Introduction to Regulation of Gene Expression - Video Tutorials & Practice Problems
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Introduction to Regulation of Gene Expression
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Video transcript
In this video, we're going to begin our introduction to regulation of gene expression. And so it's important to know that both prokaryotic 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 2 step process. The first step is transcription which converts, or which uses DNA to build RNA. And then the second step of gene expression is translation, which uses the RNA to build a protein. And so it turns out that gene expression, basically using the DNA to build proteins, it has many different stages of regulation. And so gene expression can be controlled or regulated at any of 5 stages. And notice that we have these 5 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 chromatin rearrangements. And so chromatin rearrangements is just referring to the regulation of chromatin confirmations and, basically controlling DNA's accessibility for transcription. And and we'll get to talk more about chromatin rearrangements later in our course. Now the second stage of regulation of gene expression is transcriptional control. And just as this sounds, this is going to be controlling or regulating transcription, regulating RNA polymerases binding to the promoter and the initiation of transcription. Now it turns out that most prokaryotic gene regulation actually occurs at this transcriptional control level or stage. And so we'll be able to talk more about transcriptional control as we move forward in our course as well. Now the 3rd stage of gene expression regulation is going to be post transcriptional control and post is a root that means after. And so post transcriptional control is going to be the regulation, of modifications to the RNA after transcription has already occurred. Now, the 4th 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 5th 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 5 stages of gene expression and regulation of gene expression. And so, at the first stage, what we have here is chromatin rearrangement, which is basically going to affect the the arrangement of the DNA and the DNA's accessibility to transcription. Then we have transcriptional control which is going to be the primary way that prokaryotes regulate their, gene expression. And transcriptional control is going to, again, it's going to affect the RNA polymerase binding to the promoter and affect the initiation of transcription. Then we have post transcriptional 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 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 of of regulation as we move forward in our course. Now it is important to know that, again, prokaryotes like bacteria and archaea tend to use transcriptional control as their primary way of regulating, their gene expression. And that's what we're seeing here in this line up above. However, when it comes to eukaryotes, it's important to know that eukaryotic gene regulation can actually occur at any of these 5 stages, which would include all 5 stages here. And so moving forward in our course, we're going to talk more and more about gene regulation, and we're gonna start by talking about transcriptional control at the prokaryotic level. And then, later in our course, we'll double back and talk more about each of these other stages of regulation. But for now, this here concludes gene expression as we move forward. So I'll see you all in our next video. Gene expression as we move forward. So I'll see you all in our next video.
2
concept
Positive vs Negative Gene Regulation
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2m
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Video transcript
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 2 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 gene's 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 gene's 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, Genes 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 here 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.
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Problem
Problem
Post-translational control refers to:
A
Regulation of gene expression after transcription.
B
Regulation of gene expression after translation.
C
Control of epigenetic activation.
D
Period between transcription and translation.
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Problem
Problem
Which of the following is an example of positive regulation of gene expression?
A
Transcription is halted on a specific gene to limit the amount of protein being created by the gene's expression.
B
The protein that is translated is immediately degraded by the cell before it can serve its function.
C
Elongation of translation comes to a stop and the ribosome dissociates when a regulatory protein binds.
D
A protein binds to DNA and then stimulates the initiation of transcription of a specific gene.
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Problem
Problem
In prokaryotes, control of gene expression usually occurs at the