EC L2b Flashcards
RNA processing is also known as…?
post transcriptional modification
what is primary transcript made by?
RNA polymerase
when is primary transcript made?
when RNA polymerase has finished the job
primary transcript has to be made into what…?
Mature RNA
what is RNA processing…?
everything that happens in the process between primary transcript and mature RNA
processing rRNA and tRNA involves what?
chemical modification
cleavage and trimming
which type RNA does NOT get processed?
Bacterial mRNA
processing of mRNA- only talking about eukaryotic here as bacteria mRNA is not processed
capping
splicing
tailing
which (‘) end is capped and tailing during processing of mRNA
5’ capped
3’ is tailing
capping
info
This might (or might not) be a protective device against nucleases (eukaryotic mRNAs are typically longer-lived than bacterial mRNAs) but, more importantly, the cap is recognised by specific proteins that enable ribosomes to bind to the mRNA and initiate protein synthesis.
tailing
info
Tailing. By far the majority of eukaryotic mRNAs (but not all of them) acquire tails.
Describe the tail It’s a strand of A resedue (polyA tail n-200), when mRNA is first made, it has a long tail, it get shorter with usage and when it ends up with 10 nucleotides in length it gets degraded.
splicing
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Splicing. This involves the processing of mRNA primary transcripts.
Mature eukaryotic mRNAs are typically much shorter than the genes from which they are transcribed, but the primary transcripts are not.
info card
RNA pol 2 does not know the difference between exons and introns, therefore it transcribes, and you get a primary transcript with equal pcs of the introns and exons.
to get rid of the introns, splicing takes place, it takes out the introns and joins the exons in the right order of which they exists in the gene.Spliceosomes preform splicing.
