2025 – 2026 MB (ASCB) EXAM WITH
CORRECT ACTUAL QUESTIONS AND
CORRECTLY WELL DEFINED ANSWERS
LATEST ALREADY GRADED A+
Southern Blot - ANSWERS-DNA
Western Blot - ANSWERS-protein
Northern Blot - ANSWERS-RNA
steps of pre-transfer for membranes - ANSWERS-1. de-purinate DNA to reduce
the size of fragments to transfer
2. denature DNA
3. neutralize to equlibrate gel and membrane
capillary transfer to membrane - ANSWERS-transfer buffer drawn up through a
reservoir and passes through gel into a stack of paper towels weighted; DNA
moves from gel with movement of buffer
,does NOT work forpolyacrylamide gels
dot blots - ANSWERS-bind DNA or RNA to membrane without first separating
the components by electrophoresis
less discrimination in hybridization
purpose of pre-hyb - ANSWERS-equlibrates membrane and minimizes
nonspecific binding
NASBA - ANSWERS-RNA is target
RNA-->cDNA
Reverse transcriptase (RNA-->cDNA) followed by DNA dependent polymerase
(cDNA-->RNA)
RNAse H degrades original RNA template
Evaluated gene EXPRESSION - ANSWERS-RNA
ratio for organic extraction - ANSWERS-Phenol (50): Chloroform (49): isoamyl
alcohol (1)
phenol - ANSWERS-denatures proteins, dissolves lipids
, chloroform - ANSWERS-assists in dissolving remaining lipids, gives a clear
interphase between aqueous phase
Long term storage of RNA - ANSWERS-70% EtOH at -70 C
ratio for 28S to 18S subunits - ANSWERS-2:1 (can see this in a gel)
A260 - ANSWERS-nucleic acids
A280 - ANSWERS-protein
A230 - ANSWERS-organic compounds, phenol
A270 - ANSWERS-phenol
optical density of ds DNA - ANSWERS-50 ug/ml
optical density ssDNA - ANSWERS-33 ug/ml
optical density RNA - ANSWERS-40 ug/ml
CORRECT ACTUAL QUESTIONS AND
CORRECTLY WELL DEFINED ANSWERS
LATEST ALREADY GRADED A+
Southern Blot - ANSWERS-DNA
Western Blot - ANSWERS-protein
Northern Blot - ANSWERS-RNA
steps of pre-transfer for membranes - ANSWERS-1. de-purinate DNA to reduce
the size of fragments to transfer
2. denature DNA
3. neutralize to equlibrate gel and membrane
capillary transfer to membrane - ANSWERS-transfer buffer drawn up through a
reservoir and passes through gel into a stack of paper towels weighted; DNA
moves from gel with movement of buffer
,does NOT work forpolyacrylamide gels
dot blots - ANSWERS-bind DNA or RNA to membrane without first separating
the components by electrophoresis
less discrimination in hybridization
purpose of pre-hyb - ANSWERS-equlibrates membrane and minimizes
nonspecific binding
NASBA - ANSWERS-RNA is target
RNA-->cDNA
Reverse transcriptase (RNA-->cDNA) followed by DNA dependent polymerase
(cDNA-->RNA)
RNAse H degrades original RNA template
Evaluated gene EXPRESSION - ANSWERS-RNA
ratio for organic extraction - ANSWERS-Phenol (50): Chloroform (49): isoamyl
alcohol (1)
phenol - ANSWERS-denatures proteins, dissolves lipids
, chloroform - ANSWERS-assists in dissolving remaining lipids, gives a clear
interphase between aqueous phase
Long term storage of RNA - ANSWERS-70% EtOH at -70 C
ratio for 28S to 18S subunits - ANSWERS-2:1 (can see this in a gel)
A260 - ANSWERS-nucleic acids
A280 - ANSWERS-protein
A230 - ANSWERS-organic compounds, phenol
A270 - ANSWERS-phenol
optical density of ds DNA - ANSWERS-50 ug/ml
optical density ssDNA - ANSWERS-33 ug/ml
optical density RNA - ANSWERS-40 ug/ml
