| 00:00 | Right? But yeah, thank Yeah. OK. Here. |
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| 00:28 | folks. Um Testing. Hello. . Uh Yes, 1st, 1st |
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| 01:04 | , testing, testing, testing, , I don't know, testing, |
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| 01:21 | , testing, testing, testing, , you know. OK, |
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| 01:43 | Um for some reason the wireless microphone not working, so I'll um shout |
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| 01:56 | the podium microphone. OK. Testing . OK. Uh Fortunately I can't |
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| 02:03 | around with this. That's about my . So I'll have to be tethered |
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| 02:07 | this podium. So I will make that shout as best I can. |
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| 02:13 | OK. So uh today uh we're uh unit three. OK? Um |
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| 02:27 | viruses. OK. So we'll start viruses, but I wanted to start |
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| 02:32 | a little bit of because we we didn't meet last Friday, |
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| 02:35 | excuse me, because the football game canceling class and events surrounding all |
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| 02:41 | So um uh just a couple of . Of course, exam is uh |
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| 02:46 | this week. If you have you wanna come by the office, |
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| 02:49 | fine. Just email me, let know um there is no canvas quiz |
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| 02:57 | , or any kind of mastering assignment next Monday. So it just, |
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| 03:01 | know, focus on studying for the . Don't worry about any other |
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| 03:05 | Nothing is due for another couple of uh in terms of that stuff. |
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| 03:09 | . So um so let's uh so you look at the lecture video, |
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| 03:17 | , this material about the chapter 12 general, right? It's, it's |
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| 03:24 | to be just more descriptive than anything . OK. Um If I went |
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| 03:29 | any detail, it was just some with fungi and kind of differences between |
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| 03:35 | , you know, yeast and mold whatnot. Uh But I didn't get |
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| 03:39 | detailed on it. So just keep at kind of a descriptive level. |
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| 03:43 | if you look at the different groups fungi per zos algae, um uh |
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| 03:50 | , uh helmets, right? Just . Here's the groups. What, |
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| 03:53 | each one about? How, how I describe them, you know, |
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| 03:56 | getting super detailed, it's gonna be features for each one. So it's |
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| 04:00 | of that's the way to approach that . You don't need to memorize that |
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| 04:06 | . OK. You don't need to that cycle. It's just an example |
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| 04:09 | that, that this group in particular they call it at the complex which |
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| 04:14 | malaria, which is what that life is. These are types that are |
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| 04:18 | um protozoan types that have these complex cycles, they have different hosts, |
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| 04:22 | have different hosts of different types as of their development and in the stages |
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| 04:27 | they kind of have a, a stage and they kind of have a |
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| 04:32 | stage and maybe a uh um a dormant stage. And so that's kind |
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| 04:37 | these terms referred to here. Trolls needs to eat. So a |
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| 04:42 | stage, a a infective stage is one, this is kind of um |
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| 04:47 | malaria, at least these are the of infected red blood cells. And |
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| 04:50 | , um so it's more about this group has, is characterized by |
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| 04:54 | kind of complex cycles at different OK. Um The protozoans in general |
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| 05:01 | are a diverse group in terms of of shapes, forms and sizes, |
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| 05:07 | types of features you see there What undulating means is basically these are |
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| 05:22 | for pro zones that are kind of more flat. OK? You'll kind |
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| 05:26 | do this, that's that's undulating. . Kind of traveling through the matrix |
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| 05:31 | of like that. OK. Kind a flat body, that kind of |
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| 05:34 | that's undulating. OK. So, and so that's kind of how to |
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| 05:38 | it. So it's more like here's this, here's the, here's |
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| 05:41 | groups and here's what the descriptions of and kind of features unique to |
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| 05:45 | So that that's kind of how to it. OK. It's not, |
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| 05:47 | not trying to get down deep just be kind of AAA surface uh |
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| 05:53 | of a uh surface survey, better survey of here's this group that I |
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| 05:58 | at some point encounter in terms of disease. Uh in, in terms |
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| 06:03 | that, uh o obviously, that's depend on where you end up in |
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| 06:06 | world in terms of your um uh . But, you know, certainly |
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| 06:11 | other parts of the world, things um protozoal infections, um infections by |
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| 06:17 | uh put this up help uh here , these things, right? Uh |
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| 06:23 | these of all the groups, um , protozoan algae, um these uh |
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| 06:31 | , are certainly multicellular animals. Is what these are OK. And |
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| 06:36 | the in terms of complexity, So nematodes, round worms, things |
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| 06:41 | heart worms, um um hookworms, are kind of uh human human parasites |
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| 06:48 | the skin, hookworm. Uh Trone is a foodborne disease, undercooked |
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| 06:54 | uh uh meat contaminated with these parasites ingest. And so nematodes round |
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| 07:00 | these are fully, you know, more developed multi cerebral animals, complete |
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| 07:05 | system, et cetera. So uh gonna be the more most advanced of |
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| 07:10 | of, of everything we've looked at this, in this chapter. |
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| 07:14 | And so once you may be familiar tapeworm, OK. So tapeworm is |
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| 07:18 | just stuck on your intestines and it's basically eating the food you eat. |
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| 07:25 | . Classic parasite. But it can it and many of these things have |
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| 07:30 | for, for living the life they . So, a tapeworm has that |
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| 07:36 | head on it that allows it to for your intestinal wall and sit |
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| 07:42 | Um You can even chop it up the individual pieces can grow into a |
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| 07:47 | blown tape one. Ok. Um so the, uh uh and |
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| 07:53 | the flukes is like flat uh um, creatures, they are uh |
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| 08:01 | uh characterized by the organ they So a lung fluke, a liver |
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| 08:06 | . That's how you characterize these So, they're, they're more primitive |
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| 08:09 | a sense. They, they have of an, they don't have a |
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| 08:13 | digestive system, they kind of just material through their, their skin, |
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| 08:17 | to speak. Um And, and how they feed. So again, |
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| 08:22 | get too bogged down in details OK. And, and uh it's |
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| 08:28 | descriptive. So that's kind of how approach it. OK. Um |
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| 08:33 | I I'm gonna go ahead and move us if there's any specific questions |
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| 08:37 | OK. All right. OK. , and again, use that um |
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| 08:44 | two review guide. So stick to in terms of, of content. |
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| 08:50 | . Uh And of course you have , let me know. OK. |
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| 08:55 | we go as we go into this unit. OK. We are um |
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| 09:02 | we, we're spending the rest of semester in call it medical microbiology, |
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| 09:10 | clinical microbiology. You gonna be, know, basically the health care |
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| 09:14 | right? In terms of microbiology. . And so with viruses. Um |
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| 09:20 | and then into a heads up here chapter 14. So we do, |
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| 09:24 | do 13 14, uh 15, sorry, 13, 14, 16 |
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| 09:33 | 17. In that order, I flipped 15 at the end, |
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| 09:37 | makes more sense because for uh 15 16 are about uh sorry, 16 |
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| 09:44 | 17 are about your immune system. is about how pathogens get around your |
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| 09:51 | system to cause disease. So it more sense to go see how your |
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| 09:55 | attacks them in the, in a of ways, the immune system and |
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| 10:00 | and then see how they get around various defenses. Ok. 14, |
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| 10:06 | is that obviously is coming after this is, is heavily uh just |
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| 10:11 | it's like term definition, term So you'll see that if you haven't |
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| 10:16 | , you'll see it just uh it's basically in 14, we're kind |
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| 10:20 | describing disease and all the different terms use to do that. It's kind |
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| 10:24 | what it is. So, um there's really a lot of that. |
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| 10:27 | 14 is probably just the right term the right to definition is how to |
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| 10:31 | for that. OK. But we'll go through it, but that's |
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| 10:34 | of how 14 is, you're gonna a lot of terms in there which |
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| 10:38 | know, if you're talking about different to describe disease, that's, |
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| 10:41 | that's what's gonna happen. OK? to give you a heads up on |
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| 10:45 | . OK. So with uh So we break this down the two |
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| 10:51 | . Uh first part is kind of , what, how do you define |
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| 10:54 | virus? What is it? And then is, um here's |
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| 10:58 | here's a basic life cycle that we apply to all viruses. But |
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| 11:03 | um in part two, we get more specifics, a little bit more |
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| 11:08 | about life cycles because there's variations, have in terms of the generic life |
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| 11:15 | . Uh And then the other part part one is kind of the structure |
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| 11:19 | virus. Uh and we'll go through . OK. Uh Part two is |
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| 11:23 | just about life cycles. OK? particularly um focused on uh animal |
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| 11:31 | OK? And so we're gonna have few questions here just to kind of |
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| 11:36 | introduce the subject uh warm up if will. OK. And so let's |
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| 11:43 | here. Uh So these are kind just some basic features of virus, |
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| 11:48 | what fits with them and what OK, in terms of a |
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| 11:54 | OK. So I just kind of beginnings here of how we uh look |
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| 11:59 | these, how we describe them. I testing testing. Stay. Hm |
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| 12:28 | . And while you're, I meant mention this earlier, but while you're |
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| 12:30 | at this, so do not in of canvas and giving you a |
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| 12:37 | All right. So if you I already got some emails about, |
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| 12:39 | , canvas is giving me a grade the course. Is this accurate? |
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| 12:43 | not, do not pay attention, not pay attention to any grade. |
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| 12:49 | canvas is giving you. Ok. things that are posted, quizzes, |
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| 12:55 | quizzes uh um uh the exam scores , and homework scores, of |
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| 13:01 | that's legit, but canvas can come with a quote grade. Don't pay |
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| 13:07 | to it. Ok? Um I'll need to go in there and |
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| 13:11 | out how to do the algorithm to the grade out and let the canvas |
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| 13:14 | it out at you, but not yet. OK. So you can |
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| 13:17 | go to the syllabus pages seven and sort of step 1234, how to |
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| 13:22 | your grade, right? So use and if you need help, just |
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| 13:25 | me know, but just don't the canvas will give you a grade, |
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| 13:29 | . What you think is a grade it's not accurate. OK. So |
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| 13:32 | just wanted to mention that. So terms of this question, um which |
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| 13:38 | false. So uh yeah, they're a type of cell. Of |
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| 13:42 | they're not a pro they're not a , we call them a cellular. |
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| 13:46 | ? Um They may or not have envelope, of course, they may |
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| 13:49 | DNA RRN A. Of course, may be uh they're gonna have a |
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| 13:53 | size range and, and yeah, virus we can characterize at its most |
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| 13:58 | . It has this a genome and cap that surrounding protein coke. |
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| 14:04 | And so that uh of course, going to see variations that they'll have |
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| 14:09 | . But they can have other features with that. Um The other thing |
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| 14:13 | while we're here, next time we'll about um Vy Roids and prions. |
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| 14:21 | . So those are not viruses. . So just make, make that |
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| 14:26 | now, right? So we have , we have vids and we have |
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| 14:31 | , right? Each three different OK. Um Anyway, so, |
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| 14:37 | OK. So, yeah, defining . So I think we have um |
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| 14:42 | here we can look at the uh course, the size, obviously the |
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| 14:47 | of it. So if we have cross section of a animal cell, |
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| 14:49 | the bacterium and then the virus. so um but um the the features |
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| 14:55 | the three, right? So bacteria have forms that are kind of |
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| 15:01 | Remember, viruses are pretty much just parasite, you need a host, |
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| 15:05 | ? And so um you do have types, that kind of have those |
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| 15:11 | , there's still cells. OK. they were Kia chlamydias, these do |
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| 15:16 | go inside your cells because they've lost lot of their functions. But, |
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| 15:21 | they, and they, and they a host cell to kind of help |
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| 15:23 | out with those functions, but they're , they still are certainly cells, |
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| 15:27 | ? They're classified as bacteria, but of course, are next are next |
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| 15:32 | beyond that. OK. So uh , they don't have a plasma membrane |
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| 15:37 | any of the features that you associate a cell. OK. Um |
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| 15:43 | the um the here, OK. discovery. So uh so in this |
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| 15:53 | , OK. Of uh this is an 18 nineties, I think 19 |
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| 15:57 | era in that period, um tobacco virus, OK. So called tobacco |
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| 16:04 | his big industry. But certainly back , um the the appearance of leaves |
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| 16:11 | showed up like this um with these uh uh uh features to them um |
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| 16:18 | not, are diseased. Obviously, can't photosynthesize properly, the plant |
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| 16:22 | And so during this time, of , the germ theory was known, |
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| 16:26 | ? We knew about Coke and Coke . And so it was very active |
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| 16:30 | , to look at uh especially bacteria the context of disease. And so |
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| 16:35 | they saw this, they go oh . This is clearly gotta be some |
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| 16:38 | of uh micro bacterium that's causing We can easily find out how |
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| 16:43 | how to isolate it. OK. easy experiment, right? You just |
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| 16:47 | a normal leaf and disease, leaf each one up separately, uh suspend |
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| 16:53 | in buffer or something. OK. then um and they had filters, |
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| 16:58 | were able to um filters designed to able to trap microbe sizes, |
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| 17:03 | Micron or bigger. And so they OK. We'll take uh crunch, |
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| 17:07 | this up, take the f the that we get that little paste, |
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| 17:12 | it through the filter. OK? the filter will track then boom, |
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| 17:16 | got our, we've got our disease organs. OK. Uh we'll, |
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| 17:19 | take that material on top of the containing presumably the, the disease causing |
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| 17:26 | , put it on a healthy leaf we'll see it get diseased. They |
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| 17:30 | did. It wasn't somebody had the to go. OK. Let's not |
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| 17:33 | what's on top of the filter. look what went through. OK. |
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| 17:37 | when they looked at that material, it on a healthy leaf, then |
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| 17:41 | got the disease form. So they they were dealing with something super, |
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| 17:45 | tiny. OK? Much smaller than they're used to seeing in terms of |
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| 17:50 | sizes. So it wasn't until 30 years later that they actually were able |
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| 17:55 | see it uh because it required electron . OK. So in that particular |
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| 18:01 | mosaic virus, it's called is on size scale of really the lower end |
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| 18:07 | nanometers. So that's very tiny, , probably about double that. Uh |
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| 18:11 | uh in terms of length and width um 20 nanometers probably, but length |
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| 18:15 | longer. But nonetheless, it's, small, you can't see it with |
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| 18:18 | light microscope. OK. So um this then of course, led |
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| 18:23 | you know, studying viruses and, what they're all about. OK. |
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| 18:29 | like any living thing, you're gonna a span of sizes, right? |
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| 18:34 | here's that uh uh uh tobacco mosaic is kind of on a lower |
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| 18:40 | you have large ones. Ebola can almost a micron size. Um And |
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| 18:45 | anything and everything in between. but we are talking, you |
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| 18:48 | nanometer scale size. OK? And um everything, well, it's say |
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| 18:56 | but uh most likely every um cell life form on earth probably has some |
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| 19:03 | that infects it. Ok? So are very prevalent. OK? You've |
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| 19:08 | them as well. You have viruses your microbiome in your gut, for |
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| 19:13 | , uh of course you have virus can affect us, You know, |
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| 19:17 | virus doesn't affect us. Of in terms of human health, |
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| 19:20 | flu COVID et cetera. But uh they're, they're prevalent and found almost |
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| 19:26 | same term we use for bacteria you with this, you can use the |
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| 19:28 | thing for viruses pretty much. And so um one thing that uh |
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| 19:34 | just mention this briefly because when I this stuff, um the the the |
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| 19:40 | was OK, viruses, there's really good about a virus, right? |
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| 19:43 | cause disease. The only good thing you can, we can use them |
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| 19:47 | a tool in the lab just to a way to do different techniques and |
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| 19:53 | . But beyond that, that's pretty it, right? It wasn't until |
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| 19:56 | the last 20 years where their importance ecosystems and ecology really became a |
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| 20:04 | OK. So it's real quick, know, in, in, you |
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| 20:07 | , ecology kind of ecology evolution, , right? If you have uh |
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| 20:13 | with lots of diversity, right? other words, lots of species are |
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| 20:18 | in that ecosystem. OK. Think think of rainforest, OK, lots |
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| 20:24 | productivity, lots of photosynthesis and lots uh heterotrophic and you know, lots |
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| 20:30 | food levels and very very robust, ? Uh you can mainly picture |
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| 20:36 | A AAA a a rain forest and the types of plant and animal |
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| 20:40 | everything, right? Insects, what you uh compared to like uh a |
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| 20:45 | , right? Not as much, as much diversity. Ok. Um |
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| 20:50 | viruses because they infect cells and can them, right? Um That can |
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| 20:56 | host populations, right? So you populations and that can actually contribute to |
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| 21:02 | more diversity, right? Um Here East Texas, if you drive north |
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| 21:09 | Nacogdoches, right? What do you lots of pine trees, right? |
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| 21:13 | forest. And so that's the dominant , the pine trees, right? |
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| 21:18 | that, and they're the predominant they're the dominant species and they control |
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| 21:22 | because there are a lot of control their needles drop, it's acidic, |
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| 21:26 | can affect the soils. Ph, affects what can grow there, that |
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| 21:30 | affect them. What types of herbivores carnivores can live there? So, |
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| 21:35 | compared to an environment that's more Ok. Diversity is always a good |
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| 21:40 | . Um Both ecologically and culturally and um virus can help to do |
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| 21:46 | Ok. Uh But don't think though a virus will a virus um make |
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| 21:53 | host extinct. Is that something a will do. Yes. No, |
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| 22:01 | . And does it help the virus , for the, for its host |
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| 22:05 | become extinct? No. So it . There are mechanisms in place uh |
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| 22:11 | the viruses evolve and so does its . So they both are evolving, |
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| 22:17 | ? And a, a virus uh infect its host. Uh But then |
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| 22:23 | will be some members in the population will be resistant to the virus. |
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| 22:30 | And, and, and, or develop a resistance and then those |
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| 22:34 | will begin to grow uh in, greater numbers, they'll take over. |
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| 22:38 | then of course, the virus then and it, it, it then |
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| 22:41 | it is probably able to affect those well. So it goes back and |
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| 22:44 | . So population numbers go kind of and down. But the end result |
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| 22:47 | to, you know, um support diversity in the ecosystem. So that's |
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| 22:52 | one of the biggest things in terms positivity for a virus. OK. |
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| 22:57 | terms of what they can provide. . So, um now, so |
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| 23:02 | infection, so let's look at um question here. OK. So while |
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| 23:09 | at that just to recap here, viruses are uh not cells. So |
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| 23:15 | call them a cellular, we call parasitic. OK. Um And we |
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| 23:21 | them, they're, they're obliged, obliged. They're, they're obligate a |
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| 23:27 | parasites. They have to do OK. And so, um being |
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| 23:32 | virus means you rely on the hope things like protein synthesis, um the |
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| 23:38 | to copy the genome. OK. And other features, we'll talk about |
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| 23:44 | as we go along. OK. so um so here we're looking at |
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| 23:50 | life cycle, so we're gonna go a basic life cycle. Uh but |
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| 23:55 | there's, there's gonna be variations as look at specific viral types. |
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| 24:01 | So here, here we're like basically , what would be step one of |
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| 24:06 | viral life cycle. OK. Let's count down from four. Mhm |
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| 24:30 | . So um yeah, it's got be recognized and attached. So think |
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| 24:34 | the viral process of, of its cycle is uh lock and key. |
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| 24:40 | gotta find the door, which would the host cell, then you gotta |
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| 24:44 | the key that fits in the right? And so that's that recognition |
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| 24:48 | host and uh virus. OK? is gonna be what's on the surface |
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| 24:54 | on the surface. OK. So get this first and then you get |
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| 25:03 | probably get this, this, it depends. So we'll learn that this |
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| 25:09 | on the virus type. OK? Translation. Uh probably that third. |
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| 25:17 | probably fourth, of course, that's . OK. So we're gonna |
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| 25:21 | we'll go through the steps here in second, right? If we have |
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| 25:24 | one. So which is not necessarily requirement, replication of all virus |
|
| 25:35 | So underlying. Oh Not. Oh . Oh Sorry for me. Open |
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| 25:50 | bad. OK. Now, go . Yeah. OK. OK. |
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| 26:38 | down from 10. Yeah, I see. OK. Good Lord. |
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| 26:59 | , there we go. All Oh, we got. Oh |
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| 27:04 | Oh goodness. OK. Try OK. So we have here uh |
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| 27:10 | and F OK. So if, , integration in the hosting number is |
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| 27:19 | necessarily for all viruses can be for uh HIV is one that does that |
|
| 27:27 | but not all OK? Um Most these other things, B for |
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| 27:33 | C for sure. E for D D yes, I should clarify |
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| 27:41 | . D um an RN A virus not have a need for the oxy |
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| 27:46 | nucleotides. OK. Uh But um but certainly uh they don't all integrate |
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| 27:53 | the chromosome. OK. Uh So look at uh again, definition, |
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| 28:01 | ? Parasites are host. Uh The , the caption is the name for |
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| 28:05 | protein coat. OK. Uh They have the geometric shapes like you |
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| 28:11 | they're 20 sided uh But they can other forms as well as we |
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| 28:16 | So, um so the other thing is that you can't all, |
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| 28:21 | they're not c so they don't uh , they don't synthesize their own |
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| 28:26 | Uh They don't have ribosomes. Um , they rely on the host for |
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| 28:33 | for um you know, the machinery of protein synthesis, the uh replication |
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| 28:40 | genome. But uh you know, do some do, it depends on |
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| 28:43 | viral type or have some of their things. They bring, bring with |
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| 28:47 | . Ok. So they're not completely , you know, can't do anything |
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| 28:52 | because they do have a genome that for virus specific protein. So, |
|
| 28:56 | course they're gonna have some things they . Um, now, uh, |
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| 29:00 | you can't, you cannot, you give a virus glucose and say |
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| 29:06 | start growing, right? Because they have a metabolism like that. They |
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| 29:10 | , they don't take in carbon sources break them down, right? They |
|
| 29:14 | do that. OK. So um what you see here, that's |
|
| 29:20 | These are what can be variable. all kind of virus type dependent. |
|
| 29:27 | ? Some have some don't. And so um but of course, |
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| 29:32 | constants are, you know, they don't have, they need virus |
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| 29:35 | from a host, they need the synthesis machinery. Um So yeah, |
|
| 29:42 | of course, it all begins or with this step here. OK? |
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| 29:48 | the host. OK? And um they do, then the next step |
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| 29:54 | getting the genome in and again, , there's different variations of, of |
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| 29:58 | this happens for some types. The thing comes in for other types, |
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| 30:03 | your genome comes in. It just of depends. OK. Now, |
|
| 30:07 | that happens, right? If it's about if the virus is about |
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| 30:13 | immediate, immediately making new viral then yeah, this, this, |
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| 30:17 | copying the genome. OK? Uh it may be that it doesn't do |
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| 30:23 | immediately. Maybe it's a type that into the chromosome first. OK? |
|
| 30:28 | if it does do that, eventually, if it wants to reproduce |
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| 30:34 | make rhubarb particles, it will have come back and make copies and it'll |
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| 30:39 | to go back this way. um and so what happens basically is |
|
| 30:45 | whole cell takes this, this uh sorry, the virus takes over the |
|
| 30:49 | cell and makes it a virus reproduction if you will. OK. Taking |
|
| 30:55 | all the resources to do this. so uh which is of course involves |
|
| 31:01 | , translate, make viral proteins, , then assemble and then uh |
|
| 31:10 | OK. Now, so the the to think about this is what's coming |
|
| 31:16 | , right? And then what's going ? All right. So you can |
|
| 31:21 | here, I kept it relatively but this could be 10, 2030 |
|
| 31:29 | 50. It was a bacterial It could be 500 of these coming |
|
| 31:34 | of the cell. OK? But about what that entails if this is |
|
| 31:39 | coming in and this is what's going . You need a lot of |
|
| 31:42 | right? Need lots of stuff, lots of proteins to make these things |
|
| 31:46 | you need genomes to fit in to one of these, right? So |
|
| 31:52 | part here in the middle is about all that stuff. OK? Lots |
|
| 31:57 | one, yes, a virus enters its genome enters, but that's not |
|
| 32:02 | to do anything you gotta make make lots of proteins, assemble, |
|
| 32:06 | it all together, right? So is gonna be an active part obviously |
|
| 32:11 | the process right now, of this takes a toll on the host |
|
| 32:17 | , right? The host cell is used is is its energy is being |
|
| 32:21 | away to do this. Um And the mean meantime, the host cell |
|
| 32:26 | obviously not happy, right? So there's different effects, you know, |
|
| 32:30 | the virus can kind of do this a low rate. OK? Of |
|
| 32:37 | where it literally may be this amount out. OK. That's less of |
|
| 32:42 | burden on the wholesale and, and, and in that state, |
|
| 32:45 | host can actually creep, creep along a low low um reproduction rate. |
|
| 32:52 | ? While this is going on, ? But it, it spans the |
|
| 32:56 | . I mean, it could be virus type that bam goes in and |
|
| 33:00 | 400 viruses and obliterates the cell. one outcome. It could be inserts |
|
| 33:06 | the chromosome and does nothing to the and the cell is just happily |
|
| 33:11 | although that virus is in there. ? And so, and, and |
|
| 33:16 | in between and anything in between. . So it all depends on the |
|
| 33:20 | type. OK. Um Any questions if you got any questions. |
|
| 33:33 | Um Yeah, it depends. So it's a, if it's like say |
|
| 33:37 | HIV virus retrovirus, it, it's generally what they will do, |
|
| 33:42 | will come in and then go right here. They can stay in that |
|
| 33:45 | for weeks, months or years and do anything and just sit in a |
|
| 33:51 | . But remember while it's doing the cells divide it right. So |
|
| 33:55 | all the daughter cells that have resulted the, over that time period, |
|
| 34:02 | will all contain a copy of that genome. OK. So when |
|
| 34:08 | when it decides, OK, I make viruses, then it will go |
|
| 34:13 | way and through. OK. And and that's happening at all, potentially |
|
| 34:19 | happen in all the cells in which , it's inserted itself. OK. |
|
| 34:25 | uh but there's some that don't do at all. This is not even |
|
| 34:29 | part of the equation for some viral and they just go through this |
|
| 34:33 | OK? Um And they can go this route in different speeds, let's |
|
| 34:40 | some can do it very quickly, lots of Rob Park and some not |
|
| 34:44 | fast. OK. So we're gonna , but I mean, overall what |
|
| 34:49 | see here is applicable to, you , uh viral, almost all viral |
|
| 34:55 | . But remember there's the variations, ? Some do this in certain |
|
| 35:00 | chromosomes, some don't, but the of replication. OK. The making |
|
| 35:06 | of genome, the transcription translation, assembly that's a constant, right? |
|
| 35:12 | the exit. So that, that's this is all pretty much |
|
| 35:16 | But even there, you're gonna see and the most of the variations come |
|
| 35:22 | animal viruses, right. So animal are gonna be more, more complicated |
|
| 35:28 | a bacterial virus. Simply because the cells, animal viruses infect are more |
|
| 35:34 | , right? Eu periodic cells are bacterial cells are by comparison, less |
|
| 35:40 | . So it's a little more simpler to see this in a bacterial virus |
|
| 35:45 | , right? But an animal some stuff can happen in nucleus, |
|
| 35:49 | stuff can happen outside the nucleus and and forth. And so it |
|
| 35:52 | again, depends on the viral but it can get kind of |
|
| 35:57 | OK. But it's because the host is complicated itself. OK. Um |
|
| 36:04 | I answer your question? I'm not if it did. Yeah, but |
|
| 36:07 | , we're gonna get more specific as go and look at different viral types |
|
| 36:10 | we'll see some differences there. But step one is always that |
|
| 36:17 | So it begins to answer that. . Any other questions? OK. |
|
| 36:23 | let's look at this question. So now we're gonna get into a |
|
| 36:26 | bit about the structure. OK. Of a virus. Yeah, I |
|
| 36:41 | know. OK. Let's see Well, so um remember if you |
|
| 37:24 | see an answer, it's OK. pick none of the above. You |
|
| 37:30 | something that doesn't make sense then, know. Yeah, you don't see |
|
| 37:35 | answer accordingly, right? Yeah, predict with that hand, I should |
|
| 37:46 | 100% here. Yeah. OK. a dramatic pause here. Come on |
|
| 38:05 | there we are. Yeah, I it. OK. Yes, |
|
| 38:10 | it's the um naked virus is lacking . So the we'll see that |
|
| 38:22 | So the uh basic structure. So the protein coach, the capsid, |
|
| 38:30 | ? And it can, again, can have this this uh polyhedral 20 |
|
| 38:34 | structure. Um They can be in filament forms like a Ebola. |
|
| 38:41 | Um Genome of course can be double stranded DNA or RN A. |
|
| 38:47 | . So the envelope viruses will have envelope, of course, surrounding the |
|
| 38:55 | structure. Ok. The envelope comes the hose cell, right? So |
|
| 38:59 | it exits the hose, it kind wraps around it and gives it the |
|
| 39:03 | . Uh it will contain the viral in that envelope. Ok. Uh |
|
| 39:10 | viruses, of course, don't have . Uh And so the um the |
|
| 39:16 | uh here's an, I'm sorry, a naked virus down here in the |
|
| 39:22 | that's lacking an envelope, but it's the glycoprotein spikes or, or can |
|
| 39:26 | a feature whether it's an envelope or . Ok. And typically that's how |
|
| 39:31 | recognition occurs with the host cell. . It's through these, um and |
|
| 39:36 | gonna be other proteins sticking out here well. Um uh for various functions |
|
| 39:41 | we'll see. Ok. So, the complex viruses are kind of a |
|
| 39:48 | . So this is a typical bacterial . So you see the that capsule |
|
| 39:54 | top. So, that's we're used seeing that. But now we got |
|
| 39:57 | other structures, right? And so are for um recognition. So this |
|
| 40:03 | be sitting on a, on a cell like that, the tail fibers |
|
| 40:07 | recognize molecules on the surface. And this part here what they call the |
|
| 40:13 | , this actually compresses. So kind kind of like a syringe, it |
|
| 40:19 | . And in doing so the genome inside here is shot out much like |
|
| 40:25 | syringe kind of under pressure. It the genome into the cell. |
|
| 40:31 | Um Typical for bacterial virus. so the infectivity um is all about |
|
| 40:41 | what's common between the surface here and surface here, right? Because |
|
| 40:45 | that's the lock and key bit, what's gonna either allow it to enter |
|
| 40:50 | not. OK. And so um , the uh and so you see |
|
| 40:57 | and multiple, another thing I should in a viral infection, you can |
|
| 41:02 | more than uh a viral type infecting cells, more than one one can |
|
| 41:07 | , you can have two or three the same cell. OK. Um |
|
| 41:14 | the uh host range. So what refers to is how many different, |
|
| 41:21 | , so rabies is a perfect example rabies can affect humans, squirrels, |
|
| 41:26 | , rats, cats, dogs, have you, right? Whole range |
|
| 41:31 | different mammals. OK, as And so that's a broad range, |
|
| 41:36 | , right? So things like a or measles, a cold virus |
|
| 41:41 | these only affect humans. Ok. they don't have it. It's a |
|
| 41:45 | range. Ok. Um, now term fancy term for this what we |
|
| 41:54 | , um, tropism. Ok. is tissue specificity. So, what |
|
| 42:02 | means is, let's just take right? So, rabies is a |
|
| 42:07 | host range virus. Ok. But just look inside a squirrel. |
|
| 42:15 | So within that one host, the . Ok. How many different cell |
|
| 42:21 | can infect in that squirrel? Um Babies. That's a narrow, |
|
| 42:27 | has a narrow tissue specificity or narrow , right? It only, it |
|
| 42:34 | really affects uh nerves, nerve Ok. Uh doesn't go beyond |
|
| 42:40 | And so, uh so it has broad host range, can affect |
|
| 42:43 | bats, rats, mice, blah, blah, blah, but |
|
| 42:46 | a particular host only affects a certain type, right? So broad host |
|
| 42:51 | , narrow tissue specific. Ok. um has a broad um tissue |
|
| 43:02 | That's one of the reasons it's so is that it has like uh those |
|
| 43:05 | contract Ebola have uh anywhere from 10% of living to at best, maybe |
|
| 43:13 | 40% chance of it. Ok. of different cell types, it |
|
| 43:18 | Ok. It can infect epithelial It can infect the what are called |
|
| 43:24 | cells that make up your blood Uh And if they do that, |
|
| 43:28 | , you have fluid leaking out, , your blood vessels become leaky, |
|
| 43:31 | other vessels become leaky. Um you , dying for Ebola is a pretty |
|
| 43:36 | death fluid coming out of everywhere. . Ok. So, but |
|
| 43:41 | because it can infect many different cell in the body. Ok. That |
|
| 43:46 | I had to say, you what's the norm to have a broad |
|
| 43:50 | narrow tissue specificity, the norm is they have just a fairly narrow |
|
| 43:56 | So Ebola is kind of unique in way. So many uh tissue types |
|
| 44:01 | be infected. But um anyway, that's the difference between, between those |
|
| 44:07 | post range and tissue specificity. Um Now, uh let's look at |
|
| 44:15 | . So, genome. So just get an idea of, you |
|
| 44:18 | what, what size are we talking in terms of genomes, right? |
|
| 44:21 | , of course, viruses are they can't hold so much, |
|
| 44:25 | So, you know, averages may 10 to 15 genes, uh larger |
|
| 44:32 | like polio virus, maybe up to . Uh but um you know |
|
| 44:37 | so what do they code for? , it's gonna be virus specific um |
|
| 44:43 | that they need. OK. Because do go through an infection uh |
|
| 44:50 | right? So, first they have recognize the host, right? That |
|
| 44:53 | specific viral proteins and they have to in a host that can involve specific |
|
| 44:59 | proteins to help them do that. then as part of the infection |
|
| 45:03 | maybe it has to have its own to copy his genome. Uh um |
|
| 45:09 | maybe something to help it get out the cell once it exits. So |
|
| 45:14 | are the kind of the common um proteins involved in, you know, |
|
| 45:19 | it carry out its infection from recognizing to exiting the cell. And some |
|
| 45:26 | the steps in between, OK. the form of the genome. So |
|
| 45:32 | it can be DNA RN, a stranded, double stranded. Um but |
|
| 45:36 | can also be um not just a entity if you will. OK? |
|
| 45:43 | Zika virus. OK. Uh But could be, and here's just an |
|
| 45:49 | of some of the enzymes this virus use, don't need to memorize |
|
| 45:52 | but just an idea of kind of , what are these things code |
|
| 45:56 | Um And these would be a acid , that's a viral protein, of |
|
| 46:00 | , that will be uh a uh these other proteins associated with like |
|
| 46:05 | attachment to the host and what have . Um So of course, virus |
|
| 46:10 | , the um uh so the flu , I thought I had it hold |
|
| 46:17 | . OK. I'll come back to picture in a second. So the |
|
| 46:19 | virus has a segmented genome, So segmented means it's not one |
|
| 46:25 | it's broken up in the little right? So you see 1234678 segments |
|
| 46:30 | up the flu virus. OK. so um the uh and so it |
|
| 46:38 | also these uh proteins on the surface call H and in. Ok. |
|
| 46:47 | , these are for two different types enzymes. Uh One helps it, |
|
| 46:51 | get into the cell when he helps exit the cell. Ok. But |
|
| 46:57 | H and N, you might be with the flu virus and H and |
|
| 47:00 | numbers, right? H two N virus and H this H that and |
|
| 47:04 | virus, it's a way to identify them and, um, what |
|
| 47:10 | can do. Uh flu virus has origins really back in uh wild birds |
|
| 47:16 | um ducks and geese, uh these of things uh that then kind of |
|
| 47:22 | to domestic birds, chickens, uh ducks, et cetera, um then |
|
| 47:29 | into um swine and um and And so it kind of has, |
|
| 47:34 | you can see that history in the . That's what these color codes are |
|
| 47:38 | to show you. So H two three kind of domestic ducks like the |
|
| 47:43 | uh wild birds, kind of a color uh chickens here, a reddish |
|
| 47:48 | . So these different variants you see then they can remember a flu virus |
|
| 47:54 | two type, different types can infect cell. OK. And because that |
|
| 47:58 | genome, you can kind of do occurring here. So, mixing and |
|
| 48:04 | if you will, right. So see the different color coatings here, |
|
| 48:07 | for the domestic poultry red. Here's origins from the wild bird, uh |
|
| 48:13 | duck. So uh forming this particular the H seven and nine. And |
|
| 48:20 | , uh and, and there's a of this that so what you have |
|
| 48:22 | do is to change, have an that leads to a change in one |
|
| 48:27 | these uh proteins, right? And this is the the key, |
|
| 48:33 | so it has to be able to the right cell to get in. |
|
| 48:36 | in a human, you have association humans, maybe one form of this |
|
| 48:40 | able to infect human cells. And now you've got a another variant, |
|
| 48:44 | ? And so, and so, course, in the course of a |
|
| 48:47 | season, as I'm sure, you , uh, one season to the |
|
| 48:51 | , this is constantly changing. And so you'd never get a, |
|
| 48:55 | flu shot you got last year is gonna likely work at all this flu |
|
| 49:00 | because the thing evolves and uh changes uh through different hosts and whatnot and |
|
| 49:07 | , um why it's why you, why they formulate a different flu shot |
|
| 49:11 | season. So, um, doesn't hit though, right? Some seasons |
|
| 49:15 | worse than others in terms of right? Because you can only predict |
|
| 49:20 | can't, you don't know exactly how will evolve, right? You kind |
|
| 49:24 | make a prediction based on what you uh in the previous season. So |
|
| 49:30 | it's kind of hit or miss. , uh, um, but the |
|
| 49:34 | thing here is that viruses in uh particularly uh RN A viruses are |
|
| 49:42 | this guy is um mutate rather OK. Uh Take humans, for |
|
| 49:49 | , we when we undergo, when cells undergo cell division, OK. |
|
| 49:56 | If you remember s phase, the of the cell cycle, right? |
|
| 50:02 | phases where all the chrome where the are replicated, right? Of |
|
| 50:05 | mistakes are made here and there. we stop the cell cycle to fix |
|
| 50:11 | mistakes, right? And if if a, if A A is |
|
| 50:15 | A G should be, we have to find it and fix it. |
|
| 50:18 | . And we actually we are very at that. Uh But viruses don't |
|
| 50:22 | that mechanism. RN A viruses in don't. OK. So they make |
|
| 50:27 | and it goes there, it's not . OK. So you can have |
|
| 50:34 | you know, so, so a that affects a host cell, what's |
|
| 50:38 | out of it, the viral they're not gonna be identical to |
|
| 50:43 | that one that infected it, there's be some variation, even among all |
|
| 50:48 | viral particles that come out of they're gonna be a little bit likely |
|
| 50:52 | somewhat dissimilar, right? So because of that, the mistakes aren't |
|
| 50:58 | during replication. So you get this and higher mutation rate. Um The |
|
| 51:05 | DNA viruses don't seem to be as in terms of mutation rate. They |
|
| 51:10 | do. But I think because they're viruses, they can kind of use |
|
| 51:14 | of the host um mechanisms to kind fix and repair. I think that's |
|
| 51:19 | going on. But, but RN A viruses are certainly one that |
|
| 51:22 | really, and there, there's a of, a lot of ones that |
|
| 51:26 | humans are in that group, like and measles and COVID and flu and |
|
| 51:32 | . I mean, all these are A types of RN A viruses. |
|
| 51:34 | , a lot of them are, what the, we have to deal |
|
| 51:38 | . OK. Um Let me, me go back to the side. |
|
| 51:41 | skipped here. OK. So what I wanna mention? OK. So |
|
| 51:48 | is just a, a variation in of structure, right? So we |
|
| 51:54 | at kind of the basic uh we geometric type. I was draw it |
|
| 51:58 | like a like this. OK? so we had the genome, |
|
| 52:05 | And the capsule, OK? G correct. So basic structure we |
|
| 52:16 | , we've already seen right now. viruses um like coronavirus is one. |
|
| 52:24 | kind of combine uh they take the, the protein and instead of |
|
| 52:32 | like a, a capsule like a house around the genome, if you |
|
| 52:37 | , they take those capsule proteins and stick it directly onto the genome. |
|
| 52:43 | . And that's what you see So the there's like a blue line |
|
| 52:49 | through this right here. So that's genome. OK. So the pink |
|
| 52:54 | reddish parts that you see here, ? Looks like an intestine almost, |
|
| 53:03 | ? So the reddish parts. That's , that's the protein stuck to the |
|
| 53:07 | . So we call nucleoprotein, they call it a nucleocapsid. So think |
|
| 53:12 | it as a, a capsule that's stuck directly on top of the |
|
| 53:17 | OK to help protect it. So another variation you see in terms of |
|
| 53:22 | . OK. So, so if instead, again of like having |
|
| 53:26 | house, like we see up here the genome, it's intimately stuck to |
|
| 53:32 | DNA. OK? And we see and I think the Coronavirus flu |
|
| 53:36 | I think has that and some OK. So just, just a |
|
| 53:40 | you see. OK. And and this is just to show the |
|
| 53:44 | uh again, the the um viral , right? For COVID, it's |
|
| 53:50 | these um uh specific receptors that are in lung, lung cells, alveolar |
|
| 53:55 | are found in the lung. It's I mean way deep in the |
|
| 53:59 | So those with um that were in uh particularly in the deep in the |
|
| 54:06 | system like this is, it can issues. Certainly inflammation occurs here. |
|
| 54:12 | fluid build up occurs as a result inflammation be really bad, especially in |
|
| 54:18 | immunocompromised. So we get the worst of, of this. OK. |
|
| 54:25 | Let's see. Any questions. Yeah. Right. How much, |
|
| 54:38 | , how many bases? Oh that's, that's like an average size |
|
| 54:43 | most, I would say most viruses fit in that range about 1300. |
|
| 54:48 | probably about a dozen or so. , something like that. Uh, |
|
| 54:53 | , there's some little bit bigger than , some little smaller, but that's |
|
| 54:56 | of an average size. Any other ok. Um, ok, let's |
|
| 55:04 | about that. Ok. So let's at this question. Ok. |
|
| 55:11 | I put that up. So, could not be used as a way |
|
| 55:22 | identify the virus? Ok. Come, ok. Counting down. |
|
| 56:08 | . Sorry. Oh, yeah. . Let's see. Yeah, |
|
| 56:22 | you couldn't use a CD E you reason that all those could be a |
|
| 56:27 | to identify a virus. Um but certainly not B right? They don't |
|
| 56:32 | that kind of metabolism or any metabolism all. Really? OK. So |
|
| 56:40 | all right. So this is kind summarizes the structure and we just went |
|
| 56:45 | some definition, of course here uh type. So you can have that |
|
| 56:52 | polyhedral geometric form or you can be in a string helical, OK? |
|
| 56:58 | you know, type naked or right? Um Other stuff like a |
|
| 57:05 | spikes, et cetera. OK. um basic structure. All right. |
|
| 57:12 | don't memorize this. OK. Uh threw it up there just to show |
|
| 57:18 | , you know, basically that the way to not modern way but the |
|
| 57:21 | to classify viruses is through really the of genome they have and envelope lacking |
|
| 57:28 | having an envelope very common. Um like I said before, a lot |
|
| 57:33 | your disease causing viruses. Uh human causing viruses are in this RN |
|
| 57:39 | these aren't a groups uh uh cold , polio, um SARS COVID, |
|
| 57:46 | cetera, um Ebola flu measles, , rabies. So, uh a |
|
| 57:52 | of that we're familiar with. So, um ok, so let's |
|
| 57:58 | at, so the introduction of viral cycles always begins with uh bacterial viruses |
|
| 58:06 | they are less complicated, right? so um compared to animal viruses, |
|
| 58:13 | we'll take a little a look at . But remember um look, we |
|
| 58:17 | kind of through a generic life cycle just remembering the basics of this, |
|
| 58:24 | ? But knowing that there's variations, ? So it's all about um beginning |
|
| 58:28 | recognition, attachment specific proteins, entry be various ways with bacterial viruses. |
|
| 58:37 | rule is um only the genome enters else stays outside. That's pretty much |
|
| 58:44 | rule for bacterial viruses. Genome enters else out. But there's gonna be |
|
| 58:49 | kinds of variations for animal viruses. ? Um Of course, then |
|
| 58:56 | we're trying to assemble stuff, we're to make new viral particles and you're |
|
| 59:00 | , you're gonna execute uh steps um , OK, 2345, right? |
|
| 59:09 | um produce viral proteins, assemble, new viral particles. OK. Now |
|
| 59:15 | term, so I, I use term Vons and viruses interchangeably same thing |
|
| 59:27 | the same thing. OK. So because you see Von don't think, |
|
| 59:31 | OK, what's that the same thing the virus. OK. It's infectious |
|
| 59:35 | particle. OK. Um Then of , once you've assembled these particles, |
|
| 59:40 | have to exit the cell, there's ways that can happen as well. |
|
| 59:44 | . So uh so here the question uh so this is a vi a |
|
| 59:55 | life cycle. So phage refers to viruses. Always you see fade, |
|
| 60:04 | go bacterial virus. Yeah. Um take a minute to look at that |
|
| 60:21 | um mhm mm Yeah. OK. we're talking about a lighting page, |
|
| 60:47 | ? So lighting page is a very thing. OK? OK. Let's |
|
| 61:10 | down here, right? See how it is b the um that's not |
|
| 61:29 | part of a lot of faith. lighting page is pretty much inner cell |
|
| 61:36 | cell more or less make viral particles then kill it. That's kind of |
|
| 61:41 | its mode. OK. So um call for that reason, we kind |
|
| 61:47 | call so we call light page right? That they there is no |
|
| 61:53 | switch. It's like infect cell, bar particles kill cell, that's its |
|
| 61:58 | . OK? And so, and can produce like 203 100 plus page |
|
| 62:06 | one cell. OK. During an . OK. So um obviously we |
|
| 62:11 | to begin with and it's one of types that has this structure, it |
|
| 62:15 | the that um uh they call it complex virus. Some call it a |
|
| 62:20 | virus. Nonetheless, this uh this of the virus here is what compresses |
|
| 62:26 | you see, shooting that genome into cell. And then these is |
|
| 62:30 | they call these things ghosts that are here left behind. It's like a |
|
| 62:34 | less protein husk if you will sitting . Ok. Um Lysogenic cycle kind |
|
| 62:43 | ha has the Mitic part as part its cycle. But it also has |
|
| 62:48 | dormant part where it integrates into the , really does nothing. But then |
|
| 62:53 | some point it enters aly cycle. it has both of those uh |
|
| 62:58 | OK? And so when it integrates the chromosome, we call it a |
|
| 63:04 | . OK, there's gonna be a term. We talk about animal viruses |
|
| 63:08 | called a provirus. So it's very in terms of how it looks. |
|
| 63:12 | for bacterial viruses, we use the prophage that do this. OK. |
|
| 63:17 | it's all about how long it stays a kind of this dormant state is |
|
| 63:22 | about kind of the health of the it's living in. OK. So |
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| 63:26 | kind of guides us to what it do. OK. So in the |
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| 63:32 | uh so I was looking at the cycle, so we have kind of |
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| 63:35 | stepwise process here. Um of attachment, a specific attachment, then |
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| 63:42 | entry of the genome into the OK, which is followed fairly quickly |
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| 63:48 | the uh page, basically destroying or up the host chromosome. So you |
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| 63:55 | it kind of here intact here in here. Right. So it's |
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| 63:59 | it, it's gonna use, it'll the nucleotides for its own use. |
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| 64:05 | . And so, um then that's by uh biosynthesis. So we're gonna |
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| 64:13 | stuff, we're gonna make the size viral proteins, then we're gonna begin |
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| 64:16 | assemble everything. So it's called kind maturation. They're assembling into fully formed |
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| 64:24 | particles and then the eclipse period. . But that refers to as kind |
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| 64:31 | the period uh from here, somewhere this range here to uh prior to |
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| 64:41 | complete uh e exit of the right? So kind of in this |
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| 64:47 | here, that's that eclipse period. . So we haven't quite finished development |
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| 64:54 | the virus and exited. It's right that point from, from when we |
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| 64:59 | building to almost complete, that's what call the eclipse tree. OK. |
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| 65:05 | then uh of course, what's going is we're assembling all these parts, |
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| 65:09 | ? Like like an assembly line, the car together, right? And |
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| 65:13 | uh once that happens very quickly, the cell lyss and so lysozyme is |
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| 65:20 | enzyme that breaks down pepto glycan. it breaks down the cell wall. |
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| 65:25 | that plus just the sheer, you , having 500 of these things inside |
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| 65:29 | a cell just, just bursts, open. OK. And so it |
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| 65:34 | quickly then goes on to infect more . So it's a, it's an |
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| 65:38 | process. So once these come out quickly, it it finds other cells |
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| 65:43 | attack and continues the process. So you know it uh uh a |
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| 65:49 | of E coli in a test you had a drop of sage to |
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| 65:54 | in about 30 minutes. The whole is wiped out. And so that's |
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| 65:57 | fast this can happen. OK. that's the nature of a lighting cycle |
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| 66:02 | virus. That's what it does uh , enter, build, make particles |
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| 66:08 | cell. That's, that's the, a lighted page. OK. |
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| 66:13 | the lysogenic one. So this, just to clarify here. So um |
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| 66:20 | sage or what we call t even number, there's like a T two |
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| 66:27 | T four T six type. These all lighting page or V lytic or |
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| 66:33 | , same thing. OK. Um example of a lysogenic type is lambda |
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| 66:41 | . OK. Um The uh so the page is um also what we |
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| 66:51 | uh so lysogenic page is also a page. OK. Temperate means it |
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| 66:56 | , it can run hot and cold you will, it can kind of |
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| 67:01 | out, don't do any damage as in a lysogenic state or can flip |
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| 67:06 | to the light cycle, of causing all kinds of damage. So |
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| 67:10 | the nature of a temperate phase can kind of both ways, right? |
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| 67:15 | , um so once it enters the , the g the genome enters the |
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| 67:21 | , uh it can uh again, kind of all dictated by the, |
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| 67:25 | health of the host cell, And so it can integrate and sell |
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| 67:31 | forms. OK? And, and that state, the the host cell |
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| 67:35 | completely fine, right? It can to grow at its normal rate, |
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| 67:41 | ? And so it does, and course, all the all the progeny |
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| 67:48 | contain a piece of that contain that , right. So we already know |
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| 67:54 | fast bacteria can grow, right. you know, if you, you |
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| 68:01 | a million cells in eight hours, , all those 8 million cells will |
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| 68:05 | a copy of that pro, So it's kind of like a ticking |
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| 68:09 | bomb if you will. OK. so um so what's the signal then |
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| 68:14 | it to get out of that lysogenic into the lighting state? Because this |
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| 68:18 | the only way going over here is is it's the only way it can |
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| 68:23 | bar particles. So it's gonna have go that way if it wants to |
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| 68:26 | that. And what makes it do is, let's say if this host |
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| 68:31 | all of a sudden is running out food or is bombarded with radiation or |
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| 68:36 | temperature or high ph some kind of . OK. So that's likely a |
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| 68:43 | for OK. I'm not going down the ship, right? So I |
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| 68:48 | gonna die because this, I'm getting . So that's typically a trigger to |
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| 68:54 | that lysogen cycle and produce lots of progeny before it's too late. |
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| 69:01 | So, um So again, and , we don't, we don't get |
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| 69:04 | this here, but, uh, prophet itself is sending out protein signals |
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| 69:11 | the cell and those signals kind of , there's, there's molecular ways to |
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| 69:18 | to check the state of the whole . That's kind of what it's doing |
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| 69:23 | while it's in here. And so it senses, hm, not so |
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| 69:28 | , then it'll initiate that lighting Right. So, it's all kind |
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| 69:31 | driven by, you know, is a good thing to stay in the |
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| 69:35 | like it is or should I get ? That's kind of what's driving |
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| 69:40 | Um So again, uh so the phase operates between these two cycles. |
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| 69:47 | . And so inevitably, uh in , in a lysogenic type phase, |
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| 69:53 | lighting cycle is an inevitability. It'll at some point just how soon or |
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| 70:01 | late is pretty all dependent on the of the host set. Ok. |
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| 70:05 | the nature of, of this kind virus. Ok. Um Is, |
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| 70:12 | there any questions about that? All right. All right, |
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| 70:18 | if not, then I'll see you Thursday and, |
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