Ribosomal tRNA Binding Sites

by Jason Amores Sumpter
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in this video we're going to talk more details about the ribosomes specifically the ribosomes. T. RNA binding sites. And we'll talk about an overview of translation as well. Now keep in mind that this video is really just going to be the introduction and the overview of the ribosomes, Tr binding sites and this process of translation. But as we move forward in our course we're going to break down the process of translation into its steps. And so we're going to talk more details about translation as we move forward in our course. And this video here is really just the overview. So keep that in mind as we move forward through this video. And so each of the ribosomes is going to have three T. R. N. A binding sites. And so recall that the Tr nasr the transfer RNA. Is that are going to be attached to amino acids and bring amino acids to the ribosome. And so the T. RNA binding sites are going to be found within the ribosome and there are three T. RNA binding sites. The first T. RNA binding site is going to be the amino acid L. T. RNA binding site, otherwise just abbreviated as the A site. And so the a site is going to be the site where the T. R. N. A. S. Are going to originally enter into the rib zone. And so it holds the T. RNA that's carrying the next amino acid to be added. And again T. R. And S. Will enter into the rib zone through the a site. And so if we take a look at our image down below, which you'll notice is we've got our ribs um are complete intact ribosome here in the background and the complete intact rivers um is going to be bound to our M. R. N. A. And so this right here represents our M. RNA are messenger RNA. And so what this ride zone does is it will receive T. R. N. A. S. Like this one right here. Uh This box here represents the T. RNA and because it's attached to an amino acid, this little purple circle here represents an amino acid that makes this Tr nay a charged tr nay. And again the charge has nothing to do with the positive or negative electrical charge. Instead the charge tr Nasr attached to amino acids. And so amino T. RNA is charged TR Nasr originally going to enter into the rib zone into the A site. So you can see the first site here is the A site. Now the second ribosomes, T. RNA binding site is going to be the P site or the peptide T. RNA binding site, otherwise known as the P site. Now the p site is going to be the site that is going to be holding the T. RNA that's carrying the growing polyp peptide chain or the growing protein chain. And so if we take a look at our image down below, which you'll notice is the P site is here in the middle and the p site is going to be holding the T. R. N. A. Uh that is attached to this growing polyp peptide chain here. So uh this background right here it represents the growing polyp peptide chain. And so the P site is going to have the amino, the T. R. N. A. That is bound to the growing polyp peptide chain. And so notice that the TR N. A. Is going to have the antique odin and the antique odin is going to pair with the code of the M. RNA. And so this will be a process that we'll talk more details about as we move forward in our course. Now the third and final site of the tr nay the ribs on T. RNA binding site is going to be the E site or the exit site. And so the E site or the exit site of course is going to be where the discharged TR N. A. S. Are going to leave the ribosome from this site. And so the east side is going to be on this end of the rib zone and the east side is the exit site. And so the discharged tR N. A. S. Which again has nothing to do with the electrical charge positive or negative. Instead discharged tR names are not attached to an amino acid and that's because the amino acid was transferred over to this growing chain here. This growing polyp peptide chain. And so the discharge T. RNA is without the amino acids are going to exit the ribosome through the east site. And so what we're seeing here is that charge T. R. N. A. S. Are bringing amino acids to the ribosome and they're entering into the A site. Then the p site is going to be contained the growing polyp peptide chain where the amino acid is just going to be added to the growing polyp peptide chain. And then uh the ribs um is just going to continue to shift along the M. R. N. A. And what happens is that the T. R. S. And the P site will shift into the east site and then eventually exit the ribs. Um in this way. So basically what's happening is charged TR s come in. They make their way from the A site to the P site to the east site and then ultimately leave the ribosome. And again this is a very detailed and complex process that involves a lot of moving pieces. And so the this here is really just the introduction to these three ribosomes T. RNA binding sites. And we're going to talk more details in a step by step manner of the process of translation involving all of this as we move forward in our course. But for now this year concludes our overview of the T. RNA binding sites and we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video.