ASCP Molecular Biology Certification Exam Questions and Answers with Complete Solutions

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ASCP Molecular Biology Certification Exam Questions and Answers with Complete Solutions Pyrimidine ✔✔ One carbon ring Cytosine, Thymine, Uracil What is the function of mRNA? ✔✔ Carries ... genetic info out of nucleus Transcript translated to protein What is the function of tRNA? ✔✔ Carries aa to ribosome Anticodon pairs with codon on mRNA strand What is the function of rRNA? ✔✔ part of ribosome structure most abundant RNA coordinated coupling of tRNA to mRNA codons Feedback inhibition ✔✔ Product of pathway is noncompetitive inhibitor Binds to allosteric site to slow down rxn b/c too much product Endonucleases (Prok) ✔✔ Restriction enzymes Cleaves phoshpodiester bonds w/i poly-nt chain Recognition site is palindromic sequence Types I-V ORI sites ✔✔ nt sequence where replication is initiated Topoisomerase I ✔✔ 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 ✔✔ cuts both strands of one DNA double helix, passes another unbroken DNA helix through it, and then reanneals the cut strands Gyrase (topoisomerase II) ✔✔ Unwinds supercoiling caused by unwinding at the rep fork by introducing DSBs Helicase ✔✔ Breaks H-bonds of double helix at the replication fork single-strand DNA binding proteins (SSBPs) ✔✔ Binds ssDNA and prevents it from re-annealing during TXN, replication, repair, and recombination Telomeres ✔✔ Repeat sequence (TTAGGG) at the ends of chr, protect chr from degradation RNA polymerase ✔✔ DNA dependent RNApol Transcribes DNA template to RNA (3'-->5'; anti-parallel) Splicesomes ✔✔ Complex of snRNPs Removes introns from pre-mRNA and splices exons together Enhancers ✔✔ Short regions of DNA that bind proteins (TXN factors) that enhance TXN of a gene Reverse transcriptase ✔✔ enzyme that transcribes RNA to cDNA (lacks introns) RNA --> RNA:DNA --> cDNA (dsDNA) Open Reading Frame (ORF) ✔✔ 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 ✔✔ Measures amount of light absorbed Quantitative measurement of [DNA/RNA] At what wavelength does DNA and RNA absorb? ✔✔ 260 nm At what wavelength does protein absorb? ✔✔ 280 nm Organic isolation method ✔✔ 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? ✔✔ Allows formation of ds molecules Formamide acts as a __________ in a hybridization. ✔✔ denaturing agent Line Probe Assay (LiPA) ✔✔ reverse hybridization assay using sequence-specific oligonucleotide probes (reverse SSOP) multi-parameter testing --> single strip Single-Stranded Conformational Polymorphism Ananlysis (SSCP) ✔✔ 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? ✔✔ Intercalates into the double helix Absorbs UV ~300 nm, emits ~600 nm Pulse Field Gel Electrophoresis steps ✔✔ 1. culture 2. embed pellet in agarose plug 3. treat w/ lysozyme (cell lysis) 4. proteinase K 5. gel What are the 3 steps of PCR and their temperatures? ✔✔ Denature 90-96C Anneal 50-70C Extension 68-75C Bisulfite DNA sequencing/Methylation specific ✔✔ 1. RE digest 2. Electrophorese and purify fragment of interest 3. Denature and incubate w/ sodium bisulfate (turns C>U, methylated C is unchanged) 4. clean, ppt, and resuspend 5. PCR --> sequence 6. Compare treated vs untreated, note where CG are not changed to TA NASBA steps ✔✔ 1. Hybridize oligo-T7P primer to target seq 2. RT/RNase H 3. Hybridize with target-specific oligo primer (P2) 4. RNA transcript of T7 RNA pol Do you have to know the gene sequence in order to do DNA sequencing? ✔✔ Yes, in order to design primers You do NOT need to know the mutation Sanger sequencing method ✔✔ Divided into 4 samples (ddA, T, G, C) Label with radioactive/dye oligo at 3' end Mix with taq, dNTPs, ddNTP and incubate run on gel --> frags will terminate at different lengths Fluorescent in situ hybridization (FISH) ✔✔ Uses fluorescent probes to detect DNA sequences on chr [Show More]

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