in this video, we're going to begin our introduction to regulation of gene expression. And so it's important to know that both pro carry attic and eukaryotic cells have the ability to regulate or control their gene expression. And so recall from our previous lesson videos that gene expression is just referring to the ability to express a gene or to create the final product that's associated with a gene. And in many cases, the final product of a gene is going to be a protein. And so if we take a quick look at our image down below notice, we're showing you an image that's showing you some gene expression. Because gene expression typically requires a two step process, the first step is transcription, which converts or which uses D N A to build RNA. And then the second step of gene expression is translation, which uses the R N A to build a protein. And so it turns out that gene expression basically using the D N A. To build proteins. Uh, it has many different stages of regulation, and so gene expression can be controlled or regulated at any of five stages, and notice that we have these five stages of regulation or control numbered down below. And, of course, these numbers correspond with the numbers that you see in our image. And so the very first stage of gene expression is going to be chroma, tin rearrangements and so chromosome rearrangements is just referring to the regulation of chroma Tim confirmations and basically controlling Deanna's accessibility for transcription. And we'll get to talk more about chroma tin rearrangements later. In our course now, the second stage of regulation of gene expression is transcription allele control. And just as this sounds, this is going to be controlling or regulating transcription regulating RNA preliminaries is binding to the promoter and the initiation of transcription. Now it turns out that most pro carry attic gene regulation actually occurs at this transcription all control level or stage. And so we'll be able to talk more about transcription control as we move forward in our course as well. Now, the third stage of gene expression regulation is going to be post transcription. All control and post is a route that means after and so post transcription all control is going to be the regulation of modifications to the R N. A after transcription has already occurred. Now, the fourth stage of regulation that we have is translational control and translational control is, of course, going to be regulating the initiation and elongation steps of translation. And then the fifth and final stage of gene expression. Regulation is post translational control, and, of course, post again means after and so post translational control is going to come after translation. It regulates modifications to proteins after translation has occurred. And so we'll get to talk more about each of these stages of gene expression regulation as we move forward in our course. But if we take a look at our image down below, what you can see is we're showing you an image of the five stages of gene expression and regulation of gene expression. And so, at the first stage we have here is chromosome rearrangement, which is basically going to affect the the arrangement of the D. N A and the D. N. A is accessibility to transcription. Then we have transcription all control, which is going to be the primary way that pro Kerasiotes regulate there. Uh, gene expression and transcription control is going to again. It's going to affect the RNA preliminaries binding to the promoter and affect the initiation of transcription. Then we have post transcription all control, which is going to be modifications to the RNA after transcription has already occurred. Then we have translational control, which is going to affect the, um, initiation and elongation steps of translation. And then last but not least, we have post translational control, which is going to be modifying the protein and affecting the proteins. Activity after translation has occurred and again, we'll get to talk more about each of these levels of regulation as we move forward. In our course. Now it is important to know that again pro carry It's like bacteria and archaea tend to use transcription all control as their primary way of regulating, uh there gene expression. And that's what we're saying here in this line up above. However, when it comes to eukaryotes, it's important to know that eukaryotic gene regulation can actually occur any of these five stages, which would include all five stages here and so moving forward in our course, we're going to talk more and more about gene regulation, and we're going to start by talking about transcription control at the pro carry attic level and then later in our course will double back and talk more about each of these other stages of regulation. But for now, this year concludes our brief introduction to the regulation of gene expression, and we'll continue to talk more and more about regulation of gene expression as we move forward. So I'll see you all in our next video.

in this video, we're going to talk about positive versus negative gene regulation, and so cells can regulate their gene expression in one of two different ways. The first way is via positive gene regulation, and the second way is via negative gene regulation. Now, positive gene regulation is going to stimulate gene expression by turning on the gene so that the genes final product is actually being made at a higher rate. Now. Negative gene regulation, on the other hand, is the opposite because it prevents gene expression by turning off the gene so that the genes final product is being made at a lower rate. And so it turns out that positive and negative gene regulation can actually resemble a light switch in a way. And so, just like light switches can be turned on to turn on the light and can be turned off to turn off a light. Jeans can also be turned on and turned off via positive and negative regulation. And so, over here on the left hand side of our image, notice that we're showing you a light switch being turned on into the on position, and so this is going to resemble positive gene. Regulation the stimulation of gene expression by turning the gene on and notice over here on the right hand side of our image, we're showing you the switch light switch being turned into the off position. And so this is going to resemble negative gene regulation, since with negative gene regulation. This prevents gene expression by turning off the gene. And so as we move forward in our course, we're going to see more specific examples of both positive regulation and negative regulation as well. But for now, this year concludes our brief introduction to positive and negative gene regulation, and we'll be able to get some practice applying the concepts that we've learned as we move forward in our course, So I'll see you all in our next video.