Prokaryotic Gene Regulation via Operons

in this video, we're going to begin our lesson on pro carry attic gene regulation via operations, and so pro carry attic organisms, or pro Kerasiotes, must be able to survive in environments that constantly change in the availability of nutrients in the surroundings. And so this requires the pro cariocas to be able to rapidly change their metabolic pathways by regulation or regulating the expression of certain genes. Now, pro corrodes commonly control expression of their genes using what are known as operations. And so we'll get to talk more about these operations and the structure and components of operations as we move forward in our course. So I'll see you all in our next video.

in this video, we're going to talk about the structure of an opera. And so an opera is defined as a set or a group of pro carry attic jeans, usually of related function, that are controlled by a single promoter and recall from our previous lesson videos. When we talked about transcription that the promoter of a gene is going to be just ahead of a gene, a DNA sequence just ahead of the gene where the RNA preliminaries will bind. And so if we take a look at our image down below, notice that our operation is being labeled from this region here, over to this region over here, and what you'll notice is that the operation contains a group or a set of related genes. And here in our image, the related genes are gene a gene B and jean. See and notice that these related genes A, B and C are all controlled by a single promoter region, and the promoter region is up here and grain, and you'll notice that the opera also includes this other yellow region here that's called the operator. And so the transcription of the opera is regulated by the operator and the operator is a region of D N A. So it's a small D n, a sequence where regulatory proteins will bind and these regulatory proteins well buying to the operator and effect the RNA preliminaries binding to the promoter. And so some regulatory proteins will repress or block the RNA. Preliminaries from binding and other regulatory proteins will promote or stimulate the RNA Preliminary findings and so down below. What we're showing you are that repressors our regulatory proteins themselves that will block or inhibit RNA polymerase binding, preventing transcription. And then, of course, activators are going to be regulatory proteins themselves that will actually promote RNA polymerase binding, stimulating transcription. And so, if we take a look at our image down below again, notice that the opera on itself contained an operator and the operator is going to be the site for the binding of a regulatory protein here. And so the regulatory protein is going to have its own gene. And so the regulatory gene is over here and the regulatory gene has its own promoter. Okay, so you can see the promoter for the regulatory gene is here. The regulatory gene is here. The regulatory gene gets transcribed and translated into this regulatory protein, and the regulatory protein will bind. This is the regulatory protein it will when it's active. It will bind to the operator, as you see here, and depending on if the regular protein regulatory protein is a repressor or an activator, it will either block or promote the RNA polymerase binding. And so here we have the RNA preliminaries that will buy into the promoter, and it will not be able to bind if there is a repressor bound. But if there is an activator bound, then the RNA polymerase will be able to buy. And, of course, RNA preliminaries binding is necessary for transcription. And so this is really an opera. And opera is going to be again. A group of related genes like a B and C here that are controlled by a single promoter and transcription of these genes is controlled by this operator region, which will be the site for the regulatory protein binding. And so, as we move forward in our course, will be able to talk more and more about operations and specific types of operations and exactly how they function. But for now, this year concludes our introduction to the structure of an opera, and we'll be able to get some practice moving forward, so I'll see you all in our next video.

in this video, we're going to introduce, induce a ble operas and so induce a ble operations our operations themselves that are normally turned off, and when they are turned off, the genes will not be expressed, and so induce double operations are normally turned off. However, they can be turned on under very specific conditions, and when they can be turned on, that means that they can be induced. And those conditions where they can be turned on include the presence of what's known as an inducer, which will introduce here very shortly. And so, uh, induce herbal aprons are normally turned off but can be turned on. Yeah, and so what happens is an active repressor protein is going to repress transcription under normal conditions, and so the induce double opera and will be normally turned off when there is an active repressor protein repressing transcription. However, the active repressor protein can be inactivated by the inducer molecule, and so the inducer molecule will bind to the active repressor protein and inactivate the repressor, which will allow for transcription to proceed. And so, in other words, what we're saying here is that the inducer molecule is going to inactivate the repressor protein, and so when it in activates, the repressor protein transcription will be turned on. And so this is why it's called an induce a bill opera and because it can be induced, even though it's normally turned off. And so if we take a look at our image down below, we can get a better understanding of an induced herbal opera in the presence of an inducer inducer molecule. And so here we're showing you the induce double opera in which is very aligned with positive gene regulation, because what you can see from our previous lesson videos when we talked about positive gene regulation, it's when you turn a gene on, and so over here on the left hand side, what we're showing you is the induce double operation under normal conditions. So normally the inducer opera is turned off, and so the reason that it's turned off is because an active repressor protein will bind to the operator and block or prevent transcription, blocked the RNA preliminaries and block transcription. And so none of these genes will be expressed normally, however, under very, very specific conditions that include the presence of an inducer molecule Okay, Um, in the presence of this inducer molecule, the inducer molecule will bind to the repressor and cause the repressor to change its shape. Change its confirmation. And so the inactive repressor here can no longer bind to the operator. And so that means that the operator here is going to be free. And the RNA preliminaries is capable of binding to the promoter and proceeding with transcription. And so, in the presence of an inducer molecule, the induce herbal operation can be turned on. And so you can see here we have our light switch being flipped into the on state here. And of course, when transcription is turned on, uh, the M RNA will be made. And of course, the proteins will follow with translation. And so the products here are being made. And so what you can see here is that induce a bill operations are undergoing positive gene regulation, which means that they can be turned on although there normally off. And so this year concludes our brief introduction to induce a ble operas and as we move forward, will continue to learn more and more about operations and be able to get some practice. So I'll see you all in our next video

in this video, we're going to introduce repress herbal operas, and so a repressive ble opera is actually an opera and that is normally turned on. And so normally it's jeans are going to be expressed. However, it is a repressive ble opera because even though it is normally turned on, it can be turned off. Or it can be repressed under the right conditions, which includes having an active repressor protein. And so it's important to note here is that the inactive repressor protein cannot repress transcription without a co repressor molecule. And so the co repressor is a small molecule itself that will bind to the repressor, forming an active repressor protein. And so the repressor protein bound to the co repressor is what forms the active repressor protein. And so, in other words, the co repressor protein or molecule, is going to activate the repressor protein, so that transcription is turned off when there is an active repressor protein. So let's take a look at this image down below to get a better understanding of a repressive ble opera and so a repressive rule opera and falls right in line with negative gene regulation because what happens is, the gene can be turned off, and so, with repress herbal opera under normal conditions, they are normally turned on. And so what you, which will note, uh, here is that when it is normally turned on the RNA, polymerase is capable of binding and transcribing forming an M R N A. And then the M RNA will be translated into the gene products. And so when the gene is turned on, the genes are being expressed, and the reason that the genes are turned on here is because the repressor is in an inactive form. We have an inactive repressor protein here that cannot bind to the operator. And that's because this repressor protein here requires a co repressor in order to bind and so notice that under specific conditions, if there is a co repressor molecule which is represented by this little red molecule, the Little Red Co repressor combined to the inactive repressor to form an active repressor molecule. And so the active repressor is capable of binding to the operator to block or inhibit or prevent transcription, turning off the gene and turning off the operations. And so repressed herbal operations are normally turned on but can be turned off under the right conditions, which includes having a co repressor molecule present. And so notice that here we have the little image of the switch, the light switch being turned off. Because that is what repress herbal operations are capable of doing. They're capable of being turned off. And so this here concludes our brief introduction to repress herbal operations, 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.

in this video, we're going to complete the table that you see down below as we review induce herbal versus repress herbal operas. And so notice that here in this row, with the greenish background, we're focusing on induce herbal operations and then down below in this row with the pinkish background, we're focusing on repress herbal operations and so recall from our previous lesson videos of induce herbal operations that they are normally turned off, which means that they will not be transcribed Normally. However, these induce double operas they can be turned on, and that is why they are called Induce a Bill operas because they can be induced now. The repressor protein is normally going to be active with induce herbal a bronze and of course, the repressor protein is going to repress transcription. And because the repressor protein is normally active, it will be normally repressing transcription to turn off transcription. Normally, however, under the right conditions, when the regulatory molecule is present, specifically, the inducer is present. This little circle right here, the inducer will bind to the repressor protein and inactivate the repressor protein, and so we have here and inactivated repressor protein. The effect of the regulatory molecule. The effect of the inducer is to inactivate the repressor protein, and, of course, in activating the repressor protein is going to allow for transcription to proceed. And so transcription will be on and the induce herbal opera and will be induced. It will be turned on in the presence of a regulatory molecule inducer. And so an example of an induced herbal opera is actually the lack opera, which we're going to talk more details about as we move forward in our course. Now, of course, recall from our previous lesson videos of repress herbal opera is that they are pretty much the exact opposite of induce double operations, and so they're actually normally turned on. Their gene expression is normally on, and so transcription is usually occurring with these repressive all operations. However, under the right conditions, repress herbal operations can be turned off or they can be repressed. And that's why they're called repress herbal opera because they can be turned off or repressed. Now, of course, the repressor protein is normally going to be inactive with an repress herbal opera. And in the inactive state, the repressor protein will not be able to repress transcription. And so transcription will be able to be on, however, in the presence of the regulatory molecule, which in this case is actually going to be a co repressor, this little red circle here, the co repressor will bind to the inactive repressor protein to activate the repressor protein. And so the effect of this regulatory molecule, the effect of the co repressor is to lead to an activated repressor protein. And so notice that the activated repressor protein is now able to bind to the operator and that will repress or block transcription, and so transcription will be turned off. And so notice uh, that an example of a repressive ble opera is going to be the trip opera, which we're going to talk more details about as we move forward in our course. But for now, this year concludes our review of Induce herbal versus repress herbal operations, and we'll be able to get some practice as we move forward. So I'll see you all in our next video