HLSC 2110U Lecture Notes - Lecture 13: Pribnow Box, Dihydrouracil, Tata Box
19 Mar 2019
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Document Summary
Working copies of dna = rna how the master plan is expressed. Starts with the recognition of transcription signals on dna by rna polymerase. Pribnow box tata box in prokaryotes. Then there is local unwinding of the dna double helix, initiation, elongation, and termination. There are also post-transcriptional modifications of the rna. Mrna includes the 5" cap (with methylguanosine to initiate translation) and poly-a tail (stabilizes mrna and facilitates the exit from the nucleus) and the removal of introns. 3 major types of rna differ in size, function, and structural modifications. In eukaryotes small rna molecules found in the nucleus perform specialized functions. Smallest (4s) of the 3 major species of rna molecules. Contain unusual bases (eg. dihydrouracil) and have extensive intra-chain base-pairing that leads to characteristic secondary and tertiary structure. Serves as an adaptor molecule that carries specific amino acid covalently attached to its 3" end to the site of protein synthesis.
