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15 Cards in this Set
- Front
- Back
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List 3 differences between RNA and DNA.
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1)RNA has Hydroxly at 2' carbon, while DNA has H only
2)RNA uses Uracil,DNA - thymine 3)RNA single stranded, DNA double stranded, double helix |
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What helps assist RNA polymerase to bind to the promotor sequences?
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Transcription Factors such as CREB and c-fos
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What is Upstream/Downstream?
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upstream - before the start point of transcription on 3' side of DNA.
downstream- after the start point of the 5' side. |
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What is a consensus sequence?
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A promoter region that is a conserved DNA sequence such as the Pribnow box in bacteria.
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Why is RNA polymerase essentially irreversible? And which way does it move?
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polymerase moves in the 3' to 5' direction along the DNA. Irreversible because nucleac acid synthesis is coupled to exergonic pyrophosphate hydrolysis producing phosphate.
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What is the transcription factor in bacteria?
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Sigma factor
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In bacteria, explain the transcription process.
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sigma factor binds with RNA polymerase the to produce a holoenzyme. Sigma factor falls off after RNA chain gets long enough. The polymerase stops transcription when it reaches the rho sequence.
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How many RNA polymerases do eukaryotes have? Explain.
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3, 4-plants.
RNA II - does most of work RNA I - large rRNA's RNA III - Small RNA's |
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What is the common promoter sequence across mammalian species?
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TATA box
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Explain the Transcription process in mammalian species.
(pre-initiation complex) |
Transcription factor for Polymerase II, Fraction D (TFIID) has subunit called TATA box binding protein (TBP). 1)TBP bind to the TATA promoter region. 2)two other TBP-associated facors bind (TAFs) bind to DNA 3)RNA polymerase II with TFIIF binds 4)TFIIE and TFIIH bind and enable the polymerase to begin
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TFIIH is the only part of the pre-initiation complex with enzymatic activity. Explain its purpose.
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TFIIH is a helicase, also phosphorylates RNA polymerase II
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What is the CTD? What is its purpose?
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The carboxyl-terminal domain. Contains 7 amino acid sequence repeated 52 times. 3 serine resides which get phosphorylated which stabilizes transcription by uncoupling RNA polymerase from promoter.
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What do enlongation factors do in RNA transcription?
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They prevent the dissocation of RNA polymerase II before completion.
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What additions are on mature RNA?
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5' end has a methylguansine cap and 3' have a non-coding region with a poly-adenosine (polyA) tail.
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What are exxons and interons?
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exxons are parts of the DNA coding sequence that form the mRNA. interons are DNA sequences that do not form the mRNA, but have regulatory functions.
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