BS 161 1st Edition Lecture 30 Outline of Last Lecture I. Transcription translationOutline of Current Lecture II. Transcription translation continuedCurrent Lecture-promoter: the DNA sequence where RNA polymerase attaches-terminator: the sequence signaling the end of transcription-three stages of transcription:-initiation-elongation-termination-transcription factors: mediate the binding of RNA polymerase-transcription initiation complex: the completed assembly of transcription factors and RNA polymerase II bound to a promoter-TATA box: crucial in forming the initiation complex in eukaryotes-TATA box is at -25 relative to the RNA synthesis start site-as RNA polymerase moves along the DNA, it untwists the double helix, 10 to 20 bases at a time-transcription progresses at a rate of 40 nucleotides per second in eukaryotes-a gene can be transcribed simultaneously by several RNA polymerases-the mechanisms of termination are different in bacteria and eukaryotes-in bacteria, the polymerase stops transcription at the terminator-in eukaryotes, the polymerase continues transcription after the pre-mRNA is cleaved from the growing RNA chain and the polymerase eventually falls off the DNA-DNA polymerase requires a primer, RNA polymerase does not-post transcriptional processing: during RNA processing both ends of the primary transcript are usually altered-introns: noncoding sequences-exons: other
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