Chapter 20 Campbell Biology – Flashcards
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Bacterial cells protect their own DNA from restriction enzymes (endonucleases) by _____.
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adding methyl groups to adenines and cytosines
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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 (endonucleases). 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.
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III, II, IV, V, I
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A principal problem with inserting an unmodified mammalian gene into a plasmid and then getting that gene expressed in bacteria is that _____.
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bacteria cannot remove eukaryotic introns
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Yeast cells are frequently used as hosts for cloning because they _____.
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are eukaryotic cells
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Sequencing an entire genome, such as that of C. elegans, a nematode, is most important because _____.
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a sequence that is found to have a particular function in the nematode is likely to have a closely related function in vertebrates
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The reason for using Taq polymerase for PCR is that _____.
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it is heat stable and can withstand the heating step of PCR
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A laboratory might use dideoxyribonucleotides to _____.
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sequence a DNA fragment
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What information is critical to the success of polymerase chain reaction (PCR) itself?
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The DNA sequence of the ends of the DNA to be amplified must be known.
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Which of the following is in the correct order for one cycle of polymerase chain reaction (PCR)?
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Denature DNA; anneal primers; extend primers.
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A gene that contains introns can be made shorter (but remain functional) for genetic engineering purposes by using _____.
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reverse transcriptase to reconstruct the gene from its mRNA
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DNA microarrays have made a huge impact on genomic studies because they _____.
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allow the expression of many or even all of the genes in the genome to be compared at once
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In large scale, genome-wide association studies in humans we look for _____.
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SNPs where one allele is found more often in persons with a particular disorder than in healthy controls
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Imagine that you compare two DNA sequences found in the same location on homologous chromosomes. On one of the homologs, the sequence is AACTACGA. On the other homolog, the sequence is AACTTCGA. Within a population, you discover that each of these sequences is common. These sequences _____.
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contain an SNP that may be useful for genetic mapping
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Which of the following uses labeled probes to visualize the expression of genes in whole tissues and organisms?
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in situ hybridization
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Which of the following is most like the formation of identical twins?
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organismal cloning
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In 1997, Dolly the sheep was cloned. Which of the following processes was used?
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fusion of an adult cell's nucleus with an enucleated sheep egg, followed by incubation in a surrogate
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Which of the following is true of embryonic stem cells but not of adult stem cells?
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They can give rise to all cell types in the organism.
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The first cloned cat, called Carbon Copy, was a calico, but she looked significantly different from her female parent because _____.
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X inactivation in the embryo is random and produces different patterns
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Genetically engineered plants _____.
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include transgenic rice plants that can grow in water of high salinity
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Scientists developed a set of guidelines to address the safety of DNA technology. Which of the following is one of the adopted safety measures?
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Microorganisms used in recombinant DNA experiments are genetically crippled to ensure that they cannot survive outside of the laboratory.
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What characteristic of short tandem repeats (STRs) DNA makes it useful for DNA fingerprinting?
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The number of repeats varies widely from person to person or animal to animal.
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Gene therapy requires _____.
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knowledge and availability of the normal allele of the defective gene, an ability to introduce the normal allele into the patient, and an ability to express the introduced gene at the correct level, and time, and tissue site within the patient
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Using retroviral vectors for gene therapy might increase the patient's risk of developing cancer because they might _____.
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integrate recombinant DNA into the genome in ways that misregulate the expression of genes at or near the site of integration
