CAMPBELL BIOLOGY CHAPTER 20
TEST PREPARATION QUESTIONS &
ANSWERS(GRADED A+)
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. - ANSWERC) cut the DNA again with restriction enzyme Y and insert these
fragments into the plasmid cut with the same enzyme.
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 - ANSWERE) a YAC with appropriate
cellular enzymes
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 - ANSWERC) a BAC
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 -
ANSWERA) by adding methyl groups to adenines and cytosines
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 - ANSWERC) III, II, IV, V, I
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. - ANSWERC) bacteria cannot remove
eukaryotic introns.
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. - ANSWERC) reverse transcriptase to reconstruct the gene from its
mRNA.
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. - ANSWERD) They are eukaryotic
cells.
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. - ANSWERA) BACs.
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 - ANSWERE) centromeres,
telomeres, and an origin of replication
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 - ANSWERA) 2, 1, 4
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. - ANSWERD) a sequence that is
found to have a particular function in the nematode is likely to have a closely related
function in vertebrates.
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 - ANSWERB) electroporation followed by
recombination
TEST PREPARATION QUESTIONS &
ANSWERS(GRADED A+)
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. - ANSWERC) cut the DNA again with restriction enzyme Y and insert these
fragments into the plasmid cut with the same enzyme.
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 - ANSWERE) a YAC with appropriate
cellular enzymes
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 - ANSWERC) a BAC
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 -
ANSWERA) by adding methyl groups to adenines and cytosines
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 - ANSWERC) III, II, IV, V, I
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. - ANSWERC) bacteria cannot remove
eukaryotic introns.
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. - ANSWERC) reverse transcriptase to reconstruct the gene from its
mRNA.
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. - ANSWERD) They are eukaryotic
cells.
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. - ANSWERA) BACs.
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 - ANSWERE) centromeres,
telomeres, and an origin of replication
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 - ANSWERA) 2, 1, 4
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. - ANSWERD) a sequence that is
found to have a particular function in the nematode is likely to have a closely related
function in vertebrates.
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 - ANSWERB) electroporation followed by
recombination
