Question 1

Nucleic acid blotting is widely used in recombinant DNA technology.In a Southern blot,one generally ________.
A) hybridizes filter-bound DNA with a DNA probe
B) hybridizes filter-bound RNA with a DNA probe
C) examines amino acid substitutions with radioactive probes
D) cleaves RNA with restriction endonucleases
E) ligates DNA with DNA ligase

Accepted Answer

Southern blotting specifically involves the transfer of restriction enzyme-digested DNA fragments to a filter membrane which is then hybridized with a labeled DNA probe. Therefore, choice A is the correct answer. The other choices are not relevant to Southern blotting.

Question 2

What is meant by the designation EcoRI?

Accepted Answer

one of the first restriction enzymes isolated from E.coli

Question 3

Some restriction enzymes cleave DNA in such a manner as to produce blunt ends.Most often ligation of blunt end fragments is enhanced by the use of the enzyme terminal deoxynucleotidyl transferase.Speculate on the function of deoxynucleotidyl transferase in terms of using blunt end fragments in cloning.

Accepted Answer

Terminal deoxynucleotidyl transferase extends single-stranded ends by the addition of nucleotide tails.If complementary tails are added,the fragments can hybridize and the recombinant molecules can be ligated.

Question 4

A ddNTP,used often in DNA sequencing,lacks a(n)________ at the ________ and ________ carbons.
A) OH; 2′; 3′
B) methyl; 2′; 3′
C) carboxyl; 5′; 3′
D) OH; 2′; 5′
E) None of the above is correct.

Accepted Answer

ddNTPs lack a hydroxyl group (OH) at the 3′ carbon, which is necessary for forming the phosphodiester bond with the next nucleotide during DNA synthesis. The absence of this group prevents further elongation of the DNA strand, making ddNTPs crucial for terminating DNA synthesis in sequencing reactions. The 2′ carbon is also mentioned, but the key aspect for ddNTP function is the lack of an OH group at the 3′ position.

Question 5

What might be a reasonable function of restriction endonucleases in a bacterium,distinct from their use by molecular biologists?

Accepted Answer

The answer of What might be a reasonable function of...

Question 6

In which of the following biochemical reactions is it common to use ddNTPs (dideoxyribonucleoside triphosphates)?
A) citric acid cycle
B) DNA sequencing
C) restriction digestion
D) electron transport
E) plasmolysis

Accepted Answer

Dideoxyribonucleoside triphosphates (ddNTPs) are commonly used in DNA sequencing reactions, specifically in the Sanger method, to terminate DNA synthesis at a specific point, allowing for the identification of the nucleotide at that position.

Question 7

One of the primary reasons for generating a large number of clones in a eukaryotic genomic library is that ________.
A) each cosmid replicates in coordination with the host chromosome
B) lysogenic phages continue to integrate their DNA into the host chromosome, thus reducing the number of desired recombinant clones
C) each vector can take up only a relatively small fraction of the eukaryotic DNA
D) each ligation product is sequence specific
E) the host range of the vector is limited

Accepted Answer

Each vector has a limited capacity of DNA it can take up, therefore generating a large number of clones increases the chance of capturing a representative portion of the eukaryotic genome.

Question 8

Some vectors such as pUC18 and others of the pUC series contain a large number of restriction enzyme sites clustered in one region.Which term is given to this advantageous arrangement of restriction sites?
A) palindrome
B) consensus sequence
C) multiple cloning site
D) β-galactosidase
E) complementation

Accepted Answer

The advantageous arrangement of restriction sites in vectors such as pUC18 and others of the pUC series is called the multiple cloning site (MCS) or polylinker. The MCS consists of a short stretch of DNA that contains multiple unique restriction enzyme recognition sequences, allowing for easy and efficient cloning of DNA fragments. Palindromes are sequences that read the same backward as forward, which may be present in some restriction enzyme recognition sequences but is not specific to the clustered arrangement in pUC vectors. Consensus sequence refers to the most commonly observed nucleotide at each position of a DNA sequence, which is not relevant in this context. β-galactosidase and complementation are terms related to gene expression and complementation analysis, respectively, and are not directly relevant to the arrangement of restriction sites in pUC vectors.

Question 9

In the context of molecular genetics,reverse transcription PCR (RT-PCR)refers to ________.
A) assembling a DNA sequence from an mRNA
B) assembling an RNA sequence from a DNA sequence
C) translating in the 3′ to 5′ direction
D) transcribing first, then translating
E) making an amino acid sequence from a DNA sequence

Accepted Answer

RT-PCR involves creating a complementary DNA (cDNA) sequence from an mRNA template, effectively reversing the usual transcription process.

Question 10

In the context of recombinant DNA technology,what is meant by the term vector?

Accepted Answer

The answer of In the context of recombinant DNA technology,what...

Question 11

Assume that a plasmid (circular)is 3200 base pairs in length and has restriction sites at the following locations: 400,700,1400,2600.Give the expected sizes of the restriction fragments following complete digestion.
A) 400, 800, 1000 (2 of these)
B) 400, 1200, 1600
C) 300, 700, 2200
D) 700, 400, 1400, 2600
E) 300, 700, 1000, 1200

Accepted Answer

The plasmid is cut at 400, 700, 1400, and 2600 base pairs. The fragments will be: 400-700 (300 bp), 700-1400 (700 bp), 1400-2600 (1200 bp), and 2600-400 (1000 bp).

Question 12

The PCR (polymerase chain reaction)protocol that is currently used in laboratories was facilitated by the discovery of a bacterium called Thermus aquaticus in a hot spring inside Yellowstone National Park,in Wyoming.This organism contains a heat-stable form of DNA polymerase known as Taq polymerase,which continues to function even after it has been heated to 95ᵒC.Why would such a heat-stable polymerase be beneficial in PCR?
A) Each cycle includes a "hot" saturation phase (95°C), which allows the primers to anneal to the target DNA.
B) Each cycle includes a "hot" denaturation phase (95°C), which serves to sterilize the culture.
C) Each cycle includes a "hot" denaturation phase (95°C), which activates the Taq polymerase.
D) Each cycle includes a "hot" denaturation phase (95°C), which separates the hydrogen bonds that hold the strands of the template DNA together.
E) More than one of the above are correct.

Accepted Answer

The heat-stable Taq polymerase is beneficial in PCR because each cycle includes a "hot" denaturation phase (95°C), which separates the hydrogen bonds that hold the strands of the template DNA together. This allows the Taq polymerase to access and extend the primers along the template DNA. Taq polymerase can withstand the high temperature used for denaturation, making it ideal for the PCR process. Therefore, option D is the correct choice.

Question 13

What is recombinant DNA technology? What would you list as safety issues associated with recombinant DNA technology?

Accepted Answer

The answer of What is recombinant DNA technology? What would...

Question 14

Restriction endonucleases are especially useful if they generate "sticky" ends.What makes an end sticky?
A) single-stranded complementary tails
B) blunt ends
C) poly-A sequences
D) 5′ cap
E) interference

Accepted Answer

Sticky ends are created when restriction endonucleases cleave DNA in a staggered fashion, leaving single-stranded overhangs, or tails, that are complementary to each other. These tails can base pair with each other, allowing for easy ligation of two different DNA fragments together.

Question 15

List,in order,the steps usually followed in producing recombinant DNA molecules in a plasmid vector.

Accepted Answer

The answer of List,in order,the steps usually followed in producing...

Question 16

Assume that a given plasmid vector to be used in a cloning experiment contains 4000 base pairs of DNA.Assume also that the restriction endonuclease Cuj cuts this plasmid at the following sites (starting from an arbitrary zero point): 1000,1500,and 3000.Given complete digestion of the plasmid with the endonuclease so that only linear fragments are produced,what sizes of DNA are expected?

Accepted Answer

The answer of Assume that a given plasmid vector to...

Question 17

List two especially useful characteristics of cloning vectors.
A) high copy number and antibiotic resistance gene(s)
B) virulence and lysogenicity
C) ability to integrate into the host chromosome and then causing a lytic cycle
D) nonautonomous replication and transposition
E) reverse transcriptase and ligase activities

Accepted Answer

High copy number of the cloning vector is useful for producing a large amount of recombinant DNA, and antibiotic resistance genes allow for selection of only the cells that have taken up the vector, ensuring that the plasmid is present in all the progeny of the transformed cell.

Question 18

Words such as level,civic,and kayak have something in common compared to the fundamental tool of recombinant DNA technology.In the context of recombinant DNA technology,which term would be used to describe such words?
A) lysogenic
B) prototrophic
C) palindromic
D) conjugation
E) insertion

Accepted Answer

The common characteristic among level, civic, and kayak is that they are palindromic words, meaning they can be read the same way forward and backward. In recombinant DNA technology, palindromic sequences are important because they provide recognition sites for restriction enzymes, which cut DNA at specific sequences. These cuts allow for the insertion of foreign DNA or the removal of specific sections of DNA.

Question 19

Molecular biologists rely on many,often sophisticated,techniques to pursue their discipline.One may list ultracentrifugation,electron microscopy,X-ray diffraction,electrophoresis,and computer interfacing as fundamental tools.Model organisms provide the raw materials for study.List three "organisms" (or organismic groups)often used by recombinant DNA technologists and describe a major advantage of each group.

Accepted Answer

The answer of Molecular biologists rely on many,often sophisticated,techniques to...

Question 20

Over the years,sophisticated plasmid vectors have been developed for use in recombinant DNA technology.List at least two features that have been introduced in particularly useful vectors.

Accepted Answer

The answer of Over the years,sophisticated plasmid vectors have been...

Quiz 20: Recombinant DNA Technology

Nucleic acid blotting is widely used in recombinant DNA technology.In a Southern blot,one generally ________.

What is meant by the designation EcoRI?

A ddNTP,used often in DNA sequencing,lacks a(n) at the and carbons.

What might be a reasonable function of restriction endonucleases in a bacterium,distinct from their use by molecular biologists?

In which of the following biochemical reactions is it common to use ddNTPs (dideoxyribonucleoside triphosphates) ?

One of the primary reasons for generating a large number of clones in a eukaryotic genomic library is that ________.

Some vectors such as pUC18 and others of the pUC series contain a large number of restriction enzyme sites clustered in one region.Which term is given to this advantageous arrangement of restriction sites?

In the context of molecular genetics,reverse transcription PCR (RT-PCR) refers to ________.

In the context of recombinant DNA technology,what is meant by the term vector?

Assume that a plasmid (circular) is 3200 base pairs in length and has restriction sites at the following locations: 400,700,1400,2600.Give the expected sizes of the restriction fragments following complete digestion.

What is recombinant DNA technology? What would you list as safety issues associated with recombinant DNA technology?

Restriction endonucleases are especially useful if they generate "sticky" ends.What makes an end sticky?

List,in order,the steps usually followed in producing recombinant DNA molecules in a plasmid vector.

List two especially useful characteristics of cloning vectors.

Words such as level,civic,and kayak have something in common compared to the fundamental tool of recombinant DNA technology.In the context of recombinant DNA technology,which term would be used to describe such words?

Over the years,sophisticated plasmid vectors have been developed for use in recombinant DNA technology.List at least two features that have been introduced in particularly useful vectors.

Quiz 20: Recombinant DNA Technology

Nucleic acid blotting is widely used in recombinant DNA technology.In a Southern blot,one generally ________.

What is meant by the designation EcoRI?

A ddNTP,used often in DNA sequencing,lacks a(n) ________ at the ________ and ________ carbons.

What might be a reasonable function of restriction endonucleases in a bacterium,distinct from their use by molecular biologists?

In which of the following biochemical reactions is it common to use ddNTPs (dideoxyribonucleoside triphosphates) ?

One of the primary reasons for generating a large number of clones in a eukaryotic genomic library is that ________.

Some vectors such as pUC18 and others of the pUC series contain a large number of restriction enzyme sites clustered in one region.Which term is given to this advantageous arrangement of restriction sites?

In the context of molecular genetics,reverse transcription PCR (RT-PCR) refers to ________.

In the context of recombinant DNA technology,what is meant by the term vector?

Assume that a plasmid (circular) is 3200 base pairs in length and has restriction sites at the following locations: 400,700,1400,2600.Give the expected sizes of the restriction fragments following complete digestion.

What is recombinant DNA technology? What would you list as safety issues associated with recombinant DNA technology?

Restriction endonucleases are especially useful if they generate "sticky" ends.What makes an end sticky?

List,in order,the steps usually followed in producing recombinant DNA molecules in a plasmid vector.

List two especially useful characteristics of cloning vectors.

Words such as level,civic,and kayak have something in common compared to the fundamental tool of recombinant DNA technology.In the context of recombinant DNA technology,which term would be used to describe such words?

Over the years,sophisticated plasmid vectors have been developed for use in recombinant DNA technology.List at least two features that have been introduced in particularly useful vectors.

A ddNTP,used often in DNA sequencing,lacks a(n) at the and carbons.