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55) Which of the following is an example of a genetically modified organism but not a
transgenic organism?
A) Flavr Savr peaches (peaches that express larger quantities of a peach stability enzyme)
B) Golden Rice (rice that expresses daffodil and bacteria beta-carotene synthesis enzymes)
C) AquAdvantage salmon (Atlantic salmon that expresses Chinook salmon growth hormone)
D) Roundup Ready soybeans (soybeans that express bacterial pesticide enzymes)
56) You are setting up a PCR reaction and add a primer for one end of the target sequence, but
you forget to add the primer for the other end of the target sequence. If you added the other
necessary components, what do you expect to observe after running the PCR reaction for 40
cycles?
A) The PCR reaction will produce billions of copies of the target DNA.
B) The PCR reaction will produce millions of copies of the target DNA.
C) The PCR reaction will produce one copy of the target DNA.
D) The PCR reaction will produce zero copies of the target DNA.
57) Biotechnology companies sell kits that allow you to do PCR to amplify STR regions from
human blood samples that you have collected. What components would you expect to find in the
kit in order to be able to do successful PCR reactions?
A) human DNA polymerase, primers that flank STR regions
B) heat-stable DNA polymerase, primers that flank STR regions
C) human DNA polymerase, primers that flank STR regions, free nucleotides
D) heat-stable DNA polymerase, primers that flank STR regions, free nucleotides
58) TPOX is one of the STRs that is used to compare DNA between different people. Why is
TPOX useful for comparing DNA between different people?
A) TPOX varies in the number of repeats between different people.
B) TPOX varies in sequence between different people.
C) TPOX is only present in some people's genomes.
D) TPOX is present in different places in different people's genomes.
59) Cystic fibrosis is a genetic disease that results from a defective CFTR protein that alters ion
flow through the cell membrane such that water does not cross the cell membrane. Gene therapy
is being used to attempt to help cystic fibrosis patients. Which of the following steps is not
needed to develop a gene therapy treatment for cystic fibrosis?
A) Clone the normal-functioning CFTR gene and make an RNA version of the gene.
B) Make antibodies to the defective CFTR protein to enhance the patient's immune system.
C) Remove cells from a patient and infect them with the recombinant virus.
D) Insert the RNA version of the CFTR gene into a virus.
60) When cloning a gene, one of the steps is to use restriction enzymes to insert the gene of
interest into a vector. If you separated the empty vector (the vector without the gene of interest)
and the cloned vector (the vector that has the gene of interest added) using agarose gel
electrophoresis, what do you expect to observe on the agarose gel if both vectors are loaded at
the same position at the top of the gel?
A) The empty vector would migrate farther down than the cloned vector.
B) The cloned vector would migrate farther down than the cloned vector.
C) The empty vector would migrate the same distance as the cloned vector.
D) It is impossible to know without knowing the identity of the gene of interest.
61) Which of the following is an example of a transgenic organism?
A) a fern grown from a single fern root cell
B) a rat with rabbit hemoglobin genes
C) a cow that has been fed pig growth hormone in its food
D) a human given a corrected human blood-clotting gene
62) The restriction enzyme BamHI recognizes the DNA sequence GGATCC and always cuts
between the two G nucleotides. How many bases long is the sticky end of a DNA molecule that
has been cut with BamHI?
A) two
B) three
C) four
D) five
63) When DNA molecule "A" is cut with the restriction enzyme EcoRI, it is cut into four pieces.
When DNA molecule "B," which is exactly identical to DNA molecule "A" except for the
presence of one SNP, is cut with EcoRI, it is cut into three pieces. What is the best explanation
for this observation?
A) The SNP occurs in all EcoRI restriction sites in DNA molecule "B."
B) The SNP occurs in a single EcoRI restriction site in DNA molecule "B."
C) Not enough EcoRI was used to cut DNA molecule "B."
D) An excess of EcoRI was used to cut DNA molecule "A."
18
64) Some restriction enzymes do not leave sticky ends when cutting DNA molecules; rather,
they cut a restriction site down the middle and leave "blunt-ended" DNA molecules, which do
not have any single-stranded nucleotide extensions. Which of the following is not a likely
outcome when trying to insert a gene into a plasmid when have both been cut with the same
"blunt-ended" restriction enzyme?
A) The gene might be inserted into the plasmid by forming hydrogen bonds.
B) The gene might be inserted into the plasmid multiple times in a row.
C) The gene might insert into the plasmid in the proper (forward) orientation.
D) The gene might insert into the plasmid in the wrong (backward) orientation.
65) You prepare a genomic library and use this as a source to produce recombinant proteins in E.
coli. However, after producing the proteins you find that they are all too long or too short. In
fact, you don't find a single protein that is the correct size. What is the best explanation for this
result?
A) Since a genomic library was used as the source of the genes, the introns were included during
transcription and translation.
B) Since bacteria were used to produce the proteins, sugar groups were not properly added on to
the proteins that were being made.
C) Since a genomic library was used as the source, the recombinant bacterial plasmid DNA was
likely incorporated into the proteins being made.
D) Since bacteria were used to produce the proteins, the native bacterial plasmid DNA was likely
incorporated into the proteins being made.
66) You are trying to produce a cDNA library starting from mRNA in skeletal muscle cells. You
add the following components to a tube and let the reaction proceed: skeletal muscle mRNA, free
nucleotides, and DNA polymerase. After inspecting the products of the reaction, you do not find
any cDNA molecules at all. What is the most likely explanation for this result?
A) You used mRNA instead of genomic DNA as the source material.
B) You used DNA polymerase instead of reverse transcriptase.
C) cDNA libraries can only be made from skin cell mRNA molecules.
D) You forgot to add a radiolabeled nucleic acid probe to the tube.
67) Gel electrophoresis is normally set up with the negative electrode at the top of the gel and the
positive electrode at the bottom of the gel. The DNA products are loaded at the top of the gel,
and then a current is applied to separate them. However, when preparing to run a gel, you
accidentally switched the locations of the negative and positive electrodes such that the positive
electrode is at the top and the negative electrode is at the bottom. You still loaded the DNA
products at the top of the gel as normal. What result are you most likely to observe if you apply
an electric current to this gel setup?
A) All DNA molecules will migrate up the gel toward the positive electrode.
B) All DNA molecules will migrate down the gel toward the negative electrode.
C) Shorter DNA molecules will move up the gel, and longer DNA molecules will move down
the gel.
D) Longer DNA molecules will move up the gel, and shorter DNA molecules will move down
the gel.
20
12.2 Art Questions
1) Which step in this process requires use of restriction enzymes?
A) step A
B) step B
C) step C
D) step D
2) Which step in the creation of cDNA involves the use of reverse transcriptase?
A) step 1
B) step 2
C) step 3
D) step 4
3) Use the figure below to answer the following question. The bands in the ladder are in 10-base
increments, starting with 10 bases at the bottom and going to 70 bases at the top.
Approximately how many bases are in the DNA molecule that the arrow is pointing to?
A) 30 bases
B) 36 bases
C) 40 bases
D) 44 bases
4) Use the figure below to answer the following question. The bands in the ladder are in 10-base
increments, starting with 10 bases at the bottom and going to 70 bases at the top. CS, crime
scene; S1, suspect 1; S2, suspect 2; S3, suspect 3.
Which suspect is likely to have committed the crime?
A) suspect 1
B) suspect 2
C) suspect 3
D) suspect 1 or 2
5) Below is a figure depicting the whole-genome shotgun method. Which step is most similar to
a step used when preparing a genomic library?
A) step 1
B) step 2
C) step 3
D) step 4
25
12.3 Scenario Questions
After reading the paragraph below, answer the questions that follow.
Four decades after the end of the Vietnam War, the remains of an Air Force pilot were
discovered and returned to the United States. A search of Air Force records identified three
families to which the remains might possibly belong. Each family had a surviving twin of a
missing service member. The following STR profiles were obtained from the remains of the pilot
and the surviving twins from the three families.
1) In order to match the pilot's remains to the correct family using DNA profiling,
A) the majority of the STR bands must match.
B) each of the 13 STR bands must match.
C) the bands for site 13 must match.
D) bands 5 and 7 must match.
2) Based on analysis of the STR sites shown, does the missing pilot belong to any of these three
families?
A) No, none of the families match.
B) Yes, family 1 matches.
C) Yes, family 2 matches.
D) Yes, family 3 matches.
3) Based on analysis of the STR sites shown, which family is the missing pilot least likely to
belong to?
A) family 1
B) family 2
C) family 3
D) Family 1 and family 2 are equally unlikely.
After reading the paragraphs below, answer the questions that follow.
Cystic fibrosis is an autosomal recessive genetic disorder that most severely affects the lungs and
respiratory tract. Cystic fibrosis is caused by a mutation in the gene for the protein cystic fibrosis
transmembrane regulator (CFTR), which regulates the movement of chloride and sodium ions
across epithelial cell membranes. When the CFTR gene is mutated in cystic fibrosis, the
defective CFTR protein cannot transport ions properly, which results in too little water drawn
across the membrane and the buildup of thick and sticky (viscous) mucus, especially in the
airways. This leads to difficulty of breathing and frequent lung infections.
Research has shown that some of the increased thickness and viscosity of the mucus in the
respiratory tract is due to the presence of human DNA. If DNA is present in high concentrations
in solution, the DNA molecules can get entangled and lead to a thick, viscous solution. To
combat this, pharmaceutical companies have developed recombinant forms of the human
deoxyribonuclease I (DNase I) protein. DNase I, after being translated and modified with sugar
groups, is normally produced in human cells and possibly plays a role in DNA breakdown during
apoptosis (programmed cell death).
4) If you wanted to produce a recombinant form of DNase I, what cell type should you use?
A) E. coli
B) yeast
C) mammalian
D) plant
5) If recombinant DNase I is added to a vial of respiratory secretions from a cystic fibrosis
patient, which of the following results would indicate that the recombinant DNase I is
functional?
A) The secretions become thicker and more viscous.
B) The secretions become less viscous.
C) There is no effect on the secretions.
D) This experiment could not tell you if the DNase was functional or not.
6) A scientist produced a batch of recombinant DNase I in E. coli cells and a batch in
mammalian cells. She placed 0.1 mg of the E. coli-derived DNase I in a vial containing a
solution of DNA, and she placed 0.1 mg of the mammalian cell-derived DNase I in a separate
vial containing the same solution of DNA. The initial viscosity of the DNA solutions was
identical. What do you expect the viscosity of the DNA solutions to be after ten minutes have
passed, and why?
A) The viscosity of the mammalian cell DNase I vial will be lower than that of the E. coli DNase
I vial because the mammalian cell DNase I will be functional and able to degrade the DNA.
B) The viscosity of the mammalian cell DNase I vial will be higher than that of the E. coli
DNase I vial because the mammalian cell DNase I will be functional and able to degrade the
DNA.
C) The viscosity of the E. coli DNase I vial will be lower than that of the mammalian cell DNase
I vial because the E. coli DNase I will be functional and able to degrade the DNA.
D) The viscosity of the E. coli DNase I vial will be higher than that of the mammalian cell
DNase I vial because the E. coli DNase I will be functional and able to degrade the DNA.
