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
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
