Chapter 20 Recombinant DNA Technology1) Words such as did, mom, and pop 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) lysogenicB) prototrophicC) palindromicD) conjugationE) insertionAnswer: CSection: 20.12) Restriction endonucleases are especially useful if they generate "sticky" ends. What makes an end sticky?A) single-stranded complementary tailsB) blunt endsC) poly-A sequencesD) 5' capE) interferenceAnswer: ASection: 20.13) List two especially useful characteristics of cloning vectors.A) high copy number and antibiotic resistance gene(s)B) virulence and lysogenicityC) ability to integrate into the host chromosome and then causing a lytic cycleD) nonautonomous replication and transpositionE) reverse transcriptase and ligase activitiesAnswer: ASection: 20.14) 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) palindromeB) consensus sequenceC) multiple cloning siteD) β-galactosidaseE) complementationAnswer: CSection: 20.11Copyright © 2012 Pearson Education, Inc.5) 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 chromosomeB) lysogenic phages continue to integrate their DNA into the host chromosome, thus reducing the number of desired recombinant clonesC) each vector can take up only a relatively small fraction of the eukaryotic DNAD) each ligation product is sequence specificE) the host range of the vector is limitedAnswer: CSection: 20.16) In the context of molecular genetics, reverse transcription PCR (RT-PCR) refers to ________.A) assembling a DNA sequence from an mRNAB) assembling an RNA sequence from a DNA sequenceC) translating in the 3' to 5' directionD) transcribing first, then translatingE) making an amino acid sequence from a DNA sequenceAnswer: ASection: 20.37) Nucleic acid blotting is widely used in recombinant DNA technology. In a Southern blot, one generally ________.A) hybridizes filter-bound DNA with a DNA probeB) hybridizes filter-bound RNA with a DNA probeC) examines amino acid substitutions with radioactive probesD) cleaves RNA with restriction endonucleasesE) ligates DNA with DNA ligaseAnswer: ASection: 20.48) 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, 1600C) 300, 700, 2200D) 700, 400, 1400, 2600E) 300, 700, 1000, 1200Answer: ESection: 20.12Copyright © 2012 Pearson Education, Inc.9) In which of the following biochemical reactions is it common to use ddNTPs (dideoxyribonucleoside triphosphates)?A) citric acid cycleB) DNA sequencingC) restriction digestionD) electron transportE) plasmolysisAnswer: BSection: 20.510) 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.Answer: ASection: 20.511) 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 95°C. 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 toanneal to the target DNA.B) Each cycle includes a "hot" denaturation phase (95°C), which serves to sterilize theculture.C) Each cycle includes a "hot" denaturation phase (95°C), which activates the Taqpolymerase.D) Each cycle includes a "hot" denaturation phase (95°C), which separates the hydrogenbonds that hold the strands of the template DNA together.E) More than one of the above are correct.Answer: DSection: 20.312) What is recombinant DNA technology? What are the safety issues related to recombinant DNA technology?Answer: Recombinant DNA technology refers to the creation of new combinations of DNA molecules that are not normally found in nature. Safety issues generally center on the creation and release (accidental or intentional) of genetically engineered organisms that are a threat to human health or to animals and plants in the environment. Many organisms that are "genetically engineered" carry genes for antibiotic resistance.Section: 20.13Copyright © 2012 Pearson Education, Inc.13) Nucleic acid blotting is commonly used in molecular biology. Two types, Southern blots and northern blots, involve gel electrophoresis and a filter, which holds the nucleic acid. Briefly describe the procedure of "blotting" in this context and differentiate between Southern and northern blots.Answer: In a Southern blot, the DNA to be "probed" is cut with a restriction enzyme(s); then thefragments are separated by gel electrophoresis. Alkali treatment of the gel denatures the DNA, which is then "blotted" onto the filter (nylon or nitrocellulose). A labeled probe (RNA or DNA) is then hybridized to complementary fragments on the filter. In a northern blot, RNA is separated in the gel and "probed" with the labeled DNA.Section: 20.414) Assume that you have cut 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.Answer: Since the smaller fragments migrate toward the "+" pole, away from the origin, they bind less stain than the larger fragments near the origin.Section: 20.415) In the context of recombinant DNA technology, what is meant by the term vector?Answer: A vector is a vehicle to carry recombinant DNA molecules into the host cells where independent replication can occur. Most common vectors are plasmids, bacteriophages, and cosmids.Section: 20.116) Molecular biologists rely on many, often sophisticated, techniques to pursue their discipline. One may list