Biology Question Chapter 10: Analyzing Genes and Genomes (Multiple Choice Questions Sample)

CHAPTER 10
ANALYZING GENES AND GENOMES
2009 Garland Science Publishing
10-1Recombinant DNA technologies involve techniques that permit the creation of custom-made DNA molecules that can be introduced back into living organisms. These technologies were first developed in the ______.
(a)1930s
(b)1950s
(c)1970s
(d)1990s
Manipulating and Analyzing DNA Molecules
10-2Which of the following statements about restriction nucleases is false?
(a)A reproducible set of DNA fragments will be produced every time a restriction nuclease digests a known piece of DNA.
(b)Restriction nucleases recognize specific sequences on single-stranded DNA.
(c)Some bacteria use restriction nucleases as protection from foreign DNA.
(d)Some restriction nucleases cut in a staggered fashion, leaving short single-stranded regions of DNA at the ends of the cut molecule.
10-3You have purified DNA from your recently deceased goldfish. Which of the following restriction nucleases would you use if you wanted to end up with DNA fragments with an average size of 70 kilobase pairs (kb) after complete digestion of the DNA? The recognition sequence for each enzyme is indicated in the right-hand column.
(a)Sau3AIGATC
(b)BamHIGGATCC
(c)NotIGCGGCCGC
(d)XzaIGAAGGATCCTTC
10-4You have a piece of circular DNA that can be cut by the restriction nucleases XhoI and SmaI, as indicated in Figure Q10-4.
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Figure Q10-4
If you were to cut this circular piece of DNA with both XhoI and SmaI, how many fragments of DNA would you end up with?
(a)1
(b)2
(c)3
(d)4
10-5You have a piece of circular DNA that can be cut by the restriction nucleases EcoRI, HindIII, and NotI, as indicated in Figure Q10-5.
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Figure Q10-5
Which of the following statements is false?
(a)One piece of DNA will be obtained when this DNA is cut by NotI.
(b)A piece of DNA that cannot be cut by EcoRI will be obtained by cutting this DNA with both NotI and HindIII.
(c)Two DNA fragments that cannot be cut by HindIII will be obtained when this DNA is cut by EcoRI and NotI.
(d)Two DNA fragments of unequal size will be created when this DNA is cut by both HindIII and EcoRI.
10-6You have accidentally torn the labels off two tubes, each containing a different plasmid, and now do not know which plasmid is in which tube. Fortunately, you have restriction maps for both plasmids, shown in Figure Q10-6. You have the opportunity to test just one sample from one of your tubes. You have equipment for agarose-gel electrophoresis, a standard set of DNA size markers, and the necessary restriction enzymes.
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Figure Q10-6
* Outline briefly the experiment you would do to determine which plasmid is in which tube.
ANSWER
You would first digest your sample with a combination of restriction enzymes selected so that they give a set of fragment sizes that could have come from only one of the plasmids. Then you would run the resulting mixture of DNA fragments on a gel alongside a set of size markers anddetermine the size of each fragment. By looking at the restriction maps, you should then be able to match your results to one of the plasmids.
* Which restriction enzyme or combination of restriction enzymes would you use in this experiment?
ANSWER
Digestion with any of the following combinations will enable you to distinguish which plasmid you have: HindIII + BglII; EcoRI + BglII; EcoRI + BglII + HindIII. The plasmids are the same size, so you cannot distinguish between them simply by making a single cut (with HindIII) and determining the size of the complete DNA by gel electrophoresis. Nor can you distinguish them by cutting with all four restriction nucleases, Because the set of fragment sizes produced from both plasmids will be the same. Cutting with BamHI or EcoRI on their own is not sufficient because you will get bands of the same size from both plasmid A and plasmid B. The only difference between the two plasmids is in the location of the BglII site relative to the two BamHI sites, so if you cut with an enzyme that cuts outside the BamHI fragment and with BglII, you willget different-sized fragments from the two plasmids.
10-7Assume that defects in a hypothetical gene X have been linked to antisocial behavior. Two copies of a defective gene X predispose a child to bad behavior from childhood, whereas a single copy of the gene seems to produce no symptoms until adulthood. Because early treatment can counteract the effects of the gene, a program of voluntary genetic testing is being performed with delinquent prospective parents. Charles S. and Caril Ann F. have been arrested on charges of robbery and assault, and Caril Ann is pregnant with Charles’s child. You obtain DNA samples from Charles, Caril Ann, and the fetus. You digest these samples with NotI and use these samples to perform two Southern blots, which you probe with two different oligonucleotide probes, A and B, that hybridize to different parts of the normal gene X, as shown in Figure Q10-7A. Your results are shown in Figure 10-7B.
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Figure Q10-7
A.Which of the three individuals have defects in gene X?
B.Which individuals have a single defective gene and which have two defective copies of the gene?
C.Indicate the nature (single-base-pair mutation or deletion) and location of each individual’s defects on gene X.
10-8Figure Q10-8 shows a restriction map of a piece of DNA containing your favorite gene. The arrow indicates the position and orientation of the gene in the DNA. In part (B) of the figure are enlargements showing the portions of the DNA whose sequences have been used to make oligonucleotide probes A, B, C, and D. Which of the oligonucleotides can be used to detect the gene in each of the following?
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Figure 10-8
* A Southern blot of genomic DNA cut with HindIII.
All four oligonucleotide probes.
* A Northern blot.
Oligonucleotide probe B and oligonucleotide probe D. Both the upper and lower strands of DNA are present in genomic Southern blots, so all four oligonucleotides will hybridize to either Southern blot. (Oligonucleotides A and B will still be able to hybridize to genomic DNA cut with BglII, because they can still base-pair with the individual fragments that result from the digest.) Northern blots contain only RNA, which has the sequence of the upper strand of the DNA.Hence, only oligonucleotide probe B and oligonucleotide probe D will hybridize to a Northern blot.
10-9During gel electrophoresis, DNA fragments _______________________.
(a)travel through a matrix containing a microscopic network of pores
(b)migrate toward a negatively charged electrode
(c)can be visualized without stains or labels
(d)are separated on the basis of their sequence
10-10A double-stranded DNA molecule can be separated into single strands by heating it to 90°C because _______________________.
(a)heat disrupts the hydrogen bonds holding the sugar-phosphate backbone together
(b)DNA is negatively charged
(c)heat disrupts hydrogen bonding between complementary nucleotides
(d)DNA is positively charged
10-11You are interested in a single-stranded DNA molecule that contains the following sequence:
5′- ..... GATTGCAT .... -3′
Which molecule can be used as a probe that will hybridize to your sequence of interest?
(a)5′-GATTGCAT-3′
(b)5′-TACGTTAG-3′
(c)5′-CTAACGTA-3′
(d)5′-ATGCAATC-3′
DNA Cloning
10-12For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below. Not all words or phrases will be used; use each word or phrase only once.
A nuclease hydrolyzes the phosphodiester bonds in a nucleic acid. Nucleases that cut DNA only at specific short sequences are known as restriction nucleases. DNA composed of sequences from different sources is known as recombinant DNA. gel electrophoresis can be used to separate DNA fragments of different sizes. Millions of copies of a DNA sequence can be made entirely in vitro by the polymerase chain reaction technique.
DNA sequencingphosphodiester
endonucleasespolymerase chain reaction
exonucleasesrecombinant DNA
gel electrophoresisrestriction nucleases
hydrogenribonucleases
nucleic acid hybridization
10-13For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below. Not all words or phrases will be used; use each word or phrase only once.
Two fragments of DNA can be joined together by __________________. Restriction enzymes that cut DNA straight across the double helix produce fragments of DNA with __________________. A fragment of DNA is inserted into a __________________ in order to be cloned in bacteria. A __________________ library contains a collection of DNA clones derived from mRNAs. A __________________ library contains a collection of DNA clones derived from chromosomal DNA.
blunt endsDNA polymeraseRNA
cDNAgenomicstaggered ends
DNA ligaseprobevector
ANSWER
Two fragments of DNA can be joined together by DNA ligase. Restriction enzymes that cut DNA straight across the double helix produce fragments of DNA with blunt ends. A fragment of DNA is inserted into a vector in order to be cloned in bacteria. A cDNA library contains a collection of DNA clones derived from mRNAs. A genomic library contains a collection of DNA clones derived from chromosomal DNA.
10-14Name three features that a cloning vector for use in bacteria must contain. Explain your answers.
A cloning vector for use in bacteria must contain the following:
1. a bacterial replication origin (to allow the plasmid to be replicated)2. at least one unique restriction site (to allow easy insertion of foreign DNA)3. an antibiotic-resistance gene or some other selectab...