Campbell s Biology 9e Reece et al Chapter 20 Biotechnology The new questions in Chapter 20 cover all of the chapter s concepts and are primarily at the higher skill levels In addition the chapter presents several scenarios that are accompanied by a series of questions Multiple Choice Questions 1 Assume that you are trying to insert a gene into a plasmid Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y You have a plasmid with a single site for Y but not for X Your strategy should be to A insert the fragments cut with restriction enzyme X directly into the plasmid without cutting the plasmid B cut the plasmid with restriction enzyme X and insert the fragments cut with restriction enzyme Y into the plasmid C cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme D cut the plasmid twice with restriction enzyme Y and ligate the two fragments onto the ends of the DNA fragments cut with restriction enzyme X E cut the plasmid with restriction enzyme X and then insert the gene into the plasmid Answer C Topic Concept 20 1 Skill Application Analysis 2 How does a bacterial cell protect its own DNA from restriction enzymes A by adding methyl groups to adenines and cytosines B by using DNA ligase to seal the bacterial DNA into a closed circle C by adding histones to protect the double stranded DNA D by forming sticky ends of bacterial DNA to prevent the enzyme from attaching E by reinforcing the bacterial DNA structure with covalent phosphodiester bonds Answer A Topic Concept 20 1 Skill Knowledge Comprehension 1 Copyright 2011 Pearson Education Inc 3 What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium I Transform bacteria with a recombinant DNA molecule II Cut the plasmid DNA using restriction enzymes III Extract plasmid DNA from bacterial cells IV Hydrogen bond the plasmid DNA to nonplasmid DNA fragments V Use ligase to seal plasmid DNA to nonplasmid DNA A I II IV III V B II III V IV I C III II IV V I D III IV V I II E IV V I II III Answer C Topic Concept 20 1 Skill Knowledge Comprehension 4 A principal problem with inserting an unmodified mammalian gene into a BAC and then getting that gene expressed in bacteria is that A prokaryotes use a different genetic code from that of eukaryotes B bacteria translate polycistronic messages only C bacteria cannot remove eukaryotic introns D bacterial RNA polymerase cannot make RNA complementary to mammalian DNA E bacterial DNA is not found in a membrane bounded nucleus and is therefore incompatible with mammalian DNA Answer C Topic Concept 20 1 Skill Synthesis Evaluation 5 A gene that contains introns can be made shorter but remain functional for genetic engineering purposes by using A RNA polymerase to transcribe the gene B a restriction enzyme to cut the gene into shorter pieces C reverse transcriptase to reconstruct the gene from its mRNA D DNA polymerase to reconstruct the gene from its polypeptide product E DNA ligase to put together fragments of the DNA that code for a particular polypeptide Answer C Topic Concept 20 1 Skill Application Analysis 6 Why are yeast cells frequently used as hosts for cloning A They easily form colonies B They can remove exons from mRNA C They do not have plasmids D They are eukaryotic cells E Only yeast cells allow the gene to be cloned Answer D Topic Concept 20 1 Skill Knowledge Comprehension 2 Copyright 2011 Pearson Education Inc 7 The DNA fragments making up a genomic library are generally contained in A BACs B recombinant viral RNA C individual wells D DNA RNA hybrids E radioactive eukaryotic cells Answer A Topic Concept 20 1 Skill Knowledge Comprehension 8 Yeast artificial chromosomes contain which of the following elements A centromeres only B telomeres only C origin of replication only D centromeres and telomeres only E centromeres telomeres and an origin of replication Answer E Topic Concept 20 1 Skill Knowledge Comprehension 9 Which of the following best describes the complete sequence of steps occurring during every cycle of PCR 1 The primers hybridize to the target DNA 2 The mixture is heated to a high temperature to denature the double stranded target DNA 3 Fresh DNA polymerase is added 4 DNA polymerase extends the primers to make a copy of the target DNA A 2 1 4 B 1 3 2 4 C 3 4 1 2 D 3 4 2 E 2 3 4 Answer A Topic Concept 20 1 Skill Knowledge Comprehension 10 A researcher needs to clone a sequence of part of a eukaryotic genome in order to express the sequence and to modify the polypeptide product She would be able to satisfy these requirements by using which of the following vectors A a bacterial plasmid B BAC to accommodate the size of the sequence C a modified bacteriophage D a human chromosome E a YAC with appropriate cellular enzymes Answer E Topic Concept 20 1 Skill Application Analysis 3 Copyright 2011 Pearson Education Inc 11 A student wishes to clone a sequence of DNA of 200 kb Which vector would be appropriate A a plasmid B a typical bacteriophage C a BAC D a plant virus E a large polypeptide Answer C Topic Concept 20 1 Skill Application Analysis 12 Sequencing an entire genome such as that of C elegans a nematode is most important because A it allows researchers to use the sequence to build a better nematode which is resistant to disease B it allows research on a group of organisms we do not usually care much about C the nematode is a good animal model for trying out cures for viral illness D a sequence that is found to have a particular function in the nematode is likely to have a closely related function in vertebrates E a sequence that is found to have no introns in the nematode genome is likely to have acquired the introns from higher organisms Answer D Topic Concept 20 1 Skill Synthesis Evaluation 13 To introduce a particular piece of DNA into an animal cell such as that of a mouse you would find more probable success with which of the following methods A the shotgun approach B electroporation followed by recombination C introducing a plasmid into the cell D infecting the mouse cell with a Ti plasmid E transcription and translation Answer B Topic Concept 20 1 Skill Application Analysis 14 The major advantage of using artificial chromosomes such as YACs and BACs for cloning genes is that A plasmids are unable to replicate in cells B