BIOL 2153 : Exam 2 Transcription W Book Notes In Blue
Document Summary
Inititation in e. coli: contains oric, clustor of 3 copies of a 13-bp at-rich region, acts as replicator, dnaa is the initiator protein, binds to 9-bp regions in multiple copies. In viruses: a nick is created in one of 2 strands at origin, the unharmed single strand rolls out & makes tongue. Initiation: cell-specific, arss, autonomously replicating sequences, appx 100-bp. Similar to rxn in dna replication: rna polymerase selects ntp to be added through base pairing, bacterial transcription occurs in 3 stages: Sequence upstream of start of gene in rna: attracts rna polymerase, tells it which strand is the template & where to transcribe. Found 10-35 bp"s up from gene: concensus sequence = base found most frequently at each sequence. -> transcribed --> forms hairpin loop due to invert: prevents rna from bpp"ing w/ dna & transcription. -> rna poly slows down & falls off: mutations in the hairpin sequence can prevent transcription termination, ex.
