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00:08 Okay. Yeah. 1122. No not no. First oh this is

00:53 first day yes. Technologies and so right okay. Yes. Okay.

01:47 Whoa okay let's uh see So I out the email yesterday I think.

01:58 the usual stuff uh C so this quiz, a unit quiz so it's

02:04 be more comprehensive. Um uh So basically covered 789 10 21 or

02:15 I don't have it We don't have on each of those uh sections.

02:21 so again you'll have longer time completed like 20 34 questions something like

02:28 Uh Smart work uh do Next Um whatever I'm gonna finish up 10

02:39 finish up unit three but you were on thursday so we may or may

02:50 start before I don't know. Uh are um we have lots of time

02:59 finish the last unit somewhat. Um maybe enough everyone you have to come

03:04 class on the first but we'll But um so but uniforms stuff if

03:15 didn't talk about it on thursday and be a little bit. Um But

03:21 that unit is open so uh you four folder and all this stuff is

03:27 . Uh If you want to start at it like I said we start

03:30 chapter 23. Uh Like I said might just do a little bit of

03:36 but we'll see. Um Confiscations that's course, remember that exam is next

03:47 of next week so I think that's . So we've got uh basically this

03:54 the last month you know? So get more units and I think we

04:01 cover that. Six lectures, we'll . Okay, step on it.

04:08 But now we're on schedule. So I think that's all ahead. Uh

04:15 questions or anything. Alright, so little bit of recap. So let's

04:24 let's see uh put this in the . So um we're looking at the

04:31 . Okay, so expression of genes our control of course. And so

04:40 any cell, even your own cells going to carry out functions that are

04:48 only time. Okay, You're already every one of your genes. That

04:53 be crazy because you no longer have need for to express genes that need

04:59 development of of from the state. , what do you need those jeans

05:05 for? Okay, so pretty much cold storage unless you decide to clone

05:13 . Right then. You take uh take some of those cells and have

05:16 reprogram them, get them to then how to do that. A lot

05:20 the story. Okay. Uh But that of course is gonna be

05:26 right? You have to only carry functions that are needed at any given

05:32 and especially going out in the natural and competing with others that that's essential

05:41 be efficient. Okay, not waste . So um so obviously from bacterial

05:47 Kia lots of stimuli may uh it's different kinds and you see there

05:54 it's kind of action that produces in is to um set aside some kind

06:01 protein that turns on a pathway or have you? Okay so that process

06:06 gene expression is basically what we're recovering the control aspect which is important of

06:14 having knowing knowing the different layers N. A. Protein. No

06:21 will help you understand how to control that's where you're controlling, controlling you

06:28 control the level of D. A. Control at the level of

06:31 you gonna make a transcript or Uh At the level of the transcript

06:38 . Maybe maybe more unstable and or with the protein itself. So any

06:50 them are executed um and combinations of things. It's not just do one

06:58 that's all we can operate. So on the effort to either quickly

07:03 down express some certain genes depending on on what the need is what's the

07:13 is. Okay so there's always a set of genes that are always

07:19 These constituent of ones. Those are critical function type um processes replication,

07:29 synthesis, certain metabolite and always need be on uh those findings constituent

07:35 Okay um and and then the terminology regulation, right, repression. The

07:45 , induction code oppressor. We'll get more of that today but to remember

07:52 it is to be a active inactive because that is the same. But

07:58 changes are the conditions that bring about you will see today. Okay.

08:04 do you know that you know an pressure basically does its job which is

08:10 lot of expression United pressure. The is inactive. It can't do its

08:16 . So it will not repress, will allow transcription to occur.

08:21 so that basic fundamental definition is the . Regardless of what operating talking

08:27 Again, it's what this economy, can be completely out that causes those

08:33 . Very often there is a there other molecules involved in addition to the

08:39 . Okay, so you can have . Right? You're gonna have a

08:46 repressor. Right? And they do functions. So and I will talk

08:56 today. So in addition to that also may need to have all that

09:02 may have if one is expressing a , that means you've got and then

09:08 pressure from then you may in addition that you need to have something

09:13 That's where an activator. So you even have an activator to enhance

09:19 So a lot of expression to occur not be enough hands to increase

09:25 Maybe the addition of a of an . So we'll see all of this

09:30 as we go through lactose and trip opera. Okay, so let's I

09:37 we ended last time but this question let's just do it once more.

09:44 . Um so we'll probably lack first all that's involved in that. There

09:56 uh links to on blackboard I think helpful especially for the outran material

10:03 So there's animations and blackboard that will you to uh Black Opteron. I

10:11 it helps to kind of see if . Plus there's little text box that

10:15 with it along with um And well um we'll take a look at

10:23 we look at those next time. So let me count down here.

10:49 . 10 98 54. Okay let's . B. And a consensus.

11:07 um It is B. Okay so y. And as we'll see is

11:17 critical to the process, right? binds lactose. It's it's how to

11:21 nobody's lactose is even present. Um So lactose is a cata bolic

11:31 . It's not about it's about breaking like um the is the opposite,

11:38 is about synthesizing defense. So they have because of that is kind of

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

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

12:28 . Okay what's what's the organization, what's expressed and what does it

12:33 Right. And so the genes for pathway Z. Y. A.

12:39 they lack of side aces and then that cleaves lactose into glucose and galactose

12:46 is a dissect. Okay? Um uh lactose permeates the lack why it

12:55 a transporter for lactose. So combined bring in lactose into itself.

13:01 Now the lack this last one lack as far as I know it's there's

13:10 the function hasn't been nailed down. the other thing is it has nothing

13:14 do with bringing lactose in the cell otherwise tantalizing lactose. So you don't

13:20 about hands up with the X. top of it. Okay. It's

13:24 it's like Z. And Y. that's what we're gonna be talking about

13:27 of course the lack of pressure. , so like the presser is going

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

13:57 expression always occurs of this opera. . There's a reason for that.

14:04 And it has to do with that Y. Product. Okay, so

14:10 uh that's the only way to sell can determine at all if there's life

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

14:26 go through kind of processor. So comes if it's there it will come

14:30 to sell a little bit of it initially be pointed to anaphylactic. So

14:35 is actually using, Right? So gets produced. And then if if

14:43 lactose comes in, it kind of up production. And what that happens

14:49 that lactose come in and is then to lactose and glucose. This goes

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

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

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

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

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

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

17:20 much is present? If it it can bring it in like so

17:25 then it can lead to obstruction of lactose. We've broken down a lactose

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

17:46 to glucose and this goes into what . Okay, so uh to produce

17:52 can abolish pathway. Okay, so , so any difference expression from like

18:01 the beginning with just a little low to a full blown, It's like

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

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

18:39 the black white. It does become allow yourself to see sea and airports

18:46 black present. Okay, So, so here is again the process.

18:53 when there's, excuse me, uh black. Okay, so called

18:59 repression or induction repression, repression needs repressing. Okay. In that

19:07 the lac repressor uh because of the of lack post present, especially sitting

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

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

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

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

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

22:57 lactose present, lactose absent. Okay need more than that. So the

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

42:39 out because there's obviously a need for . But as soon as again growth

42:45 , we get to a point where we're getting limited, we can't sustain

42:51 . Let's stop. No need to making crypto fine at that same

42:56 There's not, there's no need for . So of course it begins to

43:00 but then very quickly shuts down. and this is this is not all

43:05 this, this is um it's not offer on process really. It's kind

43:10 a different switch right? In all set, it's gonna be a little

43:16 on a little bit off, more more on. So it all depends

43:22 how much of this, how much trip to is floating around in the

43:26 , right? And that kind of how much is on locks off

43:33 Yeah. So how does the um with the progressive if there's like it

43:44 out with like a lot and then binds the pressure and then say,

43:47 well because if the cell has, really has a need for trip to

43:52 then I'm sure that the enzymes evolved will somehow and maybe also the concentration

44:01 concentration maybe have to combine from the . I see what you're saying because

44:07 overwhelming need for this then I'm assuming through hey binding constant and maybe is

44:16 as get low and that brings about unbinding of it. That's that's my

44:22 think or interaction with the enzyme japan to kind of say hey we did

44:30 use this. So that would be guess more so the delivering uh unbalanced

44:38 squeeze it more the other way really . Uh Okay so this again this

44:51 the vast majority of to japan simply the levels of japan present and

44:57 the you're buying professor activate it or and allowing expressions having an active

45:08 So um that controls most of But there is again because binding is

45:16 typically irreversible it can come off and on at different rates. Right?

45:21 there are times even this scenario where small fraction of the time it's not

45:27 and you get a little bit of . So if you want to really

45:31 down on it and stop it altogether there's no way to do that.

45:38 whole attenuation mechanism is about okay, before we go to that mechanism this

45:43 look at this question and compare lack off if you want to be able

45:50 differentiate between these two things and so have e coli that is lack

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.

46:22 with respect to lack and hip So the lack opera on is the

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,

47:01 So it'll take that in and use . So if that's the case why

47:05 it I've got to be handed to I'll use it. And so no

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

47:37 right? Pressure has to be inactive it's like professors inactive. It won't

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

48:19 high they're not applicable to. Okay um Okay that's one summary. Any

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

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

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

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