Question 1

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

Accepted Answer

A) True 
 B)False  False

Question 2

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. 
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. C

Question 3

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. 
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. D

Question 4

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. 
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.

Question 5

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. 
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.

Question 6

Transposons are frequently used as cloning vectors.

Accepted Answer

A) True 
 B)False

Question 7

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. 
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.

Question 8

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. 
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.

Question 9

Restriction endonucleases were discovered by

Accepted Answer

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

Question 10

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/operator 
A) metabolic activation 
B) antibiotic resistance 
C) insertion sequence 
D) promoter/operator

Question 11

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. 
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.

Question 12

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 13

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

Question 14

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

Accepted Answer

A) True 
 B)False

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 sequence 
A) introns 
B) exons 
C) enhancers 
D) 3' poly A sequence

Question 16

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. 
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.

Question 17

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 hybridization 
A) Southern blot 
B) End-point PCR 
C) Real-time PCR 
D) DNA hybridization

Question 18

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

Accepted Answer

A) True 
 B)False

Question 19

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

Accepted Answer

A) exonuclease. 
B) endonuclease. 
C) ligase. 
D) methylase. 
A) exonuclease. 
B) endonuclease. 
C) ligase. 
D) methylase.

Question 20

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 sequence 
A) the F factor 
B) a selectable marker 
C) an ARS 
D) a CEN sequence

Exam 17: Recombinant DNA Technology

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

Which of the following is true about restriction endonucleases?

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

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

Transposons are frequently used as cloning vectors.

Cloning a gene involves all of the following except

Restriction endonucleases were discovered by

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

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

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.

The enzyme reverse transcriptase was discovered by

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

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

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?

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

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

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

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

The Evolution of Microorganisms and Microbiology

Microscopy

Bacterial Cell Structure

Archaeal Cell Structure

Eukaryotic Cell Structure

Viruses and Other Acellular Infectious Agents

Microbial Growth

Control of Microorganisms in the Environment

Antimicrobial Chemotherapy

Introduction to Metabolism

Catabolism: Energy Release and Conservation

Anabolism: the Use of Energy in Biosynthesis

Bacterial Genome Replication and Expression

Regulation of Bacterial Cellular Processes

Eukaryotic and Archaeal Genome Replication and Expression

Mechanisms of Genetic Variation

Microbial Genomics

Microbial Taxonomy and the Evolution of Diversity

Archaea

The Deinococci, Mollicutes, and Nonproteobacterial Gram-Negative Bacteria

The Proteobacteria

Firmicutes: The Low G-C Gram-Positive Bacteria

Actinobacteria: the High G-C Gram-Positive Bacteria

Protists

Fungi Eumycota

Viruses

Biogeochemical Cycling and Global Climate Change

Methods in Microbial Ecology

Microorganisms in Marine and Freshwater Ecosystems

Microorganisms in Terrestrial Ecosystems

Microbial Interactions

Innate Host Resistance

Adaptive Immunity

Pathogenicity and Infection

Clinical Microbiology and Immunology

Epidemiology and Public Health Microbiology

Human Diseases Caused by Viruses and Prions

Human Diseases Caused by Bacteria

Human Diseases Caused by Fungi and Protists

Microbiology of Food

Biotechnology and Industrial Microbiology

Applied Environmental Microbiology

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