Question 1

A molecular biologist treats a 600-kb length of linear DNA with HindIII restriction endonuclease.Following gel electrophoresis,the biologist observes that there is only one band on the gel corresponding with the migration distance of the 200-kb molecular weight marker.Assuming that no procedural errors were made,what can be concluded from these results?

Accepted Answer

A)  Two HindIII recognition sequences were present in the original DNA.
B)  Three HindIII recognition sequences were present in the original DNA.
C)  There were no HindIII recognition sequences present in the original DNA.
D)  One HindIII recognition sequence was present in the original DNA.E) A) and D)
F) None of the above

Question 2

Cloning a gene involves all of the following except

Accepted Answer

A)  isolating the fragment of DNA containing the desired gene.
B)  insertion of the gene into an appropriate vector.
C)  expression of the vector and the gene in a cell-free environment.
D)  introducing ligated DNA into
E)  coli cells.F) A) and C)
G) B) and C)

Question 3

When separating DNA fragments by gel electrophoresis,what is the purpose of including molecular weight markers?

Accepted Answer

A)  Markers are used as a control to determine the relative size of restriction fragments.
B)  Markers provide an indication as to the total number of restriction fragments on the gel.
C)  Markers are needed to estimate the relative charges on each of the restriction fragments.
D)  Markers ensure that fragments having a greater molecular weight migrate at the same rate as those having a lighter molecular weight.E) All of the above
F) B) and D)

Question 4

Which of the following is true about restriction endonucleases?

Accepted Answer

A)  They make a blunt cut on the two DNA strands so that there are no single-strand regions.
B)  They make staggered cuts on the DNA so that single-strand ends are formed that can be used to insert foreign DNA cut with the same enzyme.
C)  Some make a blunt cut on the two DNA strands so that there are no single-strand regions and some make staggered cuts on the DNA so that single-strand ends are formed that can be used to insert foreign DNA cut with the same enzyme.
D)  Depending on the incubation conditions,the same enzyme can either make a blunt cut on the two DNA strands so that there are no single-strand regions OR make staggered cuts on the DNA so that single-strand ends are formed that can be used to insert foreign DNA cut with the same enzyme.E) None of the above
F) B) and D) C

Question 5

Which of the following PCR procedures includes all of the others?

Accepted Answer

A)  DNA is amplified for one cycle.
B)  DNA is denatured at 95oC.
C)  DNA is reannealed at 50oC
D)  Primers are extended at 72oC.E) B) and C)
F) A) and D)

Question 6

Electroporation is commonly used to introduce recombinant DNA molecules into cells.

Accepted Answer

A) True 
 B)False

Question 7

Transposons are frequently used as cloning vectors.

Accepted Answer

A) True 
 B)False

Question 8

An enzyme that cleaves internal phosphodiester bonds of a DNA molecule is a (n)

Accepted Answer

A)  exonuclease.
B)  endonuclease.
C)  ligase.
D)  methylase.E) A) and B)
F) C) and D)

Question 9

You and a friend are student assistants in a research laboratory that investigates the anti-cancer properties of proteins isolated from marine organisms.Your friend mentions that she is using a BAC vector to insert shark DNA into Escherichia coli,but after repeated attempts,has found that the bacterial cells fail to synthesize the encoded protein.What is your advice?

Accepted Answer

A)  If the shark DNA is unmodified,it contains introns that are not recognized by bacteria,therefore protein synthesis will not occur.
B)  Since shark DNA is eukaryotic,the cloning vector should be a YAC derived from yeast rather than a BAC derived from bacteria.
C)  It is impossible to clone eukaryotic DNA into a bacterial host,since eukaryotic DNA has introns and prokaryotic DNA does not.
D)  Because Escherichia coli is not naturally competent,it cannot serve as the cloning host for foreign DNA.E) B) and C)
F) C) and D)

Question 10

The enzyme reverse transcriptase was discovered by

Accepted Answer

A)  Arber and Smith.
B)  Jackson,Symons,and Berg.
C)  Boyer and Cohen.
D)  Temin and Baltimore.E) B) and C)
F) C) and D)

Question 11

When a eukaryotic gene is expressed in a bacterium,the eukaryotic regulatory sequences should be maintained in order to achieve maximum expression of the gene.

Accepted Answer

A) True 
 B)False

Question 12

Which procedure is most useful in quantifying the active transcription of botulism toxin genes in a can of food that is contaminated?

Accepted Answer

A)  Southern blot
B)  End-point PCR
C)  Real-time PCR
D)  DNA hybridizationE) All of the above
F) C) and D)

Question 13

The thermostable enzyme most commonly used in PCR is reverse transcriptase.

Accepted Answer

A) True 
 B)False  False

Question 14

Restriction endonucleases were discovered by

Accepted Answer

A)  Arber and Smith.
B)  Jackson,Symons,and Berg.
C)  Boyer and Cohen.
D)  Temin and Baltimore.E) B) and C)
F) C) and D)

Question 15

In order to express eukaryotic genes in a bacterium,the __________ must first be removed.

Accepted Answer

A)  introns
B)  exons
C)  enhancers
D)  3' poly A sequenceE) None of the above
F) A) and B)

Question 16

Promoters for genes that code for proteins can be isolated from a cDNA library.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following best describes the basis for separation of DNA fragments during agarose gel electrophoresis?

Accepted Answer

A)  The fragments with the highest percentage of G and C will migrate fastest.
B)  The fragments with the highest percentage of A and T will migrate fastest.
C)  The largest fragments will migrate fastest.
D)  The smallest fragments will migrate fastest.E) All of the above
F) A) and B) D

Question 18

Plasmid vectors often contain __________ genes that can be used to screen for recombinants.

Accepted Answer

A)  metabolic activation
B)  antibiotic resistance
C)  insertion sequence
D)  promoter/operatorE) B) and C)
F) A) and B)

Question 19

Which of the following is not part of a yeast artificial chromosome (YAC) ?

Accepted Answer

A)  the F factor
B)  a selectable marker
C)  an ARS
D)  a CEN sequenceE) B) and D)
F) All of the above

Question 20

A microbiologist would like to use a noncompetent genus of streptococcal bacteria,Enterococcus faecalis,as a cloning host to express genes from Streptococcus pneumoniae,which is naturally competent.Is this possible?

Accepted Answer

A)  Yes; electroporation or chemical transformation can be used to make Enterococcus competent,and then genes from Streptococcus can be introduced via a cloning vector.
B)  Yes; electroporation or chemical transformation can be used to make non-competent Streptococcus mutants,from which genes can be inserted into a cloning vector and introduced into Enterococcus.
C)  No; competence factor is an essential protein that enables the uptake of foreign DNA,therefore a cloning host such as Enterococcus that lacks competence factor protein is unable to be transformed by electroporation or chemical transformation.
D)  Yes; since the cloning host and the DNA to be introduced are both from bacteria that are streptococci,natural competence in this case is not necessary as long as the appropriate vector is used.E) B) and C)
F) None of the above

Exam 17: Recombinant DNA Technology

Correct Answer
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Cloning a gene involves all of the following except

Correct Answer
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When separating DNA fragments by gel electrophoresis,what is the purpose of including molecular weight markers?

Correct Answer
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Which of the following is true about restriction endonucleases?

Correct Answer
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C

Which of the following PCR procedures includes all of the others?

Correct Answer
verified

Electroporation is commonly used to introduce recombinant DNA molecules into cells.

Correct Answer
verified

Transposons are frequently used as cloning vectors.

Correct Answer
verified

An enzyme that cleaves internal phosphodiester bonds of a DNA molecule is a (n)

Correct Answer
verified

Correct Answer
verified

The enzyme reverse transcriptase was discovered by

Correct Answer
verified

When a eukaryotic gene is expressed in a bacterium,the eukaryotic regulatory sequences should be maintained in order to achieve maximum expression of the gene.

Correct Answer
verified

Which procedure is most useful in quantifying the active transcription of botulism toxin genes in a can of food that is contaminated?

Correct Answer
verified

The thermostable enzyme most commonly used in PCR is reverse transcriptase.

Correct Answer
verified
False

Restriction endonucleases were discovered by

Correct Answer
verified

In order to express eukaryotic genes in a bacterium,the __________ must first be removed.

Correct Answer
verified

Promoters for genes that code for proteins can be isolated from a cDNA library.

Correct Answer
verified

Which of the following best describes the basis for separation of DNA fragments during agarose gel electrophoresis?

Correct Answer
verified
D

Plasmid vectors often contain __________ genes that can be used to screen for recombinants.

Correct Answer
verified

Which of the following is not part of a yeast artificial chromosome (YAC) ?

Correct Answer
verified

A microbiologist would like to use a noncompetent genus of streptococcal bacteria,Enterococcus faecalis,as a cloning host to express genes from Streptococcus pneumoniae,which is naturally competent.Is this possible?

Correct Answer
verified

Exam 17: Recombinant DNA Technology

Correct AnswerverifiedShow Answer

Cloning a gene involves all of the following except

Correct AnswerverifiedShow Answer

When separating DNA fragments by gel electrophoresis,what is the purpose of including molecular weight markers?

Correct AnswerverifiedShow Answer

Which of the following is true about restriction endonucleases?

Correct AnswerverifiedC

Which of the following PCR procedures includes all of the others?

Correct AnswerverifiedShow Answer

Electroporation is commonly used to introduce recombinant DNA molecules into cells.

Correct AnswerverifiedShow Answer

Transposons are frequently used as cloning vectors.

Correct AnswerverifiedShow Answer

An enzyme that cleaves internal phosphodiester bonds of a DNA molecule is a (n)

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The enzyme reverse transcriptase was discovered by

Correct AnswerverifiedShow Answer

When a eukaryotic gene is expressed in a bacterium,the eukaryotic regulatory sequences should be maintained in order to achieve maximum expression of the gene.

Correct AnswerverifiedShow Answer

Which procedure is most useful in quantifying the active transcription of botulism toxin genes in a can of food that is contaminated?

Correct AnswerverifiedShow Answer

The thermostable enzyme most commonly used in PCR is reverse transcriptase.

Correct AnswerverifiedFalse

Restriction endonucleases were discovered by

Correct AnswerverifiedShow Answer

In order to express eukaryotic genes in a bacterium,the __________ must first be removed.

Correct AnswerverifiedShow Answer

Promoters for genes that code for proteins can be isolated from a cDNA library.

Correct AnswerverifiedShow Answer

Which of the following best describes the basis for separation of DNA fragments during agarose gel electrophoresis?

Correct AnswerverifiedD

Plasmid vectors often contain __________ genes that can be used to screen for recombinants.

Correct AnswerverifiedShow Answer

Which of the following is not part of a yeast artificial chromosome (YAC) ?

Correct AnswerverifiedShow Answer

A microbiologist would like to use a noncompetent genus of streptococcal bacteria,Enterococcus faecalis,as a cloning host to express genes from Streptococcus pneumoniae,which is naturally competent.Is this possible?

Correct AnswerverifiedShow Answer

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C

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False

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D

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