Uploaded by Fatimah Abidogun

QUIZ 9 (2)

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QUIZ 9
Question 1
1 out of 1 points
What is the purpose of having rrnBT4 in an expression vector?
Selected Answer:
Enhances the stability GOI transcript
Answers:
Enhances binding by transcriptional activators
Enhances the stability GOI transcript
Provides translation termination in 3 reading frames
Allow high level transcription of the GOI
Promotes strong binding of the ribosome to the translation initiation region

Question 2
1 out of 1 points
Having codons in the gene of interest that are not preferred in the expression host can lead to:
Selected Answer:
amino acid mis-incorporation
Answers:
full-length protein product
Reduced mRNA degradation by ribonucleases
Increased recombinant protein production
Efficient translation
amino acid mis-incorporation
Enhanced mRNA stability

Question 3
1 out of 1 points
One source of the gene of interest for cloning is cDNA. What step is not part of cDNA synthesis?
Selected Answer:
Genomic DNA is isolated from the nucleus of eukaryotic cells
Answers:
ribonuclease is used in one of the steps to get rid of mRNA
polyT primer is used to prime synthesis of cDNA
dNTPs are added to the 3' end of primers
Genomic DNA is isolated from the nucleus of eukaryotic cells
DNA polymerase synthesizes the second complementary DNA strand

Question 4
0 out of 1 points
Why must reverse transcriptase be used to create a eukaryotic expression library?
Selected
Answer:
Reverse transcriptase is able to add convenient cloning sites
Answers:
The resulting cDNAs do not contain non-protein coding introns
Reverse transcriptase synthesizes double stranded RNA that is ligation-ready.
Only reverse transcriptase can replicate eukaryotic DNA
Reverse transcriptase ensures the gene is in the correct orientation in the expression
vector
Reverse transcriptase is able to add convenient cloning sites

Question 5
1 out of 1 points
What does not apply to restriction enzymes?
Selected Answer:
Restriction enzymes are proteins that restrict the activity of ligases
Answers:
Restriction enzymes are proteins that restrict the activity of ligases
Some restriction enzymes generate single-stranded DNA overhangs
Most restriction enzymes work as dimers
Restriction enzymes break phosphodiester bonds between two nucleotides
Restriction enzymes are a type of endonucleases

Question 6
1 out of 1 points
What is not associated with the colony blotting technique?
Selected
Answer:
"Lysis of cells on the blot using the detergent, SDS, and the salt, calcium chloride"
Answers:
Denaturation of DNA that's on the blot
Growing of bacteria containing the genomic libraries on agar with antibiotic for
selection
Transfer of transformed bacteria from an agar plate and onto a membrane
"Lysis of cells on the blot using the detergent, SDS, and the salt, calcium chloride"
Use of an X-ray film for autoradiography
Use of a radio- or fluorescently labelled DNA probe to hybridize with the target gene

Question 7
1 out of 1 points
"As a new hire in a biotech company, you prepared the medium to be used for plating of E. coli after
transformation. You added ampicillin to the medium, but got distracted, and forgot to add X-Gal. What of
the following statements will apply? "
Selected Answer:
All colonies will be white
Answers:
No colonies will grow on the plates
Only cells with gene X inserted in the cloning vector will grow
All the colonies will be b-galactosidase positive
All colonies will be white
All the colonies on the plate will be ampicillin sensitive
Only cells that don’t have gene X inserted in the cloning vector will grow

Question 8
1 out of 1 points
"After cleavage of the formyl-methionine from the N-terminus of a peptide, certain amino acids remaining
on the N-terminus will make the protein susceptible to proteases. Which is not one of those amino acids?"
Selected Answer:
V - Valine
Answers:
Y- Tyrosine
L-leucine
W- Tryptophan
V - Valine
F-phenylalanine

Question 9
1 out of 1 points
Which type of ligation-independent cloning technique takes advantage of the recombination between
lambda phage attB and attP sequences in the vectors and in the DNA fragment to be inserted?
Selected Answer:
Gateway cloning
Answers:
Restriction cloning
Recombineering
Exonuclease-mediated cloning
Topo cloning
Lysogenic cloning
Gateway cloning

Question 10
0 out of 1 points
What will increase protein levels by increasing mRNA levels?
Selected Answer:
Secreting recombinant protein to periplasm where there are less proteases
Answers:
Having fusion partners at tne C-terminus of the protein
Mutating sequences found in an operator region
Removing proteolytic sites in the gene of interest by site-directed mutagenesis
Mutating sequences in the GOI that blocks ribosome access to the start codon
Secreting recombinant protein to periplasm where there are less proteases

Question 11
1 out of 1 points
"In the construction of recombinant DNA, what will increase the number of recombinant plasmids over
non-recombinant plasmids?"
Selected
Answer:
Increasing the insert:plasmid ratio
Answers:
Treating the fragment containing the gene of interest with alkaline phosphatase
Cutting the plasmid with a blunt cutting restriction enzyme
Using two different restriction enzymes with compatible overhangs
Increasing the insert:plasmid ratio
Phosphorylating the cloning vector
Cutting the plasmid with a single restriction enzyme which generates sticky
overhanging ends

Question 12
1 out of 1 points
What is true of alkaline phosphatase?
Selected
Answer:
Answers:
Alkaline phosphatase works on both strands of a cut DNA fragment
Alkaline phosphatase removes the phosphate group from the 3’ ends of restrictionenzyme digested DNA strand
Alkaline phosphatase transfers a phosphate group from a sensor protein to a
transcriptional response regulator
Alkaline phosphatase works on both strands of a cut DNA fragment
Alkaline phosphatase promotes the formation of phosphodiester bonds between the
restriction-enzyme digested plasmid ends
"In restriction cloning, both cloning vector and insert are treated with alkaline
phosphatase"
QUIZ 10

Question 1
1 out of 1 points
Which of these strain engineering approaches will not increase mRNA levels of the gene of interest?
Selected Answer:
Increasing expression of a gene for a repressor that binds to the GOI operator region
Answers:
Introducing T7 RNA polymerase for GOI driven by T7 promoter
Increasing expression of a gene for a repressor that binds to the GOI operator region
Deleting EcoKI
Mutating rne1
Deleting recA

Question 2
1 out of 1 points
"When inoculating a bioreactor with starter culture, to avoid a long lag phase, the inoculum should be at
what growth stage?"
Selected Answer:
Exponential phase
Answers:
Start of death phase
Mid-stationary phase
Exponential phase
Middle of death phase
Late stationary phase
Also at lag phase

Question 3
1 out of 1 points
Which E. coli strain improves translation of heterologous genes by overexpressing genes for tRNAs that are
rare in E. coli?
Selected Answer:
Rosetta
Answers:
DH5alpha
Rosetta
BL21 Star
TRex
BL21(DE3)
Origami

Question 4
1 out of 1 points
Deletion of the genes for gor and _______ in the E. coli Origami strain enhances the formation of disulfide
bonds in recombinant proteins expressed in the cytoplasm.
Selected Answer:
trxB
Answers:
groEL
ompT
arcA
trxB
fhuA2

Question 5
0 out of 1 points
Proteins are very fragile biomolecules. During downstream product recovery and capture what is not a
practice which will help stabilize proteins?
Selected Answer:
All the other choices will help stabilize proteins
Answers:
Add proteases
All the other choices will not help stabilize proteins
All the other choices will help stabilize proteins
Add antibiotics to minimize bacterial contamination
Work at low temperatures as much as possible
Use appropriate buffers

Question 6
1 out of 1 points
Which step is not part of downstream bioprocess?
Selected Answer:
Optimizing pH of the growth media
Answers:
Optimizing pH of the growth media
Chromatographic purification
Filtration
Dialysis or buffer exchange
Vial filling and lyophilization
Centrifugation

Question 7
1 out of 1 points
What is an advantage of fed-batch to continuous culture?
Selected Answer:
Mutations in the gene construct is less of a concern
Answers:
There’s better automation and process control in fed-batch
Fed-batch yields a more uniform product quality
"There’s more savings in time, labor, and energy with fed-batch"
Fed-batch has higher volumetric productivity
Mutations in the gene construct is less of a concern

Question 8
0 out of 1 points
"Which gene, when deleted, might decrease degradation of recombinant proteins?"
Selected Answer:
rne
Answers:
lonA
rne
fhuA2
groEL
arcA

Question 9
1 out of 1 points
"Overexpressing chaperones, like groEL, can increase recombinant protein levels in E. coli by:"
Selected Answer:
Reducing levels of misfolded proteins
Answers:
Improving carbon utilization of E. coli
Reducing levels of misfolded proteins
Enabling cell cultures to reach higher cell densities
Improving the stability of recombinant plasmids
Increasing the DNA templates for transcription
Prolonging the half-life of mRNA transcripts

Question 10
1 out of 1 points
"After centrifugation, aside from ethanol, what can be used to precipitate or concentrate the recombinant
protein from the supernatant?"
Selected Answer:
Ammonium sulfate
Answers:
Sodium hydroxide
Ethidium bromide
Ammonium sulfate
Thioredoxin
Dithiothreitol
Glutathione

Question 11
1 out of 1 points
When is the best growth phase to start inducing the expression of recombinant proteins?
Selected Answer:
Early stationary
Answers:
Early logarithmic phase
Early stationary
Before end of stationary phase
Start of death phase
Late decline phase
Lag phase

Question 12
0 out of 1 points
The recA gene when knocked out may lead to increased recombinant protein production by:
Selected Answer:
Prolonging the half-life of mRNA transcripts
Answers:
Reducing mRNA degradation
Prolonging the half-life of mRNA transcripts
Reducing recombinant protein degradation
Reducing levels of misfolded proteins
Decreasing proteolysis of recombinant proteins
Improving the stability of recombinant plasmids
QUIZ 11

Question 1
1 out of 1 points
What is not true about chymosin?
Selected
Answer:
Chymosin is a lipase used to promote the curdling of milk
Answers:
Chymosin is an enzyme used in cheesemaking
A recombinant chymosin was the first enzyme produced by recombinant DNA technology
that was approved by the FDA for food use
"Before recombinant biotechnology, chymosin had to be purified from calf stomach"
Chymosin is a lipase used to promote the curdling of milk
"Chymax is recombinant chymosin produced in fungus, Aspergillus"

Question 2
1 out of 1 points
"In the chromatographic separation used in the purification of recombinant human insulin peptides fused
with b-galactosidase sequences, antibodies immobilized in the column beads were used to capture the
fusion proteins. The type of chromatographic separation is:"
Selected Answer:
Affinity chromatography
Answers:
Ion exchange chromatography
Mass chromatography
Size exclusion chromatography
Hydrophobic Interaction chromatography
Affinity chromatography

Question 3
1 out of 1 points
What is not true about Pyrolase?
Selected Answer:
Pyrolase is an enzyme that retains activity at very acidic (pH 2) conditions
Answers:
Pyrolase has optimum enzymatic activity around 100oC
"Native pyrolase is produced by the hyperthermophiic archeon, Pyrococcus furiosus"
Pyrolase is an enzyme used in the oil industry to thin out the fracking solution
Pyrolase is an enzyme that retains activity at very acidic (pH 2) conditions
Pyrolase is a cellulase that breaks down polysaccharides

Question 4
1 out of 1 points
"___________________ is the largest product of industrial fermentation ton-wise, and is mainly used for
___________________."
Selected Answer:
Ethanol:fuel
Answers:
Petroleum: fuel
Polyvinyl:plastics
MSG:flavoring
Ethanol:fuel
Xanthan gum: Thickener
Acrylamide:plastics

Question 5
1 out of 1 points
"An improved version of nucleoside phosphorylase which gave a higher yield of inosine or guanosine
monophosphate, was produced by performing which type of mutagenesis technique?"
Selected Answer:
Error-prone PCR using Taq polymerase
Answers:
CRISPR-CAS9
Flippase-FRT
UV mutagenesis
Error-prone PCR using Taq polymerase
Transposon mutagenesis
Marker exchange using Flippase-FRT

Question 6
0 out of 1 points
"Which approach might increase formation of inclusion bodies in E. coli during recombinant protein
expression, instead of decreasing them?"
Selected Answer:
Grow E. coli cultures at 25oC instead of 37oC
Answers:
Secrete recombinant protein to periplasm
Employ a weaker promoter for the GOI
"For lac promoter driven GOI, decrease lactose concentration"
"For GOIs that are driven by CAP-regulated promoters, reduce glucose in the media "
Overexpress certain chaperones
Grow E. coli cultures at 25oC instead of 37oC

Question 7
1 out of 1 points
What is not true of inclusion bodies?
Selected
Answer:
IBs consist mostly of highly active proteins
Answers:
IBs consist mostly of highly active proteins
"For disulfide bond stabilized recombinant proteins, IBs can be lessened by secreting the
protein to the periplasm"
Inclusion bodies form due to the cell folding machinery being overwhelmed by protein
overexpression
Inclusion bodies form due to high numbers of exposed hydrophobic amino acids
IB formation can be decreased by overexpressing chaperones

Question 8
1 out of 1 points
In ion-exchange chromatography:
Selected Answer:
Negatively charged proteins binds strongest to a positively charged stationary phase
Answers:
The largest proteins elute last from the column and the smallest ones come out first
Hydrophobic proteins elute fastest from the column
Negatively charged proteins elute slowest from similarly charged resins
Negatively charged proteins binds strongest to a positively charged stationary phase
The elution buffer gradient goes from high to low salt concentration
QUIZ 12

Question 1
1 out of 1 points
What does not apply to the regulation and process of T-DNA transfer by Agrobacterium tumefaciens to
plant cells?
Selected
Answer:
virD4 synthesizes the complementary strand of the T-DNA once inside the plant cell
Answers:
virB codes for the pili component that serves to attach A. tumefaciens to plant cells
VirD2 is a relaxase that nicks the left and right border of the T-DNA (transfer) DNA.
virD4 synthesizes the complementary strand of the T-DNA once inside the plant cell
"Upon binding by chemicals that leak out of plant wounds, the sensor kinase, VirA,
autophosphorylates in a conserved histidine residue"
virE2 are single-strand-DNA binding proteins which protects the T-DNA from plant
nucleases
"The response regulator, VirG, gets phosphorylated by VirA and goes on to activate
expression of other vir genes"

Question 2
1 out of 1 points
"To engineer -carotene production in Golden Rice, genes from the bacterium, Erwinia uredovora, and
_____________________were transformed using Agrobacterium. "
Selected Answer:
daffodil or corn
Answers:
corn
dandelion
daffodil
daffodil or corn
squash
carrots

Question 3
1 out of 1 points
What is not true about FrostBan or ice-nucleation active (INA) protein?
Selected
Answer:
Answers:
"In the presence of wild-type P. syringae, ice crystals begin forming on leaves at lower
temperatures than in the absence of the bacterium"
Inactivation of ina gene renders P. syringae less damaging on plants
Spraying FrostBan extends the winter growing season of treated crops
"In the presence of wild-type P. syringae, ice crystals begin forming on leaves at lower
temperatures than in the absence of the bacterium"
INA protein causes freezing injury to plant tissues
Mutated ina gene was transformed and recombined into pathogenic P. syringae to make it
avirulent

Question 4
1 out of 1 points
VectorVax protects turkeys from Newcastle disease virus. How was it made into a vaccine?
Selected
Answer:
Answers:
NDV gene was encapsulated in the coat protein of less-virulent fowlpox virus
NDV was passed several times into non-host rabbits until an attenuated NDV was
produced
NDV was passed into media deficient in iron to produce a weakened NDV
NDV was treated with formaldehyde to kill NDV
NDV gene was encapsulated in the coat protein of less-virulent fowlpox virus
NDV virulence genes were inactivated by marker exchange mutagenesis to weaken
NDV

Question 5
1 out of 1 points
"The barnase gene from Bacillus amyloliquefaciens, is engineered in GM plants to: "
Selected Answer:
Make transgenic plants that have non-viable pollen
Answers:
Make transgenic plants that have non-viable pollen
Make transgenic plants which are resistant to insect pests
Make transgenic plants which are resistant to viruses
Make transgenic plants which are resistant to nematodes
Make transgenic plants which are resistant to herbicides

Question 6
0 out of 1 points
What is not true about FlavrSavr tomato?
Selected
Answer:
FlavrSavr was the first recombinant food approved by the FDA
Answers:
FlavrSavr was the first recombinant food approved by the FDA
FlavrSavr was genetically engineered to delay fruit ripening in tomato
"In FlavRSavR, the target gene was inactivated using cre-loxP site-specific
recombination "
"FlavrSavr has decreased levels of polygalacturonase, a cell-wall degrading enzyme"
FlavrSavr is edible

Question 7
0 out of 1 points
The plant resistance to viruses in more recently engineered transgenic plants is due to:
Selected
Answer:
The coat protein interfering with the assembly of viable virus particles
Answers:
The transgene reducing the levels of viral mRNAs
The coat protein interfering with the assembly of viable virus particles
The coat protein causing a systemic immune response in transgenic plants
The transgene interfering with the integration of the viral genome into the plant
genome
The coat protein interfering with the entry of the virus into the plant cells

Question 8
1 out of 1 points
Avermectin is produced by Streptomyces avermitilis and kills insects and worms by:
Selected Answer:
blocking transmission of electrical signals between nerve and muscle cells
Answers:
"killing cells lining the intestines thereby leading to insect starvation, then death"
interferes with proper food digestion
blocking transmission of electrical signals between nerve and muscle cells
interfering with molting
blocking the production of exoskeleton

Question 9
0 out of 1 points
What does not apply to the lysostaphin gene that has been engineered into cows:
Selected Answer:
leads to increased milk production
Answers:
kills Staphylococcus aureus
codes for a peptide that has antimicrobial properties
leads to increased milk production
prevents mastitis
is from a Bacillus strain

Question 10
1 out of 1 points
"Phy9X is an optimized version of the E. coli enzyme, phytase (AppA). Which of the statements below is
incorrect about Phy9X?"
Selected
Answer:
Answers:
"Phy9X catalyzes the removal of nitrates from phytate, thus making nitrates available for
absorption by livestock."
"In Phy9X, there are 9 amino acids that have been changed from the native E. coli
phytase "
Phy9X in feeds increase retention of dietary metals by pigs
"Phy9X catalyzes the removal of nitrates from phytate, thus making nitrates available for
absorption by livestock."
Site saturation mutagenesis was used to make amino acid changes in the wild-type appA.
Phy9X remains active longer at lower gastric pH than the wild-type protein.
Phy9X has a longer half-life at higher temperatures than the wild-type protein.

Question 11
0 out of 1 points
What is not true of inactivated vaccines?
Selected
Answer:
Answers:
Inactivated vaccines have lower risk of reversion to pathogenic state compared to
attenuated vaccines
Inactivated vaccines can be prepared by treating pathogens with chemicals like
formaldehyde
Inactivated vaccines are less immunogenic than attenuated vaccines
Inactivated vaccines have lower risk of reversion to pathogenic state compared to
attenuated vaccines
Inactivated vaccines are designed to replicate slowly in animals
Inactivated vaccines can be prepared by autoclaving pathogens

Question 12
1 out of 1 points
One of the very first crop engineered to be resistant to plant viruses was engineered to be resistant to
PRSV. PRSV stands for:
Selected Answer:
Papaya Ringspot Virus
Answers:
Papaya Ringspot Virus
Pineapple Roughshod Virus
Potato Ringworm Virus
Papaya Roughspot Virus
Pineapple Ringspot Virus

Question 13
1 out of 1 points
What is not true of RNA-induced gene silencing?
Selected Answer:
RISC stands for RNA-Induced Splicing Complex
Answers:
The RISC loaded with short antisense ssRNA binds to target mRNAs.
The slicer component of RISC cleaves the target mRNA.
RNA silencing can result from blockage of translation of target mRNA.
RISC stands for RNA-Induced Splicing Complex
"Double stranded RNA is cut into short pieces by the RNase, DICER."

Question 14
0 out of 1 points
Which statement is true regarding the use of plant versus animal cell for producing biotherapeutic protein
production?
Selected Answer:
Extraction and purification of proteins from animal cells are more complicated
Answers:
Animal cell cultures require less complex growth media
"Using plants,there is little need for process optimization and monitoring"
Animal cells require less expensive facilities and equipment to grow
Cheaper to produce pharmaceutical proteins in mammalian cell cultures than in plants
Extraction and purification of proteins from animal cells are more complicated
Contamination of animal cell cultures by animal viruses is less of a concern
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