ASCP Molecular Biology
Certification Exam
Questions and Complete
Solutions Graded A+
Denning [Date] [Course title]
,Pyrimidine - Answer: One carbon ring
Cytosine, Thymine, Uracil
What is the function of mRNA? - Answer: Carries genetic info out of nucleus
Transcript translated to protein
What is the function of tRNA? - Answer: Carries aa to ribosome
Anticodon pairs with codon on mRNA strand
What is the function of rRNA? - Answer: part of ribosome structure
most abundant RNA
coordinated coupling of tRNA to mRNA codons
Feedback inhibition - Answer: Product of pathway is noncompetitive inhibitor
Binds to allosteric site to slow down rxn b/c too much product
Endonucleases (Prok) - Answer: Restriction enzymes
Cleaves phoshpodiester bonds w/i poly-nt chain
Recognition site is palindromic sequence
Types I-V
ORI sites - Answer: nt sequence where replication is initiated
Topoisomerase I - Answer: Induces ss breaks
Remove DNA supercoils during TXN and DNA replication; for strand breakage during recombination; for
chr condensation; and to disentangle intertwined DNA during mitosis
topoisomerase II - Answer: cuts both strands of one DNA double helix, passes another unbroken DNA
helix through it, and then reanneals the cut strands
,Gyrase (topoisomerase II) - Answer: Unwinds supercoiling caused by unwinding at the rep fork by
introducing DSBs
Helicase - Answer: Breaks H-bonds of double helix at the replication fork
single-strand DNA binding proteins (SSBPs) - Answer: Binds ssDNA and prevents it from re-annealing
during TXN, replication, repair, and recombination
Telomeres - Answer: Repeat sequence (TTAGGG) at the ends of chr, protect chr from degradation
RNA polymerase - Answer: DNA dependent RNApol
Transcribes DNA template to RNA (3'-->5'; anti-parallel)
Splicesomes - Answer: Complex of snRNPs
Removes introns from pre-mRNA and splices exons together
Enhancers - Answer: Short regions of DNA that bind proteins (TXN factors) that enhance TXN of a gene
Reverse transcriptase - Answer: enzyme that transcribes RNA to cDNA (lacks introns)
RNA --> RNA:DNA --> cDNA (dsDNA)
Open Reading Frame (ORF) - Answer: sections of DNA that begin with start codons and end with stop
codons
DNA: 5' --> 3'
transcription: 3' --> 5' DNA --> RNA (promoter)
translation: 5' --> 3' mRNA
Spectrophotometer - Answer: Measures amount of light absorbed
Quantitative measurement of [DNA/RNA]
, At what wavelength does DNA and RNA absorb? - Answer: 260 nm
At what wavelength does protein absorb? - Answer: 280 nm
Organic isolation method - Answer: 1. Lyse
2. Add phenol/ chloroform > vortex/spin
3. Transfer aqueous layer (top) to new tube
4. Add chloroform:IAA (removes phenol) > vortex/spin
5. Transfer aqueous layer to new tube
6. Add NaOAc and EtOH > vortex/spin
7. Decant
8. Resuspend
What does the incubation step in hybridization do? - Answer: Allows formation of ds molecules
Formamide acts as a __________ in a hybridization. - Answer: denaturing agent
Line Probe Assay (LiPA) - Answer: reverse hybridization assay using sequence-specific oligonucleotide
probes (reverse SSOP)
multi-parameter testing --> single strip
Single-Stranded Conformational Polymorphism Ananlysis (SSCP) - Answer: Used for known gene,
unknown mut
Mutation screening
Short PCR products form 3D conformation when cooled --> muts have different conformation than WT
Non-denaturing PAGE, muts migrate different than WT
How does EtBr cause DNA to fluoresce? - Answer: Intercalates into the double helix
Certification Exam
Questions and Complete
Solutions Graded A+
Denning [Date] [Course title]
,Pyrimidine - Answer: One carbon ring
Cytosine, Thymine, Uracil
What is the function of mRNA? - Answer: Carries genetic info out of nucleus
Transcript translated to protein
What is the function of tRNA? - Answer: Carries aa to ribosome
Anticodon pairs with codon on mRNA strand
What is the function of rRNA? - Answer: part of ribosome structure
most abundant RNA
coordinated coupling of tRNA to mRNA codons
Feedback inhibition - Answer: Product of pathway is noncompetitive inhibitor
Binds to allosteric site to slow down rxn b/c too much product
Endonucleases (Prok) - Answer: Restriction enzymes
Cleaves phoshpodiester bonds w/i poly-nt chain
Recognition site is palindromic sequence
Types I-V
ORI sites - Answer: nt sequence where replication is initiated
Topoisomerase I - Answer: Induces ss breaks
Remove DNA supercoils during TXN and DNA replication; for strand breakage during recombination; for
chr condensation; and to disentangle intertwined DNA during mitosis
topoisomerase II - Answer: cuts both strands of one DNA double helix, passes another unbroken DNA
helix through it, and then reanneals the cut strands
,Gyrase (topoisomerase II) - Answer: Unwinds supercoiling caused by unwinding at the rep fork by
introducing DSBs
Helicase - Answer: Breaks H-bonds of double helix at the replication fork
single-strand DNA binding proteins (SSBPs) - Answer: Binds ssDNA and prevents it from re-annealing
during TXN, replication, repair, and recombination
Telomeres - Answer: Repeat sequence (TTAGGG) at the ends of chr, protect chr from degradation
RNA polymerase - Answer: DNA dependent RNApol
Transcribes DNA template to RNA (3'-->5'; anti-parallel)
Splicesomes - Answer: Complex of snRNPs
Removes introns from pre-mRNA and splices exons together
Enhancers - Answer: Short regions of DNA that bind proteins (TXN factors) that enhance TXN of a gene
Reverse transcriptase - Answer: enzyme that transcribes RNA to cDNA (lacks introns)
RNA --> RNA:DNA --> cDNA (dsDNA)
Open Reading Frame (ORF) - Answer: sections of DNA that begin with start codons and end with stop
codons
DNA: 5' --> 3'
transcription: 3' --> 5' DNA --> RNA (promoter)
translation: 5' --> 3' mRNA
Spectrophotometer - Answer: Measures amount of light absorbed
Quantitative measurement of [DNA/RNA]
, At what wavelength does DNA and RNA absorb? - Answer: 260 nm
At what wavelength does protein absorb? - Answer: 280 nm
Organic isolation method - Answer: 1. Lyse
2. Add phenol/ chloroform > vortex/spin
3. Transfer aqueous layer (top) to new tube
4. Add chloroform:IAA (removes phenol) > vortex/spin
5. Transfer aqueous layer to new tube
6. Add NaOAc and EtOH > vortex/spin
7. Decant
8. Resuspend
What does the incubation step in hybridization do? - Answer: Allows formation of ds molecules
Formamide acts as a __________ in a hybridization. - Answer: denaturing agent
Line Probe Assay (LiPA) - Answer: reverse hybridization assay using sequence-specific oligonucleotide
probes (reverse SSOP)
multi-parameter testing --> single strip
Single-Stranded Conformational Polymorphism Ananlysis (SSCP) - Answer: Used for known gene,
unknown mut
Mutation screening
Short PCR products form 3D conformation when cooled --> muts have different conformation than WT
Non-denaturing PAGE, muts migrate different than WT
How does EtBr cause DNA to fluoresce? - Answer: Intercalates into the double helix
