Deck 7: Recombinant Dna and Biotechnology

Question 1

In Southern blot hybridization analysis

A) reverse transcriptase is used to synthesize a radioactive nucleic acid probe
B) nick translation is used to obtain a protein-derived probe.
C) DNA is denatured and lifted from the agar surface with a nitrocellulose filter.
D) restriction fragments containing a specific nucleotide sequence can be identified.
E) DNA fragments are resolved on a CsCl density gradient.

Answer 1

restriction fragments containing a specific nucleotide sequence can be identified.

Question 2

PCR is used for all of the following EXCEPT

A) detection of exon deletions.
B) amplification of a target DNA sequence.
C) in vivo correction of a mutated gene.
D) detection of trinucleotide repeat expansions.

Answer 2

in vivo correction of a mutated gene.

Question 3

The genomic DNA library

A) contains DNA sequences from all species.
B) contains plasmid DNA copies of human total RNA.
C) contains amplified copies of a specific gene.
D) is often constructed using phage lambda.
E) is often screened by Southern blot hybridization.

Answer 3

is often constructed using phage lambda.

Question 4

For an expression vector that will be used to produce mRNA in a prokaryotic system, which of the following is not required?

A) origin of replication.
B) selectable marker.
C) bacterial promoter.
D) polyadenylation signal.
E) Shine_Dalgarno sequence.

Question 5

RFLP linkage analysis followed by chromosome walking is used to find disease-causing genes. Which of the following would be a good indication that the disease-causing gene has been found by this analysis?

A) The gene is at least one cM from the RFLP.
B) The gene is homozygous in the affected individual.
C) The gene contains a nonsense mutation.
D) The gene is heterozygous in the individual.
E) The gene contains numerous polymorphisms.

Question 6

M17476PCR (Polymerase Chain Reaction) products are of discrete length because

A) Taq polymerase can synthesize only 1000 base pairs of DNA at a time.
B) polymerization proceeds to the ends of the DNA.
C) Taq polymerase is denatured after each cycle is complete.
D) the DNA is cut with restriction enzymes prior to PCR.
E) the reaction contains a limiting amount of nucleoside triphosphate precursors.

Question 7

All of the following are used to construct genomic libraries EXCEPT

A) DNA ligase.
B) bacteriophage lambda.
C) reverse transcriptase.
D) restriction enzymes.

Question 8

M17482Reverse transcriptase is employed in cDNA cloning as a

A) terminal transferase.
B) ligase.
C) RNA-dependent DNA polymerase.
D) DNA-dependent RNA polymerase.
E) kinase.

Question 9

Segments of pure samples of identical, relatively short DNA molecules from plasmids can be subdivided into smaller pieces by

A) Southern blot analysis.
B) colony hybridization.
C) restriction enzyme digestion.
D) agarose gel electrophoresis.
E) ethidium bromide treatment.

Question 10

Yeast artificial chromosome vectors contain all of the following EXCEPT

A) centromeric sequences.
B) telomeric sequences.
C) an origin of replication.
D) a locus control region.
E) a selectable marker gene.

Question 11

Restriction enzymes have all of the following properties EXCEPT

A) they cleave double stranded DNA.
B) they modify DNA by methylation.
C) they recognize specific DNA sequences.
D) they cleave DNA, producing staggered ends.

Question 12

Screening a recombinant DNA library using an 125I-labeled antibody prepared against a eukaryotic protein

A) requires that cDNA inserts have been used in the library being screened.
B) requires the utilization of vector sequences that provide high efficiency translation of the cloned insert DNA including signals for initiation and termination of translation.
C) requires the utilization of vector sequences that provide high efficiency transcription of the cloned insert DNA including signals for initiation and termination of transcription.
D) will isolate any gene that encodes a protein product recognized by the antibody.
E) all of the above statements are true.

Question 13

A technique that is used to determine the abundance of a particular mRNA is

A) gel shift assay.
B) dideoxy chain termination.
C) Southern blotting.
D) DNA ligation.
E) Northern blotting.

Question 14

In the dideoxy method of DNA sequencing, the dideoxy analog

A) allows specific chemical cleavage of the DNA strand at random sites.
B) is required for the synthesis of the primer.
C) causes termination of DNA chain elongation.
D) cannot be utilized by DNA polymerase.
E) lacks a 5' phosphate group.

Question 15

Allele-specific oligonucleotide (ASO) analysis is used primarily for

A) identification of point mutations.
B) detection of deleted exons.
C) linkage analysis.
D) detection of trinucleotide repeat expansions.

Question 16

All of the following are TRUE regarding restriction endonucleases EXCEPT

A) they recognize specific palindromic sequences.
B) they may produce staggered ends when they cleave DNA into fragments.
C) they may produce flush ends when they cleave DNA into fragments.
D) they are used in gene cloning to cleave the single stranded regions of the cDNA produced by reverse transcriptase.
E) they are used to cleave plasmid DNA in specific places in gene cloning experiments.

Question 17

Restriction enzymes are:

A) DNA polymerases
B) RNA polymerases
C) endonucleases
D) exonucleases
E) none of the above

Question 18

According to the Holliday model, the initial steps in recombination are which of the following?

A) Double strand breakage and rejoining of nonhomologous chromosomes
B) Double_strand breakage and rejoining of homologous chromosomes
C) Single-strand breakage and strand transfer between non-homologous chromosomes
D) Single_strand breakage and strand transfer between homologous chromosomes

Question 19

A technique that is used to determine the abundance of a particular mRNA is

A) gel shift assay.
B) dideoxy chain termination.
C) Southern blotting.
D) DNA ligation.
E) Northern blotting.

Question 20

Reverse transcriptase and terminal deoxynucleotidyl transferase are used in gene cloning to

A) remove single stranded DNA and repair the restriction enzyme site after transformation respectively.
B) make cDNA and create sticky ends on the cDNA and the staggered ends of the cleaved restriction site.
C) repair the restriction enzyme site before transformation.
D) repair the restriction enzyme site after transformation.
E) remove the sticky ends prior to the DNA ligase step.

Question 21

Which of the following statements about homologous recombination is TRUE?

A) recombination can only occur at Chi sites
B) recombination only occurs at specific DNA sequences
C) recombination requires a single_stranded region and a duplex DNA region with closely related DNA sequence
D) recombination requires an RNA intermediate
E) recombination is site-specific

Question 22

Accessibility of DNA to trans-acting molecules is, in general, reduced by its being packaged into a nucleosome core, both in vitro and in vivo. A prominent exception to this is the behavior of:

A) The TATA box-binding protein, TBP, which binds within the minor groove.
B) Retrovirus proviral DNA, which integrates within the major groove.
C) Topoisomerase II, which binds to the sugar-phosphate backbone.
D) SV40 large T-antigen, which binds to the major groove.
E) None of the above.

Question 23

Segments of pure samples of identical, relatively short DNA molecules from plasmids can be subdivided into smaller pieces by

A) Southern blot analysis.
B) Colony hybridization
C) Restriction enzyme digestion.
D) Agarose gel electrophoresis.
E) Ethidium bromide treatment

Question 24

Applications using transgenic mice include all of the following EXCEPT

A) rescue of mutants.
B) generation of chemically_induced mutant loci.
C) synthetic bioreactors.
D) testing drug or gene therapies.
E) studies of structure_function relationships.

Question 25

Which of the following enzymes can be used for the construction of a recombinant DNA molecule in vitro?

A) DNA polymerase + DNA ligase
B) DNA polymerase + RNA polymerase
C) Restriction enzyme + DNA ligase
D) Phosphorylase + DNA ligase
E) Acetylase + single stranded DNA specific deoxyribonuclease

Question 26

Which of the following techniques can be used to screen the general population for a single base-pair mutation in disease-causing gene?

A) RFLP linkage analysis
B) Allele specific oligonucleotide (ASO) analysis
C) Fluorescence in situ hybridization (FISH)
D) Multiplex PCR

Question 27

Human genomic libraries would be expected to contain all of the following EXCEPT

A) introns.
B) exons.
C) promoters.
D) spliced sequences.
E) Alu sequences.

Question 28

Two general types of viral vectors utilized frequently for gene therapy include.

A) bacteriophage and HIV
B) DNA viruses and RNA viruses
C) adenoviruses and foamy viruses
D) influenza viruses and liposomes

Question 29

Topoisomerase I

A) unwinds double stranded DNA by breaking base pairs
B) will decrease the writhing number of negatively supercoiled DNA
C) will decrease the linking number of negatively supercoiled DNA
D) nicks one strand of double stranded DNA
E) cuts both strands of double stranded DNA

Question 30

In the preparation of labeled probes, which steps do nick-translation and random oligonucleotide priming have in common?

A) Labeling reactions are initiated by synthetic oligonucleotides.
B) The incorporation of labeled precursor involves an in vitro DNA replication reaction.
C) Nuclease activity can degrade newly synthesized, labeled DNA.
D) They both incorporate -labeled ribonucleotides.

Question 31

DNA sequencing by the Sanger technique makes use of ____________for chain termination.

A) dNTPs
B) dideoxynucleotides
C) AZT
D) DNA polymerase

Question 32

Recombination does not

A) play a role in the repair of DNA.
B) generate new combinations of genes.
C) generate point mutations.
D) regulate the expression of DNA.
E) involve single strand breaks.

Question 33

Which one of the following statements about Southern blot analysis is true?

A) It will identify which RNA in a population is complementary to a specific DNA probe.
B) It is used to purify a gene by electrophoretic separation from a population of genes.
C) It is useful for repetitive DNA but not unique sequence DNA.
D) It is used to amplify a specific DNA sequence in vitro.
E) It identifies a specific fragment of DNA based on complementarity to a radioactive DNA probe.

Question 34

Recombinant DNA techniques currently can be used for all of the following except

A) preparation of large amounts of DNA for structural analysis.
B) preparation of proteins such as alpha globin, insulin, and interferon.
C) creation of phage collections which, in total, represent the entire genome of an organism.
D) prenatal identification of some genetic diseases.
E) repair of genetic damage caused by radiation.

Question 35

In constructing a genomic DNA library, limited digestion with a restriction enzyme that recognizes and cuts a 4 base pair sequence

A) ensures that the DNA fragments being cloned are very small.
B) ensures that introns are separated from exons.
C) generates overlapping fragments of the genome.
D) separates repetitive sequences from unique sequences.

Question 36

Isolation and identification of a disease-causing gene by chromosome walking requires all of the following EXCEPT

A) Genomic library
B) DNA sequence analysis
C) Comparison of the normal and mutant genes
D) Prior knowledge of the protein product
E) Overlapping genomic clones

Question 37

Which of the following statements pertaining to genome organization is true?

A) The fibroin gene undergoes DNA amplification within moth silk gland cells to enable the synthesis of up to 109 silk fibroin proteins per cell.
B) Up to 98% of the human genome encodes proteins and structural RNA's.
C) Histone genes are tandemly repeated and localized in nucleoli.
D) Amplification of protein- encoding genes is commonly seen during amphibian oogenesis, when enormous stores of protein are needed.
E) Eukaryotic chromosomes each consist of a single linear DNA molecule.

Question 38

To obtain recombinant DNA clones that encode a specific protein, a high affinity antibody to that protein can be utilized to screen

A) a cDNA library in pBR.
B) a cDNA library in an expression vector.
C) a genomic DNA library cloned into a YAC vector.
D) a cDNA library cloned into a YAC vector.
E) a genomic DNA library cloned into a phage vector.

Question 39

Which of the following are not required for expression of a human cDNA cloned in

A) promoter
B) ribosome binding site
C) initiation codon
D) DNA-dependent RNA polymerase II
E) coli?

Question 40

Reverse transcriptase catalyzes which of the following reactions?

A) synthesis of ribosomal RNA from pre-existing ribosomal RNA
B) synthesis of RNA primers for Okazaki fragments
C) synthesis of RNA using a single stranded RNA template
D) synthesis of mRNA from double stranded viral RNA
E) synthesis of DNA using a RNA template

Question 41

DNA sequencing makes use of

A) chemical base-modification reactions to fragment the DNA.
B) base-specific enzymes to obtain the sequence.
C) families of restriction enzymes of known specificity to obtain the sequence.
D) alkaline hydrolysis and thin layer chromatography to obtain the base composition.
E) reassociation kinetics to determine the sequence complexity of DNA.

Question 42

Eukaryotic chromosomes are characterized by each of the following, EXCEPT

A) contain negatively supercoiled DNA.
B) consist of linear DNA polynucleotide chains.
C) contain both repetitive and nonrepetitive DNA.
D) contain nucleosomes spaced approximately 200 bp apart.
E) contain restriction enzymes.

Question 43

Two small plasmids undergoing recombination will look like a figure 8. If they are each cut once at a unique restriction site, they will form a Chi structure. Which of the following will be true

A) each of the arms of the Chi structure will be a different length
B) each of the arms will be the same length
C) two of the arms will be the same length and the other two arms will be the same length
D) three of the arms will be the same length and the fourth arm will be a different length
E) none of the above are true

Question 44

The Holliday model of general recombination provides for

A) exchange of genetic information between nonhomologous chromosomes.
B) reciprocal translocation of unlike DNA between sister chromatids.
C) conversion of one allele to another by DNA repair.
D) exchange of genetic information between homologous chromosomes.

Question 45

DNA libraries contain

A) copies of genes.
B) mRNAs.
C) fragments of genomic DNA.
D) DNA copies of mRNA.
E) intron DNA sequences.

Question 46

Techniques utilized to produce mouse models of human disease include all of the following EXCEPT

A) knock-in mutation.
B) transgenesis.
C) nuclear transfer.
D) transposition.
E) knockout mutation.

Question 47

RFLP analysis can be used for all of the following except

A) classical genetic mapping.
B) DNA fingerprinting.
C) locating a disease gene.
D) prenatal screening for a possible genetic defect.
E) creating a cDNA library.

Question 48

In the Holliday model for recombination, which is not true

A) one of two recombination products are formed depending on how the branch is cleaved
B) strand exchange leads to an intermediate structure with crossed single strands
C) two homologous duplexes are aligned
D) the branch can move along the strands leading to additional strand exchange
E) the strand exchange is initiated by DNase I nicking.

Question 49

The Sanger method of nucleotide sequence determination involves

A) the activity of DNA polymerase
B) the use of chemical agents that modify DNA
C) the transfer of electrophoretically resolved DNA to a nitrocellulose filter.
D) the incorporation of poly dT the 3'-OH end of a DNA strand.

Question 50

It is sometimes possible to design a degenerate oligonucleotide probe for screening a DNA library if the amino acid sequence of the protein is available. These probes are

A) composed of a mixture of different oligonucleotide sequences.
B) composed only of the most frequently used codon for each amino acid.
C) completely random oligonucleotide sequences.
D) small restriction enzyme fragments.

Question 51

RNA-dependent-RNA-polymerases are required by all

A) viruses.
B) non-tumor forming RNA viruses.
C) single stranded RNA viruses.
D) segmented-genome viruses.

Question 52

The best technique for determining on which chromosome a specific human gene is located would probably involve

A) digestion of total human DNA with restriction endonucleases, separation of fragments by gel electrophoresis and hybridization with a labeled gene probe.
B) somatic cell hybridization.
C) isolation of fetal messenger RNA and in vitro translation.
D) None of the above techniques could yield such information.

Question 53

Transgenic animals are defined as

A) Those that have been treated with a drug regimen.
B) Those that are bred for polymorphic alleles of one gene.
C) Clones derived by nuclear transfer.
D) Those that carry a foreign gene that was deliberately inserted into their genomes.
E) Those that are infected with a virus to test vaccine efficacy.

Question 54

Restriction enzymes have all of the following characteristics EXCEPT that they cut

A) DNA sequence specifically.
B) each DNA strand separately.
C) palindromic sequences.
D) DNA using an exonuclease activity.

Question 55

Vector development, design of the corrective gene construct, proliferation and maintenance of target cells, efficient transfection and transport of nucleic acid to the nucleus for integration into the genome, and expansion of engineered cells and implantation into the patient are all examples of

A) challenges to successful gene therapy.
B) techniques used to study developmental regulation.
C) protocols used in the production of transgenic and chimeric mice.
D) problems encountered in the development of pharmaceuticals.

Question 56

For an expression vector that will be used to produce mRNA in a prokaryotic system, which of the following is not required?

A) origin of replication
B) selectable marker
C) bacterial promoter
D) polyadenylation signal
E) Shine-Dalgarno sequence

Question 57

Enzymes necessary for the construction of a recombinant molecule of DNA are

A) restriction endonucleases and DNA ligase.
B) restriction endonucleases and Pol I.
C) Pol I and DNA ligase.
D) recombinase and DNA gyrase.

Question 58

Attenuation is dependent upon all of the following EXCEPT

A) direct physical interaction between the ribosome and RNA polymerase.
B) pausing of a ribosome in the leader peptide due to low levels of an operon-specific charged tRNA.
C) no proteins other than those in ribosomes and RNA polymerase.
D) the formation of a stem loop structure in the nascent mRNA strand that acts as a transcriptional terminator.

Question 59

All of the following statements concerning DNA cloning are true EXCEPT which one?

A) Vectors such as plasmids or bacterial viruses can be used for cloning foreign DNA in bacterial cells.
B) Recombinant molecules between plasmid DNA and foreign DNA can be generated by using restriction endonucleases.
C) cDNA synthesized from the messenger RNA of a desired gene can be cloned.
D) If foreign DNA is inserted into a bacterial plasmid, the recombinant plasmid cannot be used for transforming eukaryotic cells.
E) Some eukaryotic genes can be expressed when transformed into bacteria.

Question 60

Which of the following would be required for the efficient expression of human low density lipoprotein (LDL) in a bacterial host?

A) a cDNA construct encoding LDL, under the control of a bacterial promoter
B) the human gene encoding LDL, under the control of a bacterial promoter
C) a cDNA construct encoding LDL, under the control of the LDL promoter
D) the human gene encoding LDL, under the control of the LDL promoter

Question 61

Which of the following would most likely be found in a recombinant plasmid containing a copy of DNA from a human gene?

A) The entire protein coding sequence of the gene.
B) A sequence complementary to the 3' poly-A tail of the mRNA encoded by the gene.
C) The chromosome containing the gene.
D) A segment of intron DNA.

Question 62

In general, PCR primers need to have which of the following characteristics?

A) Each primer needs to base-pair with a site on one of the two DNA strands.
B) The primers need to base-pair with each other.
C) Each primer needs to base-pair with two sites on each of the two DNA strands.
D) The two primers need to base-pair with sites that are repetitive in the genome.

Question 63

Eukaryotic genes coding for proteins usually have introns. The production of recombinant eukaryotic proteins (insulin, for example) in bacteria does not necessarily pose a problem because

A) bacteria possess the necessary enzymes to correctly process the primary transcript containing intron sequences.
B) a cDNA copy of the mRNA can be cloned and expressed.
C) the protein synthetic machinery of the bacteria will only translate the exon portions of the resulting RNA.
D) the translation of intron regions will not alter the activity of the protein if they are removed by proteolytic processing.

Question 64

Reverse transcriptase has all of the following characteristics EXCEPT that it

A) is a viral DNA polymerase.
B) requires a primer.
C) uses either DNA or RNA as a template.
D) synthesizes both DNA and RNA.

Question 65

A nuclease is an enzyme which catalyzes

A) the synthesis of nucleotides from bases and sugar-phosphates.
B) the hydrolysis of nucleotides to nucleosides and inorganic phosphate.
C) the hydrolysis of cyclic AMP.
D) the synthesis of a polynucleotide chain from nucleotide units.
E) the hydrolysis of internucleotide linkages of a polynucleotide chain.

Question 66

Southern blots are used to analyze DNA that has been fractionated based on difference in

A) length.
B) sequence.
C) GC content.
D) AT content.
E) density.

Question 67

Knockout mice are characterized by all of the following EXCEPT

A) They contain null mutations in mouse genes.
B) They are generated by homologous recombination of a gene targeting vector in embryonic stem cells.
C) The initial mice produced are chimeric.
D) The effects of the mutations are usually pleiotropic.
E) The mutations are usually lethal during the embryonic stage of development.

Question 68

Hybridization (Southern) analysis is best used to

A) compare polypeptide conformation.
B) prepare large, unilamellar lipid vesicles.
C) determine enzyme turnover numbers.
D) establish DNA sequence homologies.
E) investigate ribosome assembly.

Question 69

Jumping clones expedite chromosomal walking by generating inserts that

A) are compatible with YAC vectors.
B) contain non-contiguous but linearly related fragments.
C) can be amplified by the polymerase chain reaction.
D) contain unclonable sequences.

Question 70

Polymerase chain reaction (PCR) results in discrete length products because

A) Taq polymerase can only synthesize DNA of discrete size from any DNA template.
B) the reaction is terminated by denaturation at the same time following each round of polymerization.
C) the primers are of discrete size.
D) of the exponential production of run-off products.
E) the template for amplification is always a specific cloned DNA fragment.

Question 71

Transgenic mouse lines are useful for studies of human disease for all the following reasons EXCEPT

A) Mice are physiologically similar to humans.
B) New diseases can be induced in mice for which there is no human counterpart yet.
C) They allow the study of polygenic disease.
D) Technology advances have increased the ability to create mouse models of human disease.
E) A large reservoir of potential models exists in spontaneous or induced mutant loci.

Question 72

Which ONE of the following single stranded DNA molecules would be understood to contain a palindrome in the double stranded state as this term has been defined for DNA sequence arrangements?

A) ApTpGpCpCpGpTpAp
B) GpCpTpApTpGpApCp
C) ApTpGpCpTpApCpGp
D) GpTpCpApTpGpApCp

Question 73

Construction of a plasmid containing a human beta globin cDNA may involve all of the following EXCEPT

A) isolation of human beta globin mRNA.
B) use of poly dT as a primer for reverse transcriptase.
C) transcription with
D) homopolymer tailing of the cDNA and ligation of the tailed cDNA to the vector.
E) coli RNA polymerase.

Question 74

Bacteria were infected with phages labeled with 35S and then whirled in a food blender. Cells were then separated from the fluid medium supernatant. Which of the following would be true?

A) No radioactivity would be detected in either cells or supernatant.
B) The radioactivity would be found in the progeny phage particles if infection of the cells was allowed to continue.
C) The supernatant fluid would contain most of the radioactivity
D) The radioactivity would be found in the phage DNA within the infected cells

Question 75

DNA libraries are constructed from

A) genomic DNA from specific tissues.
B) reverse transcribed cellular RNA.
C) reverse translated cellular proteins.
D) reverse transcriptase.
E) satellite DNA.

Question 76

Which one of the following properties would make a plasmid an ineffective vehicle?

A) very small size
B) multiple copies are incorporated per cell
C) codes for the protein required for tetracycline resistance
D) contains three sites for the restriction endonuclease to be used

Question 77

In constructing a genomic DNA library, limited digestion with a restriction enzyme that recognizes and cuts a 4 base pair sequence

A) ensures that the DNA fragments being cloned are very small.
B) ensures that introns are separated from exons.
C) generates overlapping fragments of the genome.
D) separates repetitive sequences from unique sequences.

Question 78

Restriction endonucleases

A) digest DNA duplex molecules from the 5'-OH ends.
B) attack only single stranded DNA.
C) have base sequence specificity.
D) randomly digest double stranded DNA molecules.
E) are not produced by bacteria.

Question 79

Reverse transcriptase carries out all of the following activities except?

A) RNA directed DNA synthesis.
B) DNA directed DNA synthesis.
C) DNA directed RNA synthesis.
D) Hydrolysis of RNA.

Question 80

Southern blotting is used for all of the following, EXCEPT

A) to determine restriction fragment sizes.
B) to detect deleted genes.
C) to detect gene rearrangements.
D) to measure mRNA size.