BIO130H1 Lecture 6: Lecture 6 Part 2 (lec 7)
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BIO130H1 Full Course Notes
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Document Summary
Functions as rrna and trna, most rna are in these forms: one gene can code many rna sequences. Transcription process controls: abundance of rna produced, timing of protein synthesis, location of creating the proteins. Enhancer + ntrc: kisses rna polymerase, helps increase speed of transcription. Prokaryotic mrna is polycistronic, single mrna generates multiple proteins. Transcription process: dna is introduced into rna polymerase holoenzyme that loosely scans dna, when sigma factor recognizes promoter region, it binds to a specific promoter portion called consensus sequence. Localized unwinding of dna occurs, no atp required. Promoter (consensus sequence) signals that start of transcription, but is not transcribed itself. Initial transcription is slow: rna polymerase makes copies a 10 nucleotide rna sequence until an optimal is found (abortive phase, sigma factor is then released, rna elongation occurs rapidly (processive phase) Termination of transcription occurs when template dna includes many g/cs followed by many a/ts: a/ts have weaker bond strengths which allow rna to detach.
