Deck 20: Recombinant Dna Technology

Question 1

Transformation of cells using the technique of heat shock requires which of the following?

A)the use of zinc ions
B)brief electric shock
C)brief exposure to elevated temperature
D)the use of calcium and brief exposure to elevated temperature
E)the use of calcium ions

Answer 1

D

Question 2

Recombinant DNA technologies are methods used to do which of the following?

A)induce homologous recombination inside a cell
B)manipulate DNA for the study of specific sequences
C)combine chromosomes to make them easier to study
D)integrate DNA in computers to make them faster
E)join together DNA molecules from the same source

Answer 2

B

Question 3

Restriction mapping is used to characterize cloned DNA.What does a restriction map tell the researcher about the cloned DNA?

A)The size of the genome the cloned DNA was isolated from.
B)The restricted conditions under which the organism can grow.
C)The number of restriction sites for the specific restriction enzyme.
D)The distances between restriction sites for the specific restriction enzyme.
E)The number of sites and distance between them for the specific restriction enzyme.

Answer 3

E

Question 4

Assume that a plasmid circular is 2800 base pairs in length and has restriction sites for EcoRI at the following locations: 400,700,1400,and 2600.Give the expected sizes of the restriction fragments following complete digestion with EcoRI.

A)200,400,700,1200
B)700,400,1400,2600
C)300,600,700,1200
D)300,700,2200
E)400,1200,1600

Question 5

There are multiple cloning vector types in modern recombinant DNA technology ranging from plasmids to viral vectors.Which vector type is most useful when cloning an insert of approximately 500kb?

A)bacterial plasmid
B)human artificial chromosome
C)yeast artificial chromosome
D)viral vector
E)bacterial artificial chromosome

Question 6

DNA ligase________ .

A)reconnects the bases together between the DNA strands
B)adds bases into a growing DNA molecule
C)removes bases from a DNA molecule
D)reconnects the phosphodiester linkage between bases on the same strand of DNA
E)cuts the DNA to produce sticky or blunt ends

Question 7

A scientist is troubleshooting the synthesis of a cDNA library.The scientist performs both a Northern and a Southern blot.The Northern blot demonstrated the presence of RNA while the Southern blot indicated that no cDNA was present in the sample.What is likely to be the cause of the failed synthesis of the cDNA library?

A)proper primers
B)temperature too cold for annealing
C)too many dNTPs
D)defective reverse transcriptase

Question 8

Which of the following best describes a cloning vector?

A)The direction in which DNA is cloned.
B)The fragment of DNA encoding a gene of interest.
C)A DNA molecule that accepts DNA fragments and replicates the fragment in a host.
D)A DNA molecule that accepts DNA fragments and degrades them in a host.

Question 9

What is necessary to generate a genomic DNA library?

A)Many overlapping fragments of the genome with at least one copy of every DNA sequence in the organism.
B)A single fragment that contains at least one copy of the DNA sequence in the organism's genome.
C)Many fragments of the genome with at least one copy of every DNA sequence in the organism.
D)Many overlapping fragments of the genome with at least one copy of every DNA sequence in the organism's genome.
E)Many fragments of the genome with at least one copy of every DNA sequence in the organism's genome.

Question 10

The following are four processes common to most cloning experiments: i)transforming bacteria
Ii)plating bacteria on selective medium
Iii)cutting DNA with restriction endonucleases
Iv)ligating DNA fragments
Place the components of this list in the order in which they would most likely occur during a cloning experiment

A)iii,iv,i,ii
B)i,ii,iii,iv
C)ii,iii,i,iv
D)iv,i,iii,ii
E)ii,i,iv,iii

Question 11

The genomics era began with the development of which of the following?

A)whole- transcriptome sequencing
B)third- generation sequencing
C)whole- genome sequencing
D)PCR

Question 12

What is the most serious drawback to using library screening to study genetics?

Question 13

When choosing a restriction enzyme for use in recombinant DNA technologies,it is often preferred that the enzyme generate cohesive,or "sticky," ends.Why is this preferred?

A)The sticky ends prevent the DNA from re- annealing to any DNA.
B)The sticky ends make the DNA bind tighter to any cut DNA.
C)The sticky ends stick to the purification medium making the fragments easier to purify.
D)The sticky ends have hydrogen bonds that help re- anneal the cut DNA.
E)The sticky ends do not have hydrogen bonds to help in re- annealing the cut DNA.

Question 14

A plasmid contains a multiple cloning site inside the coding region of the lacZ gene and also contains an ampicillin resistance gene at a separate locus.When cells are transformed with a successfully recombinant plasmid containing a piece of DNA cloned into the multiple cloning site,what color will the colonies be when grown on an agar plate containing ampicillin and X- gal?

A)blue
B)clear
C)white
D)colonies will not grow
E)green

Question 15

If one wishes to clone a gene using typical restriction endonucleases,how does the restriction endonuclease identify the appropriate cut sites in the genome?

A)The endonuclease cannot identify the cut sites.
B)The endonuclease recognizes the gene of interest.
C)The endonuclease cuts randomly in the genome.
D)The endonuclease identifies its specific recognition sequence.

Question 16

A restriction enzyme that uses a six 6 base recognition sequence will cut DNA,on average,every________ bases,if all four nucleotides are present in equal proportions.

A)256
B)4096
C)500
D)1296
E)5000

Question 17

When generating a cDNA library,one may get different sequences returned if samples are taken at different times.Why is this the case?

Question 18

A probe with the sequence 5'- A- T- G- C- C- A- G- T- 3' will serve as a probe for which sequence?

A)3'- T- G- S- C- C- G- T- A- 5'
B)3'- T- A- C- G- G- T- C- A- 5'
C)3'- A- C- T- G- G- C- A- T- 3'
D)3'- A- T- G- C- C- A- G- T- 5'

Question 19

Cloned DNA is useful in studying which areas)of genetic manipulation?

A)learning about translation of a gene
B)determining size of an organism's genome
C)learning about introns
D)learning about the structure and organization of DNA
E)producing commercial products

Question 20

Recognition sequences for restriction enzymes possess the unique quality of being the same when read 5' to 3' on either strand.What is this property called?

A)recombination sequence
B)palindromic sequence
C)consensus sequence
D)gene sequence
E)origin sequence

Question 21

Nucleic acid blotting is commonly used in molecular biology.Northern blotting is used to detect the presence of which type of nucleic acid?

A)ribonucleic acids
B)unnatural nucleic acids
C)deoxyribonucleic acids
D)triphosphate nucleic acids
E)transfer ribonucleic acids

Question 22

Due to single nucleotide polymorphisms SNPs),all humans have a slightly different nucleotide sequence for their genome.Restriction mapping is used in forensic sciences to match DNA evidence to a potential suspect of a crime.How does restriction mapping reduce the likelihood of misidentifying a suspect?

A)SNPs change the genes that are expressed
B)SNPs only remove restriction sites from the genome resulting in a unique "fingerprint" for each person
C)SNPs add and remove restriction sites resulting in a unique "fingerprint" for each person
D)SNPs only add new restriction sites to the genome resulting in a unique "fingerprint" for each person

Question 23

RT- PCR reverse transcription- polymerase chain reaction)can be used to compare gene expression levels during an organism's response to the environment.A scientist monitoring a tetracycline resistance gene will see what response in the expression when the organism is challenged?

A)increased gene expression
B)no change in gene expression
C)decreased gene expression

Question 24

What is the main purpose of a DNA probe?

A)cuts DNA targets
B)hybridizes to a target sequence
C)binds to proteins
D)extend the growing polynucleotide

Question 25

Briefly explain the three major steps in the polymerase chain reaction.

Question 26

A PCR was designed to clone a DNA sequence of 1.5 kb.When the products were run on an agarose gel,there was a smear of bands ranging from 1.5 kb to 6 kb.Which of the following is a reason for this result?

A)one of the primers did not bind
B)the thermocycler malfunctioned
C)the polymerase overran the reverse primer
D)the polymerase denatured

Question 27

In a PCR,the polymerase adds nucleotides to the 3'- hydroxyl of the terminal nucleotide of each primer.Briefly describe how this results in the amplification of the single region of interest in the genome.

Question 28

Third- generation sequencing strategies are based on which of the following?

A)sequencing a single strand of DNA
B)sequencing DNA using PCR
C)sequencing an ensemble of DNA strands with the same sequence
D)sequencing multiple strands of DNA with different sequences to generate a library

Question 29

Genomic libraries are constructed from the fragments generated from a________ digest.

A)incomplete
B)random
C)complete
D)gene specific

Question 30

Fluorescence in situ hybridization is another way to visualize the presence of a nucleotide sequence.Which of the following is an advantage of FISH over Northern and Southern blots?

A)Probes are not needed in FISH.
B)There are no advantages to FISH over Northern and Southern blots.
C)Blotting is not used in FISH.
D)Fluorophores are not used in Northern or Southern blots.

Question 31

During the hybridization/annealing phase of a PCR reaction,the primers bind to the target DNA sequence at a specific temperature.What effect would an increase in the GC content of the primer have on the optimal temperature for annealing the primer to a target DNA sequence?

A)the annealing temperature would increase
B)the annealing temperature would decrease
C)the annealing temperature would remain the same

Question 32

What is the order of the three main steps in a PCR?

A)denaturation,elongation,annealing primers
B)annealing primers,denaturation,elongation
C)elongation,annealing primers,denaturation
D)denaturation,annealing primers,elongation

Question 33

The development of polymerase chain reaction PCR)was a watershed event in recombinant DNA technology.What are two characteristics of PCR that make it such an important development?

Question 34

When a 5- kb circular plasmid is digested with a restriction enzyme that has three recognition sites on the plasmid,how many bands can be visualized on an agarose gel?

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

Question 35

Why are DNA binding dyes such as SYBR green integral to the technique of qPCR?

Question 36

Assume that you have cut 2 DNA with the restriction enzyme HindIII.You separate the fragments on an agarose gel and stain the DNA with ethidium bromide.You notice that the intensity of the stain is less in the bands that have migrated closer to the "+" pole.Give an explanation for this finding.

Question 37

Agarose gels separate DNA fragments based on what property?

A)amount of adenine bases in the sequence
B)charge of the DNA molecule
C)amount of agarose in the DNA
D)size of the fragment

Question 38

Next- generation sequencing takes advantage of the concept of sequencing- by- synthesis.What is sequence- by- synthesis?

A)The use of PCR to incorporate ddNTPs,followed by electrophoresis.
B)The use of a multiwell system and microfluidics to detect incorporated nucleotides at each base.
C)The use of firefly luciferase and pyrophosphate to report on nucleotide incorporation.
D)The use of a single polymerase in a nanopore that reports on a single molecule of synthesized DNA.

Question 39

Sanger sequencing is based on the order in which ddNTPs are added to a growing polynucleotide.Why are ddNTPs integral to the Sanger sequencing method?

A)They have a 3' hydroxyl that allows for extension of the polynucleotide.
B)They do not have a 2' hydroxyl,which does not allow the extension of the polynucleotide.
C)They do not have a 3' hydroxyl,which does not allow the extension of the polynucleotide.
D)They have a 2' hydroxyl that allows for extension of the polynucleotide.

Question 40

Spectral karyotypes take advantage of which of the following?

A)Probes can be made with different radioactive isotopes.
B)Probes can be labeled with different color fluorophores.
C)Chromosomes are different colors under a microscope.
D)Chromosomes can be labeled with different radioactive isotopes.

Question 41

Protospacer adjacent motifs,PAMs,allow bacteria to do which of the following?

A)recognize and integrate foreign DNA
B)recognize and digest foreign DNA
C)recognize proper spacing for bacterial transcription initiation
D)recognize and digest their own DNA

Question 42

High throughput sequencing takes advantage of automated reading of sequencing data.Which of the following assists in automating the sequencing readout?

A)radioactive dNTPs
B)fluorescently tagged ddNTPs
C)fluorescently tagged dNTPs
D)radioactive ddNTPs

Question 43

ddATP,ddTTP,ddCTP,and ddGTP are labeled with red,green,yellow,and blue fluorescent dyes,respectively.A five- base read from a sequencing reaction produced the following color sequence,read by the computer: red,yellow,yellow,green,green.What is the sequence of the template DNA?

A)TGGAA
B)AAGGT
C)ACCTT
D)TTCCA

Question 44

Which of the following describes a "knock- out" organism?

A)An organism that is capable of out- competing another organism.
B)An organism that loses consciousness randomly.
C)An organism that is positive for alleles coding a gene of interest.
D)An organism that is negative for alleles coding a gene of interest.

Question 45

The generation of a knock- out organism generally requires all the following EXCEPT________ .

A)a targeting vector
B)knowledge of the sequence product
C)knowledge of the target sequence
D)a selectable marker
E)embryonic stem cells

Question 46

When performing a sequencing reaction using Sanger sequencing,which ddNTPs must be included in the reaction?

A)ddGTP
B)ddCTP
C)ddATP
D)ddTTP
E)all four ddNTPs must be present

Question 47

Transgenic animals are useful in studying the effects of a gene product on the organism's phenotype.Briefly describe how you would study the effect of overexpression of a pancreatic enzyme using a transgenic animal.

Question 48

A knock- out mouse is made with respect to the PFKL gene,and this mouse is now described as which of the following?

A)a gain- of- function PFKL mouse
B)an enhancement- of- function PFKL mouse
C)a loss- of- function PFKL mouse
D)a retention- of- function PFKL mouse

Question 49

Which of the following is not a common system for generating knock- out organisms?

A)homologous recombination
B)CRSPR- CAS
C)cre- lox
D)transformation

Question 50

Conditional knock- out organisms provide which advantage over full knock- out organisms?

A)They allow scientists to render the organism unconscious at any time.
B)They allow scientists to turn the gene off at any time during the organism's development.
C)They allow scientists to study genome size.
D)They allow scientists to turn on the gene at any time during the organism's development.

Question 51

What is the function of a ddNTP in DNA sequencing?

A)termination of DNA synthesis
B)methylation of guanine
C)provide a 3' hydroxyl for continued elongation
D)enhancing the processivity of the polymerase

Question 52

The CRISPR- Cas system of gene editing is based on what naturally occurring biological process?

A)viral defense against eukaryotic defenses
B)bacterial defense against viral infection
C)eukaryotic defense against viral infection
D)viral defense against bacterial defenses