in this video, we're going to begin our lesson on pro carry attic gene expression by first talking about the location of transcription and translation, which is different between eukaryotes and pro curios. And so in eukaryotes or in eukaryotic organisms that have a nucleus transcription. First occurs in the nucleus of the eukaryotic organisms and then later translation will occur in the cytoplasm or in the rough end, a plasmid, articulable or rough er of the eukaryotic cell. Now in pro carry outs on the other hand, which lack a membrane bound nucleus transcription and translation. Both occur simultaneously in the cell's cytoplasm, specifically in the region of the cell known as the nuclear thyroid. And so the nuclear OID uh noticed in our image down below that we're showing you the locations of transcription as a star and the location of translation as this green shape that you see here. And so notice on the left we're showing you pro carry outs and on the right we're showing you eukaryotes and notice that pro Kerasiotes uh they have this nuclear oid region represented by this dashed circle here and that nuclear oid region is not membrane bound. So it's not to be confused with the nucleus that is found in eukaryotic cells which is membrane bound. And so notice that with the UK roads they have a nucleus a membrane bound nucleus. And this is the location of transcription transcription represented by the star here is going to occur in the nucleus of eukaryotes and translation. Notice does not occur in the nucleus translation will occur outside of the nucleus. Either and the rough end a plasma critical um or the rough er or just somewhere in the cytoplasm. Now, with the pro corrodes over here on the left again, they have this nuclear oid region, not to be confused with the nucleus. And the nuclear Lloyd is not membrane bound. And that's why you can see it's represented by this dashed line and which you'll notice is that transcription which is again represented by the star and translation. Uh this shape right here both occur simultaneously in the cell's cytoplasm, specifically in this nucleotide region. And so this box that you see right here is labeling the cytoplasm of the cells. Okay. And so which you'll notice is that in pro carry outs and in new carry out the locations of transcription and translation are going to be different. And so this is uh concludes our brief introduction to the location of transcription and translation. And we'll be able to get some practice and learn more about pro carry attic gene expression as we move forward in our course. So I'll see you all in our next video

in this video, we're going to further emphasize the idea of simultaneous transcription and translation. That occurs only in pro corrodes and not in eukaryotes. And so unlike eukaryotes or eukaryotic organisms that have a nucleus and have transcription and translation occur in different locations within the cell. Pro carry arctic organisms or pro carry oats. Uh and their pro carry attic gene expression can actually start translation of a messenger RNA before the messenger RNA. Or the Mrna is even fully synthesized. And so free ribosomes that are in the cytoplasm of the pro carry attic cell are able to bind to the messenger RNA and initiate translation while the messenger RNA is still being transcribed before the messenger RNA is even fully synthesized. And in fact multiple ribosomes are capable of translating the M. R. N. A. At once, making pro carry attic gene expression very, very efficient because transcription, transcription and translation can occur simultaneously and that's again very efficient. Now once again, this simultaneous transcription and translation only occurs in pro Kerasiotes. It does not occur in eukaryotes because in eukaryotes transcription and translation occur in different locations within the cell because the eukaryotes have a membrane bound nucleus, whereas in precarious they do not have a membrane bound nucleus. And this allows for transcription and translation to both occur in the same place in the cytoplasm of the pro carry its. And so if we take a look at this image down below, what it's focusing on is the simultaneous transcription and translation that occurs only in pro Karros. And so what you'll notice is that here, what we have is the RNA preliminaries which is in the process of elongating the messenger RNA. And so transcription is in the process in the middle of its formation. The messenger RNA is still being formed here. But what you'll notice is that ribosomes, these green structures that you see here, we can label them as ribosomes are capable of binding to the messenger RNA at this ribosome binding site over here and uh starting the translation process before transcription is even over. And so transcription and translation are occurring simultaneously. And you'll notice that each of these ribosomes are creating a protein binding amino acids together. And you'll notice that there can be multiple ribosomes bound to the messenger RNA at once so that multiple proteins are being built simultaneously as the RNA polymerase is continuing transcription. And once again this simultaneous transcription and translation only occurs in pro Kerasiotes like bacteria for example, that do not have a nucleus but simultaneous transcription translation does not occur in eukaryotes. And so this year concludes our lesson on simultaneous transcription and translation and precarious and we'll be able to get some practice moving forward with these concepts as well as learn more about pro periodic gene expression. So I'll see you all in our next video

in this video we're going to further emphasize the importance of pro carry attic sigma factors. And so recall in our previous lesson videos when we talked about the initiation of transcription, we mentioned that sigma factors are important for pro carry outs to initiate transcription. And so here we're recalling from our previous lesson videos that pro carry attic transcription initiation requires a sigma factor molecule and the sigma factor molecule is going to bind to the promoter sequence and helped to recruit the RNA. Preliminary so that the RNA polymerase can bind and initiate transcription. Now cells can actually have many different sigma factors and these different sigma factors can recognize different promoters on the DNA. And so different sigma factors are needed to express different genes within precarious. Now standard sigma factors are going to be sigma factors that are used for expressing genes during routine growth. And so standard sigma factors are almost always going to be expressed because they're always needed for a routine growth. However, alternative sigma factors are going to recognize different promoters and control expression of alternative gene groups And these alternative gene groups do not are not routinely expressed. And so these alternative gene groups are only going to be needed and very specific very certain scenarios. And so these alternative sigma factors will need to be present in order for these alternative gene groups to be expressed. For example, alternative sigma factors control the expression of specific gene group during heat shock and bacterial cells. And so that's what we're showing you over here on the left hand side is just the example of these alternative sigma factors. And so again, these sigma factors are only present and pro carry outs and they are not used by you curios. And so over here on the top what we have is a pro carry attic cell and notice it saying it isn't that hot, I'll be fine. And so this pro carry out excel is just in its normal temperature conditions. However, if we heat shock this bacterial cell here by applying lots of heat in a short period of time. Uh then uh this bacterial cell will need to rely on heat shock proteins and those heat shock proteins will need to be expressed. And the only way those Heat shock proteins can be expressed is if the appropriate sigma factors are available. And so if the sigma factor is present, like what we see over here on the left hand side, then transcription of the heat shot jeans will occur. And those heat shock proteins will protect the bacterial cell from high temperatures. And so notice on the left hand side over here we're showing you the bacterial cells surviving the heat shot and it's saying the heat never bothered me Anyways. Now on the right hand side, what we're showing you is what happens if the sigma factor is not present. If the sigma factor is absent and not available then no transcription of the heat shock genes will occur. And if there are no heat shock proteins made, then that is ultimately going to lead to the death of the bacterial self. And so these pro carry attic sigma factors must be present in order for these specific genes to be expressed at the right time when they are needed. And so over here, on the right hand side, we're just showing you some examples of gene groups that are regulated by alternative sigma factors. Not that you need to memorize this list here, but just showing you a few different examples. For example, Heat shock, like what we just talked about relies on the presence of very specific alternative sigma factors, the stationary phase of survival during a normal growth curve for bacteria nitrogen assimilation flow gellar synthesis, misfolded protein response and ion transport and uptake are all examples of some processes that require and rely on alternative sigma factors. And so really the biggest takeaway from this video is that pro carry arctic organisms rely on sigma factor molecules to initiate transcription during very specific um for very specific genes to be expressed. And so this year concludes our brief lesson on pro carry attic sigma factors and we'll be able to apply these concepts as we move forward and learn more about pro carry attic gene expression as well. So, I'll see you all in our next video

in this video, we're going to briefly point out some of the important differences between pro carry attic and eukaryotic Martinez. And so recall from our previous lesson videos that Eukaryotic Martinez must be processed after transcription. For example, the addition of a five prime cap and the addition of a poly a tail as well as the removal of entrance all must occur. Uh And for eukaryotic M. R. And S to be expressed. However, pro carry attic Martinez actually do not have any entrance. And so these pro carry attic Martinez do not require processing after transcription, like what Eukaryotic Mrna is require and so on the left hand side over here, what we're showing you is a pro carry attic Mrna, which will notice consists only of Exxon's and there are no entrance and the pro carry attic mrna. However, with the eukaryotic M. R. N. A. Again recall from our previous lesson videos that the Mrna is initially transcribed as a premature mrna. A pre mrna that contains both exxons and entrance. And so the entrance are these blue regions. And we know from our previous lesson videos that these introns must be removed during the RNA processing and spicing as well as adding the addition of a five prime cap and a poly a tail. And so this is what a eukaryotic Mrna fully mature you carry out again, Mrna might look like And so you can compare the differences between the two and so this year concludes our brief lesson on procreative versus eukaryotic and Marnie. So I'll see you all in our next video

in this video we're going to briefly differentiate between monos histrionic M. R. N. A. And policy histrionic M. R. N. A. And so you Kerasiotes tend to only make mono sis tronic M R N. A. Whereas pro carry outs on the other hand, they can either make monos histrionic MRNA. Or they could make policy. S Tronic Mrna. Now Mona's S tronic as its name implies with the root mono is referring to M. RNA molecules that can only carry one single gene. Whereas polish histrionic on the other hand, as its name implies with the root poly, which means many or multiple is referring to M. RNA molecules carrying multiple jeans. Now these policies, Tronic M RNA molecules tend to contain what are known as spacers and these spacers are random non coding sequences that are found in between different genes. And so if we take a look at our image down below, which will notice is on the left hand side, we're focusing in on mono sis tronic M. RNA molecules. And again, the route mono means that it's only gonna contain one single gene. And so notice that this monos astronomy M. RNA molecule only has one gene which is jean A. And this gene A. Is being flanked by Stark Odin and a stop code on and the gene A. And codes for protein as you see here. And so because there's only one single gene gene A. This is a mono SIs tronic M RNA molecule now within gene A If it is a eukaryotic monos S. Tronic Mrna. Uh there will be introns and exons and again we know that the entrance get removed whereas the Exxon's are going to remain and get spliced together. But eukaryotic organisms tend to make monos. S. Tronic M. RNA. Like what you see here containing only a single gene such as gina. Now on the right hand side, of course, what we're showing you is holly sis tronic Mariana. And again, the route poly means many or multiple. And so it's going to contain multiple genes. So notice that in the image not only does it contain gene A. Which codes for protein A. But it also contains jean B. Which codes for a protein B. And so because there are two genes within this M. RNA molecule right here, gina and jean B. This is an example of a policy S tronic M. RNA molecule. Now I've noticed that in between jean A and jean B. Uh is this region right here in pink. And this region here in pink is what we call the spacer. And so once again, the spacer region is going to be a random non coding sequence that's found in between different genes. Uh Again, spacers are not to be confused with entrances because introns are not found in between different genes. Entrants are found within a single gene and those entrance eventually would get removed. Okay. But the spacers are not found inside jean. The spaces are found in between different genes. And so once again eukaryotes tend to only make mono sis sis tronic M. RNA. Like what you see over here. However, pro Kerasiotes can make either mono or policy. S tronic so prokaryotes can do either of these and we'll be able to see some examples of policy S tronic M RNA molecules later in our course when we start to talk about the lack opteron um and operations and pro curios. But for now this year concludes our brief lesson on the difference between Mona's Histrionic Amarna and policies. Tronic Amarna 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.