NRSC 2200 EXAM 1 QUESTIONS WITH VERIFIED ANSWERS LATEST
UPDATE 2026
What is a Cq value - what does the acronym stand for and what does it represent? -
Answers -The number of cycles that were needed for the fluorescence to reach a
quantification threshold.
-quantification cycle
Ct value - Answers threshold cycle value
independent variable - Answers variable that is manipulated
dependent variable - Answers The measurable effect, outcome, or response in which
the research is interested.
If a positive control does not generate a Cq value in qPCR, then you need to run the
whole experiment again, and generate better quality RNA from the tissue - Answers
True
What is the ideal A260:A280 ratio - Answers -2:1
-2.0
Why is PCR not good for quantitative analysis? - Answers It doesnt quantify how
many times the cDNA was replicated and it has been replicated X times.
What is the difference between PCR and qPCR? - Answers PCR products are
analyzed after the cycling is completed while in qPCR, the products are monitored as
the PCR is occurring. (PCR = endpoint, qPCR = quantitative).
What is the purpose of running a second PCR for B-actin? - Answers provide a
baseline of stable gene expression against which to compare another gene's expression
levels
What do we assume when regarding B-actin expression in cockraoches? - Answers
The independent variable doesn't affect it.
Positive control - Answers Group expected to have a positive result, allowing the
researcher to show that the experimental set up was capable of producing results.
positive control - Answers - cDNA that contains the qPCR target sequence.
- Should give a Cq value
negative control - Answers Control group where conditions produce a negative
outcome. Negative control groups help identify outside influences which may be
present that were not accounted for when the procedure was created.
, negative control - Answers -cDNA that does not contain the qPCR target sequence. -
Should not give a Cq values
Positive control - Answers -should produce a Ct/Cq value between 1 and 40
-Uses a DNA sample known to contain the gene target for the qPCR reaction
The no reverse transcription control (NRT) - Answers -contains the master mix plus
RNA that has not been reverse transcribed and therefore should not contain DNA
-should not produce a Ct/Cq value
For qPCR, each experimental sample will be run? - Answers in triplicate (i.e. in 3
separate wells)
SYBR green - Answers only fluoresces when bound to double stranded DNA
The no template control(NTC) - Answers -checks for general/extraneous DNA
contamination
-contains only the master mix
-should not produce a Ct/Cq value
NTC - Answers - Contains only Master Mix (no DNA template).
- Should not give a Cq value. If it does, there is extraneous DNA contamination (eg
splashing, not changing pipette tips when contaminated with DNA etc)
NRT - Answers - Contains Master Mix + RNA.
- Should not give a Cq value. If it does, and NTC does not give Cq value, suggests
genomic DNA (gDNA) contamination of RNA sample. The gDNA comes from
cockroach cell nuclei.
Which of the following is true for the Ct/Cq value? - Answers -It's measured in the
exponential phase of the qPCR reaction
-It's measured when the amount of fluorescence is proportional to the starting material
-It's measured when the amount of fluorescence can be detected above background
Which of the following is true for the melt curve run after qPCR? - Answers If there
is only one type of double stranded DNA in the sample, there will only be one peak
on the melt curve
For the qPCR used to assess period mRNA levels, - Answers two primers specific for
the period gene are used
What are the basic steps of PCR? - Answers -Hot Start*
-Denaturation
-Annealing
-Extension
UPDATE 2026
What is a Cq value - what does the acronym stand for and what does it represent? -
Answers -The number of cycles that were needed for the fluorescence to reach a
quantification threshold.
-quantification cycle
Ct value - Answers threshold cycle value
independent variable - Answers variable that is manipulated
dependent variable - Answers The measurable effect, outcome, or response in which
the research is interested.
If a positive control does not generate a Cq value in qPCR, then you need to run the
whole experiment again, and generate better quality RNA from the tissue - Answers
True
What is the ideal A260:A280 ratio - Answers -2:1
-2.0
Why is PCR not good for quantitative analysis? - Answers It doesnt quantify how
many times the cDNA was replicated and it has been replicated X times.
What is the difference between PCR and qPCR? - Answers PCR products are
analyzed after the cycling is completed while in qPCR, the products are monitored as
the PCR is occurring. (PCR = endpoint, qPCR = quantitative).
What is the purpose of running a second PCR for B-actin? - Answers provide a
baseline of stable gene expression against which to compare another gene's expression
levels
What do we assume when regarding B-actin expression in cockraoches? - Answers
The independent variable doesn't affect it.
Positive control - Answers Group expected to have a positive result, allowing the
researcher to show that the experimental set up was capable of producing results.
positive control - Answers - cDNA that contains the qPCR target sequence.
- Should give a Cq value
negative control - Answers Control group where conditions produce a negative
outcome. Negative control groups help identify outside influences which may be
present that were not accounted for when the procedure was created.
, negative control - Answers -cDNA that does not contain the qPCR target sequence. -
Should not give a Cq values
Positive control - Answers -should produce a Ct/Cq value between 1 and 40
-Uses a DNA sample known to contain the gene target for the qPCR reaction
The no reverse transcription control (NRT) - Answers -contains the master mix plus
RNA that has not been reverse transcribed and therefore should not contain DNA
-should not produce a Ct/Cq value
For qPCR, each experimental sample will be run? - Answers in triplicate (i.e. in 3
separate wells)
SYBR green - Answers only fluoresces when bound to double stranded DNA
The no template control(NTC) - Answers -checks for general/extraneous DNA
contamination
-contains only the master mix
-should not produce a Ct/Cq value
NTC - Answers - Contains only Master Mix (no DNA template).
- Should not give a Cq value. If it does, there is extraneous DNA contamination (eg
splashing, not changing pipette tips when contaminated with DNA etc)
NRT - Answers - Contains Master Mix + RNA.
- Should not give a Cq value. If it does, and NTC does not give Cq value, suggests
genomic DNA (gDNA) contamination of RNA sample. The gDNA comes from
cockroach cell nuclei.
Which of the following is true for the Ct/Cq value? - Answers -It's measured in the
exponential phase of the qPCR reaction
-It's measured when the amount of fluorescence is proportional to the starting material
-It's measured when the amount of fluorescence can be detected above background
Which of the following is true for the melt curve run after qPCR? - Answers If there
is only one type of double stranded DNA in the sample, there will only be one peak
on the melt curve
For the qPCR used to assess period mRNA levels, - Answers two primers specific for
the period gene are used
What are the basic steps of PCR? - Answers -Hot Start*
-Denaturation
-Annealing
-Extension
