1) RNA Processing

by Jason Amores Sumpter
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in this video, we're going to talk about RNA processing. And so Arna processing Onley occurs in Eukaryotic organisms, not in pro carry attic organisms. And so eukaryotic RNA processing involves to events that are gonna alter both ends of the premature Mara or the pre M Arna. And so the first event is going to be the addition of a five prime cap, which is really just a modified guanine nucleotide that's going to be added specifically to the five prime end of the pre mRNA. And then the second event that's going toe alter. The end of the pre Amarna is the addition of a poly a tail, and the poly A tail is really just a sequence of a bunch of adding nucleotides that are gonna be added specifically to the three prime end of the pre m r N A. And so both of these alterations are going to modify the ends of the pre Amarna. And so if we take a look at our image down below, which you'll notice is over here on the left hand side. What we've got is our premature Mara, our pre m Arna immediately after transcription and so this pre m r N A. We know that in eukaryotic cells is going to go undergo Arna processing, which involves modifying the end of the pre Amarna so you can see the ends are being modified. The first modification involves the addition of a five prime cap, which is added to the five prime end of the RNA molecule. And again, the five prime cap is really just a modified guanine nucleotide. Now on the three prime end of the Arna molecule, it is also going to be modified. But with a poly, a tail and the poly, a tail is just a stretch of a bunch of adding nucleotides. That air added to the three prime end of yarn a molecule. Now you might be wondering. Why is it that the five prime cap and the poly a tail need to be added to the RNA? And so it turns out that the five prime cap and the poly a tail actually share several important functions, including the following functions that were listing down below. The five prime cap and poly a tail are both important for facilitating exports of the Marna from the nucleus where its first transcribed in eukaryotic organisms to the cytoplasm where the RNA molecule needs to be in order for translation to take place, which again we'll talk more about translation later in our course. But the pop five Prime Captain Poly a tail are really important toe export the Marna, from the nucleus to the cytoplasm. Now the five prime cap in poly a tail are also really important to protect the Marna from degradation by enzymes. And so the addition of the five prime cap and the poly a tail helps to again protect the Marna from degradation by enzymes that might otherwise degrade the RNA. Now, lastly, the five prime cap and poly a tail are both important for helping ribosomes attach to the Amarna for translation to take place. And so we'll be able to talk again, Maura, about translation later in our course. But these ribosomes are cellular structures that are important for translation. And so these ribs owns need to be able to attach to the marina and the five prime Captain Poly a tail play a role in that attachment. And so, uh, this here is going to conclude our brief introduction to Arna processing and so in our next video will be able to talk about RNA splicing, so I'll see you all in that video.