| 00:31 | Okay folks. Welcome. So um , today We start unit two. |
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| 00:46 | , so obviously no information today is exam one. So uh example of |
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| 00:55 | starts tomorrow and Saturday. Um anything related to content looking on that |
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| 01:04 | one review sheet. That's literally what look at when I'm making sure that |
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| 01:09 | is aligned with that. Okay, there's nothing there's no nothing other than |
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| 01:15 | exam. So there's no blackboard there's no smart work any of |
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| 01:19 | So that's off for a week and resume of course next week. So |
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| 01:27 | that's pretty much all I had um have any questions at this point? |
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| 01:35 | , so uh so today. so today is one of those flip |
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| 01:43 | classes, there's like seven questions, of them repeats and there's one that's |
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| 01:49 | a clipper question. But uh so today's goal is okay. One |
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| 01:54 | is pretty much follow the sequence of it's in the lecture notes. So |
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| 02:01 | one topic that's pushed at the end that there's one slide on viral |
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| 02:08 | So I'm pushing that way to the . We'll talk about that next |
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| 02:13 | Okay, so we're gonna basically be after today, hopefully. Alright, |
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| 02:21 | will know all about uh certainly get far in terms of defining a |
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| 02:28 | So we should probably gonna get to yet, but once we get finished |
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| 02:35 | part one here, well, you what a virus is how we define |
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| 02:40 | will know uh features and structures of virus. We'll know the basics of |
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| 02:48 | viral life cycle. Okay, there's of variations there and it's really part |
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| 02:54 | where we get into life cycles of , but for now we're just gonna |
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| 02:58 | here's you know pretty much the same . They all do it from the |
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| 03:04 | . But I'll mention here and there some variations and we'll get into specifics |
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| 03:09 | week besides that. It's um you , certain terminology we use with viruses |
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| 03:16 | the way we describe them and then . So I'm not gonna expect you |
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| 03:21 | memorize the because there's a couple of that are in the notes, I'm |
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| 03:26 | gonna expect you to memorize, you in what in what group is this |
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| 03:30 | and so on and so forth. just meant to kind of show you |
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| 03:33 | how we classify them here are some of important ones. A lot of |
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| 03:38 | um ones that are human, human , a lot of them are really |
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| 03:43 | our RNA viruses. So your flu covid and uh common cold virus |
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| 03:53 | um mumps and these, a lot what you're familiar with are really RNA |
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| 03:57 | and we'll talk to that and probably you know of the types of viruses |
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| 04:03 | RNA virus, animal. RNA viruses probably the ones that can be the |
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| 04:08 | problematic because they can be kind of complicated in terms of how they do |
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| 04:14 | replication. So hopefully I can break down. So it's not as |
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| 04:19 | but because there is a logic to they do it the way they do |
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| 04:22 | . Okay. But again really that next time. So we'll start with |
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| 04:28 | few questions here kind of to build here's what the virus is. Some |
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| 04:33 | of basic facts about them and then of go from there. Okay, |
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| 04:38 | you'll see questions and you'll see electronic all mixed in here. Okay, |
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| 04:44 | let's I think let's start with this here. Okay. So which of |
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| 04:48 | following? Okay. Which the following 80 E is false. So is |
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| 04:55 | a is there a statement here that's or are they all true? |
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| 05:03 | I was the clock there for a . Okay. It's for timer again |
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| 05:35 | down from 10 oz. Okay. we go. 5432. Yes. |
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| 05:58 | . Yeah. It's uh it is Okay. So They they're not basically |
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| 06:08 | . So we talked about the base basics viruses back in Chapter one but |
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| 06:15 | becomes a question of are they are life are they non living? Are |
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| 06:21 | living? They're kind of occupy that between gray area to some degree. |
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| 06:27 | . So they they're not eukaryotic. don't call them pro periodic or we |
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| 06:31 | call them bacteria or archaea. There was the archaea bacteria. You |
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| 06:37 | our domains. Right. So we they're not one of those kind of |
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| 06:41 | own thing, more or less. . Um certainly everything else here is |
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| 06:46 | . Okay. There's very likely. tend to not ever use the word |
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| 06:54 | in biology because it's always something that's exception. So, but I meant |
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| 06:59 | say every life form on earth probably some virus that exploits it. |
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| 07:05 | Um, the genome certainly can be RNA size range. That's on the |
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| 07:10 | scale. So this is basically 20 900 nano nano meters or this or |
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| 07:18 | in micrometers. And you can really state in terms of all viruses that |
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| 07:24 | going to have a genome of course protein sack or protein covering around |
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| 07:32 | That's the most basic structure of any begins with that. Right. Then |
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| 07:36 | build on that because there's, there'll variations of that and more added to |
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| 07:42 | . It's all depending on the viral . Okay. Um, okay. |
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| 07:49 | we look at uh, discovery. . So just briefly about history |
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| 07:54 | So this uh, Janowski and buyer this, this this is the time |
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| 08:01 | of late 19 hundreds, I'm late 18 hundreds, early 19 |
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| 08:07 | So by then, um, it well established. You know, remember |
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| 08:12 | uh germ theory of disease. That was all like, you |
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| 08:17 | 18 sixties, seventies eighties. So was well established by them. And |
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| 08:21 | naturally as a result, they assumed yeah, it's probably some kind of |
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| 08:28 | or some sort that's causing this So, the disease is this, |
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| 08:32 | , uh, disease of tobacco Right. So when it gets |
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| 08:38 | of course tobacco is a huge industry then. It still is today. |
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| 08:43 | . Um And the disease shows itself kind of a the leaves of the |
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| 08:50 | plant become yellowish um spotted um not . Right? Leaves should be |
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| 08:57 | Right? If your photo synthesizing so you know damaged And so they go |
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| 09:04 | what's causing us it must be some of bacteria or something in there. |
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| 09:08 | , so let's just use post apocalypse his framework. Right? Let's uh |
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| 09:12 | gonna assume that disease disease leaves contain microbe, right, healthy ones |
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| 09:18 | Right. So we'll do control and and so they basically crunched up the |
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| 09:24 | into paste kind of added some liquid it to to be able to filter |
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| 09:29 | . Okay, they filter it and go okay we're gonna trap the bacteria |
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| 09:33 | top of the filter will then take scrape it off, take that |
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| 09:38 | put it on a healthy plant and will come down with disease. |
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| 09:42 | That never happened. Right? So go, okay well what's going on |
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| 09:47 | ? That filter traps microbes. so trapped the bacterium. Alright. |
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| 09:54 | but when they looked at the material went through the filter the filter trait |
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| 09:58 | call it And applied that to the then they saw this disease process. |
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| 10:05 | so they knew they were dealing with they hadn't seen before. Something very |
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| 10:09 | . Right? They knew of bacterial range but they didn't think anything would |
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| 10:14 | more than that. Okay. And but of course during this time they |
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| 10:19 | have electron microscopy yet. It was about 30 years down the road. |
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| 10:24 | so it wasn't until then when the actually see What these things look |
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| 10:29 | And here's an example of that right . That's the tobacco Mosaic virus which |
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| 10:34 | actually on very small and viral 20 nm. So um no wonder |
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| 10:41 | through the filter. Okay. So know, since that time obviously we've |
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| 10:46 | out that there are viruses specific in life forms that they need a host |
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| 10:51 | replicate all these um features that we about viruses right? For current host |
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| 10:57 | replicate as you see there at the left and lower right. Um And |
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| 11:02 | like like microbes are ubiquitous, found . So are viruses, right? |
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| 11:09 | the viruses are gonna be where the is at. So of course they're |
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| 11:12 | be ubiquitous as well. Okay, we'll talk about at the beginning. |
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| 11:18 | time is kind of this future Okay, so when I was studying |
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| 11:26 | , learning about viruses way back um honestly couldn't think of anything that was |
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| 11:34 | or good about a virus. Other than these viruses in the lab |
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| 11:40 | ways to do experiments. But you , just being out in nature only |
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| 11:46 | of the viruses were just bad cause but since that time we've shown that |
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| 11:51 | have a very important role ecologically. , so, you know, if |
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| 11:56 | remember basic ecology right? We have a dominant species in an ecosystem that |
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| 12:02 | really minimize what else can thrive And so the diversity in those areas |
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| 12:08 | kind of low. Um, and especially in marine environments and elsewhere can |
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| 12:15 | controls on populations. Okay. By them, killing some of them |
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| 12:21 | They can manipulate the population numbers and And that when you do that, |
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| 12:27 | makes room for others to kind of not take over but to come about |
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| 12:33 | well. So you get more diversity many cases when you have viruses that |
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| 12:37 | kind of doing their thing. Um, now, so we'll look |
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| 12:43 | some of that next time. But point is, yeah, viruses have |
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| 12:47 | very important role in the, in ecology and we have them in our |
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| 12:53 | that kind of manipulates populations in Um, so, and we talked |
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| 12:59 | faith therapy last time. So that's upcoming role using pages to specifically get |
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| 13:05 | of certain types of control certain types pathogens. So, um, but |
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| 13:10 | , undoubtedly were aware of the bad of viruses. Right. Covid have |
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| 13:15 | a pandemic for the last three Uh, we're all well aware of |
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| 13:21 | bad viruses can do. But so like with most things are good |
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| 13:26 | there's bad just like uh, as bacteria as with viruses. Okay, |
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| 13:31 | , um, uh, so this is just a show kind of |
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| 13:35 | rages they can span uh very big the larger end Ebola. A smaller |
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| 13:43 | tobacco Missouri virus with a saw and between and different shapes and sizes |
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| 13:50 | And so of course um the since don't have a lot of stuff they're |
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| 13:56 | cells okay they will have um some have more features than others and often |
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| 14:04 | it relates to their size. They have a bigger genome more genes maybe |
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| 14:08 | more components. So you know we're see variations in different ways with |
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| 14:14 | Okay so uh let's look at this . Okay um Are you looking at |
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| 14:23 | um Any questions so far? Okay me stop the clock. Give me |
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| 14:35 | time to read that. All right count down from mine. Okay. |
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| 15:33 | Alright so we have B. And . So the ability to ferment so |
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| 15:41 | really can't do that but they can't that. Okay so they have um |
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| 15:49 | don't really have a metabolism in the sense as cells do like having policies |
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| 15:56 | . You can't provide sugar for a and hopeful growth. Okay viruses are |
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| 16:04 | reliant on the host cell. Okay they can have this feature an |
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| 16:11 | They'll have some kind of a genome ache acid. They'll have uh you |
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| 16:16 | identify them through shape and science caps that's covering around them. So the |
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| 16:20 | of host cell so you know for of you could you know theoretically A |
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| 16:25 | C. D. And E. way to identify. Okay but not |
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| 16:30 | not any kind of metabolism like respiration . That kind of stuff that doesn't |
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| 16:35 | apply to viruses. Okay so um if we look at the basic structure |
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| 16:44 | we always use the term a cellular viruses or not cells. Okay. |
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| 16:49 | have the properties themselves like metabolism like able to replicate on their own. |
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| 16:55 | But they do have some features compared themselves. They can evolve certainly uh |
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| 17:00 | can uh do some of the features of replication. Sometimes they'll have to |
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| 17:10 | a host enzymes but sometimes they may their own to do this. |
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| 17:14 | Um but undoubtedly they have to have host right to do their functions. |
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| 17:18 | . And what basically happens is they over the host cell and basically make |
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| 17:25 | a virus producing factory. Okay. , when that occurs and vary depending |
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| 17:32 | the viral type. Okay so I explore some of these variations. Okay |
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| 17:38 | the so the most basic right the has a genome and you have that |
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| 17:44 | that protein covering the capital in fact made of multiple uh monetary units called |
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| 17:52 | mirrors. Okay and so uh so look at this question. Okay this |
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| 18:00 | to we're gonna talk a little bit basic replication of the virus. So |
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| 18:04 | of these um is not necessarily a replication of all viral types. We've |
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| 18:13 | at all viruses. There will be things that all have in common in |
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| 18:19 | of replication but there's gonna be some that some will have and some |
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| 18:25 | And that's kind of what this is you time. Okay it's count down |
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| 19:08 | 876. Okay. Um 22 of picked a who picked a picked a |
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| 19:30 | ? Did did you pick a? you are correct. So why did |
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| 19:35 | take a correct um Is are you of a virus that does not, |
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| 19:52 | . Whatever virus that does do a know what that does it? |
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| 19:59 | Yeah that's probably the most famous when knows that can do a integrated in |
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| 20:08 | genome. We all know this. it forever begin to the H into |
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| 20:14 | V. H. I. That's the one that does it. |
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| 20:19 | doesn't do a. Um So the is they will all have this. |
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| 20:28 | will all do this. Okay sorry up. They were all pen is |
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| 20:37 | working again so let me try it more time. That okay so they |
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| 20:44 | all do not gonna look for Hold on. Yeah well we all |
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| 20:49 | this. Okay so recognition. I that's got to pick one out. |
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| 20:56 | really big. That's a big Right. You have to be able |
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| 20:59 | recognize the host the virus does. whatever is on the surface is what |
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| 21:04 | look at what's on the surface of . Different types of molecules proteins etcetera |
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| 21:09 | what they look for. They have ones they look for and that brings |
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| 21:13 | passion and then that starts can start whole cycle for them. So kind |
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| 21:18 | more or less begins or ends with B. Up there. Okay of |
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| 21:24 | then if they are they're inside their to exploit the host then certainly protein |
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| 21:30 | things like ribosomes transfer our N. . They don't have those things. |
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| 21:36 | uh certainly popular genome or make an for during transcription. Don't need |
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| 21:46 | Right so that comes from the host well. Obviously replicating viral genome is |
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| 21:51 | if you're going to make viral particles gotta make genomes for them. So |
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| 21:55 | those are all gonna be part of viral life cycle. But a is |
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| 21:59 | of those variations some do it some . Okay and so uh those that |
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| 22:07 | even those that do it there's Okay and so what they will actually |
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| 22:11 | what this actually means is that the genome integrates into the host genome. |
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| 22:19 | and so that's one of those things explore. So let's look at um |
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| 22:25 | of the basics of the reproduction Okay so then we're going to show |
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| 22:30 | applies to pretty much any viral life . We next week when we get |
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| 22:36 | specifics you'll see different variations of Okay so uh of course it starts |
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| 22:44 | recognition. Okay lock, lock and mechanism. Okay um that that then |
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| 22:55 | bring about what it might need to host. Okay so asterisk. So |
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| 23:03 | may or may not need the asterisk . Um certainly if there are any |
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| 23:11 | they won't need um most RNA viruses a different than what they get from |
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| 23:18 | host. Okay. Uh DNA viruses need to get some sometimes they have |
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| 23:24 | own sometimes they use the host. just depends. But certainly things like |
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| 23:30 | T RNA nucleotides are gonna be Okay um and so again metabolism so |
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| 23:43 | don't have to generate energy to do functions. So who do they |
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| 23:48 | They use the host energy. Right basically sapping all the energy from the |
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| 23:52 | during this process. Okay. And it begins when the genome has to |
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| 24:00 | . Now this part's process here from to here will have different variations, |
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| 24:08 | viruses and to leave everything outside the . And only the genome comes |
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| 24:13 | Animal viruses sometimes very often it's gonna this whole structure that comes into the |
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| 24:21 | . Okay. But regardless what type is, the viral genome has to |
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| 24:27 | freed. It has to be able be accessed so it can be |
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| 24:32 | Right and transcribed, translated. But is what we see one variation. |
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| 24:36 | copies. Is this right, integrating host comes in question because some do |
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| 24:41 | don't. Okay. If it is that does this Okay, it |
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| 24:49 | We'll have to eventually go into this . Okay, so integrating the host |
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| 24:56 | zone is a it's kind of a thing. Okay, that's kind of |
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| 25:06 | because HIV can sit in the host for months, years before anything |
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| 25:11 | Okay. So it kind of depends the viral type. But ultimately, |
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| 25:16 | it's going to replicate itself and make viral particles, it will have to |
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| 25:22 | that genome and then go through the , make copies of genome, then |
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| 25:28 | form basically what's gonna form is that will take over the cell forming this |
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| 25:34 | complex basically. And again, it's be more a little more complicated eukaryotic |
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| 25:41 | and character approved periodic sell no You were just looking at the diagram |
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| 25:48 | an animal virus replication cycle versus a one. It just looks more complicated |
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| 25:55 | the animal viruses infecting an animal cell is by nature more complicated nucleus |
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| 26:03 | et cetera, and animal animal virus use all those structures. Some some |
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| 26:10 | go to begin their cycle, some have part of this part of the |
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| 26:15 | cycle in the nucleus and outside and back and forth. Some many would |
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| 26:21 | the endo plastic particular and the Golgi . So that's why I can get |
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| 26:26 | complicated with these things because the cells infecting is complicated. Ok. Compared |
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| 26:31 | bacterial virus, it doesn't look is easier to comprehend. Probably. |
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| 26:37 | so um regardless of whatever type it , it's going to use that cell |
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| 26:43 | a means to make lots of Okay. Which means it's using wholesale |
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| 26:49 | . Right? So transcribed, translated teens uh pretty special proteins assemble. |
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| 26:56 | . And so these terms here vary and because you'll see both in the |
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| 27:05 | um I use them interchangeably. I have heard other people do |
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| 27:10 | So I know I'm not the only . So you hear me say those |
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| 27:15 | terms. So don't let it confuse . Burian equals virus to me. |
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| 27:23 | . Um Okay, so once you in the course you then they then |
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| 27:30 | the cell. Okay um now this okay of replication is so all of |
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| 27:42 | . Okay, of course takes energy resources from the host. So it |
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| 27:53 | Certainly um slow down in terms of growth but it may be killed by |
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| 28:00 | , bacterial virus can infect the cell within hours produce 500 page in that |
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| 28:06 | . Okay, that's not gonna host can't survive that. Okay, so |
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| 28:13 | have viral types that basically all they is infect lots of viruses kill |
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| 28:18 | Okay. And um types that are of do this integrate into the |
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| 28:25 | They can kind of prolong the process you will. Right, so they |
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| 28:28 | just be in the whole things going . The virus is just sitting in |
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| 28:35 | genome sitting in there as a the cell replicates all the generations of |
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| 28:42 | settles are not carrying that viral Like I said, ultimately even those |
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| 28:48 | have to come back and do this they want to make far apart, |
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| 28:55 | ? They ultimately go to that Okay. So you can have the |
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| 29:00 | of viral type. You can have end of the spectrum where they make |
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| 29:05 | kill cell Okay. To the other where they just kind of hang out |
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| 29:13 | the cell for a long period of and really don't do much of |
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| 29:17 | Right. And even then when they in production, they can do it |
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| 29:23 | only having a few cells being a viruses being formed and if you come |
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| 29:29 | so you can kind of do it a little bit of time. |
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| 29:32 | And the host cell can handle that it's not, it's not being overwhelmed |
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| 29:37 | the virus. So the host can of limp along to a degree and |
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| 29:42 | to replicate. Right. So you have that. Right. And so |
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| 29:45 | almost anything in between all depending on viral type. So how much the |
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| 29:50 | cells affected is really about how much the virus using it to replicate and |
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| 29:56 | many particles because that's what's taking air that. Okay, ultimately detrimental to |
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| 30:03 | host. Okay, so retroviruses one those, the HIV virus is one |
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| 30:08 | those that can do that. You just remain dormant, so to speak |
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| 30:12 | a long time. You can then to crank up viral production at a |
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| 30:17 | rate and they can ramp it up we can you know in each of |
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| 30:22 | is gonna have a different effect on host cell. Okay. So like |
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| 30:26 | said we'll get into specifics of these week. Uh but but what you |
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| 30:31 | here is more or less what happens any kind of viral replication? But |
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| 30:36 | I said, we'll point out some next week. Um Any questions. |
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| 30:44 | . So um Okay so infective viral relates to what you think? What |
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| 30:56 | that word or term pops in your anybody? What's that? You |
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| 31:08 | What you think about it for a anybody. Somebody throw something at me |
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| 31:17 | matter how crazy it makes sound, think about? Do you think of |
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| 31:31 | ? Yeah. Like a right in the host. Okay. What does |
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| 31:39 | entail? That's step one. But what's that boiled down to if it |
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| 31:50 | happen or not? Right, getting to sell and what's that? Rely |
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| 32:03 | right recognition. Right. So infectivity or ends with um if it sees |
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| 32:13 | potential hope if the host has the um surface components that it's involved too |
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| 32:24 | to recognize the tax identical effect. . So uh respiratory viruses infect you |
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| 32:32 | either operable respiratory tract among these respiratory . Epithelial tissues and they have specific |
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| 32:40 | components on the surface that these viruses . Okay um the virus recognizes specific |
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| 32:50 | in lung tissue. Right? Uh it is varies from virus the |
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| 32:56 | Okay. And so uh if if compatible right recognize if it recognizes then |
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| 33:05 | can occur. Okay. And so there are drugs antiviral drugs that are |
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| 33:12 | to block that like Tamiflu is one is meant to stop the infectivity process |
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| 33:19 | flu viruses. Um So if you at a uh sell obviously this is |
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| 33:27 | infection occurring. Right? And so have the viral particles. And so |
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| 33:34 | were talking about this process here. entry right well it's gettin. Okay |
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| 33:40 | it is okay as we see all viral particles already being assembled. Okay |
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| 33:48 | um so we look at that effectivity can Okay one level is how many |
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| 34:00 | um types can a virus infect? think of it can affect me and |
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| 34:09 | can affect the squirrels that are running out there. And the birds that |
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| 34:13 | flying around can sing virus infect all different animal types. Okay. That's |
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| 34:19 | post branches about. Okay, broad narrow, obvious example. Always used |
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| 34:25 | this is rabies, rabies can affect types of mammals like squirrels and raccoons |
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| 34:31 | wolves and dogs and cats and humans bats and etcetera etcetera. Right. |
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| 34:36 | large, wide range. Um the narrow range of course can't do |
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| 34:45 | Right. So HIV infects only humans those measles in months um as those |
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| 34:54 | , okay, infects humans. And so narrow range obviously. And |
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| 34:59 | that's one level. Right. So we can go from post range how |
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| 35:05 | different animal types if you will? there's also plant viruses and whatnot. |
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| 35:10 | then we go to the individual single . Okay, so stay with |
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| 35:18 | rabies virus can infect humans and various of mammals. Okay, well what |
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| 35:25 | one? Oh inhuman. How many cells in a rabies virus? In |
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| 35:33 | , that's what this is about. is. Um I think of that |
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| 35:37 | specificity. Cell specificity within the Right. And so can it infect |
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| 35:47 | cells, liver cells, um muscle . Okay. They have a wide |
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| 35:53 | of a wide scope is um Uh for the most part most viruses |
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| 35:59 | usually in the narrow spectrum here. , so coronavirus recognizes these kinds of |
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| 36:08 | proteins. These are actually a type receptor that are found on uh cells |
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| 36:14 | the respiratory tract. Okay. And in long and so this kind of |
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| 36:26 | to a host can actually also induce and talk about this later in the |
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| 36:33 | . And so one of the effects the inflammation is your immune system is |
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| 36:36 | . But then by project that is build up self. Covid, bad |
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| 36:41 | of covid can lead to fluid build in the lungs as I'm sure you |
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| 36:44 | know and that can produce some of more severe effects of the disease. |
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| 36:51 | That's one example. So a very trumpism is HIV so in a similar |
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| 37:00 | a narrow host range but also a narrow trope is um okay so in |
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| 37:08 | one type of multiple t helper cell infect one type of one cell type |
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| 37:13 | that group. Okay. And it so happens as we'll see later that |
|
| 37:19 | help ourselves particularly the type of effects instrumental in really controlling the whole adaptive |
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| 37:27 | response. Which is how you proves , how your other cells to deal |
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| 37:33 | infected cells. And so you're affecting cell type that kind of controls all |
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| 37:40 | . Imagine if you have if I with that and those cells are |
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| 37:45 | your immune system is really really um . And so not surprisingly people die |
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| 37:53 | HIV die from a cold or pneumonia their bodies can't fight any kind of |
|
| 38:01 | . Um now on on the broader Ebola so that that accounts really a |
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| 38:08 | part for the lethality of Ebola. about at at best. It's about |
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| 38:18 | gives you about a 50% mortality So if you catch a ball you |
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| 38:22 | about a 5050 chance of living. . Or so it's upwards of |
|
| 38:27 | mortality rate. Okay. And that large part is because Ebola can affect |
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| 38:34 | cell types in the body. Okay different types of epithelial cells. Endothelial |
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| 38:42 | that line blood vessels. So you to infect those now your blood vessels |
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| 38:46 | leaking. Right? People have died Ebola, horrific because it's fluids coming |
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| 38:51 | of everywhere. Okay. Blood and have you. And so it's |
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| 38:56 | that accounts I would assume in large for its uh, deadliness. |
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| 39:02 | Um, so any questions about host tissue specificity. So, um, |
|
| 39:12 | right. So, they get into little bit about structure, viral |
|
| 39:17 | So, here is uh, interesting virus. So naked virus is lacking |
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| 39:24 | missing what? Okay, let's count . 10. Okay, If so |
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| 40:19 | is a naked virus lacking? All envelope lacking an envelope. Okay, |
|
| 40:27 | they can they will have a caps they will have a genome. They |
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| 40:31 | have black or protein spikes. of course we'll have a host. |
|
| 40:37 | , but um, technically naked one that's lacking an envelope. |
|
| 40:44 | so naked or envelope viruses. so, um, which means it's |
|
| 40:53 | is so envelopes not listed here. it's none of the above. |
|
| 40:57 | so buyer structure. So, we at this in terms of categorized in |
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| 41:03 | of cemetery symmetrical asymmetrical fila mentis. , symmetrical means of course the cut |
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| 41:12 | half there. You have identical Alright, so very often with viruses |
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| 41:19 | have a policy federal shape. 20 . Okay. Um, captured |
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| 41:26 | So remember the individual units are called mirrors. Uh, there can be |
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| 41:33 | of those, but but structurally each mirror is not necessarily going to be |
|
| 41:40 | . Right? So Usually 3-5 Different of captured proteins come together assembled to |
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| 41:49 | the caption. Okay, you have remember that viruses are small but you |
|
| 41:54 | do a small genome which means they have a lot of genes that code |
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| 41:58 | lots of different things. Right? kind of very efficient that way. |
|
| 42:02 | we captured proteins. They produce every different ones and they assemble. |
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| 42:08 | And so um and so you can an envelope virus as this is. |
|
| 42:15 | so you see the capsule in the then the envelope on the periphery. |
|
| 42:20 | then you have these are all virus proteins. Alright. The envelope is |
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| 42:28 | from the wholesale Okay, envelopes are of as far as I know of |
|
| 42:35 | animal viruses, not bacteria viruses. , so when the virus exit the |
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| 42:42 | the animal cell um it will acquire membrane as it kind of wraps around |
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| 42:50 | as it exits the host. Um but there will have virus improved |
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| 42:57 | sticking out of it. Right? call uh proteins those are viable. |
|
| 43:03 | . And they have different functions from recognition and passion to the host to |
|
| 43:10 | of them are involved in helping the exit to sell. Uh Some may |
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| 43:14 | functions in in uh interacting with immune selves immune system selves to kind of |
|
| 43:24 | those uh defenses of that because remember virus inside of the body has to |
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| 43:30 | around defenses. So it's gonna have to do that. Um Now the |
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| 43:39 | spike. So these are just as implies sugar cocaine structures. Right? |
|
| 43:47 | can be quite prominent. Okay of . Hence they call them spikes when |
|
| 43:52 | when they look like that. But enveloped and naked viruses. The naked |
|
| 43:58 | over here on this side. this is a that's a naked |
|
| 44:10 | Okay. You can see a book have spikes. Doesn't have an envelope |
|
| 44:14 | requirement for that. Okay, um the Elementos viruses have this kind of |
|
| 44:26 | looking appearance. Okay, he'll close sometimes call it that um they can |
|
| 44:32 | be uh inside of a inside of uh envelope. As you see there |
|
| 44:42 | see the actual filament is virus here then here is the envelope surrounding |
|
| 44:50 | Ok, so they can have some different shapes. And so the uh |
|
| 44:57 | viruses, this is more common in types. So bacterial stage basically means |
|
| 45:06 | virus specific for infecting bacterial cells. . And they also often called called |
|
| 45:13 | also complex viruses. Okay, have mixture of different structures. So you |
|
| 45:19 | the classic you know viral shape here the genome. But then you see |
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| 45:26 | other parts here. Okay, so called tail fibers. So just imagine |
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| 45:32 | is sitting on top of a Okay, bacterial cell and um tail |
|
| 45:39 | help recognize and attached to the And you see this part here. |
|
| 45:45 | . This sheet that can actually compress it can go downward so something like |
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| 45:52 | . All right. And here's the head. Okay. And the genome |
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| 45:59 | as it compresses is kind of under and the genome enters the cell. |
|
| 46:04 | . That's very common for bacterial So where all of this stays outside |
|
| 46:11 | cell and only the genome interest very for bacterial viruses to do that. |
|
| 46:18 | . Whereas animal viruses is very common the whole thing. Okay. Uh |
|
| 46:24 | the opposite. Okay. Um and asymmetrical viruses. So you're looking at |
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| 46:31 | that's a flu virus. And you're well that's symmetrical. I can throw |
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| 46:36 | line there and both halves look the . Well you get a better picture |
|
| 46:41 | you have to envision that uh that it's more of a blob. Not |
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| 46:50 | perfect circle. Okay so food cold viruses um can not a strict |
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| 46:59 | round ball like they will have the kind of off amorphous kind of body |
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| 47:07 | which makes it asymmetrical. Okay. you do see the captain in here |
|
| 47:12 | green. You see the envelope. the flu viruses you always see a |
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| 47:20 | of an H. And an Right? There's a church one |
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| 47:24 | One H. Two and three or the number is. The agent. |
|
| 47:30 | in numbers because there's different variations of . And they refer to this one |
|
| 47:35 | the age hemagglutinin that's the end. . And so the human gluten in |
|
| 47:43 | spike, so to speak is for to the cell. They know many |
|
| 47:50 | . One is for exit. So one works in attachment one |
|
| 47:54 | But they both are types that can uh response. So you can have |
|
| 48:01 | number designations that differentiate them. H N one and so forth. |
|
| 48:07 | The Okay, so here's one thing don't think it's mentioned in chapter |
|
| 48:15 | Okay. And so the coronavirus is example is the covid virus. |
|
| 48:22 | so if you look at the okay, you don't see this traditional |
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| 48:29 | of enveloped virus. Right? Here's here's the Captain. Right. The |
|
| 48:34 | is the Captain and surrounding the genome the envelopes around. Right. Uh |
|
| 48:40 | don't see that in these diagrams. . But so what it has, |
|
| 48:45 | an envelope virus has a genome but caps it is Are these nuclear what |
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| 48:55 | called nuclear capsule proteins? Okay, they basically cover The genome. |
|
| 49:02 | So that in essence is the Okay. It's not uncommon to see |
|
| 49:07 | in different viral types. Coronavirus is and there's other types, they don't |
|
| 49:14 | the traditional middle think of this house up the genome. It's more intimately |
|
| 49:21 | with the genome binding proteins binding to genome. Okay, the function of |
|
| 49:25 | is the same as for particularly It's just that with this one |
|
| 49:30 | The proteins are actually bound directly to genome. Okay. Hence they call |
|
| 49:36 | nuclear capsule, nucleic acid capsule kind combination. Okay. Um so uh |
|
| 49:46 | questions? So viral genome. So just put this in to kind of |
|
| 49:52 | you an idea of average size is genomes. Of course there'll be some |
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| 49:56 | the super small, some are Um you know this is part of |
|
| 50:01 | . So zika virus um is and flu virus have approximately the same sizes |
|
| 50:08 | the genome is very different in terms structure. Okay, so uh what |
|
| 50:13 | call non segmented is basically a continuous of the okay um segmented means it's |
|
| 50:24 | uh fragments of the genome. And so there will be certainly viral |
|
| 50:32 | proteins. Right. Some of these for um attachment recognition right summer for |
|
| 50:39 | from the cells. Some are for know, different types of particular enzymes |
|
| 50:45 | in the virus specific enzymes involved in replication process. So you'll see some |
|
| 50:50 | these uh again with the size limitation the virus were limited to you know |
|
| 50:57 | between 10 to 50 to 100 genes a larger and like a polio virus |
|
| 51:02 | rather large. They're going to be than 100 jean size genome. |
|
| 51:08 | Um but back to the flu So this segmented genome uh means that |
|
| 51:17 | you know their ability we combine is high. Okay. So generally speaking |
|
| 51:25 | viruses period have a higher mutation rate you know, certainly bacteria. Certainly |
|
| 51:35 | . Okay but when you look at , RNA viruses have an even higher |
|
| 51:40 | . RNA virus virus versus virus RNA have a much higher rate because there's |
|
| 51:49 | mechanism to repair any mistakes that are during replication. Okay. Um A |
|
| 51:55 | virus can potentially use a host repair to kind of fix mistakes. |
|
| 52:02 | But the virus is not so Okay so they can mutate much |
|
| 52:07 | Okay. Um And so with with viruses their origins are in like aquatic |
|
| 52:14 | like ducks um and then travel into fowl chickens um and then also into |
|
| 52:26 | . Um And so you can see of the origins in their genomes. |
|
| 52:34 | ? So this is kind of color . Here's an avian flu virus. |
|
| 52:38 | color coded yellow. Okay. The fragment segments here the human H. |
|
| 52:45 | into the believe that green is like maybe the reddest swine origin. The |
|
| 52:55 | maybe from uh chicken or duck I . But anyway you see the organs |
|
| 53:02 | these in the segments where they originated . And so of course they can |
|
| 53:08 | . Right? And so a viral you can have population of a virus |
|
| 53:15 | a specific type of flu virus. say uh they can they will be |
|
| 53:21 | genetically different from each other. Absolutely be that way. And they may |
|
| 53:26 | fact that they can both affect the cell as well. That's where you |
|
| 53:30 | get mixtures and recombining of the genomes this. Okay. And now, |
|
| 53:37 | because they have a higher mutation rate the combination can occur, it doesn't |
|
| 53:43 | we have we're all going to be right? Most aren't gonna be successful |
|
| 53:48 | terms of being a better reform. ? But you know, the it |
|
| 53:53 | lead to some variations where the vaccine not be as effective. So that's |
|
| 54:00 | thing with food vaccine. So it everywhere because of paul's um mutation |
|
| 54:08 | And so um year to year we to predict what happens with it because |
|
| 54:12 | take we know we sequence these these viruses every season. We have we |
|
| 54:19 | what their genomes look like and then try to predict. Okay, is |
|
| 54:24 | a certain trend? That's what part the devolving more so than the other |
|
| 54:29 | that we can take the vaccine toward ? And that's what all goes into |
|
| 54:34 | . And uh and the flu vaccine a it's comprised of multiple antigens in |
|
| 54:40 | . And so but as we all , the flu shot wasn't always a |
|
| 54:46 | success, right? Can bury it you can only predict it can't be |
|
| 54:50 | in terms of these things. And it's it's gonna be the same thing |
|
| 54:54 | up with Covid we're gonna have a vaccine area more likely. And uh |
|
| 55:01 | probably better than others. Its So that's the nature of viruses and |
|
| 55:06 | evolve like we do. So they change as well. Okay. |
|
| 55:13 | so any questions from viruses into I you could say virus, like over |
|
| 55:24 | , over there, not viruses. this is the price and virus. |
|
| 55:30 | is one of those that's going to a um we're gonna see it |
|
| 55:35 | So we're gonna answer log the results then just move on and then talk |
|
| 55:41 | it and then come back and revisit you're not sure this time, I |
|
| 55:48 | to be short second time around. , we pause that we tend to |
|
| 55:54 | it. So the entire sentence has be true. If only half of |
|
| 56:04 | true. Don't select. Sorry. . Okay, let's count down. |
|
| 57:03 | mm hmm. See. Okay, count to one. Alright snapshot. |
|
| 57:25 | , Alright, so let's move We'll revisit this here in a few |
|
| 57:29 | . So dr Royce and brian's first roids. So first off neither of |
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| 57:37 | is considered a virus. A virus a specific structure minimum latino for the |
|
| 57:44 | coating around it. Right, So and prions don't fit that. |
|
| 57:49 | In fact, Vier Oid actually means like Okay, one is a infectious |
|
| 57:57 | Montel ones and infectious protein. so um and that's and that's |
|
| 58:04 | It's an RNA molecule and its There's no other structures associated with |
|
| 58:09 | Okay, so Vai roids are as as I know, limited to just |
|
| 58:16 | plants of different types. Okay, not aware of any viral roid, |
|
| 58:22 | disease caused by a viral, okay think the most studied of these are |
|
| 58:28 | that affect the potato, potato, , potato plants. Um and they |
|
| 58:36 | something on your molecule. They'll have secondary structure to it that you see |
|
| 58:42 | . So they have these kind of structures. RNA molecules can have catalytic |
|
| 58:49 | um in in red zones. Remember ? It's uh I think that 16 |
|
| 58:55 | . RNA that catalyze is the peptide for me. Okay so remember the |
|
| 59:01 | S. Regardless and it's an RNA catalyze is the actual enzyme reaction. |
|
| 59:06 | that's not this is not anything And so um it does require the |
|
| 59:13 | preliminary to copy itself. That's that's its replication basically. Okay. Um |
|
| 59:19 | affect protein synthesis or protein expression and expression. Sorry, they affect gene |
|
| 59:25 | , they interfere with the ability of arrives them to express genes in the |
|
| 59:31 | and that's how they affected. And um the uh they're relatively small how |
|
| 59:40 | transmitted from plant to plant. I not sure I'm guessing like with many |
|
| 59:46 | diseases oftentimes it's insects that are involved the transmission. So it could be |
|
| 59:53 | I can't say for certain but um I can say this point is that |
|
| 59:58 | know that the humans aren't affected by as far as I know. Okay |
|
| 60:03 | they apparently can be quite damaging. I know that they forget the number |
|
| 60:07 | saw on damage to potato plant crops the U. S. Can be |
|
| 60:13 | . So it is something that uh are dealing with that are in this |
|
| 60:19 | . So um that's really all I to say about virals. Okay now |
|
| 60:25 | crayons we uh you're probably more familiar this call, have disease heard of |
|
| 60:33 | before. Um It's a um causes severe neurological condition. Um It's a |
|
| 60:42 | progressing disease over years so that's something happened suddenly. Okay. There's really |
|
| 60:49 | danger of human requirements in the United . Okay. Um the if you |
|
| 60:57 | to contract it would be from eating meat. Okay. Uh typically found |
|
| 61:04 | cases that were has happened a long ago was cattle, cattle. Uh |
|
| 61:10 | no cure for it. Um basically have to burn the carcasses of animals |
|
| 61:17 | with it killed them and burned But Um that hasn't happened for quite |
|
| 61:22 | time. There was somewhat of incidence the 80s in in England but never |
|
| 61:28 | amount to anything over here in the . Okay. Um so the there |
|
| 61:35 | different variations of this I think depending on the animal host. Okay so |
|
| 61:43 | Jacob is what they call it in . There is apparently a some evidence |
|
| 61:48 | a genetic link to this that um it's seen in some humans that there's |
|
| 61:58 | of a somewhat of a history of in certain families so there's I'm not |
|
| 62:02 | it's been fully fleshed out but there some evidence to support that. Aside |
|
| 62:09 | that, like I said, acquiring through eating contaminated meat food. The |
|
| 62:15 | so scrapie is the form, I this was first discovered. This is |
|
| 62:20 | sheep, scrapie in sheep. Um so the so what is this |
|
| 62:27 | Right, so it's a it's a that is normally found. It's found |
|
| 62:34 | us. It is in our Okay, fancy er membranes and um |
|
| 62:40 | there is a normal form approach and still not really sure what the function |
|
| 62:46 | . I've seen everything from involved in metabolism of all things to um other |
|
| 62:52 | of functions, but I don't think yet been nailed down what it is |
|
| 62:56 | the function. But um it it there's two configurations. That's what they |
|
| 63:04 | the normal form, which is the functioning form of the protein. And |
|
| 63:08 | misfolded form and that's the one that produce the disease symptoms. Okay, |
|
| 63:15 | how does this thing replicate? well, to quote replication in air |
|
| 63:21 | , all right, is by binding a normal form of the protein. |
|
| 63:27 | , so what you see right Okay, uh here's the abnormal thirst |
|
| 63:35 | normal. Okay, so the normal becomes misfolded by binding with this prion |
|
| 63:42 | . Okay, and that sets off of a chain reaction. It binds |
|
| 63:48 | a normal form changing into a prion and you accumulate these prion forms. |
|
| 63:55 | , misfolded forms. Again, it's slow progressing disease. Okay, so |
|
| 64:01 | builds up over time. Okay. so um what happens is so again |
|
| 64:10 | could result from eating ingesting attempted meat if it's this genetic component, you |
|
| 64:18 | the mutation, the genetic mutation and actually produce these kinds of proteins. |
|
| 64:24 | um the uh in any case, they accumulate over time and can uh |
|
| 64:34 | I think in some cases they can like large polymers. They can distort |
|
| 64:38 | cell. Obviously it destroys the functioning the cell and where these accumulate. |
|
| 64:46 | , so basically holds. Okay. the brain tissue. Okay, I |
|
| 64:54 | they sometimes call these plaques as So the space for the neuron used |
|
| 64:58 | be functioning is no longer and now have a whole, right, so |
|
| 65:04 | name really tells you kind of what your spongiform, right? So you |
|
| 65:08 | holes in brain tissue, it becomes different consistency. Okay, obviously you |
|
| 65:15 | want to have a brain that looks swiss cheese. Okay, you're not |
|
| 65:19 | function. Right, Okay, so but again, slow progressing right over |
|
| 65:26 | , many many years. Okay, is no proof for it. |
|
| 65:30 | so but surprisingly, it's having just about in Chapter five disinfectants and chemical |
|
| 65:40 | treatment. So this these proteins are very um resistant. You really have |
|
| 65:46 | if you do happen to know you're contaminated meat and well I don't eat |
|
| 65:50 | . But if you must know that will be super well done. Okay |
|
| 65:55 | it takes a pretty good long temperature to really inactivated. So um and |
|
| 66:02 | apparently resistant to different chemical treatments and . So it's uh it is a |
|
| 66:09 | thankfully you know it's not something again number of cases occur in the |
|
| 66:12 | S. Last year I think is . Right? So it's not something |
|
| 66:15 | be worried about. But what's unique it? Of course it's the |
|
| 66:21 | It's an infectious protein. That's these is a protein which is of course |
|
| 66:26 | need um many questions. I'm not of any other prion diseases beyond |
|
| 66:37 | Um Okay so this shows you again a different diagram, there's a neuron |
|
| 66:44 | so the red or the accumulation of misfolded forms and they accumulate over |
|
| 66:52 | They used to be in this normal shape, the green ones. But |
|
| 66:57 | course eventually the neuron dies as a of this process. And so so |
|
| 67:05 | revisit the question. Okay and see we get a different results. |
|
| 67:34 | Okay. Okay. Number five Okay so one from 39 to |
|
| 68:31 | Right, so uh d is the answer. So where is the that's |
|
| 68:43 | they replicate primes don't do that. the only statement there that's completely |
|
| 68:49 | Um Any questions. Okay let's look one more question here. That kind |
|
| 68:57 | relates to next target coming up. so um let me pause that for |
|
| 69:05 | second. So in reference to RNA . Right. Depending on the particular |
|
| 69:12 | virus type, this genome could be as a template for what? Cap |
|
| 69:49 | a little bit. Okay. cannot nine. Yeah. If you answer |
|
| 70:24 | the above you are correct. DNA synthesis, you may know what |
|
| 70:31 | that is. Yeah. Retro Yes. Since this retrovirus M. |
|
| 70:38 | . So this is the difference between plus R. N. A minus |
|
| 70:47 | virus. Okay, So the plus is directly translatable. The the -1 |
|
| 70:55 | not right. That's kind of where confusion comes in and how the life |
|
| 71:00 | operate for these two types of Okay, um that's I'm gonna stop |
|
| 71:07 | , folks. So we'll leave it . We'll pick it up next |
|
| 71:12 | So |
|
