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24 Cards in this Set
- Front
- Back
What is eukaryotic transcription more complex than bacteria transcription? |
Eukaryotes are larger, multicellular organisms with more cellular complexity such as organelles and Larger cells |
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RNA pol I transcribes what genes? |
rRNA (except 5s rRNA) |
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RNA pol II transcribes what genes? |
All structural/protein encoding genes (mRNA) and some snRNA |
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RNA pol III transcribes what genes? |
tRNA and 5s rRNA |
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Which RNA polymerase is essential for RNA splicing? |
RNA pol II |
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The core promoter consists of what 2 promotors? |
TATA box and transcriptional start site |
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Where is the transcriptional start site ? |
+1 |
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What is necessary for basal transcription? |
Only the elements in the core promoter |
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What would happen if the TATA box did not exist? |
Transcription start site is undefined and transcription may start in a variety of different locations |
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Where is the TATA box? |
About 25 bp upstream of start site |
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2 types of regulatory elements? What do regulatory elements do? |
Enhancers and silencers. They affect RNA polymerases ability to recognize the core promotor |
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what is the difference between trans and cis acting elements? |
Cis elements are found within the same chromosome as the genes they regulate. Trans acting may be located in a different chromosome |
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3 requirements for basal transcription at the core promoter? |
RNA pol II, general transcription factors, and a protein called mediator |
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How my GTFs are there? |
5 |
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Which transcription factor first binds to the TATA box? |
TFIID |
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What is the second and 3rd &4th transcription factors recruited to bind to TATA box? |
2nd- TFIIB 3rd- TFIIF 4th- TFIIE and TFIIH |
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The assembly of a closed complex in initiation is known as _____. |
Pre initiation complex |
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What transcription factor has the same function as helicase? |
TFIIH |
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What action causes an open complex to form and for TFIIB, TFIIE, and TFIIH to dissociate? |
TFIIH phosphorylates carboxyl terminal domain which releases the contact between RNA polymerase II and these proteins |
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What is the function of a mediator in transcription? |
Interface between CTD and RNA pol II so regulates ability of TFIIH to phosphorylate CTD |
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What is the major difference between the allo steric model and the torpedo model of transcription termination ? |
The torpedo model used exonuclease to dissociate RNA pol II from DNA. The allosteric model does not use a protein but dissociates due to release of elongation factors |
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What is the term for the correspondence between codon sequence in DNA and AA sequence of a polypeptide? |
Colinearity |
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Regions of mRNA that code for a polypeptide are called_____. Sequences between exons are called ______ |
Codons ; intervening sequences or introns |
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pre mRNA and mRNA differ how? |
does not have introns (exons have been spliced together) |