BIO 327 Chapter Notes - Chapter 7: Nucleoplasm, Telomere, Alternative Splicing
Document Summary
Rna polymerase determines which of the two dna strands to use as a template for transcription. Each strand has a different sequence and would produce a different rna transcript. Decided by promoter: each promoter has a certain polarity: it contains 2 different nucleotide sequences upstream of the transcriptional start site that position the rna polymerase. Ensures that it binds to the promoter in only one orientation. Orientation of promoter determines which direction the gene is transcribed/template strand. Transcription initiation in eukaryotes vs. that in bacteria. Bacteria has a single type of rna polymerase. Bacterial rna polymerase initiates transcription on its own. Genes lie close to one another in dna (only short lengths of non-transcribed dna) Dna lies exposed to the cytoplasm, where ribosomes for protein synthesis are. Eukaryotic cells have three types of rna polymerases: rna polymerase i, rna polymerase ii, rna polymerase iii. Requires assistance of large set of accessory proteins. General transcription factors (assemble at each promoter)
