Chapter 13 DNA
Which of the following covalently connects
segments of DNA?
A) helicase
B) DNA polymerase III
C) ligase
D) DNA polymerase I
E) primase
C) ligase
What are the coding segments of a stretch
of eukaryotic DNA called?
A) introns
B) exons
C) codons
D) replicons
E) transposons
B) exons
A mutation in this section of DNA could influence
the binding of RNA polymerase to the DNA:
A) repressor
B) promoter
C) corepressor
D) operon
E) inducer
B) promoter
In the human genome, oncogenes _____.
A) stimulate cell division
B) slow cell division
C) supress tumors
D) enhance DNA repair
A) stimulate cell division
Why are viruses referred to as obligate parasites?
A) They cannot reproduce outside of a host cell.
B) Viral DNA always inserts itself into host DNA.
C) They invariably kill any cell they infect.
D) They can incorporate nucleic acids from other viruses.
E) They must use enzymes encoded by the virus itself.
A) They cannot reproduce outside of a host cell.
Cytosine makes up 38% of the nucleotides
in a sample of DNA from an organism.
Approximately what percentage of the
nucleotides in this sample will be thymine?
A) 24
B) 12
C) 31
D) 38
B) 12
Transcription in eukaryotes requires which of
the following in addition to RNA polymerase?
A) the protein product of the promoter
B) start and stop codons
C) ribosomes and tRNA
D) several transcription factors (TFs)
E) aminoacyl synthetase
D) several transcription factors (TFs)
In both eukaryotes and prokaryotes, gene
expression is primarily regulated at the level of
A) transcription.
B) translation.
C) mRNA stability.
D) mRNA splicing.
E) protein stability.
A) transcription.
What two genes are often mutated in colon cancer?
A) ras and myoD
B) p21 and p53
C) ras and p53
D) BRCA1 and BRCA2
C) ras and p53
Which of the following molecules make up
the viral envelope?
A) glycoproteins
B) carbopeptides
C) proteosugars
D) carboproteins
E) peptidocarbs
A) glycoproteins
Which of the following removes the RNA nucleotides
from the primer and adds equivalent DNA nucleotides
to the 3' end of Okazaki fragments?
A) helicase
B) DNA polymerase III
C) ligase
D) DNA polymerase I
E) primase
D) DNA polymerase I
Which of the following DNA mutations is the
most likely to be damaging to the protein it specifies?
A) a base-pair deletion
B) a codon substitution
C) a substitution in the last base of a codon
D) a codon deletion
E) a point mutation
A) a base-pair deletion
Which of the following is a means of controlling
eukaryotic gene expression?
A) DNA packing
B) transcriptional regulation
C) mRNA processing
D) methylation of DNA
E) all of the above
E) all of the above
In 1997, Dolly the sheep was cloned.
Which of the following processes was used?
A) use of mitochondrial DNA from adult female cells of another ewe
B) isolation of stem cells from a lamb embryo and production of a
zygote equivalent
C) fusion of an adult cell's nucleus with an enucleated sheep egg,
followed by incubation in a surrogate
D) replication and dedifferentiation of adult stem cells from sheep
bone marrow
E) separation of an early stage sheep blastula into separate cells,
one of which was incubated in a surrogate ewe
C) fusion of an adult cell's nucleus with an enucleated sheep egg,
followed by incubation in a surrogate
Which of the following is characteristic of the lytic cycle?
A) Many bacterial cells containing viral DNA are produced.
B) Viral DNA is incorporated into the host genome.
C) The viral genome replicates without destroying the host.
D) A large number of phages is released at a time.
E) The virus-host relationship usually lasts for generations.
D) A large number of phages is released at a time.
Which of the following cuts DNA
molecules at specific locations?
A) restriction enzymes
B) gene cloning
C) DNA ligase
D) gel electrophoresis
E) reverse transcriptase
A) restriction enzymes
Which of the following is true for both
prokaryotic and eukaryotic gene expression?
A) After transcription, a 3' poly-A tail and a 5' cap are added to mRNA.
B) Translation of mRNA can begin before transcription is complete.
C) RNA polymerase binds to the promoter region to begin transcription.
D) mRNA is synthesized in the 3‘ 5' direction.
E) The mRNA transcript is the exact complement of the gene from
which it was copied.
C) RNA polymerase binds to the promoter region to begin transcription.
In general, operons that encode the enzymes of a
biosynthetic (anabolic) pathway (such as the trp operon)
are _____, and those encoding the enzymes of a catabolic
pathway (such as the lac operon) are _____.
A) repressible ... inducible
B) inducible ... repressible
C) permanently on ... permanently off
D) permanently off ... permanently on
E) easily mutated ... resistant to mutations
A) repressible ... inducible
"Therapeutic cloning" refers to _____.
A) the use of cloned embryos as a source of stem cells that could be used
to treat disease
B) treating patients with therapeutic proteins made using recombinant DNA
technology
C) cloning animals to obtain organs that could be used for transplantation
into humans
D) treating a genetic disease by obtaining cells from an individual with the
disease, introducing genes into the cells in order to repair the genetic
defect, and then reintroducing the cells back into the individual
E) All of the listed responses are correct
A) the use of cloned embryos as a source of stem cells that could be used
to treat disease
How do retroviruses, such as HIV, differ from other viruses?
A) They have much simpler reproductive cycles than other RNA
viruses.
B) They contain DNA that is used as a template to make RNA.
C) They can reproduce only inside living cells.
D) They contain nucleic acids that code for proteins.
E) They can transcribe a DNA copy from a RNA template.
E) They can transcribe a DNA copy from a RNA template.
Which of the following best describes the
addition of nucleotides to a growing DNA chain?
A) A nucleoside triphosphate is added to the 5' end of the DNA,
releasing a molecule of pyrophosphate.
B) A nucleoside triphosphate is added to the 3' end of the DNA,
releasing a molecule of pyrophosphate.
C) A nucleoside diphosphate is added to the 5' end of the DNA,
releasing a molecule of phosphate.
D) A nucleoside diphosphate is added to the 3' end of the DNA,
releasing a molecule of phosphate.
E) A nucleoside monophosphate is added to the 5' end of the DNA.
B) A nucleoside triphosphate is added to the 3' end of the DNA,
releasing a molecule of pyrophosphate.
Alternative RNA splicing
A) increases the rate of transcription.
B) can allow the production of proteins of different sizes
from a single mRNA.
C) is due to the presence or absence of particular snRNPs.
D) can allow the production of similar proteins from
different RNAs.
B) can allow the production of proteins of different sizes
from a single mRNA.
DNA synthesized using an RNA template is called _____.
A) reverse transcriptase
B) a restriction enzyme
C) a palindrome
D) cDNA
E) a plasmid
D) cDNA
The efficiency of cloning, and the ability to generate healthy cloned
animals, has been largely hampered by the difficulty of _____.
A) inducing recombination in differentiated donor cells in order to
restore the full genomic complement
B) transforming donor cells with genes encoding proteins required
for normal embryonic development
C) completely reversing epigenetic alterations in donor cell nuclei
such as DNA methylation and chromatin packing
D) physically removing the nucleus from the egg cell that will
ultimately receive the donor cell nucleus
E) implanting the clone into the surrogate mother
C) completely reversing epigenetic alterations in donor cell nuclei
such as DNA methylation and chromatin packing
Which of the following terms describes bacteriophage DNA
that has become integrated into the host cell chromosome?
A) intemperate bacteriophages
B) transposons
C) prophages
D) T-even phages
E) plasmids
C) prophages