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00:11 | Okay folks, let's go ahead and started. Um So I remember a |
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00:19 | of things do you do this The blackboard quiz opens tomorrow? We're |
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00:26 | gonna cover uh 78 and nine as as we've been through nine today, |
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00:32 | are probably up to congregation. Um you know, so the spot work |
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00:41 | , a couple of those due on or on sunday. Excuse me. |
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00:45 | the cost of schedule opens. Remember example, 3? It opens on |
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00:51 | ? Well I guess technically it's midnight . I guess so. Um |
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00:56 | uh so um remember these chapters have covering 21, Not at all in |
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01:06 | entirety. So remember to, you , a lot of stuff we don't |
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01:09 | about in this chapter, so make that you certainly have the exam review |
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01:14 | to keep you on track. Um so Today we're gonna um continue |
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01:23 | up the last bit of Chapter which again is one of those. |
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01:26 | a lot we talked about there, let's just, I'm gonna rehash some |
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01:30 | the main things um from last So kind of overview. This is |
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01:36 | we're looking at uh examining pro karaoke , how they're structured, how they |
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01:45 | from you carry outs. Um The I guess concept here is um this |
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01:52 | how the genes are struck to um , quote the proteins, proteins do |
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01:58 | most of the work of any Um but that he could be controlled |
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02:03 | well and we'll get more into the aspect, starting next time, uh |
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02:10 | up first with what here's how procurers in terms of their genes and organization |
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02:15 | what have you noticed that operation Uh So um organizing unions of a |
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02:25 | pathway typically under control of one It makes it very efficient to |
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02:31 | It goes to express it at once at once and to and to shut |
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02:34 | down all at once. Um Obviously nature microbes are right there, you |
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02:43 | competing with each other. Environmental changes . Uh So where they can be |
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02:50 | is of course going to be key their survival. And so this is |
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02:54 | one important aspect of that. Um control so there's always going to control |
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03:01 | . Um The Yeah. Okay so operator and um regulatory genes always gonna |
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03:19 | a part of uh and it can things of the operators. You can |
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03:24 | . Activators, transcription, activators, things. We'll talk about this as |
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03:29 | go through this section. Um but obviously a very important aspect of |
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03:35 | Okay, regulations. So we're talking regulations as well. These uh now |
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03:43 | involving of the control of multiple So multiple of these. Okay timothy |
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03:52 | that one does that if they are of a overall um function so to |
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03:59 | . We're talking about nitrogen metabolism that a lot of parts um taking out |
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04:03 | sources um Making things out of nitrogen . These are all involved different operations |
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04:10 | controlling them. Okay. And you coordinate and control these the sigma |
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04:15 | Right? So the super factor is um as well whenever as well. |
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04:22 | what guides the ornate primaries to the . Okay. And then the latitude |
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04:26 | transcribed the opera classmates at the end time. So plasmids are in addition |
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04:37 | the chromosome they replicate on their They have their own origin of |
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04:44 | enables them to do that. They certainly have other multiple genes in |
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04:50 | They in comparison the chromosome On the maybe 1-3 to 45 and jeans but |
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05:00 | can't accept their hands and they have like existence. Um uh as well |
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05:05 | other genes catholic pathways and what have . Okay. Uh they can also |
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05:11 | transferable and we'll get into that Okay. But then also we looked |
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05:15 | this other mode of replication that plasmas do. We're familiar with the bidirectional |
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05:21 | that you know the process you're familiar . But they can also execute this |
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05:26 | circle replication. And so typically this in the context of the congregation as |
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05:32 | see a little bit that copying the the other strand that's displaced can then |
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05:41 | shoveled into the recipient cell and then can make a copy of that. |
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05:49 | now each cell has a copy of plasma. So that's how genes can |
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05:52 | transferred. Okay. And so the so as we get into uh you |
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06:02 | variation. My genetic variation in bacteria archaea. Um they we of course |
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06:10 | all of the things of course we'll mutations that arise at a certain |
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06:15 | But we also have sexual reproduction that us to create genetically different combinations. |
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06:22 | . Creating variations. But bacteria don't . Don't have sexual reproduction. |
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06:28 | So they must rely on other sources variation, rotation of course. But |
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06:33 | as we'll talk about shortly these mechanisms horizontal gene transfer and many of these |
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06:39 | with plasma. Okay. And so inherited plastic means that so cannot express |
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06:45 | genes. Okay. And there may be new genes they have don't have |
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06:50 | . So uh I think the last we mentioned was sigma factors. |
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06:54 | So these are what are transient. buy their part of the memories but |
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06:59 | are not. They can come off on right their role is to uh |
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07:04 | the promoter guide it to that starting so that they can begin transcription. |
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07:12 | , so uh the minus 35 minus refers to that uh promoter region that's |
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07:18 | common in in uh in front of genes. Um we look at some |
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07:23 | of that. But so one thing do want to mention here is because |
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07:29 | talked a little bit about last at end, last time about up and |
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07:37 | Mutations. So um mutations by changing bass or two in the promoter. |
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07:44 | saw either an increase or decrease in . Okay so that brought up the |
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07:51 | of weak versus strong promoter. And some of the mention that here briefly |
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07:58 | so a the the binding of memories promote this is going to give you |
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08:09 | level of expression typically that's what we basal expression. Okay it's it's typically |
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08:16 | enough for the cell to do anything . You don't generate enough protein product |
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08:21 | is meaningful. Okay. Were Um It's we're going to see in |
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08:27 | context of the lactose opera on A little bit of this does produce |
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08:31 | effect. But by and large if cell wants um meaningful protein concentration you |
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08:38 | have to greatly jack this up in of expression. Okay and so it's |
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08:45 | about enhancing this. Okay enhancing that for the memories to to promote. |
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08:53 | one of the things that do that is where we this is where hello |
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08:57 | involves things like control elements, transcription, activators, another transcription factors |
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09:06 | . These come together at the Okay and so uh that now this |
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09:14 | . Mhm. There to that where don't see anything on the promoter. |
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09:21 | This is a site below that has high affinity that preliminary has a very |
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09:25 | affinity for that. So binding to promoter strongly equates to lots of |
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09:30 | Okay so if we can bind the binds the more it will then carry |
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09:35 | to make transcripts. Okay so we doesn't promote that level of binding. |
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09:42 | . And so but not every not operations genius and bacteria or uh in |
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09:50 | of you have a strong promoter in of them. It depends on what |
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09:52 | products are and um what they're used . So you don't necessarily have to |
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09:59 | a strong expression of everything but you have certain things but not everything. |
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10:04 | . But you know from biotechnology standpoint you're if you have a particular micro |
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10:11 | you want to. Yeah it has protein of interest to you. That |
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10:14 | a commercial value to you. And want to on an industrial scale you |
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10:19 | lots of stuff, spoonfuls won't You need bucketfuls. Okay so how |
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10:23 | you how do you make a bacteria that work? And naturally wouldn't do |
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10:26 | . Right? Why Why would it so much energy? You're making so |
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10:29 | more of a program that what it needs. It's insane and it wouldn't |
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10:33 | able to survive so but artificially in lab you can do those things. |
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10:38 | . And so one of the things do is manipulate promoters right? Uh |
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10:43 | find the promoter in front of your of interest pedal with it and see |
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10:47 | you get lots of expression. And then those are in that |
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10:52 | That's that's what you're looking for. the point here is um the difference |
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10:57 | basil and high level expression. It contribution of different factors that enhance |
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11:03 | And so our own needs certainly are complicated in terms of control and uh |
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11:11 | at that basic expression begins with transcription but then gets enhanced by the addition |
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11:17 | other factors that only arise under conditions that gene product is needed. Which |
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11:24 | then in particular factors will come into that um arrives due to the need |
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11:30 | that particular gene expression. Okay and what will enhance. And we're talking |
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11:35 | difference of you know between based on level expression, it can be 1000 |
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11:40 | fold difference. Okay so it's it's significant and it's it's also it's not |
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11:46 | an all or nothing thing. Okay a it's a continual. Okay maybe |
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11:51 | don't have all of these here. maybe some of these are not all |
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11:56 | . Well that means you don't get much expression right there all present and |
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12:00 | get lots of expression if they're not at all. Very low expression. |
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12:04 | it's a it's a continual. Okay any questions about that? Yeah. |
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12:12 | um so I think this is kind just basically puts everything together here. |
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12:18 | here is a here is a bacterial . Okay so looking at D. |
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12:24 | . A. And both the scents uh antisense strand. Right so the |
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12:30 | . Right. Plus and minus And then we have two genes in |
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12:35 | example again under control of one Right? That defines the opera and |
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12:42 | um uh we're gonna copy the template . Okay, because remember the template |
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12:47 | copying that right? Gives us a strand in this case are and |
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12:53 | Ok, and that's going to contain coding information so that can be |
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12:58 | So remember it's a it's a polycystic message. Right? It's all it's |
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13:04 | just it's not a here a transcript them be okay, it's all one |
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13:11 | . Okay, continuous place histrionic Okay. But within the within the |
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13:17 | there will be the elements you need proper translation. Right? Start, |
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13:22 | , start stop for each gene transcript then uh um and so then the |
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13:31 | . All right, we're gonna translate . Okay, well it needs also |
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13:36 | particular um punctuation marks. If you . Um It needs rather than binding |
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13:43 | like a like a is a promoter some of these problems and binding site |
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13:48 | about orienting it in front of the transcript or the gene. Okay to |
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13:55 | transcribed. Um So um and then course that brings about the formation of |
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14:01 | obviously. Okay, so that sequence called the Shine Del Garden just for |
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14:07 | two people that discover it. but that's where the riders are going |
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14:12 | . Okay, remember the whole polly rival zone zone play represent information. |
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14:18 | ? This can occur virtually simultaneously transcription their rivals also plop on uh to |
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14:26 | ribosome binding site and then migrates the arrivals binds And then starts translating. |
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14:32 | next one comes in behind it. the next one. The next |
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14:34 | The next one. Alright so you'll a rival games all along the |
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14:38 | Okay. There's lots of protein But again never never forget about you |
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14:45 | element right? Because you can all shut down in a heartbeat. |
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14:49 | All depends on what's going on within around the micro. Okay. Um |
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14:56 | questions about that? Yeah. So wrap this up with a question here |
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15:05 | um then we'll move on to horizontal transfer. Mhm. Okay mm hmm |
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16:14 | hmm. Right. Mhm. Okay uh the operator serves as the site |
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16:32 | the the consensus with D. Rather. Okay um The operator services |
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16:38 | for sigma factor binding. Is that ? Mhm. What services what what |
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16:49 | to the operator regulatory protein. Okay that's fox the opera and possesses multiple |
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17:01 | . V one promoter that defines an . Okay. One promoter multiple |
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17:07 | Uh sexual jeans have a single Code for enzymes of differing metabolic pathways |
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17:15 | that that would be inefficient. Gonna on the same pathway. A single |
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17:21 | transcript will contain information for all the genes of the opera. That's |
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17:29 | Yeah absolutely true. Okay so just it up. Here's a Here's the |
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17:41 | on there's the two structural genes and translated. So it's you know expressing |
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17:49 | contains all the information. Um The factors bind to the shindou garner sequence |
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17:55 | a transcript to initiate transcription. The . Okay so d is the correct |
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18:02 | . Okay. Um Any questions? . Alright. Chapter nine. So |
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18:13 | so what kind of back to I earlier about variation? Right so um |
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18:22 | one oh one right, variation is . Okay. Um If we're all |
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18:29 | identical clones of each other um well be operating in the same way. |
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18:36 | what kind of environmental changes or what you? It would be as one |
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18:40 | entity more or less. Right. by having variation right then you have |
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18:47 | subsets of accumulated genes in in in marriage members of the population that inherently |
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18:57 | possibly that better survival for the Because you know if if things change |
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19:03 | what had different selective pressures occur. chances are greater we have valuation because |
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19:11 | members that have that have the most combination of genes for the particular circumstance |
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19:15 | will survive and those offspring will then and then they will produce another generation |
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19:20 | so on. So variation. Genetic is key. Okay and so as |
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19:28 | , sexual reproduction. Okay that inherently lots of variation. Of course mutation |
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19:34 | well. The bacteria have brilliant Carbs you would think right to |
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19:40 | Um And that certainly works. They very fast. Right? So even |
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19:45 | the colony on the plate there will some variants in there. Okay there |
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19:50 | be a 10 million colonies or something up two million cells. Make up |
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19:55 | colony on the plate, bacteria tend have about a 1% spontaneous mutation rate |
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20:00 | a mistake is made you know every million times is not corrected. |
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20:06 | So uh considering how fast bacteria growth I said they're calling in the plate |
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20:13 | have a few variants of a single . Okay um now the computation is |
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20:21 | thing. Okay that can certainly generate . Right? And so uh those |
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20:26 | can be passed on through vertical gene . So just think of parent and |
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20:31 | . That's vertical gene transfer. That's you inherited your genes right? But |
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20:36 | have this option as well, horizontal transfer. So they can transfer genes |
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20:41 | their neighbors next to them. Okay . And um now we're not talking |
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20:47 | a whole chromosome transfers here. It's segments. So a few |
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20:54 | one or a few can be Okay. But nevertheless it provides |
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21:01 | Okay and so the mechanism will go a conjugation, transformation transaction. |
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21:09 | Each has a characteristic kind of feature it um as well. I'll show |
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21:15 | a brief overview here in a But let's look at this is e |
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21:20 | it represents e coli at different Okay so the big blue blob circle |
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21:29 | represents all of the known E coli we are aware of. Okay. |
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21:37 | is like 11. A little over genes. And we've been um sequencing |
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21:44 | coli genomes for decades so we have lot of information there. So uh |
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21:51 | no one no one E coli will all 10,000 plus genes of course. |
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21:58 | . Um it will have roughly about little less than 5000. Okay, |
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22:06 | 5000. Um and so then we down further to the red. Is |
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22:14 | core genome? Right? The core what basically all all the coaches will |
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22:20 | ? Okay, core genes Okay. they all share. Okay. And |
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22:31 | if we look at a couple of coli strains, K 12 was just |
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22:36 | basic harmless lab string that we actually . That lab Over 5 7. |
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22:42 | call the chipotle. E coli. , responsible for foodborne outbreaks related to |
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22:48 | produce. Typically I think it is obviously a pathogen. Right? So |
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22:53 | is the difference in the number of the bulk of those being um involved |
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23:01 | um as violence factors causing enabling to disease. Okay, so um just |
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23:10 | the core gene and flexible gene Okay, core genes are what you |
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23:15 | guess your call them informational molecules like involved in protein synthesis in um DNA |
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23:25 | in like core metabolic pathways like like or respiration, uh amino acid |
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23:35 | These kind of things that are critical survival according to your flexible gene pools |
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23:41 | those that generally don't aren't necessary for survival. Okay. But can be |
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23:49 | in certain cases. Okay. But members of the flexible gene pool, |
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23:54 | jeans are the ones that are typically ? Okay. Um Now when we |
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23:59 | at ecology know the percentages here. , 88% protein coding way. Big |
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24:09 | to reality. 1% of the you know is actually used for protein |
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24:17 | . Bye now. Like 2% like something like that. In that range |
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24:25 | about two middle over 2% of human is used actually code for proteins. |
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24:32 | But much more obviously much more so bacterial genes there's a lot of |
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24:37 | N. A. That we have and another a few carrots as well |
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24:43 | we don't know what it does to lot of a lot of it's for |
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24:47 | three. A lot of it's like sequences uh that are not really sure |
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24:53 | that's for either. But um but it's it's uh surprising how little of |
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24:59 | gm was actually used to coat That probably tells you how much how |
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25:04 | regulation is because a lot of the stuff is for that purpose. Um |
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25:09 | anyway, so in e. Coli is typical numbers for any any bacteria |
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25:14 | any pro cario uh 11% for regulation 20%. So for Tianna Roswell our |
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25:22 | to remember that most genes code for but some the dan product can be |
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25:28 | R. N. A. Not protein but we still call those genes |
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25:32 | then 20% of the genes of the acquired from other microbes. Okay. |
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25:39 | um so how would how do you that out that that's the case. |
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25:45 | . So what's done is something like ? So a parameter that you've been |
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25:51 | for a long time says percent C. Okay. Um if you |
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25:58 | what's his name? Charge off the graphs rule when you studied D. |
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26:03 | . A. Structure A. And G to C. Alright. |
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26:08 | those forces are equal G to And agency that was charged off |
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26:13 | Did that. Right. So he percent G. C. Uh parameter |
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26:18 | later it was used for taxonomic purposes be able to it was found that |
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26:24 | have their own characteristic percent G. . Of the DNA. And chromosome |
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26:29 | or DNA. And they kind of it as a way to for taxonomic |
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26:34 | to examine relationships and things. And what we can do is look |
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26:40 | So this is actually valued for E 50 50.8% easy content. So you |
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26:46 | look on the computer courses works done at all this information H. G |
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26:51 | . S and T. S. then you look to see is there |
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26:56 | continuous stretch of nuclear types that is above or below that percent GC |
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27:03 | Okay. Um and of course you make this determination from just looking at |
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27:09 | bases. Right. So you have type of significant number of nuclear ties |
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27:14 | 2500 bases is the average size of gene is about 1000 nucleotides. So |
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27:21 | basis is a pretty good chunk. I? So if within that, |
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27:25 | know, we see a consistent Do you see that significantly higher or |
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27:31 | this case higher, then you might that hey this this this may have |
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27:35 | from something Another organism, especially if those 2500 bases they represent jeans have |
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27:43 | common function. Okay, jeans have common function. Like maybe it's a |
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27:49 | resistance or maybe it's a maybe it's small metabolic pathway. Right? And |
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27:55 | genes are involved in it. And so that's a good evidence that |
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27:59 | that came from something else. Well would it be? Well, you |
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28:03 | say, well, what are the percent gc contents of other bacteria? |
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28:07 | , internal factor erogenous, very close of the coli has does have that |
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28:13 | . So you might suggest so maybe got it from a intro background. |
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28:16 | heck. But it's a but that's you do these kind of things. |
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28:21 | . Um and so this we're gonna in a second about what are called |
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28:28 | genomic genomic islands. Right? So islands and these are typically the segments |
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28:36 | DNA that are transferred. Okay. so this might be I still can't |
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28:43 | island apparently island. Okay, so might be in genomic island. If |
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28:52 | if the genes are part of a pathway. Okay that's what characterizes the |
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28:56 | diamond. It's it's something that's sitting the chromosome that clearly came from a |
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29:01 | species. Okay. Or general. um and they're all involved in the |
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29:06 | function that's pre indicated that was required gene transfer. One of these |
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29:12 | Okay. Um Any questions about Okay. Yeah it's it's really stands |
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29:23 | the percent of guanine and cytosine bases types in the D. N. |
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29:28 | . It's generally used to determine the of it's used it's used to the |
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29:35 | came from that guy charge off. are because we know that A. |
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29:39 | T. Base pair together GNC paper and so he came up with the |
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29:44 | for these things. Black. If if it's 50% 50.54.8% G. |
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29:50 | then obviously it's 40 6.2% 80. ? So when he was still a |
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29:57 | studies of DNA and just doing chemical he's found that these ratios are always |
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30:01 | very consistent. That's what led us believe oh A. T. And |
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30:05 | . C. Base pair together. this this predates Watson and crick by |
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30:10 | years. OK and so that allowed piece of information helped um um Watson |
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30:18 | Crick to figure out their structure But since that time since the 50s it's |
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30:23 | used for a period of time as taxonomic tool. Okay so you would |
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30:29 | general bacteria e coli other similar interests gonna have percent gc contents very similar |
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30:34 | each other if they're closely related. different if they're not so closely |
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30:39 | And that does bear out when you that with you know it's not really |
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30:45 | today as a taxonomic tool. Okay use DNA sequencing but there is some |
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30:50 | when you look at DNA sequencing it's based on DNA sequencing and this |
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30:53 | is some consistency. You have sections to have a different gcc percentage. |
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30:59 | when you. Right so that's so that context or not you're really using |
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31:04 | for taxonomic purposes here. We're using to see is there a dramatic difference |
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31:08 | the sequence of nucleotides? That's where the genome. There we go. |
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31:14 | this is you know the further and can we can identify actual jeans in |
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31:20 | and those genes are appear to be of a common function or something. |
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31:25 | I couldn't believe this may be a island required by one of these mechanisms |
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31:30 | horizontal gene transfer and finding Ireland Mhm. Just that it was it |
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31:38 | inherited by a horizontal gene transfer It wasn't it wasn't part of its |
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31:44 | original lineage. Okay. Uh look fixation. Right that's another one that |
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31:50 | here because national fixation you see across wide range of bacteria Okay from gram |
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31:56 | gram negative for the synthetic hetero trophic happy. And so it actually mocks |
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32:03 | . You know we try to figure sometimes they need just because you see |
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32:07 | that's so widely despaired organisms. But fact that horizontal transfer does occur explains |
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32:14 | . Okay, so it's kind of it's kind of like a patch on |
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32:19 | regina somewhat. Yeah. Blue sweater fantastic. Yeah it's something like |
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32:28 | Sure. But but of course it's beneficial to your it's quite the genes |
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32:35 | can potentially give them an advantage possibly know so and and can potentially transfer |
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32:44 | to another organism. Um Okay so mechanisms so here we're just gonna go |
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32:52 | quick and we'll spend a little more on each joint as we go |
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32:56 | Um So transformation. Uh huh on seemed probably the most simple simplistic process |
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33:05 | of DNA from the environment. And don't don't think in terms of the |
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33:09 | chromosomes are being taken up here. talking about fragments of DNA and the |
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33:14 | you know only has a is not stay in the chromosome right? The |
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33:17 | . And yeah we are going to getting too fragmented DNA. So we're |
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33:21 | about fragments being taken up here but it's a little more complicated than |
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33:26 | But um compared to congregation, congregation two selves. Alright, so intimate |
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33:34 | between two cells. Transfer of uh this involves transfer plasmids here. Okay |
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33:40 | fragments of DNA. So transfer plasmids during congregation. Uh so you're gonna |
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33:46 | a mating pair of donor and recipient will undergo this trans deduction virus C |
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33:55 | transaction you think virus the virus is between the two. So the virus |
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34:01 | um it's due to an error in basically. So the virus packages host |
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34:07 | . N. A. Instead of its own viral D. N. |
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34:12 | . Okay. And um then that caption now contains bacterial D. |
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34:19 | A. To infect another host. . And now that bacterium has acquired |
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34:25 | from that prior host. Okay. that's transaction transposition. So transpose seasons |
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34:35 | widespread among prokaryotes, eukaryotes. We them. Um Typically there they remain |
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34:44 | the organism there in and what they is they jump around the chromosome two |
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34:49 | spots. Okay. But occasionally they exit the host and go to a |
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34:56 | host. If they hitch a ride a plasma for example. Um And |
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35:02 | course we're talking here in the context precarious, the transposon jumps out the |
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35:06 | onto a plasma and the plasma is to congregate and then as for it |
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35:11 | way there's a couple of other mechanisms that's the idea. Okay and among |
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35:18 | it's known that there are a few resistance genes that are passed this |
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35:23 | Okay. I believe in terms of of horizontal gene transfer. Mhm congregation |
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35:33 | deduction. But the more common Okay transposition somewhat less. So although |
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35:41 | does occur obviously. But in terms proportions I'd say congregation transaction are more |
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35:47 | in terms of this horizontal gene Um Alright so speaking of just mentioned |
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35:56 | islands. So again these are elements are grouped in the chromosome. They're |
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36:04 | of a common pathways. So this just showing examples of that. So |
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36:07 | given these names. The names are labels are meant to reflect the types |
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36:16 | types of functions that genes are involved that are part of the island. |
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36:20 | pathogenesis the island relates to disease causing , jeans, symbiosis islands. Genes |
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36:27 | in bringing about the the relationship with host. So think of natural |
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36:33 | Right. Symbiotic nitrogen fixation, bacterium coming together so that the parts involved |
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36:39 | that happening could be a symbiosis island pollack pathway we mentioned before the metabolism |
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36:46 | aromatic compounds that bacteria can do This could be an example of |
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36:51 | Okay these are elements that can be uh required by one of the mechanisms |
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36:57 | horizontal gene transfer. Um But again on the chromosome having these comment |
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37:05 | Okay. Um now. Okay so before we start on the different these |
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37:12 | mechanisms. One last thing to mention recombination, recombination is an important part |
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37:22 | really all four of the mechanisms. because you are um taking D. |
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37:31 | . A. And you're inserting it another piece of D. N. |
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37:34 | . Okay and that involves your Right So if you have D. |
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37:39 | . A. External to a bacterial . For example whether it's a circular |
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37:44 | like a plasma or a fragment then fragment. Well what what can the |
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37:51 | do with that? Okay. The to sell. So you can enter |
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37:57 | conjugation for example. And it can coexist in that fashion. It cannot |
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38:03 | as a plasma inside the cell. no big deal a fragment. That's |
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38:08 | little different. Right? But you're a sense that that's a viral |
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38:13 | Perhaps it's not normal for just a piece of DNA. To be fragments |
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38:20 | DNA to be hanging out in the . That's not normal. And so |
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38:25 | typically get degraded very quickly. Okay a lifetime of something like that is |
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38:31 | short. You can use your right? For example can be used |
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38:35 | food. Um But they're not gonna a linear fragment. Like that's not |
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38:39 | to just sit like that in the . Okay. But what it can |
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38:43 | is it can recombine. Right and part of the chromosome. Right? |
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38:47 | that's that's how it can exist. kind of makes it a permanent part |
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38:52 | the. Okay so um but you we're going to see examples of this |
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38:58 | each each type of mechanism. And so the combination in general is |
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39:04 | to well a number of enzymes but main one record for the combination protein |
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39:14 | . Okay. Um it uh somewhat august to a signal factor. It |
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39:21 | align the the donor fragment with the in areas that are homologous. Right |
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39:30 | the two the two D. A. Is coming together recombining. |
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39:32 | be that different. There has to some level of cosmology because the group |
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39:38 | is all about complementary base pay O. T. G. To |
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39:42 | . Right so there has to be sequences of those that their similarity. |
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39:48 | . And that wreck a helps find and facilitate facilitate that process. So |
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39:55 | do recombine and that donor now becomes of the chromosomes. Okay. And |
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40:02 | course in the process that makes this then a permanent part or semi permanent |
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40:09 | of the genome. Okay. Um of course along the way obviously the |
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40:15 | one receiving that has gotten potentially some jeans. Okay um Again increasing |
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40:23 | Okay so I just wanted to throw in because you're gonna see a combination |
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40:28 | I said in each of the four . Okay. Um Okay so let's |
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40:34 | about transformation first. There's a question transformation. Okay so transformation requires |
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40:43 | Mhm. Yeah mm hmm. Okay let's see. Yeah it's gonna |
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41:45 | DNA fragments in the environment. So cell contact. That's um conjugation. |
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41:50 | intermediates, transaction sex pilots congregation plans going to be congregation uh to the |
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41:57 | . So transpose is is part of transposition. Okay so um so in |
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42:06 | at transformation. Okay uh Uptick of from the environment we have um we're |
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42:16 | get to processes gram positive and gram . Okay and in the gram positive |
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42:26 | involves a phenomenon we've seen before. quorum sensing phenomenon. Okay so remember |
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42:34 | is a cell density dependence. You to get to a certain cell number |
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42:38 | , producing a chemical signal of some but that signal has to accumulate a |
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42:46 | level for them to create the Right? So it depends on a |
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42:49 | of cells coming together. Okay. saw him biofilm formation. So uh |
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42:55 | were positive uh inquires this big multi complexes what they call a transformer zone |
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43:03 | called the trans loca zone because it D. N. A. |
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43:09 | Um It's contingent upon these competence So when you hear the term |
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43:15 | competence goes with congregation, I'm with , I'm sorry but transformation competence and |
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43:20 | go hand in hand. Okay, simply means that when the events have |
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43:27 | place there there now in place in cell to take A D. |
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43:30 | A. You say it's competent? prior to that point it's not but |
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43:35 | it reaches that point we say it's so it's going to take it. |
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43:39 | so there's there's um uh so competence are the little signals that need to |
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43:45 | a threshold for the process to occur a grand positive. Okay um in |
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43:52 | gram negative. Okay they have um that can do this now. Not |
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43:59 | gram positives can do and not all gram negatives can do it. So |
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44:01 | what's called natural transformation. Those are that can naturally do this. |
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44:06 | So by no means is it's something every precarious can do. No not |
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44:10 | a stretch. Right? So for souls that you know so artificial transformation |
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44:18 | obviously a something that humans do to cells pick up DNA. Okay. |
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44:26 | so why why do that? Well has to do with the utility of |
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44:32 | in the lab to help you with genetic recombination, your gene cloning |
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44:39 | Okay um you want you bacteria easy grow and they grow fast and grow |
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44:45 | large numbers. Right? So you that ability. Two replicate your |
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44:52 | Right? So if you have a for example uh that has a gene |
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44:56 | want or of interest and you want of it lots of copies of your |
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45:00 | . You put it in the Let it do the work for |
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45:03 | Okay But E coli for 30 plus has been the workhorse in the lab |
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45:10 | these kinds of things. So we coli as the vehicle for that lot |
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45:17 | of the time. Okay. But coli is not naturally transformed. So |
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45:21 | developed these methods to be able to DNA into it. So that will |
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45:25 | it. Ok that's what artificial transformation . If you took uh we took |
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45:32 | too. I think intro bio I think you did something like |
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45:35 | You had at least you had transformed your D. N. A. |
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45:38 | get competent cells and you had A . N. A. To it |
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45:41 | you made them grow the password for . So what you do is just |
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45:44 | just chemical that can be chemicals, chloride, calcium chloride. Typically a |
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45:50 | shock. You have an ice and shock it and put it back on |
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45:54 | all combined to create pores in the . Such that DNA is taken |
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46:00 | Okay. Uh more recently well last years the corporation has been the way |
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46:08 | do it much more efficient. Um uh that to create spores electric shock |
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46:15 | pours so much easier to do. So regardless so artificial transformation is only |
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46:22 | those that can't do it on the . Okay so with the graham back |
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46:27 | the gram negative over here. Okay that involves a pilot. So remember |
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46:33 | talked about different types of pilots is sex pilots will talk about in in |
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46:39 | . Um If pilots that can be for the twitching motility if you remember |
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46:44 | . Um So pilots is tend to more specialized functions. Right fewer in |
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46:49 | more specialized functions. Okay And this another one. A Type four pilots |
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46:54 | latch on two DNA fragments and bring in to the cell. Okay and |
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47:02 | Demopoulos and nice Iria Our two major types um that are able to do |
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47:10 | um I'm office causes uh one of causes of meningitis. So it's |
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47:15 | Syria causes meningitis um and gonorrhea as . Uh But we're gonna that's all |
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47:23 | gonna say about grandma. So we're focus on gram positives in that |
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47:27 | Let me see here. And so looks more complicated than the gram negative |
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47:33 | involves more parts. Okay, so goal here is to make this |
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47:38 | Okay, that's a complex that will and take up DNA. Okay, |
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47:45 | in order to do that. So , once again, right several times |
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47:49 | I mentioned um you know how much processes take energy, Right DNA replication |
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47:56 | , sensors this as well because we're proteins assembling stuff. Right? That |
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48:01 | energy. So it's not something that going to be, it's going to |
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48:07 | willy nilly. Okay so there has be a right time to do |
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48:13 | Okay and so it's time to the sensing. Okay, so is dependent |
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48:22 | the accumulation of these competence factors. , so they're produced by the self |
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48:29 | if enough cells are present right against enough cells get together you have enough |
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48:35 | accumulated enough confidence factors then you get um you get this happening here. |
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48:44 | so that's a sensor protein that binds factors when they reach a certain |
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48:50 | And then then the end result is activate a sigma factor. Okay And |
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48:57 | that acts on different operations. 1 3 4. And what do we |
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49:03 | that? He called that a Okay. Another example here multiple operations |
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49:10 | control with single element all involved in common phenomenon transformation. Okay um So |
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49:23 | so I guess the question is why density dependent why cell density dependent? |
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49:31 | have to think of of the growth . Right? Time, time and |
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49:43 | number. Right. So we have typical lag lag log stationary. |
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49:53 | And so oops this way. So any given point along this curve |
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50:01 | You have. Okay. The proportion cells that are alive and dead. |
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50:09 | ? Um And as we go along curve we accumulate more dead cells. |
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50:13 | ? We get the ratio of lying dead becomes equal a stationary phase but |
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50:19 | the dead cells that lice and then up their DNA. Those are the |
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50:24 | in the population of DNA fragments like that die that lies and there guts |
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50:31 | spilled, so to speak into the including the DNA they have. So |
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50:37 | guess is that making a cell density process. Right enhances the chances that |
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50:43 | will be D. N. Out there to grab up. Okay |
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50:47 | as more cells to commit that means dead cells are there they lie. |
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50:50 | now you have a source for of to take up. Um That's the |
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50:55 | at least. Okay um And so uh in doing so the I need |
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51:07 | back out of this because doing something . Let me just try this |
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51:12 | Okay all right and back to There we go. Okay so um |
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51:22 | so when the transformation occurs, the . N. A. On the |
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51:25 | external only one strand comes in, is degraded as it becomes as it |
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51:30 | in the cell. And so single comes into the cytoplasm. Remember it |
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51:36 | going to survive, it's gonna need recombine the chromosome, it was going |
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51:40 | become a part of that cell. . Um and so yeah that's that's |
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51:45 | profits for for for gram positive, positive that can do it. This |
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51:51 | generally the process. Um Any questions that. Yeah so yeah I can |
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52:02 | that in the operations uh kind of kind of wondering is that what triggers |
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52:11 | transparency? Oh yeah so that so yeah it's not really shown here but |
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52:16 | products of those operations uh code for different protein parts of that transformer |
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52:22 | Yeah probably as well as well the what's it called? Indo nucleus that |
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52:28 | the one DNA strand. So yeah operas code for different parts of that |
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52:32 | . Yeah. So what's the for purpose of the audience that's tied to |
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52:39 | whole quorum sensing thing. So it's about when you want to explain all |
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52:44 | energy to do this in order to a DNA from the environment is when |
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52:47 | have the greatest chance of finding DNA the environment. And that's gonna generally |
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52:52 | when you have a higher cell density you're gonna have a greater proportion of |
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52:57 | cells at that point. Those are sources for D. N. |
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53:03 | Taking it from the environment. Cell cell dies license DNA. That |
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53:06 | out of the cell. Right? that's that's what the thinking is. |
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53:15 | . Ah The confidence doctors, So the common factors initiate the process |
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53:22 | they won't until you reach a certain density. So it's tied to that |
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|
53:28 | like biofilm formation dr export is kind showing 80 ft. Yes. |
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53:40 | Right. Yeah. Um So as going on to the next process which |
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53:52 | conjugation? Okay. Um No, a restaurant here. Okay. Um |
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54:10 | uh so the congregation contact between two . Okay. Um it involves a |
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54:17 | of genes that um one of them sex pilots and a number of others |
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54:24 | helped to bring about the uh connects to selves, the copying of the |
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54:31 | and transfer. Okay, so the F factor, fertility factor refers to |
|
|
54:38 | plasma that has those components that enable to be transferred. Okay. And |
|
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54:44 | are these are what you see here components. Okay. And so these |
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54:52 | the transfer. So remember that you the plan if you say oh that's |
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54:57 | is F. Plus. Okay, means that plant, it has a |
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55:04 | that is transferable but it can have genes on it certainly can be can |
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55:10 | pathway can have anybody. Resistance genes have other stuff on there. The |
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55:15 | Plus designation means it's transferable, can ? And so uh different types of |
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55:21 | involved. So transfer genes they're called included sex, pilots. The relaxes |
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55:27 | the complex is what Bridges The two facilitates the uh the entry of being |
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55:34 | to the recipients. So then there's couple of different story origins of |
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|
55:40 | The key is where rolling rolling circle is initiated from. Okay. Um |
|
|
55:48 | so we see here in terms of process that a pilot which you see |
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55:54 | the top. Okay. Is and is all about plagiarizing putting the piling |
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56:00 | on it to make it longer or them away. Right. Diploma rise |
|
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56:04 | make it shorter. Okay, so really alternates between extending okay and contacting |
|
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56:10 | cell and that's receptor specific and then and then deploy, memorizing it. |
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56:17 | what's happening is as we go down distance between the cells is less and |
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56:23 | . Okay. Until you form that called a conjugation bridge at the |
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56:28 | And so that's all about you know that that pilot is it is rather |
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56:37 | . So if there's two cells are far apart and it stayed that |
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56:41 | The chances of breaking apart are much than if you just bring them together |
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|
56:46 | this. Okay, so the amount genetic material transfer is totally dependent on |
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56:53 | long they're connected. Okay. The they're connected and more, the more |
|
|
56:57 | that can be shoveled over to Alright. We're transferring plasmid uh you |
|
|
57:02 | , which can vary in size. gonna need to be connected for uh |
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|
57:07 | number of minutes. Okay, longer you might think. Thanks. And |
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57:14 | so certainly bringing themselves together greatly enhances ability to stay together. Okay, |
|
|
57:21 | Now the process so again the rolling circle replication occurs. Okay. And |
|
|
57:34 | close up here, so you see as the other strands displaced, it's |
|
|
57:39 | shoveled into the recipient cell. So have a donor recipient cell in F |
|
|
57:44 | N. F minus, sell the minus recipient, receives the copy of |
|
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57:48 | classmate. And then once it does then makes a double stranded copy of |
|
|
57:53 | . Right? And um the and has been converted and if mine itself |
|
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58:03 | . Okay so um and now the Plus cell is able to transfer that |
|
|
58:11 | with two other mhm. Members of population. Ok. So it's a |
|
|
58:17 | to increase the the spread of the and within the population right to create |
|
|
58:22 | F plus cells, then they can it on and pass on and so |
|
|
58:25 | . Okay, so of course antibiotic can spread it fairly quickly because of |
|
|
58:31 | phenomenon. Okay. Um So now we look at so again back to |
|
|
58:42 | . Okay. Although we're not seeing combination here because the pattern is just |
|
|
58:46 | outside the chromosome in the south. . But this plasma can also be |
|
|
58:53 | with the chromosome. Okay, so of the HFR cell is what we're |
|
|
58:56 | about. So the nature of our requires what to form. Okay, |
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|
59:07 | let me charge this here. I think I just give the answer |
|
|
59:13 | . I was explaining. Mhm. think I said began with our |
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59:49 | Mhm. Okay, let's see C. F. Factory integrated in |
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|
60:18 | chromosome. That's correct. Right. I mentioned recombination. So the so |
|
|
60:23 | plans were recombined with the chromosome, it integrates in the chromosome. Um |
|
|
60:28 | again viral intermediate. That's transaction. , A sex pilots. So HFR |
|
|
60:34 | already has the the effect of plasma it. Okay, So £6 isn't |
|
|
60:42 | . Um But it's certainly integrating. is what it's all about. |
|
|
60:46 | so it's an event happening inside the itself. Okay. And so here |
|
|
60:53 | is a pitch. Let me get out of the way. So here |
|
|
61:00 | a picture of that. Okay, we took for instance of a high |
|
|
61:04 | combination strength. So um so these now by being part of the |
|
|
61:11 | So the F factor is not So it's still an F. Plus |
|
|
61:14 | . Okay. We call it HFR . Because it's integrated into the into |
|
|
61:18 | chromosome. Okay. And so uh it's still an F plus because it's |
|
|
61:24 | of transferring but um because now it's of the whole plasma. And so |
|
|
61:30 | it what happens is you have common . So I s it stands for |
|
|
61:35 | sequence. Okay. And the plasma chromosome have that in common. And |
|
|
61:41 | where these will integrate into the And so again remember the combination requires |
|
|
61:48 | level of hm Ology. And this what provides that. And so it |
|
|
61:53 | . And so now we have integrated . And now by being part of |
|
|
61:59 | chromosome down, the whole chromosome is . Now the whole chromosome won't be |
|
|
62:06 | . It's very rare that that ever if ever but you can copy chunks |
|
|
62:12 | the chromosome and that can be transferred another cell. Okay. So in |
|
|
62:18 | think of the chromosome now as a F factor plasma if you will. |
|
|
62:25 | . But the whole thing is copying begins to be transferred. Okay now |
|
|
62:32 | congregation of and HFR with an Plus cell. Okay, so when |
|
|
62:40 | begins to get replicated it goes in direction. Okay. What's in the |
|
|
62:48 | are the genes that make it Plus? The transfer genes, et |
|
|
62:53 | . Okay, this is the the part of that second. Okay so |
|
|
63:04 | sell recipient cell inherits this portion then would become an F. Plus. |
|
|
63:13 | . But again that rarely happens. for this reason. Okay, so |
|
|
63:17 | mentioned replication begins this way. And continues. Uh and this the |
|
|
63:27 | part the transfer genes, the F factor genes, that would be the |
|
|
63:34 | bit to go into the set in very last part that would go into |
|
|
63:38 | cell. So the cells have to together for nearly two hours for that |
|
|
63:48 | happen. Okay. And like I , that rarely if ever happens. |
|
|
63:53 | . So of course, what what recipient cell inherits is um certainly, |
|
|
64:00 | know, anything from from this point here to here to here to |
|
|
64:05 | All dependent on how long they're Okay, so certainly the F minus |
|
|
64:11 | benefits because it's inheriting, you potentially a bunch of different genes. |
|
|
64:17 | . Um it just doesn't have the to then transferred horizontally to another |
|
|
64:22 | Okay. But certainly it can pass . Right? It's gonna it would |
|
|
64:28 | to become re combined with the with host chromosome. But the main point |
|
|
64:33 | want to make here, is that why an F minus recipient won't become |
|
|
64:37 | F plus when it congregates what's in Because this is the last bit to |
|
|
64:42 | transferred and they'd have to be together long time and it just doesn't it's |
|
|
64:46 | not reality, there's different forces. when it sells are, you |
|
|
64:50 | in whatever environment they're in, they're bombarded by molecules that knocking |
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64:56 | Remember brownie and movement. Brownie movement not really motion. But it's these |
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65:01 | of vibrate Torrey motions that occur because are bouncing off of them or other |
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65:05 | are bouncing off of them. Um are all forces that will break the |
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65:10 | . Okay so to be together for two hours is not a likely |
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65:17 | Um So here again we see again F minus made. Okay so so |
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65:26 | so has the integrated uh F plus in here and then congregates with F |
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65:35 | . So so we're looking at um has he's able to synthesize veiling veiling |
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65:42 | synthesis pathway via L. Plus. what that means. The F minus |
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65:47 | is incapable of doing that. So it's minus for that. And so |
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65:51 | conjugate and um and you can see the the criminal is being replicated and |
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66:00 | that copy is being pushed into the cell and if they're locked together long |
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66:06 | maybe the railing gene goes into Or railing Operandi goes into it. |
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66:13 | . An investigation that combines and now F minus cell which used to be |
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66:18 | minus is now beginning plus. Okay so again it's not it doesn't become |
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66:25 | plus but it's not necessarily a negative now it has acquired this ability to |
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66:30 | bailing which which would be a Okay so um the uh of course |
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66:38 | H. Bar still stays as Plus obviously. So um any questions |
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66:44 | that? Yeah. Yeah correct. an F minus sell um will have |
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67:00 | specific receptor that F Plus cells do . Okay so enough Plus cell that |
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67:06 | will be specific for that receptor. it only will bind with an F |
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67:10 | but that initial binding also prevents another plus cell from conjugating with it. |
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67:18 | it's going to be very specific between those two things and like you said |
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67:22 | direction. Yeah um Many of Okay so let's um look at |
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67:35 | This is a this is about the . Prime factor from it. And |
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67:39 | again um let me turn this thing here. So again remember that? |
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67:48 | so recombination again plays a part in process. Okay um and let's see |
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67:57 | we Can get this one. Okay Pepsi. Okay let's see what |
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68:58 | get. Okay um That was magically like when that happens. All right |
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69:09 | um so it is two and What are the two? What's |
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69:13 | Yeah I think it's seen Chf are yes and yeah it involves excision. |
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69:23 | it's about so plants can not only to formulate a far so they can |
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69:28 | come out okay as well. What don't know is the frequency at which |
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69:36 | occurs. I don't think it's it's I'm not exactly sure but but it's |
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69:43 | the F prime is all about the part. Okay so here's an HFR |
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69:51 | and so the main part to focus is the integrated plans with their the |
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69:57 | part. Okay. Between the two sequences. Okay so again this stuff |
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70:03 | here? right? That's that's the , right? Were inserted. |
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70:08 | So um what happens is it can , exercise needs to come out of |
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70:17 | chromosome and normally it comes out what out and what went in as you |
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70:22 | there. So the box part is integrated in the first place. And |
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70:26 | normally is what comes out. to form the the intact Klansmen |
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70:32 | uh now that that's what I don't . The frequency of, I'm not |
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70:35 | what the frequency of the HFR cell when it then comes out again, |
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70:38 | don't know. But um but even is the event where when it comes |
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70:46 | , I I used the term cockeyed the parent is what the textbook |
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70:52 | right? So what that means is shifted. So here we're taking out |
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70:58 | within the box, but we're taking this box instead. Okay, so |
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71:06 | taking that. So we're leaving this part stays behind. Right? And |
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71:12 | part with the B gene is now . A new part of the plasma |
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71:19 | . Okay, so this is gonna our new plasma, What you see |
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71:26 | . Okay, so once again, the chromosome or gene, right? |
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71:32 | wasn't initially part of that. I when it wasn't serving. Okay. |
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71:37 | so but now it is it's a that's what we call the F prime |
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71:41 | contains. So if it weren't if just f we just say F |
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71:46 | for example. Okay. it would be that would just be the purple |
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71:52 | back into a circle. Alright. because it went the skew, so |
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71:58 | speak, it's an F prime. it's carrying now basically it's carrying |
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72:04 | It didn't have before when it went but now it does. Okay. |
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72:08 | that's the F prime factor. So then I remember that part of |
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72:14 | part of the plasma is left behind chromosome. They're so focused on the |
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72:20 | . The parts of the purple are of the original plasma that integrated and |
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72:26 | end result now is part of that is left behind. But then it's |
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72:32 | part of the genes from the chromosome in this case. Okay, so |
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72:39 | the big deal about that? um what can happen is so see |
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72:45 | prime is self contained. The Prime plasma congregates with with another cell |
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72:51 | population. Okay, it means that that new cell now may acquire an |
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73:01 | copy of that gene. Okay, if they're members of the same species |
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73:07 | they both already have the B Well now it requires a plasma containing |
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73:10 | B gene. What that means is what we call a partial deployed. |
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73:16 | So partial deployed is the type that have full we contain have genes from |
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73:25 | have genes from her father. The deployed has only you know, two |
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73:30 | more one or more genes are Okay, so that's a partial |
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73:34 | So here we have to be copies gene copies part of the no no |
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73:40 | deployed anywhere else. Just with that respectively. So what happened in this |
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73:45 | is the B. Gene here can evolve independent, right? Because it |
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73:54 | whatever the function of the B. here is then that's what it will |
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73:58 | to do. Right? But now got this other one that doesn't have |
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74:02 | same selective pressure on you can mutate a higher rate, right? Because |
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74:08 | really not just it's just a secondary of a gene there. Right? |
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74:12 | maybe it acquires a mutation or two it requires a slightly different function perhaps |
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74:18 | it can be a benefit. Okay it's okay to get two copies of |
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74:22 | gene where one can um evolving the . Okay um and so let's this |
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74:32 | kind of puts it all together here terms of conjugation. So we had |
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74:38 | our our basic f minus F plus . Okay so F F minus. |
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74:45 | recipient receives a classic F f. becomes f positive f minus becomes |
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74:51 | Right then we have the HFR So fact that integrates can I? And |
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74:58 | meeting with f minus cell generally means the f minus stays epitomized because um |
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75:06 | together long enough to transfer that last of information and that's where the F |
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75:10 | is. Okay but it certainly can um some new uh one or more |
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75:17 | along the way. Okay. Whatever are on this segment it's inheriting. |
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75:22 | . So then finally the F Right? So they have prime formation |
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75:28 | an HFR cell. Okay. But occurs due to this weird weird |
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75:34 | Right? So in this example we a as part of our chromosome. |
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75:40 | . Are non planted gene and then the apparent excision it's now on our |
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75:47 | . But. Okay, so the variations here if you will. |
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75:52 | so you see where you know the of course important here. Certainly integration |
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75:59 | the F factor. That's recombination. we start a combination and transformation as |
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76:05 | where that's important. So anyway, questions about that? Okay. |
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76:12 | So for the mm. Mhm. that's minus cell. Well, the |
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76:28 | , I can see the picture is little misleading. So the so this |
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76:31 | here, Right. Uh it wouldn't initially have that plasma in it. |
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76:38 | would be plasma less. Okay, it would only have the chromosome sitting |
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76:44 | agent. Um So having following what's on. Alright, so the plasma |
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76:52 | integrated in red. Right? It the genius to transfer. But now |
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76:59 | it's part of the chromosome, the gets mobilized. Okay, so now |
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77:05 | copying the chromosome and as the copy that is funneled into the recipient. |
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77:15 | . And depending on how long we're determines how much the chromosome gets |
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77:22 | The part that gets transferred. All . It was going to exist in |
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77:26 | f minus cell. It's going to to recombine, Right? That's little |
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77:31 | the extra combining with that. F minus. So that becomes part |
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77:35 | that F minus chromosome ken. So instead of being a plasmid, |
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77:43 | outside of chromosome, it's integrated into minus chromosome because that's where the |
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77:49 | They have the age of our I have a plasma. They have the |
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77:53 | plasma and then it transferred that in fashion. Um, so we've got |
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78:00 | . So see you next. See monday. Okay. Mm hmm. |
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78:14 | , I'm still a little I didn't to stop up class. Okay. |
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78:20 | little just a little while. What's on here? So I know that |
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78:24 | cf, there's enough of them and . It comes in here. It |
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78:29 | competence factor action. Already explained |
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