BIOLOGY 2C03 Chapter Notes - Chapter 8: Chain Termination, Uracil, Deoxyribose
Document Summary
Chapter 8: molecular biology of transcription and rna processing. Dna vs. rna: thymine => uracil, deoxyribose => ribose. Bacterial transcription is a four-stage process: promoter recognition, transcription initiation, chain elongation, chain termination. Termination sequences: inverted repeat followed by a string of adenines. Transcribed mrna with the inverted repeats form into a short stem loop structure => a hairpin. Hairpin + poly u"s slow down and destabilize rna polymerase. Rna polymerase release the transcript and separate from the dna. Eukaryotic transcription is more diversified and complex than bacterial transcription. Eukaryotic genes carry introns and exons, and require processing to remove introns. Eukaryotic dna is associated with proteins to form chromatin: chromatin-based regulation: epigenetic process, chromatin modification and chromatin remodeling. Two categories of dna regulatory sequences: enhancer sequences sequences that increase level of transcription of specific genes, silencer sequences dna elements that repress transcription of their target genes. Archaeal transcription: different from bacteria, similar to eukaryotic rna pol ii.
