BIO-0013 Chapter Notes - Chapter 17: Enzyme, Polyadenylation, Tata Box
17 Nov 2016
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Enzyme catalyzes addition of nucleotides to 3" end of growing rna. Rna polymerase steers template and coding strands through channels inside enzyme, separate newly synthesized rna from dna template. All prominent channels and grooves in enzyme are filled as it synthesizes rna. Double stranded dna goes into and out of one groove. Transcription ends when rna polymerase transcribes dna sequence called transcription- termination signal. Portion of rna rapidly folds back on itself to for short double helix, held by complementary base pairing. Hairpin structure disrupts interaction between rna polymerase and rna transcript separation of enzyme and product. Each polymerase produces only certain types of rna. Example: mrnas are derived from genes transcribed by pol ii. Tata box: about 30 base pairs upstream of transcription start site. Transcription and translation separated in time and space- Rna downstream of poly(a) signal sequence cut by enzyme. Translation occurs by using ribosomes located in cytoplasm.
