QBM Exam 3 Questions With Complete Answers Graded
A+
Which of the following DNA purification techniques CANNOT be used for
genomic DNA purification?
miniprep
Which DNA purification technique involves purifying the sample using an
ultracentrifuge?
Cesium chloride gradient
What technique is used to increase plasmid copy number and purify plasmids?
Miniprep.
Which of the following wavelengths is incorrectly matched?
240 nm - RNA concentration.
The absorbance of a DNA sample at A260 = 1.0, and A280 = 1.0. Which of the
following is TRUE?
There is significant protein contamination of this sample
RNA is more difficult to work with than DNA because
the 2' hydroxyl group causes RNA to be more susceptible to degradation.
Which of the following does NOT inhibit RNase activity?
EDTA
An advantage of agarose gel electrophoresis over SDS-PAGE is that
ALL (no stacking gel is needed, DNA can be purified and extracted, SDS is not required
to maintain an equal charge-to-mass ratio, DNA can be loaded perpendicularly)
The following DNA fragments are run on a gel. The DNA fragment in Lane 4 below
is
600 bp
Ethidium bromide is frequently chosen to visualize DNA on a gel because
It is more sensitive than SYBR Green and crystal violet
If Lane 1 contains undigested plasmid DNA and Lane 2 contains the same
digested DNA sample, which of the following is TRUE about the gel below?
The DNA sample has a molecular weight of 4 kb.
Which of the following techniques is most appropriate for separating DNA
fragments (>50 kb) for genotyping?
Pulse-field gel electrophoresis.
What is the most sensitive DNA visualization method?
Autoradiography.
Which of the following is a downstream application of agarose gel
electrophoresis?
(ALL) DNA sequencing, Southern blotting for DNA samples, northern for RNA sample
To extract DNA from a gel you would perform a
gel extraction and freeze squeeze
A collection of cells that are all descendants from the same cell are called
clones
Which of the following is NOT a tool used in recombinant DNA technology?
, Using primase to catalyze the formation of phosphodiester bonds.
Which of the following is TRUE about restriction enzymes?
They generally recognize palindromic DNA
An E. coli genomic DNA fragment is run out on a gel undigested (U), and then
with two different restriction enzymes. Based on the gel below, what is the most
appropriate reason for the band
pattern displayed?
The DNA fragment is methylated at the EcoRI cut site, but not the DpnI cut site
Which is TRUE regarding EcoRI, which cuts at GAATTC?
It is naturally found in E. coli.
What is true about the following enzymes?
SmaI - CCC^GGG
XmaI - C^CCGGG
They are neoschizomers.
Based on the restriction enzyme table below, which of the following is TRUE?
Xbal and BamHI should ideally be used together in Buffer 2
Three samples are digested with EcoRI and run out on a gel as shown. What can
be done to prevent the star activity seen in Lane 4?
All (Maintain a lower DNA enzyme ratio, adjust the pH of the buffer to ensure optimal
conditions for the restriction enzyme, remove glycerol and ethylene glycol from the
buffer, remove glycerol and ethylene glycol from the buffer, use a high-fidelity enzyme
to reduce star activity)
Based on the following restriction digests with restriction enzymes A and B, what
could be a possible restriction map that fits this data? The lines in the answers
represent a single piece of DNA, and the As and Bs represent cut sites.
NOT AABB
OR A B
OR A A A B
TRY AAAB
A circular piece of DNA is cut with HpaII and generates 3 fragments. How many
HpaII cut sites were present on the circular DNA?
3
Which lane below represents a digestion with PstI and XbaI?
Lane 5
DNA polymerases have ______ downstream exonuclease activity for primer
removal, and ______ proofreading exonuclease activity.
5'→3' ; 3'→5'
The Klenow fragment is a variation of DNA polymerase I with the ________
domain removed to prevent ________.
5'→3' exonuclease ; primer removal
Which of the following is true about creating blunt ends?
T4 DNA polymerase can chew back 3' overhangs and fill in 5' overhangs.
Two pieces of DNA can be joined together by
DNA ligase
In TA cloning, the insert and plasmid can be ligated together using
A+
Which of the following DNA purification techniques CANNOT be used for
genomic DNA purification?
miniprep
Which DNA purification technique involves purifying the sample using an
ultracentrifuge?
Cesium chloride gradient
What technique is used to increase plasmid copy number and purify plasmids?
Miniprep.
Which of the following wavelengths is incorrectly matched?
240 nm - RNA concentration.
The absorbance of a DNA sample at A260 = 1.0, and A280 = 1.0. Which of the
following is TRUE?
There is significant protein contamination of this sample
RNA is more difficult to work with than DNA because
the 2' hydroxyl group causes RNA to be more susceptible to degradation.
Which of the following does NOT inhibit RNase activity?
EDTA
An advantage of agarose gel electrophoresis over SDS-PAGE is that
ALL (no stacking gel is needed, DNA can be purified and extracted, SDS is not required
to maintain an equal charge-to-mass ratio, DNA can be loaded perpendicularly)
The following DNA fragments are run on a gel. The DNA fragment in Lane 4 below
is
600 bp
Ethidium bromide is frequently chosen to visualize DNA on a gel because
It is more sensitive than SYBR Green and crystal violet
If Lane 1 contains undigested plasmid DNA and Lane 2 contains the same
digested DNA sample, which of the following is TRUE about the gel below?
The DNA sample has a molecular weight of 4 kb.
Which of the following techniques is most appropriate for separating DNA
fragments (>50 kb) for genotyping?
Pulse-field gel electrophoresis.
What is the most sensitive DNA visualization method?
Autoradiography.
Which of the following is a downstream application of agarose gel
electrophoresis?
(ALL) DNA sequencing, Southern blotting for DNA samples, northern for RNA sample
To extract DNA from a gel you would perform a
gel extraction and freeze squeeze
A collection of cells that are all descendants from the same cell are called
clones
Which of the following is NOT a tool used in recombinant DNA technology?
, Using primase to catalyze the formation of phosphodiester bonds.
Which of the following is TRUE about restriction enzymes?
They generally recognize palindromic DNA
An E. coli genomic DNA fragment is run out on a gel undigested (U), and then
with two different restriction enzymes. Based on the gel below, what is the most
appropriate reason for the band
pattern displayed?
The DNA fragment is methylated at the EcoRI cut site, but not the DpnI cut site
Which is TRUE regarding EcoRI, which cuts at GAATTC?
It is naturally found in E. coli.
What is true about the following enzymes?
SmaI - CCC^GGG
XmaI - C^CCGGG
They are neoschizomers.
Based on the restriction enzyme table below, which of the following is TRUE?
Xbal and BamHI should ideally be used together in Buffer 2
Three samples are digested with EcoRI and run out on a gel as shown. What can
be done to prevent the star activity seen in Lane 4?
All (Maintain a lower DNA enzyme ratio, adjust the pH of the buffer to ensure optimal
conditions for the restriction enzyme, remove glycerol and ethylene glycol from the
buffer, remove glycerol and ethylene glycol from the buffer, use a high-fidelity enzyme
to reduce star activity)
Based on the following restriction digests with restriction enzymes A and B, what
could be a possible restriction map that fits this data? The lines in the answers
represent a single piece of DNA, and the As and Bs represent cut sites.
NOT AABB
OR A B
OR A A A B
TRY AAAB
A circular piece of DNA is cut with HpaII and generates 3 fragments. How many
HpaII cut sites were present on the circular DNA?
3
Which lane below represents a digestion with PstI and XbaI?
Lane 5
DNA polymerases have ______ downstream exonuclease activity for primer
removal, and ______ proofreading exonuclease activity.
5'→3' ; 3'→5'
The Klenow fragment is a variation of DNA polymerase I with the ________
domain removed to prevent ________.
5'→3' exonuclease ; primer removal
Which of the following is true about creating blunt ends?
T4 DNA polymerase can chew back 3' overhangs and fill in 5' overhangs.
Two pieces of DNA can be joined together by
DNA ligase
In TA cloning, the insert and plasmid can be ligated together using
