BCH5413 TESTED QUESTIONS WITH
REVISED ANSWERS
Gel electrophoresis separates nucleic acids on the basis of... - Answer-Size
*Larger sizes have more difficult traveling through the gel matrix an run slower than
smaller fragments.
Which of the following statements regarding the stringency of a Southern Blot is
correct? - Answer-Decreasing the ionic strength increases stringency because less ions
in solution make it more difficult for DNA fragments to anneal.
A sample with higher Ct value would have ... starting material than a sample with lower
Ct value. - Answer-Less
*The higher the Ct value, the longer it takes a sample to cross the threshold, meaning
less RNA to start.
In the development of knockout mice, it is critical to genotype the mice to determine if
the gene of interest is actually knocked out. Below is a figure for the primer locations for
triplex PCR. Which of the following PCR results would represent true knockout mice? -
Answer-One band of relatively lower molecular weight
* The primer pair for the knockout gene produces a smaller fragment than the
endogenous gene. If both genes are replaced with PGK-NEO, PCR will produce one
band of a relatively smaller (lower molecular weight) size.
In the mammalian shuttle vector pcDNA3.1, the purpose of the neomycin resistant gene
is to... - Answer-To select for mammalian cells that were successfully transfected.
polylinker - Answer-to match vector and insert restriction sites
antibiotic resistance gene - Answer-to select against bacteria that did not take up the
plasmid
origin of replication - Answer-to make copies of the plasmid once in cells
LacI gene - Answer-to regulate expression of your gene of interest
LacZ gene - Answer-to screen for plasmids that contain the gene of interest
When 454 pyrosequencing was developed, what were the two main advances in the
method that allowed for faster sequences of millions of templates? - Answer--the ability
to determine the sequence without the use of a gel matrix.
-the addition of adapters to the fragmented DNA to allow sequencing of any DNA
fragment (the ligation of adapters to the ends of the DNA fragments allowed the same
primer to be used for all sequencing reactions)
REVISED ANSWERS
Gel electrophoresis separates nucleic acids on the basis of... - Answer-Size
*Larger sizes have more difficult traveling through the gel matrix an run slower than
smaller fragments.
Which of the following statements regarding the stringency of a Southern Blot is
correct? - Answer-Decreasing the ionic strength increases stringency because less ions
in solution make it more difficult for DNA fragments to anneal.
A sample with higher Ct value would have ... starting material than a sample with lower
Ct value. - Answer-Less
*The higher the Ct value, the longer it takes a sample to cross the threshold, meaning
less RNA to start.
In the development of knockout mice, it is critical to genotype the mice to determine if
the gene of interest is actually knocked out. Below is a figure for the primer locations for
triplex PCR. Which of the following PCR results would represent true knockout mice? -
Answer-One band of relatively lower molecular weight
* The primer pair for the knockout gene produces a smaller fragment than the
endogenous gene. If both genes are replaced with PGK-NEO, PCR will produce one
band of a relatively smaller (lower molecular weight) size.
In the mammalian shuttle vector pcDNA3.1, the purpose of the neomycin resistant gene
is to... - Answer-To select for mammalian cells that were successfully transfected.
polylinker - Answer-to match vector and insert restriction sites
antibiotic resistance gene - Answer-to select against bacteria that did not take up the
plasmid
origin of replication - Answer-to make copies of the plasmid once in cells
LacI gene - Answer-to regulate expression of your gene of interest
LacZ gene - Answer-to screen for plasmids that contain the gene of interest
When 454 pyrosequencing was developed, what were the two main advances in the
method that allowed for faster sequences of millions of templates? - Answer--the ability
to determine the sequence without the use of a gel matrix.
-the addition of adapters to the fragmented DNA to allow sequencing of any DNA
fragment (the ligation of adapters to the ends of the DNA fragments allowed the same
primer to be used for all sequencing reactions)
