BIOB12H3 Chapter Notes - Chapter 11: Messenger Rna, Tata Box, 28S Ribosomal Rna
Document Summary
11. 2 an overiview of transcription in both prokaryotic and eukaryotic. Nppps = ribonucleoside triphosphate precursors (hydrolyzed into nucleoside monophosphates as they are polymerized into a covalent chain) Core enzyme attaches to random sites in dna. Enzyme separates (or melts) the two dna strands in the region surrounding the start site; makes the template strand accessible to the enzyme"s active site (resides at the back wall of the channel) Eukaryotic cells have three distinct transcribing enzymes in the nucleus, each responsible for synthesizing a different group of rnas. Recently discovered a fourth group rna polymerase iv (plants only?) Eukaryotic rna polymerases can be distinguished by their susceptibility to -amanitin. 3 major types of rnas (mrnas, rrnas, and trnas are derived from precursor rna molecules that are considerable longer than the final rna product. Primary transcripts usually have a fleeting existence, being processed into smaller, functional rnas but a series of cut-and-paste reactions.
