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

Accepted Answer

Heat shock transformation involves the use of calcium ions to make the cell membrane more permeable and a brief exposure to elevated temperature to facilitate the uptake of DNA into the cell.

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

Accepted Answer

Recombinant DNA technologies are used to manipulate DNA for the study of specific sequences. This may involve making changes to DNA using techniques such as cloning, PCR, and gene editing. These methods allow researchers to study the function of genes, investigate genetic diseases, and create new genetically modified organisms.

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.

Accepted Answer

A restriction map tells the researcher about the number and distance between specific restriction sites for the enzyme used to digest the DNA sample. This information is important for determining the size and organization of the DNA molecule, as well as for identifying and mapping specific genes or regions of interest.

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

Accepted Answer

The plasmid is cut at 400, 700, 1400, and 2600 base pairs, resulting in fragments of 300 (700-400), 700 (1400-700), 1200 (2600-1400), and 600 (2800-2600+400) base pairs.

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

Accepted Answer

The answer of There are multiple cloning vector types in...

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

Accepted Answer

DNA ligase is responsible for reconnecting the phosphodiester linkage between bases on the same strand of DNA, particularly during processes such as DNA replication and repair, where breaks in the DNA strand need to be sealed to maintain the integrity of the genetic information.

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

Accepted Answer

The Southern blot indicated that no cDNA was present, which suggests that the reverse transcriptase enzyme did not successfully synthesize cDNA from the RNA sample. Thus, a defective reverse transcriptase is the most likely culprit.

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.

Accepted Answer

A cloning vector is a DNA molecule that can accept foreign DNA fragments and replicate them within a host organism. These vectors are typically designed to include features such as a selectable marker (to identify cells that have taken up the vector), an origin of replication (to allow for replication within the host cell), and a multiple cloning site (to allow for insertion of the foreign DNA fragment).

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.

Accepted Answer

A genomic DNA library requires many overlapping fragments of the genome in order to ensure that every DNA sequence in the organism's genome is represented at least once. These fragments can be generated by cutting the genomic DNA into smaller pieces using restriction enzymes or mechanical shearing, and then cloning these fragments into a suitable vector such as a bacterial artificial chromosome (BAC) or a phage vector. By generating many overlapping fragments, the library can be screened for specific genes or sequences of interest, and the full genome sequence can potentially be reconstructed.

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

Accepted Answer

The correct sequence for a typical cloning experiment is: iii) cutting DNA with restriction endonucleases to create fragments, iv) ligating DNA fragments to insert them into vectors, i) transforming bacteria with the recombinant DNA, and ii) plating bacteria on selective medium to identify those that have taken up the recombinant DNA.

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

Accepted Answer

The genomics era began with the development of whole-genome sequencing, which involves determining the DNA sequence of an entire organism's genome. This was a significant milestone in the field of genomics as it allowed researchers to study an individual's complete genetic makeup and opened up new avenues for understanding genetic diseases and personalized medicine. While PCR (polymerase chain reaction) is an essential tool for amplifying DNA and has numerous applications in genomics, it is not specific to the genomics era. Whole-transcriptome sequencing and third-generation sequencing are also important technologies in genomics, but they were developed later than whole-genome sequencing.

Question 12

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

Accepted Answer

The answer of What is the most serious drawback to...

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.

Accepted Answer

Sticky ends have overhanging sequences that can form hydrogen bonds with complementary sequences on another DNA molecule, facilitating the re-annealing or joining of DNA fragments during the cloning process.

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

Accepted Answer

When grown on agar plates containing X-gal, colonies with a functional lacZ gene will appear blue due to the hydrolysis of X-gal by β-galactosidase. However, if the lacZ gene is interrupted by cloning in the multiple cloning site, the colonies will not produce functional β-galactosidase and will not hydrolyze X-gal, resulting in white colonies. The presence of the ampicillin resistance gene in the plasmid allows only transformed cells with the plasmid to survive on the agar plates containing ampicillin.

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.

Accepted Answer

Restriction endonucleases identify their specific recognition sequence, usually a palindromic sequence of bases, in the genome and cut the DNA at that site. This specific recognition sequence is what allows researchers to target specific genes for cloning.

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

Accepted Answer

A recognition sequence of six bases means that there are 4^6 possible sequences (256). Therefore, on average, the restriction enzyme will cut every 4^6 or 4096 bases.

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?

Accepted Answer

The answer of When generating a cDNA library,one may get...

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'

Accepted Answer

The probe sequence is complementary to option B (3'- T- A- C- G- G- T- C- A- 5'), as DNA strands pair with their complementary bases (A with T, and G with C) in an antiparallel manner.

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

Accepted Answer

The answer of Cloned DNA is useful in studying which...

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

Accepted Answer

This property is called palindromic sequence because the DNA sequence is the same when read forward and backward on complementary strands.

Quiz 20: Recombinant Dna Technology

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

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

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

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.

DNA ligase________ .

Which of the following best describes a cloning vector?

What is necessary to generate a genomic DNA library?

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

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

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?

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 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.

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

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

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

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?