7-8: Transcription and Translation Flashcards
What is the function of mRNA?
messenger RNA that codes fro proteins
What is rRNA?
ribosomal RNA, that forms the basic structure of the ribosome and catalyze protein synthesis
What is tRNA?
- transfer RNA
- acts as an adaptor between mRNA and amino acidss
What is snRNA?
- small nuclear RNA
- splice pre-RNA and other nuclear function
What is snoRNA?
- small nucleolar RNA
- process and chemically modify rRNAs
What are miRNA?
- microRNA
- regulate gene expression by blocking translationof specific mRNA and produce their degradation
What are siRNA?
- small interfering RNA
- control gene expression by directing degradation of selective mRNA and establishing compact chromatin structures
Why can RNA poly have a lower fidelity than that of DNA poly?
-the mistakes that are made are not transmitted to the progeny, therefore mistakes are more allowed
What subunits make up the bacterial RNA polym?
- alpha2, beta, beta prime, sigma
The mRNA strand that is synthesized is most similar to what?
- complementary to the template strand
- identical to the coding strand
What are two common motifs in bacteria that signal for transcription initiation?
- TTGACA at -35
- TATAAT box at -10 from the initiation site
What does RNA polym encounter that helps initiate the termination of transcription?
- GC,AT rich region contributes to the formation of a hairpin which causes a pause in RNA Polym.
- the hairpin adds new tension to the RNA polym and RNA strand, causing it to destabilize due to weak attachment bc of increased AU interactions
- mRNA leaves and the transcription bubble closes
Eukaryotes require more than one RNA polymerase to perform transcription. What are these and which is the most important?
- RNA Polymerase I, II, III
2. polym II: all protein coding genes, and the other RNA types mentioned
What is the main regulator that controls the RNA poly II activity?
- the regulator is phosphorylation of Ser residues located on the carboxyl-terminal domain
What unit contains the TBP, TATA-box binding protein?
- TFII D recognizes the TATA binding region
What factors combine to form the transcription initiation complex?
TFIIB, TFIIF, RNA poly II, TFIIE, and TFIIH
What process occurs that causes the end of initiation and begins the elongation process?
- TFIIH phosphorylates the carboxyl-terminal domain, and forces the polymerase to leave the promoter
Eukaryotic polymerase TFIID TBP subunit does what function?
- recognize the TATA box
Eukaryotic polymerase TFIID TAF subunit has what function?
- regulate DNA binding by TBP, and recognize other DNA sequence near transcription start point
Eukaryotic polymerase TFIIB has what function?
- recognize BRE element in promoters. accurately positions RNA polymerase at the start site of transcription
Eukaryotic polymerase TFIIF has what function?
- stabilize RNA polym interaction with TBP and TFIIB
Eukaryotic polymerase TFIIE has what function?
- attract and regulate TFIIH
Eukaryotic polymerase TFIIH has what function?
- unwinds DNA at start point, releases RNA polymerase from the promoter
What are recruited to increase the accessibility of DNA to specific enzymes?
- chromatin modifying enzymes
- chromatin remodeling complex
- histone modifying enzymes
