| 00:08 | Okay. Yeah. 1122. No not no. First oh this is |
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| 00:53 | first day yes. Technologies and so right okay. Yes. Okay. |
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| 01:47 | Whoa okay let's uh see So I out the email yesterday I think. |
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| 01:58 | the usual stuff uh C so this quiz, a unit quiz so it's |
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| 02:04 | be more comprehensive. Um uh So basically covered 789 10 21 or |
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| 02:15 | I don't have it We don't have on each of those uh sections. |
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| 02:21 | so again you'll have longer time completed like 20 34 questions something like |
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| 02:28 | Uh Smart work uh do Next Um whatever I'm gonna finish up 10 |
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| 02:39 | finish up unit three but you were on thursday so we may or may |
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| 02:50 | start before I don't know. Uh are um we have lots of time |
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| 02:59 | finish the last unit somewhat. Um maybe enough everyone you have to come |
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| 03:04 | class on the first but we'll But um so but uniforms stuff if |
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| 03:15 | didn't talk about it on thursday and be a little bit. Um But |
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| 03:21 | that unit is open so uh you four folder and all this stuff is |
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| 03:27 | . Uh If you want to start at it like I said we start |
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| 03:30 | chapter 23. Uh Like I said might just do a little bit of |
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| 03:36 | but we'll see. Um Confiscations that's course, remember that exam is next |
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| 03:47 | of next week so I think that's . So we've got uh basically this |
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| 03:54 | the last month you know? So get more units and I think we |
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| 04:01 | cover that. Six lectures, we'll . Okay, step on it. |
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| 04:08 | But now we're on schedule. So I think that's all ahead. Uh |
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| 04:15 | questions or anything. Alright, so little bit of recap. So let's |
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| 04:24 | let's see uh put this in the . So um we're looking at the |
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| 04:31 | . Okay, so expression of genes our control of course. And so |
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| 04:40 | any cell, even your own cells going to carry out functions that are |
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| 04:48 | only time. Okay, You're already every one of your genes. That |
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| 04:53 | be crazy because you no longer have need for to express genes that need |
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| 04:59 | development of of from the state. , what do you need those jeans |
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| 05:05 | for? Okay, so pretty much cold storage unless you decide to clone |
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| 05:13 | . Right then. You take uh take some of those cells and have |
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| 05:16 | reprogram them, get them to then how to do that. A lot |
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| 05:20 | the story. Okay. Uh But that of course is gonna be |
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| 05:26 | right? You have to only carry functions that are needed at any given |
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| 05:32 | and especially going out in the natural and competing with others that that's essential |
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| 05:41 | be efficient. Okay, not waste . So um so obviously from bacterial |
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| 05:47 | Kia lots of stimuli may uh it's different kinds and you see there |
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| 05:54 | it's kind of action that produces in is to um set aside some kind |
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| 06:01 | protein that turns on a pathway or have you? Okay so that process |
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| 06:06 | gene expression is basically what we're recovering the control aspect which is important of |
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| 06:14 | having knowing knowing the different layers N. A. Protein. No |
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| 06:21 | will help you understand how to control that's where you're controlling, controlling you |
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| 06:28 | control the level of D. A. Control at the level of |
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| 06:31 | you gonna make a transcript or Uh At the level of the transcript |
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| 06:38 | . Maybe maybe more unstable and or with the protein itself. So any |
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| 06:50 | them are executed um and combinations of things. It's not just do one |
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| 06:58 | that's all we can operate. So on the effort to either quickly |
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| 07:03 | down express some certain genes depending on on what the need is what's the |
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| 07:13 | is. Okay so there's always a set of genes that are always |
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| 07:19 | These constituent of ones. Those are critical function type um processes replication, |
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| 07:29 | synthesis, certain metabolite and always need be on uh those findings constituent |
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| 07:35 | Okay um and and then the terminology regulation, right, repression. The |
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| 07:45 | , induction code oppressor. We'll get more of that today but to remember |
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| 07:52 | it is to be a active inactive because that is the same. But |
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| 07:58 | changes are the conditions that bring about you will see today. Okay. |
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| 08:04 | do you know that you know an pressure basically does its job which is |
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| 08:10 | lot of expression United pressure. The is inactive. It can't do its |
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| 08:16 | . So it will not repress, will allow transcription to occur. |
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| 08:21 | so that basic fundamental definition is the . Regardless of what operating talking |
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| 08:27 | Again, it's what this economy, can be completely out that causes those |
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| 08:33 | . Very often there is a there other molecules involved in addition to the |
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| 08:39 | . Okay, so you can have . Right? You're gonna have a |
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| 08:46 | repressor. Right? And they do functions. So and I will talk |
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| 08:56 | today. So in addition to that also may need to have all that |
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| 09:02 | may have if one is expressing a , that means you've got and then |
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| 09:08 | pressure from then you may in addition that you need to have something |
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| 09:13 | That's where an activator. So you even have an activator to enhance |
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| 09:19 | So a lot of expression to occur not be enough hands to increase |
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| 09:25 | Maybe the addition of a of an . So we'll see all of this |
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| 09:30 | as we go through lactose and trip opera. Okay, so let's I |
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| 09:37 | we ended last time but this question let's just do it once more. |
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| 09:44 | . Um so we'll probably lack first all that's involved in that. There |
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| 09:56 | uh links to on blackboard I think helpful especially for the outran material |
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| 10:03 | So there's animations and blackboard that will you to uh Black Opteron. I |
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| 10:11 | it helps to kind of see if . Plus there's little text box that |
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| 10:15 | with it along with um And well um we'll take a look at |
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| 10:23 | we look at those next time. So let me count down here. |
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| 10:49 | . 10 98 54. Okay let's . B. And a consensus. |
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| 11:07 | um It is B. Okay so y. And as we'll see is |
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| 11:17 | critical to the process, right? binds lactose. It's it's how to |
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| 11:21 | nobody's lactose is even present. Um So lactose is a cata bolic |
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| 11:31 | . It's not about it's about breaking like um the is the opposite, |
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| 11:38 | is about synthesizing defense. So they have because of that is kind of |
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| 11:43 | they have creative strategies for control. so um the black black operas example |
|
| 11:51 | transcription control. Okay so transcription control not dealing with the transcript made transcripts |
|
| 12:03 | a step before that or you can brains to make a transcript or |
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| 12:09 | That's transcription control. Okay um and the repressor prevents lack of expression. |
|
| 12:19 | it allows. Okay and so uh as we go into black opera to |
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| 12:28 | . Okay what's what's the organization, what's expressed and what does it |
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| 12:33 | Right. And so the genes for pathway Z. Y. A. |
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| 12:39 | they lack of side aces and then that cleaves lactose into glucose and galactose |
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| 12:46 | is a dissect. Okay? Um uh lactose permeates the lack why it |
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| 12:55 | a transporter for lactose. So combined bring in lactose into itself. |
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| 13:01 | Now the lack this last one lack as far as I know it's there's |
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| 13:10 | the function hasn't been nailed down. the other thing is it has nothing |
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| 13:14 | do with bringing lactose in the cell otherwise tantalizing lactose. So you don't |
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| 13:20 | about hands up with the X. top of it. Okay. It's |
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| 13:24 | it's like Z. And Y. that's what we're gonna be talking about |
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| 13:27 | of course the lack of pressure. , so like the presser is going |
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| 13:32 | interact with the operator. Okay? and that's synthesized by a back pressure |
|
| 13:40 | street. Best of lacked I. , so um now number one, |
|
| 13:50 | may be confusing but there's a logic it. Okay, so a low |
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| 13:57 | expression always occurs of this opera. . There's a reason for that. |
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| 14:04 | And it has to do with that Y. Product. Okay, so |
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| 14:10 | uh that's the only way to sell can determine at all if there's life |
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| 14:16 | there and environment is to have that in the membrane and that's gonna |
|
| 14:21 | Well you have to synthesize it Right. So uh so let's just |
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| 14:26 | go through kind of processor. So comes if it's there it will come |
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| 14:30 | to sell a little bit of it initially be pointed to anaphylactic. So |
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| 14:35 | is actually using, Right? So gets produced. And then if if |
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| 14:43 | lactose comes in, it kind of up production. And what that happens |
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| 14:49 | that lactose come in and is then to lactose and glucose. This goes |
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| 14:55 | metabolism. My assistant go this can into like all Asus etcetera. |
|
| 15:04 | Like coal ISIS. Right? And Okay. So, so that's the |
|
| 15:13 | . But again, this will not . None of this happens here. |
|
| 15:18 | . Unless we have a way to this. Okay. It's like it's |
|
| 15:23 | the eyes, it doesn't have it blind. Right? So, um |
|
| 15:30 | if you look at this diagram Okay, So, um, here's |
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| 15:39 | next race promoter operator, like Y. Okay. So, um |
|
| 15:47 | because even in the wrong situation where say there's no lactose out there. |
|
| 15:53 | . So what happens is Right? 99% of the time or more than |
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| 16:01 | , 99.99% of the time, it's this request surface bound to operate low |
|
| 16:08 | . But remember these findings are are um irreversible irreversible. And the there |
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| 16:20 | times when it's not. Right? a lot. Okay. But there |
|
| 16:25 | . So if you're down and out sell the camera and take a snap |
|
| 16:29 | of it and have a camera you know, you see that there |
|
| 16:33 | a tiny, there will be a opinion when this happens and that comes |
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| 16:41 | and when it does, that's the to make a little bit of |
|
| 16:44 | Okay, so that will have low and by low, I mean we're |
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| 16:51 | one or two molecules of black white and then can detect lactose. |
|
| 17:03 | And so um, so again, amount of expression here is so |
|
| 17:08 | Okay, uh but yet enough to a few molecules of this black white |
|
| 17:14 | now we can then see lactose in environment. Okay. And you know |
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| 17:20 | much is present? If it it can bring it in like so |
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| 17:25 | then it can lead to obstruction of lactose. We've broken down a lactose |
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| 17:33 | this inducer. Right? Find there's lot of lactose lactose out, there |
|
| 17:38 | come in in drugs, some of knockoff block expression and then the rest |
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| 17:46 | to glucose and this goes into what . Okay, so uh to produce |
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| 17:52 | can abolish pathway. Okay, so , so any difference expression from like |
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| 18:01 | the beginning with just a little low to a full blown, It's like |
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| 18:06 | full difference or more very good. that's what's going on. Okay, |
|
| 18:17 | you need like toes to start this . Like there's any environment to start |
|
| 18:22 | process either way to detect it and to bring it back and then that |
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| 18:29 | setting in motion. The expression of album. Okay, once it goes |
|
| 18:34 | , they essentially down to near Although you do have enough to still |
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| 18:39 | the black white. It does become allow yourself to see sea and airports |
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| 18:46 | black present. Okay, So, so here is again the process. |
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| 18:53 | when there's, excuse me, uh black. Okay, so called |
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| 18:59 | repression or induction repression, repression needs repressing. Okay. In that |
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| 19:07 | the lac repressor uh because of the of lack post present, especially sitting |
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| 19:14 | the actually binds the operator, both black opera and the lac repressor |
|
| 19:23 | Okay, so lac repressor also has operator sequence. Okay, so it |
|
| 19:28 | us together and so this is basically as a physical block for can't buy |
|
| 19:34 | . So you don't get any expression , but remember right. The one |
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| 19:41 | one million times is not bound. like a that much that we can |
|
| 19:46 | and make a expression. Okay. for all intents and purposes you can |
|
| 19:50 | of it as basically being shut Okay, what is the Okay, |
|
| 19:57 | like? Yeah. Um so the lactose of course, which occurs as |
|
| 20:05 | result of President. Um it will this little pink triangles here bound to |
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| 20:12 | oppressor and the oppressor cannot by the and get expression Okay, so |
|
| 20:21 | Okay, so that's um that's one of Blackhawks control. Okay, um |
|
| 20:32 | , can we do that any questions this point? Yeah. Alright so |
|
| 20:38 | get this question. All right, takes us into the next layer if |
|
| 20:44 | will. Okay so high little transcription the black opteron requires all the following |
|
| 20:53 | high level expression. High level transcription all except Mhm. Alright. Timers |
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| 21:50 | especially but at this point okay, it. 5 4. Okay. |
|
| 22:01 | Alright. Little bit of randomness Okay. Uh Let's see. It's |
|
| 22:12 | it does require absence of glucose. it um would require that because we |
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| 22:23 | to um inactivate repressor express. That's this bee is creating an inactive repressor |
|
| 22:32 | presence of black toast. Sure. . Yes we do involve this in |
|
| 22:39 | process but not that. Okay so this high not low levels of |
|
| 22:50 | M. Okay so this is the layer. So we just talked about |
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| 22:57 | lactose present, lactose absent. Okay need more than that. So the |
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| 23:04 | of lactose isn't enough. Okay, exerts a big effect. Okay. |
|
| 23:14 | just an expression of black post not but of other sugars. So for |
|
| 23:19 | can ferment 20 cluster impact those operations are controlled somewhat by. Okay um |
|
| 23:35 | is the most efficient source. Okay the cyclic GMP levels are what are |
|
| 23:44 | by the presence of glucose or Right. Second GMP levels rise involved |
|
| 23:52 | Okay so second mp is kind of someone would be an indicator of the |
|
| 24:00 | state of the cell. And so second mp works with this protein that |
|
| 24:08 | it it's called the cRP protein. , so you're psychic mp levels. |
|
| 24:13 | can fluctuate. Second BMP receptor protein kind of synthesized. That's more or |
|
| 24:20 | a kind of steady great. but the cyclic GMP levels that determine |
|
| 24:28 | their complex or not. Okay, the active complex binds to the |
|
| 24:33 | Okay, so remember this is that talked about basal levels of expression versus |
|
| 24:39 | . Okay, so without the active for me you'll get minimal expression. |
|
| 24:47 | once you involve the activator complex because we're increasing the affinity of that |
|
| 24:54 | for right, talk about that before eukaryotic systems. It's activator conscription factors |
|
| 25:02 | together the promoter and that promotes high expression. So it's the same thing |
|
| 25:07 | . Okay, so um so how we get lots of active complex glucose |
|
| 25:15 | in we have to we have to the glucose levels to increase the second |
|
| 25:21 | levels. Okay, so again, lack opera expression you want? High |
|
| 25:27 | , so glucose again is the most and efficient because um for example galactose |
|
| 25:39 | glucose the products of the lactose Okay, glucose goes right into your |
|
| 25:47 | . Just glucose stating that galactose has take a couple steps before I can |
|
| 25:56 | that. Right, so it's a less efficient. Um Other sugars are |
|
| 26:01 | ? What? Right, so black is here to take glucose and bam |
|
| 26:07 | going but with other sugars you got take one or two extra steps to |
|
| 26:12 | it in a form that can candidate policy. So that's why we have |
|
| 26:16 | glucose is kind of more efficient that . Okay, so glucose present. |
|
| 26:22 | what we used. Right? So and lactose glucose preferentially used for that |
|
| 26:28 | . Okay. And so when glucose are high, second mp levels are |
|
| 26:36 | . Okay? Vice versa glucose is . Um then second mpls rise. |
|
| 26:44 | . And so glucose is completely consumed there's another sugar present. It continues |
|
| 26:50 | sugar when glucose is exhausted. so in the diagrams here we're looking |
|
| 26:58 | the presence of lactose absence of blue . Okay, certainly get high second |
|
| 27:04 | p levels formation of the activator Okay um and then expression as second |
|
| 27:14 | then you won't get accurate complex form lack of expression is stopped. |
|
| 27:20 | Black opera. So so again we this metabolite depression right? Um glucose |
|
| 27:29 | metabolite is repressing this other carbohydrate. um and so we look at the |
|
| 27:38 | of a bacteria that can use both these and look at the curve. |
|
| 27:43 | you get what's called this kind of phase growth. What they called dioxin |
|
| 27:50 | . Okay so it looks like this here's glucose being used first and they're |
|
| 27:56 | present and of course cyclic GMP levels are writing okay is going up as |
|
| 28:09 | clothes is going down okay Um And there's a little pause and said, |
|
| 28:15 | gears like gets turned on, then can he loves black. So and |
|
| 28:21 | again to grow again as that Okay. So so what's actually going |
|
| 28:27 | here? Is that glucose um actually because it interferes with macros transport? |
|
| 28:38 | , so we talked about this in different context before, in terms of |
|
| 28:45 | transport. Okay, this is that group translocation mechanism, right? We |
|
| 28:52 | glucose In glucose six phosphate. So glucose keeps coming in because it's completely |
|
| 29:00 | to so that that gradient of diffusion maintained. So it keeps coming in |
|
| 29:07 | it never accumulates inside this thing goes away into black hollis is okay, |
|
| 29:17 | um so uh and so the foss occurs as a result of these subjects |
|
| 29:24 | are part of the transporter. so their phosphate here actually was |
|
| 29:29 | Okay, initially they get transferred to glucose. Okay, to form glucose |
|
| 29:35 | phosphate. So now it becomes a correlated or and that's what interferes with |
|
| 29:41 | lack. Why that that form it's like white. Okay, and |
|
| 29:47 | of course, no glucose can come in that instance. Okay, so |
|
| 29:52 | , lactose and glucose both present. is what happens now, once glucose |
|
| 29:59 | away the space. Okay, and no interference with black white. Black |
|
| 30:06 | free to commit. Okay, they uh exclude inducer exclusion. So we're |
|
| 30:15 | this inducer. Black coast um technically coast. But anyway it's it's glucose |
|
| 30:22 | the effect of glucose is doing that the presence of. Okay, so |
|
| 30:28 | so that's so the whole ball of here with glucose. Let's just look |
|
| 30:32 | it here in terms of levels of . Okay. Um so we got |
|
| 30:40 | offensive like toast. Right your But we have to have um in |
|
| 30:49 | presence of al lactose induction. So lactose, lactose. But they |
|
| 30:54 | this layer of control the presence of activator complex. P control back |
|
| 31:05 | If there's no second game around because classic glucose is absent then we get |
|
| 31:10 | form. Okay. And lots of . Right? So the expression here |
|
| 31:19 | 1000 times or more compared to Okay, more expression because now we |
|
| 31:35 | the actively involved making this highly high for the race compared to this, |
|
| 31:42 | is one X. Appear 1000 Okay. Um so any questions about |
|
| 31:53 | ? Okay. Yeah. Yeah. so if there is not enough glucose |
|
| 32:02 | lactose is a professor blocking the complex mining. Okay, so glucose is |
|
| 32:12 | . I mean glucose and lactose are low that what you said. |
|
| 32:17 | Okay. So glucose is low that have high second A. And |
|
| 32:22 | Um but it uh don't have uh would be no lactose coming into the |
|
| 32:34 | to really use the opera. But there's other sugars present, there's other |
|
| 32:40 | operations will use the same second mp . So there was other sugars present |
|
| 32:45 | you can use the psychic A. P. Can work with that opera |
|
| 32:51 | to turn on the genes for That yeah. And I'm gonna say |
|
| 32:58 | all sugars, you know, not the system. But I think most |
|
| 33:05 | so yeah if there's some sugar president use that or if there's not it |
|
| 33:11 | have to use something else. Has lot of options in terms of what |
|
| 33:15 | means. Okay so we'll summarize this in a second when we compare this |
|
| 33:24 | with trip to fans so we can it side by side. Um Okay |
|
| 33:28 | let's look at this one in preparation that. Okay this is about the |
|
| 33:33 | to fan operation which is true regarding tryptophan opera. So okay pete. |
|
| 34:29 | right. Time is going Okay, down 321. Okay. D um |
|
| 35:07 | D. D. Is correct. um so alright, control so that's |
|
| 35:20 | not a metabolism sentences. Um The of co repressor it is will be |
|
| 35:33 | . Mhm. So you have to repressor repressor complex that making an active |
|
| 35:39 | okay to block expression. Uh the . So that means this equals from |
|
| 35:46 | equals expression. So de repress means expression. Right? So that will |
|
| 35:57 | when the fan is absent. Okay present but absent. Okay so we'll |
|
| 36:02 | through each of these uh right So here like lactose has two |
|
| 36:11 | and look at the first layer And the first layer were presented to |
|
| 36:15 | here Is what control nine. There's also kind of this um plan |
|
| 36:24 | . That kind of really just shuts any remaining expression. In fact it's |
|
| 36:29 | the attenuation mechanism. We'll go through one first. This is easier to |
|
| 36:34 | . So um so the triple crown is bio synthetic. It's about having |
|
| 36:40 | enzymes that are part of this pathway make trip. Okay. There's five |
|
| 36:46 | . Um and so uh there's a review going back to chapter 78. |
|
| 36:53 | ? Remember this is what we call policy strong message. Right? Where |
|
| 36:58 | all finally gene transcript for basically all one. Okay. Each of their |
|
| 37:05 | starting stop code on in this Okay so since this five enzymes involved |
|
| 37:12 | the process um leading to the production Okay um now the repressive. So |
|
| 37:20 | have a trick repressor. Uh the repressor is the form that is |
|
| 37:27 | Okay. Not bound with co Okay, so two forms of course |
|
| 37:34 | . So when there's another present it's repression we get transcription of. |
|
| 37:42 | you have a man around makes Let's make some. So if you |
|
| 37:47 | to think about it in terms of . If in the big scheme of |
|
| 37:51 | . If your e coli what what be more important if you are you |
|
| 37:59 | and he lost. He had a black op that be uh as big |
|
| 38:05 | bigger deal than having a nonfunctional defend . Why you can't build anything |
|
| 38:15 | You can't girl you can't you have used your inability to make proteins or |
|
| 38:25 | proteins because I'm pretty sure that every in shirt in our body and then |
|
| 38:32 | gonna have at least one trip to man in the protein. Right? |
|
| 38:39 | a big view. Okay? But need to call it for example has |
|
| 38:44 | of options and what it can Okay? Um this has lots of |
|
| 38:49 | you need manos meet all kinds of . Right? So it's not gonna |
|
| 39:01 | what happened. Okay. But the is pretty critical. Okay. As |
|
| 39:07 | all give me an acid um papa so um so kind of it's the |
|
| 39:13 | here is let's kind of let trip advanced product have control. Right? |
|
| 39:21 | I mentioned this earlier and I'm not test you on it. But the |
|
| 39:25 | layer of control here also is trip fan can also interfere with that enzyme |
|
| 39:32 | uh feedback innovation uh blocking action. also uh that happens as well. |
|
| 39:42 | um but of course in terms of it's more efficient to stop it before |
|
| 39:50 | . Right? So let's not make protein at all. Let's stop before |
|
| 39:54 | a protein with energy. But you have it all depends on what's going |
|
| 39:58 | . So it's pretty present itself can work in conjunction with the transcription |
|
| 40:05 | Okay and so um so if your is present then of course it acts |
|
| 40:13 | a covert pressure. Okay and we an active pressure forming. Okay and |
|
| 40:22 | um that will bind to the okay that's the whole so um so the |
|
| 40:36 | that is um when when is tryptophan and they sell when is it um |
|
| 40:46 | other words when would it accumulate? they set but speaking from suppose in |
|
| 41:04 | of growth rate okay cell number Okay so if we were like say |
|
| 41:21 | here versus here um where is likely trip to family will begin to accumulate |
|
| 41:40 | . Right so there as it's getting now you are in a situation where |
|
| 41:47 | getting nutrient limited you have so many you can't support everybody and it means |
|
| 41:53 | you don't have to need to crank protein synthesis as you did earlier when |
|
| 41:58 | were growing like gangbusters right? And mid log phase. So as you |
|
| 42:03 | to this limiting point right now is these will begin to accumulate before then |
|
| 42:10 | were these were going to be they were going to protein synthesis and |
|
| 42:15 | so they're being consumed as fast as were being made. Right? So |
|
| 42:21 | during those times the amount of interest gonna be really love okay being used |
|
| 42:28 | fast as it's made like that's fast . Right? So then of course |
|
| 42:34 | sense let's keep making just being used fast before making it just keep cranking |
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| 42:39 | out because there's obviously a need for . But as soon as again growth |
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| 42:45 | , we get to a point where we're getting limited, we can't sustain |
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| 42:51 | . Let's stop. No need to making crypto fine at that same |
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| 42:56 | There's not, there's no need for . So of course it begins to |
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| 43:00 | but then very quickly shuts down. and this is this is not all |
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| 43:05 | this, this is um it's not offer on process really. It's kind |
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| 43:10 | a different switch right? In all set, it's gonna be a little |
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| 43:16 | on a little bit off, more more on. So it all depends |
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| 43:22 | how much of this, how much trip to is floating around in the |
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| 43:26 | , right? And that kind of how much is on locks off |
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| 43:33 | Yeah. So how does the um with the progressive if there's like it |
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| 43:44 | out with like a lot and then binds the pressure and then say, |
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| 43:47 | well because if the cell has, really has a need for trip to |
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| 43:52 | then I'm sure that the enzymes evolved will somehow and maybe also the concentration |
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| 44:01 | concentration maybe have to combine from the . I see what you're saying because |
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| 44:07 | overwhelming need for this then I'm assuming through hey binding constant and maybe is |
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| 44:16 | as get low and that brings about unbinding of it. That's that's my |
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| 44:22 | think or interaction with the enzyme japan to kind of say hey we did |
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| 44:30 | use this. So that would be guess more so the delivering uh unbalanced |
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| 44:38 | squeeze it more the other way really . Uh Okay so this again this |
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| 44:51 | the vast majority of to japan simply the levels of japan present and |
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| 44:57 | the you're buying professor activate it or and allowing expressions having an active |
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| 45:08 | So um that controls most of But there is again because binding is |
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| 45:16 | typically irreversible it can come off and on at different rates. Right? |
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| 45:21 | there are times even this scenario where small fraction of the time it's not |
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| 45:27 | and you get a little bit of . So if you want to really |
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| 45:31 | down on it and stop it altogether there's no way to do that. |
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| 45:38 | whole attenuation mechanism is about okay, before we go to that mechanism this |
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| 45:43 | look at this question and compare lack off if you want to be able |
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| 45:50 | differentiate between these two things and so have e coli that is lack |
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| 45:59 | positive, has both of us run we're going in minimal medium. |
|
| 46:05 | And it contains both lactose and okay, no glucose is present. |
|
| 46:16 | so glucose is absent. Okay so can you say about these cells. |
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| 46:22 | with respect to lack and hip So the lack opera on is the |
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| 46:27 | express? So on the left side opera on yes or no. Okay |
|
| 46:35 | certainly says okay um yes or no it says yes. Okay so the |
|
| 46:51 | so yeah let's let's use the The only way to do that is |
|
| 46:54 | turn on black expression right? Conversely is provided to the cells, |
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| 47:01 | So it'll take that in and use . So if that's the case why |
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| 47:05 | it I've got to be handed to I'll use it. And so no |
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| 47:10 | to have the Trip Opera being Okay so state of the repressor lack |
|
| 47:20 | . Yeah. See I made the one. Black Opera. Uh state |
|
| 47:28 | the oppressor um pressure would have to oh no you wanna get expression like |
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| 47:37 | right? Pressure has to be inactive it's like professors inactive. It won't |
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| 47:42 | you get expression. Right? So what I mean. So the definition |
|
| 47:51 | active active requesters the same. It's we're seeing how we can. Very |
|
| 47:56 | is very so in the trip opteron active right? Because remember active means |
|
| 48:03 | expression inactive oppressor you get pressure Uh second in p levels in lac |
|
| 48:12 | on E coli it's high. So um so you know it's gonna |
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| 48:19 | high they're not applicable to. Okay um Okay that's one summary. Any |
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| 48:33 | gonna continue on the trip opteron here it's part of part two. Is |
|
| 48:37 | any questions? Okay so let's look a continuation. So again as I |
|
| 48:45 | the previous mechanism accounts the vast majority the control those instances where occurs because |
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| 48:56 | actively pressure is not bound to the . Alright there's a little bit expression |
|
| 49:01 | . Right? So the things to a lot of parts to this so |
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| 49:08 | a remembering our protein synthesis works like and binds Transfer RNA has come in |
|
| 49:14 | you said the size of. Okay uh so it's a river zone. |
|
| 49:21 | the position of the river zone that's the events. Okay and because a |
|
| 49:28 | zone works in conjunction with um transfer molecules they're a part of it |
|
| 49:35 | So both of those together the tiara actually influence where will stop? The |
|
| 49:44 | of this mechanism is where shopping in A position B. And that leads |
|
| 49:52 | two different consequences. Either expression or . Okay and rhymes own movement is |
|
| 50:01 | of course by transfer RNA. Is come in? Okay and so they |
|
| 50:06 | a part as well? Okay so it's also overriding the whole thing is |
|
| 50:14 | we get expression or not? It's the availability of. Okay that's the |
|
| 50:22 | thing here. Okay so let's uh here's the this is the the the |
|
| 50:31 | . N. A. Okay so is that january sequence just for a |
|
| 50:36 | here back up. I wish I that. Here's a picture. |
|
| 50:40 | so you can see it right So we're just zeroing in on this |
|
| 50:45 | right here, zooming in the but part of this? It comes right |
|
| 50:52 | the operator. Okay. It is is transcribed? It's always a part |
|
| 50:56 | the transcript. Okay. And you see it right here. That would |
|
| 51:01 | the leader sequence right there. so it's always part of the |
|
| 51:05 | Okay? And so um so that's what it is for context. Let's |
|
| 51:10 | back to here. So we're zooming on that area. And so uh |
|
| 51:17 | it is. Right, so here's would be the motor operator sequence and |
|
| 51:21 | uh the other parts of this or . Okay. And so like |
|
| 51:31 | they'll have second beast secondary structures, loops, things like that. And |
|
| 51:39 | can form a one to what's called one to loop. And it's just |
|
| 51:42 | just a U. G. Base pair. Okay. Uh |
|
| 51:47 | And there's actually one in the Um The other thing here, I |
|
| 51:52 | our trip to fans influence where there no stops. That's what this thing |
|
| 51:57 | all about. Are we gonna stop where there's two adjacent trip to fame |
|
| 52:05 | or here whether it's the usual Are you A. U. |
|
| 52:11 | C. A. C. Anyway, so so there's three stocks |
|
| 52:19 | are part can be one of Right? So it has that, |
|
| 52:21 | also has these adjacent triple coupons and so to have a trip code on |
|
| 52:28 | means you have A T. R. N. A. That |
|
| 52:31 | it and brings a trip to fan it. Right? And so that's |
|
| 52:35 | you see here. Charged versus Okay so if you get plenty of |
|
| 52:42 | can there's an enzyme that catalyze is T. R. N. |
|
| 52:47 | To the temple fan connection. Okay you get lots of trip to fan |
|
| 52:54 | . That will happen. You have of charged tr if you don't you're |
|
| 52:58 | low or you're out you're gonna have ones on the right the uncharged more |
|
| 53:04 | . Right? So it's the remember the antique Odin right? Of the |
|
| 53:10 | . R. N. A. recognizes the coda. Mr Cardin's |
|
| 53:16 | U. G. G. Okay that's what's sitting here. That's the |
|
| 53:23 | trip cordons. Are these are Okay. Got two of those in |
|
| 53:30 | row. Okay so um so the thing to remember is 3234 is the |
|
| 53:39 | of and the positioning or where where there's a attenuated loop Anti attended |
|
| 53:48 | Sorry? Okay so it um is the middle you see that right |
|
| 53:56 | Okay that shows up. Okay now one forms is um so we did |
|
| 54:04 | this transcript into yeah buffer. Okay then we're able to see what which |
|
| 54:11 | form is. All thermodynamics. Alright is most favorable. The 23 is |
|
| 54:18 | the most favorable that is for Okay. If we have a bunch |
|
| 54:23 | these in in buffer you have to at them. The majority of would |
|
| 54:28 | in this 23 group less so in . Okay. So in 23 reforms |
|
| 54:35 | the anti theory that allows expression. . So for this to form depends |
|
| 54:44 | what are this rival zone stuff. ? You have two spots where can |
|
| 54:49 | actually can stop here. Of All right. That's the natural stop |
|
| 54:52 | on. But it also can actually here at the trip code on. |
|
| 54:58 | two positions right here early for his or the usual stopping place. |
|
| 55:06 | And that will influence if this is with the pretty big it's covering the |
|
| 55:13 | is gonna prevent certainly need to lose forming. Okay. And so the |
|
| 55:19 | here is the is Sarah because that's junction between that's the that's the tipping |
|
| 55:28 | . Okay. Right there because this the start of the structural genes. |
|
| 55:33 | trip E. D C. A. Right going that way. |
|
| 55:40 | if something's gonna happen it's gonna happen Yeah. Lot of transcription of |
|
| 55:47 | You can't you have to keep it . So is gonna be ahead of |
|
| 55:52 | right here is gonna be sitting there its thing. Let's say it's right |
|
| 55:58 | right. It's moving along. If gonna if you're gonna not have expression |
|
| 56:05 | the knock it off, get out there. If you do want that |
|
| 56:10 | happen then you have to keep it . So that's the critical point right |
|
| 56:16 | . Okay, what's gonna happen? to happen right before. Okay, |
|
| 56:23 | that's what we see here. So defend levels. Right, Okay. |
|
| 56:27 | relates to these having lots of if have hydrogen levels that we have lots |
|
| 56:32 | these lots of charged, the arteries . Okay, so as the riders |
|
| 56:40 | chugs along the trip, this this , it will blow past is adjacent |
|
| 56:46 | code up. There's plenty of trip . R. A. Nothing that |
|
| 56:50 | , it's not going to stop it if you go okay, it'll just |
|
| 56:54 | at the national stopping point, which okay, so in that scenario that |
|
| 57:01 | the 34, the perform, so can see the proximity of that to |
|
| 57:11 | primaries. Okay. And that's the contact. The closeness enables physical contact |
|
| 57:18 | knock it off the transcript right? that junction point. Right? So |
|
| 57:23 | the here's that trip. E. , and so if we prevent there |
|
| 57:33 | we don't get expression. Right? by having that itinerary reform which is |
|
| 57:37 | close to where the Liberator that ahead it, it knocks it off. |
|
| 57:41 | , And so then that expression again ties back to high Okay, and |
|
| 57:49 | means lots of charge trip to which to the zone not stalling here and |
|
| 57:56 | going and going to the stock which the 34. Okay, so the |
|
| 58:04 | scenario lower penalties. We have more these. The uncharged. Okay, |
|
| 58:11 | happens the drivers on the stalls actually we get through this black defense |
|
| 58:18 | Talk about this on thursday we have other examples of gene control beyond this |
|
| 58:25 | and one of them is the stringent . That's actually what happens when a |
|
| 58:31 | T. RNA sits inside the It just kind of just can't move |
|
| 58:37 | so that then positions positions it that forms a 23 before it covered this |
|
| 58:45 | in the three forward form. But this position 23 forms and that's again |
|
| 58:51 | wise. Alright here to here it's different than up top. Okay, |
|
| 58:59 | then that allows the to keep Okay. Again relates to ultimately ultimately |
|
| 59:08 | to tryptophan levels itself. Right load to lots of uncharged. Which equates |
|
| 59:16 | installing the can't move anymore. Which is positioning, promotes the formation |
|
| 59:22 | So one thing is the next thing the next thing, The next. |
|
| 59:27 | . And and result we have So again this this um the previous |
|
| 59:39 | talk about just the acting professor is controls the bulk of this, but |
|
| 59:44 | better take care of the rest. um as far as what he |
|
| 59:49 | you gotta kind of sit in the and just look at this for a |
|
| 59:54 | and then again I think the Thinking logic first think of. |
|
| 60:02 | what's that gonna generate Either lots of or or not. Okay then it's |
|
| 60:13 | that influences where the rides on Right? Lots of lots of |
|
| 60:19 | Well you can blow past that and at the normal stopping point. If |
|
| 60:25 | then we're gonna stop prematurely. So the positioning determines which informs right |
|
| 60:31 | loop on top at the bottom. talk leads to blocking expression. Bottom |
|
| 60:39 | to a lot of expression. This of those four steps. Um Many |
|
| 60:49 | about that. Okay so uh we'll at them next time but I do |
|
| 60:55 | at the animations. Okay so here's of question about attenuation time. So |
|
| 61:04 | attenuation mechanism that helps block expression of trip off would include all except |
|
| 61:59 | Yeah. You see. Okay count from eight five two. Alright. |
|
| 62:29 | Okay. M. R. Transcript of the leader sequence. Of |
|
| 62:32 | that's gonna be formed. That's certainly of the mechanism. Uh Attenuated loop |
|
| 62:39 | of course. Okay that's what it's . Um The higher levels of |
|
| 62:46 | Yes. Okay because that will lead lots of charge Tr nation trip to |
|
| 62:51 | which will lead to an opera on at the stop code on. Not |
|
| 63:01 | so it's it is this is That's the exception. Right? It's |
|
| 63:09 | stall at the stop. Put up make that a true statement stock. |
|
| 63:16 | so you got a continuation. I the diagram here. Let's do one |
|
| 63:21 | question here right. Kind of a . But low interest say the trip |
|
| 63:27 | versus high. Alright, so low . Set aside trip to fan. |
|
| 63:34 | . Um High levels. Of You know one you know the other |
|
| 63:42 | opteron? That's no there the strip pressure pressure, complex form O levels |
|
| 63:56 | ? High. Of course. There's of trip to fan around to buy |
|
| 64:00 | charge. Trip transfer. RNA is , correct. No. Uh Of |
|
| 64:08 | , yes. Their rivals installs at levels, yep, high levels. |
|
| 64:17 | which trip leader sequence loop forms low . Yeah and continue later. |
|
| 64:26 | Okay. Um Okay so here it , all in all it's glory, |
|
| 64:34 | of it. Okay um Again look the animations. I'll cue those |
|
| 64:43 | Next lecture, you can see them I think it helps a great deal |
|
| 64:47 | with the attenuation. So it goes the whole thing. It's not that |
|
| 64:50 | . Okay. Um The uh questions finish up with these other mechanisms next |
|
| 64:58 | folks. So see you |
|
