the antibiotic tetracycline.
C) It would be resistant to the antibiotic ampicillin.
D) It would possess at least two promoter sites.

Question 38

Exhibit 13D The plasmid pSU922 is a circular DNA containing 25000 base pairs.The b-gal gene codes for the enzyme b-galactosidase,the product of which will turn bacterial colonies blue when grown in the presence of X-gal; the Amp^R gene confers ampicillin resistance.
Refer to Exhibit 13D.Which restriction site is best for inserting a DNA fragment for analysis?

A) BamHI
B) EcoRI
C) HindIII
D) They're all equally good.

Question 39

Recombined bacteriophage particles are easy to isolate,since high concentration of phage will be found in each of the bacterial colonies that grow on the medium used for screening.

Question 40

Exhibit 13A This is a map of the pBR322 plasmid,numbers on the map refer to the base where the site is located.
Refer to Exhibit 13A.If a recombinant plasmid were obtained by inserting DNA into the EcoRV site,and the protein corresponding to the recombinant gene were expressed,which of the following statements would be false?

A) The protein will probably contain some extra amino acids on its N-terminal.
B) The plasmid will be resistant to ampicillin.
C) The plasmid will not be able to replicate autonomously.
D) The protein is not likely to be biologically active without some further treatment.
E) The question cannot be answered, since it is unlikely that the protein will be expressed at all, because there is no promoter for mRNA synthesis.

Question 41

How is human insulin produced by genetically engineered bacteria?

A) DNA that codes for each of the two polypeptide chains is introduced into two different populations of bacteria
B) DNA that codes for the insulin precursor is introduced into bacterial plasmids
C) DNA that codes for both the polypeptide chains is introduced into a single population of bacteria
D) This procedure cannot be done.

Question 42

One major obstacle to using bacteria to produce human proteins is bacteria do not have the cellular apparatus to splice introns out of mRNA.

Question 43

Which of the following plants have been genetically modified?

A) Soy beans
B) Corn.
C) Cotton
D) Tomatoes
E) All of these plants have been genetically modified.

Question 44

Which of the following statements about plants which contain the recombinant form of the gene from Bacillus thuringiensis (Bt gene),is true?

A) These plants have a natural resistance to caterpillars.
B) The gene is expressed in all the plant tissues.
C) Since the gene is expressed in the pollen of the plant, there is concern about the gene harming beneficial insects.
D) It is likely that some insects will mutate to become resistant to the Bt gene product.
E) All of these statements are true.

Question 45

Genetic engineering

A) is being used to produce improved crop plants.
B) may provide therapy for diseases of genetic origin.
C) neither of these
D) both of these

Question 46

Exhibit 13D The plasmid pSU922 is a circular DNA containing 25000 base pairs.The b-gal gene codes for the enzyme b-galactosidase,the product of which will turn bacterial colonies blue when grown in the presence of X-gal; the Amp^R gene confers ampicillin resistance.
Refer to Exhibit 13D.In three separate vessels,the plasmid is treated with the restriction endonucleases EcoRI,BamHI,and HindIII.Which of the following best represents the electrophoretic gel one would see from these digests?

A)
B)
C)
D)

Question 47

Which of the following conditions is not a requirement to assure production of a protein when a plasmid is being designed to express a eukaryotic protein in a bacterium?

A) Introns must be deleted from the gene.
B) The cloning site must include an RNA polymerase promoter.
C) The mRNA product must contain a ribosome-binding site.
D) Differences in the genetic code between eukaryotes and prokaryotes must be accommodated.
E) All of these conditions must be met.

Question 48

Which of the following is not a potential benefit of creating a fusion protein in genetic engineering?

A) If a signal peptide is included, the protein may be excreted from the cell, making it easier to isolate.
B) If certain sequences are produced (for example, a histidine oligopeptide), the protein may be isolated by affinity chromatography.
C) The protein is less likely to be antigenic.
D) Both signal peptides and histidine oligomers are useful.
E) All of these reasons are benefits to the protein product.

Question 49

Which of the following proteins has been successfully produced through genetic recombination?

A) insulin
B) human growth hormone
C) tissue plasminogen activator
D) erythropoietin
E) All of the above proteins have been produced successfully.

Question 50

Genetic recombination occurs in nature.

Question 51

When viruses are used as vectors in gene therapy

A) they are not to transform cells taken from the patient's body to give back to the patient
B) they can cause unexpected difficulties
C) both of the above
D) neither of the above

Question 52

How does an expression vector differ from a regular cloning vector?

A) An expression vector does not have an origin of replication.
B) An expression vector is always a linear molecule, while a cloning vector may be circular.
C) An expression vector has the ability to have the inserted DNA be transcribed.
D) An expression vector must be of viral origin, so that it can infect a cell naturally.

Question 53

One major obstacle to using bacteria to produce human proteins is because addition of sugar residues to the proteins,glycosylation,never occurs properly.

Question 54

Exhibit 13D The plasmid pSU922 is a circular DNA containing 25000 base pairs.The b-gal gene codes for the enzyme b-galactosidase,the product of which will turn bacterial colonies blue when grown in the presence of X-gal; the Amp^R gene confers ampicillin resistance.
Refer to Exhibit 13D.Neglecting any discussion of whether it's a good or bad choice,I attempt to insert a gene fragment into the HindIII site and transform bacteria with the plasmid.How can I tell which transformants have the insert?

A) The bacteria will not be able to grow in the presence of ampicillin, and they will be blue.
B) The bacteria will not be able to grow in the presence of ampicillin, and they will be white.
C) The bacteria will be able to grow in the presence of ampicillin, and they will be blue.
D) The bacteria will be able to grow in the presence of ampicillin, and they will be white.

Question 55

Which of the following proteins are produced by recombinant DNA technology but have had their purposes subverted for improving athletic perforrmance?

A) Erythropoietin
B) Human Growth Hormone
C) Insulin
D) Enterokinase
E) Erythropoietin and Human Growth Hormone
F) All of these

Question 56

Genetic engineering which recombines DNA from different species is

A) a molecular extension of traditional cross-breeding methods.
B) only possible with plants.
C) only possible with animals.
D) only possible with bacteria.

Question 57

Which of the following conditions is an example of how genetic engineering is currently used to increase food production?

A) Genetically modified plants have been developed that are resistant to herbicides.
B) Genetically modified plants have been developed which contain a gene that confers a natural resistance to certain insects.
C) Hormones are given to cows to increase milk production.
D) Genetically modified plants have been developed which are resistant to frost.
E) All of these are examples of genetic engineering in agriculture.

Question 58

While a large majority of people are opposed to somatic gene therapy,a large number support the use of germ-cell gene therapy.

Question 59

Modern genetic engineering allows the following manipulation,which was not available using traditional breeding methods:

A) It is now possible to cross different strains or varieties of the same species.
B) It is now possible to include genes from different species, or even different kingdoms in the same organism.
C) It is now possible to produce organisms which are more hardy or which produce bigger or more fruit.
D) The premise of the question is invalid, since there really is no substantive difference between modern genetic engineering and traditional breeding methods.
E) All of these were possible using traditional breeding methods.

Question 60

In gene therapy

A) restriction enzymes are introduced into cells to cleave specific genes.
B) new origins of replication are added to cells to promote cell division.
C) cells of specific tissues are altered in a way that alleviates the effects of a disease.
D) traits are altered so that descendents of those treated will inherit those new traits.

Question 61

The polymerase chain reaction requires

A) primers complementary to the ends of the sequence to be amplified
B) careful temperature control
C) both of these
D) neither of these

Question 62

A DNA library consists of

A) all the DNA of an organism divided up and cloned in suitable vectors
B) an alphabetical list of all the genes in an organism
C) a set of reference books on genetics
D) none of the above

Question 63

In the polymerase chain reaction

A) it is possible to amplify small amounts of DNA without cloning.
B) conditions must be carefully controlled to prevent explosions.
C) reaction mixtures must be kept chilled at all times.
D) all of these

Question 64

The "c" in cDNA stands for this word:

A) Complete.
B) Circular.
C) Complementary.
D) Chromosomal.
E) Confusing.

Question 65

If mRNA is converted to DNA,digested with restriction enzymes,and cloned into suitable vectors,the resultant library is called a:

A) DNA library
B) cDNA library
C) mRNA library
D) none of these

Question 66

A chance to be a forensic scientist.RFLP analysis has been requested by the prosecuting attorney in a murder case.DNA samples have been isolated from a blood sample at the crime scene (C),a hair follicle from the victim's hairbrush (V),and a mouth swab of the accused (A).The results of the test are shown.What would you tell the attorney?

A) The results indicate the accused is guilty.
B) The results indicate the accused is innocent.
C) The results are inconclusive.

Question 67

The RFLP technique

A) is of most use with prokaryotic DNA
B) is of no use on DNA that contains introns
C) is used on the DNA of organisms that have two sets of chromosomes
D) provides fewer genetic markers than classical genetic techniques

Question 68

Slight differences in a given gene between the two homologous chromosomes are called

A) vectors.
B) homologies.
C) alleles.
D) fingerprints.

Question 69

The use of the Bt gene is prohibited in corn plants.

Question 70

Advantages of the Polymerase Chain Reaction include all of these,except:

A) The reaction is specific for certain sequences in the DNA.
B) Only small amounts of template are needed.
C) Results can be obtained with DNA that is old or partially degraded.
D) All the products from a specific part of the DNA will be the same size.
E) All of these are advantages of PCRÒ.

Question 71

Which of the following is true?

A) When DNA evidence is used in crime cases, it is easier to prove that a person is guilty than that they are innocent.
B) When DNA evidence is used in a paternity case, it is easier to prove that a person is the father rather than the person is not the fathere
C) DNA evidence is easier to use to exclude a putative match than to include it
D) none of these is true

Question 72

The best primers for the PCR reaction have the following feature:

A) They have a high G-C content.
B) They have a high A-T content.
C) They should be palindromic.
D) The AT/GC ratio does not matter.
E) They should anneal rapidly, before the larger DNA strands reanneal.

Question 73

A gene from Bacillus thuringiensis (Bt) is used to make plants resistant against all insects which might feed on the plant.

Question 74

An expression library contains genes corresponding to all of the following,except:

A) The mRNA made in a specific cell type.
B) The genes for all the proteins found in an organism.
C) The mRNA made in a specific tissue.
D) The genes expressed during a particular developmental stage of the organism.
E) An expression library could be any of these choices.

Question 75

The following item was the most important one for the development of PCR as a commercially successful and widely-used procedure:

A) Taq DNA Polymerase.
B) Heat-resistant DNA.
C) Heat-resistant primers for DNA synthesis.
D) Robotic machines to run the PCRÒ procedure.
E) Heat-resistant nucleoside triphosphate substrates.

Question 76

The usefulness of blotting techniques in molecular biology is that

A) spills of hazardous chemicals are minimized
B) only the substance of interest is transferred to a nitrocellulose disk
C) it directly gives rise to a genetic map
D) transferred material is in the same relative position on the disk as on the original sample

Question 77

Sometimes DNA probes are used to prove that a gene has been incorporated into a eukaryotic genome.The following are all steps used in such a procedure,except:

A) Digestion of the cellular DNA to break it into manageable sizes.
B) Separation of the fragments by gel electrophoresis.
C) Hybridization of a nucleic acid strand complementary to the gene of interest.
D) Elution of the hybridized DNA from the gel for analysis.
E) All of these steps are necessary in probing for the presence of a gene.

Question 78

Expression libraries are most often made from

A) the mRNA found with a given cell or tissue.
B) the genome of a given cell or tissue.
C) the promoters of a given cell or tissue.
D) the DNA of a single chromosome from cell type or tissue.

Question 79

Which of the following is a unique feature of qPCR compared to the original PCR?

A) qPCR uses a DNA polymerase from a heat stable source
B) qPCR requires a primer
C) qPCR allows the reaction to run until all of the primers have been exhausted
D) In qPCR, the speed with which the DNA is produced is used to estimate how much of the original template was in the reaction vessel

Question 80

The following blotting procedure is named for the scientist who invented it:

A) Eastern.
B) Northern.
C) Southern.
D) Western.
E) More than one of these methods is named for the scientist who invented it.