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15 Cards in this Set
- Front
- Back
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Does RNA Synthesis require a primer?
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No. The first nucleotide retains its triphosphate group.
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What two common sequences are located upstream of the transcription start site?
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TATA box and -35 consensu sequence: TTGACA.
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RNA Synthesis usually begins with a purine or pyrimidine?
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Purine
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What are th etwo types of transcription termination sites in bacteria?
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Factor independent termination - forms base-apired hairpin loop in mRNA.
Rho termination factor - Rho recognizes rut (rho utilization) termination site. |
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What does actinomycin D do?
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Inhibits RNA transcription in pro and eukaryotes. Intercalates into the DNA.
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And Rifamycin B?
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Inhibits only intiation of transcription only in prokaryotes.
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What are the functions of RNA polymerase I, II and III?
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I) transcribes most ribosomal RNA genes
II) synthesizes precursors of mRNA and some snRNA and scRNA species III) synthesizes tRNA, S rRNA and remainder of snRNAs andscRNAs |
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How do RNA polymerases I II and III react with alpha-amanitin?
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I - resistant
II - inhibited at very low concentrations III - inhibited only at high concentrations |
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How many additional transcription factors does RNA polymerase II require in eukaryotes?
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at least 7
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What are three DNA-binding transcription factors that bind to enhancers DNA-binding motifs?
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1( helix turn helix
2) zinc finger 3) leucine zipper |
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What does the cap structure in eukaryotic mRNA consist of?
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a methylated GTP conntected to the 5' terminal nucleotide via 5'-5' triphosphate linkage.
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What type of RNA is E. coli RNA polymerase responsible for?
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all types - mRNA, tRNA and rRNA
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What enzyme performs the processing of tRNA precursors in eukaryotes?
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ribonuclease III
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What are the four types of RNA-containg viruses?
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1) +RNA - contains single-stranded RNA that functions as mRNA in the infected host cell (polio)
2) -RNA - anti-messenger RNA that has to be copied into complementary mRNA before translation can begin. (Rabies) 3) dsRNA - double-stranded RNA that also require transccription into mRNA (reovirus) 4) Retroviruses - single-stranded +RNA that must first be transcribed into DNA. (HIV, leukemia viruses) |
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What is unique about virus type 1?
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It can use the host cell's translation machinery directly for the synthesis of their replicases. Types 2 3 and 4 must carry their own replicases or transcriptases.
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