ASCP MB EXAM 2026-2027 QUESTIONS AND
CORRECT ANSWERS GRADED A+
Which probe based detection system has a chemically modified probe that does
NOT degraded at the extension step?
Taqman or Molecular Beacon?
Molecular Beacon.
When the primers are extended (after extension), the Molecular Beacon probe will
return to its hairpin state oppose to being degraded like Taqman probes.
What is the purpose of mixing isolated (aka extracted) DNA with ethanol after
isolation?
Allows DNA to precipitate out.
(Allows DNA to form a solid precipitate in pellet form.)
What is the peak absorbance for each:
230nm = ?
260nm = ?
270nm = ?
,280nm = ?
>330nm = ?
230nm = Organic compounds
260nm = Nucleic acids (DNA & RNA)
270nm = Phenol
280nm = Protein
>330nm = Particulate matter (junk)
In organic DNA isolation, which phase contains the DNA: upper aqueous phase or
the lower organic phase (aka lower hydrophobic)?
Upper aqueous phase
Note DNA is hydrophilic because of the sugar-phosphate backbone.
True or false: Rho is a helicase enzyme?
True
,Which termination process in prokaryotes uses a hairpin structure to slow or stop
transcription and is also known as intrinsic termination?
Rho-dependent termination or Rho-independent termination
Why?
Rho-independent termination
Called independent because it does not require any additional factors or enzymes
to initiate termination of transcription. Instead, the RNA strand will fold onto itself,
creating a hairpin structure, which in turn slows the RNA polymerase from moving
along the strand and ultimately stopping transcription.
How many RNA polymerases do eukaryotes have vs. prokaryotes?
Eukaryotes = Three RNA Polymerases
1.) RNA Pol I
2.) RNA Pol II
3.) RNA Pol III
Prokaryotes = One RNA Polymerase
What is the absorptivity constant of DNA?
Of RNA?
, DNA = 50ug/mL (for dsDNA)
RNA = 40ug/mL
What is the equation to find the concentration of DNA or RNA when the
absorbance reading and the dilution factor are given?
Concentration = (Absorbance reading) x (absorptivity constant DNA/RNA) x
(dilution factor)
A technologist uses the spectrophotometer to quantify the amount of DNA
extracted from a blood specimen diluted 1:30. The absorbance reading at 260 nm
was found to be 2.545. The concentration of DNA in this extract is:
Absorbance x Absorptivity constant x Dilution factor
2.545 x 50ug/mL x 30 = 3817.5ug/mL
Mutation in what gene is associated with Fragile X syndrome?
H63D
CFTR
FMR1
F5
FMR1 = Fragile X Mental Retardation 1
*H63D and HFE = Hemochromatosis
CORRECT ANSWERS GRADED A+
Which probe based detection system has a chemically modified probe that does
NOT degraded at the extension step?
Taqman or Molecular Beacon?
Molecular Beacon.
When the primers are extended (after extension), the Molecular Beacon probe will
return to its hairpin state oppose to being degraded like Taqman probes.
What is the purpose of mixing isolated (aka extracted) DNA with ethanol after
isolation?
Allows DNA to precipitate out.
(Allows DNA to form a solid precipitate in pellet form.)
What is the peak absorbance for each:
230nm = ?
260nm = ?
270nm = ?
,280nm = ?
>330nm = ?
230nm = Organic compounds
260nm = Nucleic acids (DNA & RNA)
270nm = Phenol
280nm = Protein
>330nm = Particulate matter (junk)
In organic DNA isolation, which phase contains the DNA: upper aqueous phase or
the lower organic phase (aka lower hydrophobic)?
Upper aqueous phase
Note DNA is hydrophilic because of the sugar-phosphate backbone.
True or false: Rho is a helicase enzyme?
True
,Which termination process in prokaryotes uses a hairpin structure to slow or stop
transcription and is also known as intrinsic termination?
Rho-dependent termination or Rho-independent termination
Why?
Rho-independent termination
Called independent because it does not require any additional factors or enzymes
to initiate termination of transcription. Instead, the RNA strand will fold onto itself,
creating a hairpin structure, which in turn slows the RNA polymerase from moving
along the strand and ultimately stopping transcription.
How many RNA polymerases do eukaryotes have vs. prokaryotes?
Eukaryotes = Three RNA Polymerases
1.) RNA Pol I
2.) RNA Pol II
3.) RNA Pol III
Prokaryotes = One RNA Polymerase
What is the absorptivity constant of DNA?
Of RNA?
, DNA = 50ug/mL (for dsDNA)
RNA = 40ug/mL
What is the equation to find the concentration of DNA or RNA when the
absorbance reading and the dilution factor are given?
Concentration = (Absorbance reading) x (absorptivity constant DNA/RNA) x
(dilution factor)
A technologist uses the spectrophotometer to quantify the amount of DNA
extracted from a blood specimen diluted 1:30. The absorbance reading at 260 nm
was found to be 2.545. The concentration of DNA in this extract is:
Absorbance x Absorptivity constant x Dilution factor
2.545 x 50ug/mL x 30 = 3817.5ug/mL
Mutation in what gene is associated with Fragile X syndrome?
H63D
CFTR
FMR1
F5
FMR1 = Fragile X Mental Retardation 1
*H63D and HFE = Hemochromatosis
