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00:00 I Ok folks, welcome um so I assume you got my email

00:37 back in the routine again? Blackboard this week. Smart work next

00:44 So stuff you on monday of next , so be back in that mode

00:49 a bit. The next exam is for a while because we got spring

00:54 um Kind of uh in the middle . So basically March 24 25.

01:03 a long ways away. We'll be Unit three by then. So uh

01:12 , so you started going to finish viruses part one and then get into

01:17 two, which is mainly focusing on viral life cycles. Okay, um

01:30 13 is one of those class but it's not gonna get much into

01:37 . We do a little bit, not a lot. Most of that

01:40 be left for the following Tuesday, is uh where we at right

01:46 so we'll do some here and then it up um uh in the next

01:52 here. Okay. Um Okay, regarding the exam overall, I

02:00 I was pleased with it. I this yesterday on blackboards, so the

02:07 , so I do like seeing lots fat bars on the right side.

02:13 so that's my goal, always my . So, but you know,

02:19 70 rounding up 71 average, but know, that's pretty much what I

02:27 to hit is somewhere 70 plus plus minus two points. Give or

02:33 Okay, so um I am, what I'm about to say is going

02:43 be applicable to probably focus over on side. Okay, hold on this

02:50 over here, over here. so number one um you don't don't

03:00 crazy. Okay, calm down. right too. Is um you will

03:07 be asked any more questions on unit material because the final exam is not

03:15 . Just each exam is its own covering that previous quarter of the

03:20 Okay, so that's number two. three is whatever you did that got

03:26 to this. Not so great Do not repeat that process again.

03:31 . If you do, I will you guaranteed. I'll put my hope

03:38 my money on you will make the grade next time around, guaranteed.

03:45 . Um And so don't do that . People will think, okay,

03:50 made a not so good grade. me study twice as hard now.

03:56 , I'm gonna study twice as hard the same blank blank study method.

04:02 again, guaranteed disaster. Okay, you've got to change them. All

04:07 , so um I will I'm not get the whole steel now, but

04:14 will just snip it on day one 1 17 23 that I will send

04:21 link on the email this week on to study at least at least my

04:27 on how to do it. There was a person. Is he

04:29 today? Is he at the guy he came by, I don't want

04:35 name. I don't know your You left your headphones in the lab

04:40 open the door there are he followed . He did very well.

04:47 okay. So you have to listen me. Here's one of your

04:52 Okay. So anyway, but that of the lecture, right? That's

04:57 you follow. Okay. Perfect. . So, um anyway, so

05:02 at that. You got questions obviously me know. Okay, so uh

05:08 you want to look at the just face to face virtual and we

05:15 go over it. Okay, So , so I'll leave it at

05:19 So, the other thing, the important thing is uh I think even

05:24 no matter how you perform have amnesia amnesia because now your focus is um

05:34 right here is this now your is that okay? So forget everything

05:40 . Now that so um having said not gonna ask specific questions about,

05:47 know, more material, you know some of that those concepts we're gonna

05:54 over into 13 and 14 metabolism. talked about growth and And Blah

06:02 Right. That's all gonna be applicable uh 13 or 14. Okay.

06:10 um any questions? All right, . Okay. Okay. All

06:22 So let's I think we just have little bit of a recap. Um

06:27 obviously we're talking about viruses. Like viruses um Part one was about

06:34 defining a virus structure. Just some the basic features basic life cycle.

06:40 . So he was just showing you of summarizing a definition of a you

06:46 , they're not selves they are uh we would have right. They obviously

06:56 uh structurally size side branches then um capsule rights that they have at minimum

07:04 viruses have this protein covering that covers genome uh shapes and be symmetrical

07:16 This kind of more kind of this form tailed viruses um making the envelopes

07:25 refers to whether it's required an envelope the host cell um as it exits

07:31 captain exits that kind of wraps around it can be without without a

07:36 Okay. And then um so viral proteins in the search from infectivity recognition

07:46 some of those others have different They often look like very prominent

07:53 So um yeah, but the point is you're gonna they're going viral specific

08:00 on the surface. Okay. Uh or whatever. All right. And

08:07 we looked at the reproduction rights. the basics. And so we're getting

08:13 more specifics uh viral types differ in process but pretty much overall this is

08:22 . And we know that there's gonna variation. Right? So from the

08:25 , of course they get resources depending the viral type. They may or

08:30 not need to use the host but delivered opponents. They will need uh

08:38 . So I one of them as get into. Not not so much

08:43 but likely thursday is RNA viruses that kind of the ones that typically uh

08:49 look problematic helps to kind of uh that. Okay, this is what's

08:56 in, right? And ultimately this what's coming out. Right? So

09:00 heart on the part of the it's going to make it a

09:04 It's gonna be making ultimately making viral that exits the cell. Right?

09:10 what's going on in between is everything allow that to happen? And what

09:15 you need to look at the virus ? Right. It needs proteins,

09:20 proteins, right, captured proteins and else that's there. And so I

09:25 to assemble this because what's happening is just having a genome in here,

09:32 ? You have to put everything else it to make viral particles. So

09:35 have to copy that you have to proteins, you gotta assemble, put

09:39 all together and exit. Okay, how virus viral life cycles will look

09:47 in large part is what's the nature that genome RNA Dean. Okay.

09:56 that's how the middle part here. part may not so much to redo

10:04 not so much this part. they look a little different virus the

10:09 type. Oftentimes because of what's the type. But the thing is the

10:15 . You're gonna get this no matter type you are. Okay, that's

10:19 goal. That's how the virus going produce make far apart. So remember

10:26 this idea that this right here. . It begins at four ends by

10:34 that whole set. Okay, so , okay, I do this in

10:42 remember I don't think your book even this. But we just looked at

10:48 viruses. Right. And here's your caps that shape. Right. This

10:54 sure. Is that geometric shape? , that's very common. But you

10:59 have viruses that look like this as where the caption isn't so obvious.

11:05 guess it's not like a little house tent around the genome. Right.

11:09 just basically intimately math to the Right? So the capsule proteins

11:15 Alright. Are sticking to the Right? So these will be all

11:23 top of the genome and that's how captured uh, the structure. So

11:28 call it nuclear capsule because it's right smack bound to the genome.

11:34 so you do have viruses that have coronavirus. Alright. So,

11:41 and so I think we ended with and viral. So remember crayons and

11:47 are not viruses you might call the like, okay, if you see

11:53 statement on exam question says protons and are viruses that's false. So,

12:03 , so because they don't have the of the virus, even the virus

12:06 pretty simple, viral loads are and don't have those things. Right.

12:12 prions are infectious proteins and that's all are. Nothing else associated. And

12:19 are infectious RNA. And that's Nothing else is a part of

12:22 So I think that catches us up questions about these previous things here.

12:34 so let's look at this question So this will take us into kind

12:47 classification. And as we're looking at , so in reference to an RNA

12:52 , majority of viruses, depending on particular virus type, this genome could

12:57 used as a template for what? next is going to be the

13:04 Classification table. Um You'll need to that. Okay I'm going to show

13:11 just to give you an idea of types of viruses that are out

13:15 Um Most common ones, you know the question. Oh alright I just

13:27 on let's try it again. Right while I'm blathering extend time so I

13:38 . Okay um. Oh okay. . So you don't need to memorize

13:46 but just show you some representative Um lots of human viruses. Human

13:52 of human diseases are actually in all RNA viruses. So um so this

14:00 is gonna relate to the next thing gonna talk about. So counting down

14:05 10 9 five 32. Okay I somebody saw the answers and said okay

14:18 go with these people. Okay it d all the above. Okay so

14:23 bonus points. Uh um I can't it might work anyway, so

14:33 So you have A plus RNA You have a minus R virus.

14:41 um the plus RNA virus will fit A. B. Or C.

14:54 take our question. Just answer. one of those. What would this

15:00 be a template for that is the . You need that. Okay

15:11 Yes. So plus that's a plus translations. So this goes back to

15:18 . We'll talk about this again a times because it can be taken cars

15:24 explanations plus minus. Right. So that what can we do? Pay

15:29 . That has its own language? off base pairing three problems.

15:36 And the plus minus since Auntie says non coding. Right? Uh And

15:43 the plus stand basically any plus strength all this language applies to what you

15:48 in A. Or D. A. Right? Because D.

15:52 . A. Has plus minus plus RNA and DNA. So yeah it's

15:57 so you can have this this this this. Okay in all three of

16:12 and all have a plus minus relationship each other. Once coding was non

16:17 um the five prime three prime relative each other. Right? So there

16:24 a stupid penny um the three prime prime relationship. Right? Five prime

16:31 prime. And and the carpentry strand like that. Right? So yeah

16:39 but whatever the nucleic acid types coming and all three days are possible,

16:44 all have that same kind of terminology use. Okay. And so um

16:52 and this I'm bringing this up now as you get to the next table

16:56 there are no viruses can be a complicated because of this. Okay so

17:03 template for M. RNA synthesis. this guy. Okay minus aren't virus

17:09 that genome is a template that you um talking to make A M.

17:15 . Okay basically making a plus Okay DNA synthesis that's retrovirus. So

17:29 in their own room. They can an RNA genome but they copy into

17:32 . N. A. Completely So we'll see that on the next

17:36 the next flight. Okay and again go through the plus minus all that

17:44 more more than once. Okay so go ahead and flip over here.

17:50 um Okay so here again in this . Right so the just think of

17:57 plus RNA is the M. It's the same thing happens in you

18:01 you undergo express jeans you're taking DNA , your D. N. A

18:07 that you copy it um into a . You copy the minus D.

18:13 . A. And you got a art. Okay so it's okay this

18:20 we're gonna clarify that. Um So this classification there's a question we had

18:26 time about what can you use to viruses? All of them are

18:31 Right, capsule type, genome type envelope and the envelope legitimate reasons things

18:39 can use to classify. But what's used is this Baltimore classification and it

18:44 genome? DNA. RNA double strand thread. And what's the rap?

18:52 did they get to the M. . N. A. The plus

18:57 . Because that's what enables it to which you're gonna need. Right if

19:03 gonna assemble into a viral particle. so group one into your D.

19:08 . A. That's you know that's we are. Right. So you

19:13 should have the greatest familiarity with that that's how we do it.

19:16 We don't we have double strand. would be here we have double stranded

19:20 of course. But we know how happens. Right? Um transcription to

19:27 D. N. A. Into . R. Okay. And so

19:31 the single strand D. N. . You first uh make a double

19:37 of the form. Okay and then the minus strand into A plus

19:42 R. Right? So this is this gets you enable us to make

19:47 . Okay. And then uh the groups. So here again is just

19:53 example of RNA uh with strand to . So it's RNA RNA. And

20:01 know that because remember use right use only RNA. Not in D.

20:07 . A. T. I mean a cell thing. Right? So

20:12 so the plus strand and what we the coding or the sense strand?

20:24 uh mega strand is called the non or template or not? Antisense

20:32 Okay. The current trend simply has information to make the. Okay.

20:40 so um when we make it we an M. R. A.

20:45 here topping that DNA template strength? copying minus the only copy of minus

20:53 to make a plus. Right so minus template string enables us to make

21:01 plus R. N. A. now contains the essential information to be

21:06 into a project. Okay so that's getting to the plus stray. And

21:12 with viruses is a big deal because the M. R. That's how

21:17 what that's what gets translated minus cannot contain the cooling information. Right?

21:26 with the RNA is here they have own enzyme. Okay this RNA dependent

21:33 the so you're going well we are but it's D. N.

21:41 D. As in dog D. . A. Dependent on limericks.

21:46 what we've got viruses uh can't use . Right? They didn't RNA dependent

21:53 income because they they have RNA genome that are in a into RNA.

21:59 . Us you carry out don't do kinds of things. Okay. Or

22:03 carry. Okay that's a strictly viral . So for that reason they must

22:10 their own enzyme to do this. um Which is what this R.

22:15 . R. P. Is. and so um so you have three

22:20 double stranded and single stranded plus and . Okay so when we copy we

22:30 the um minor double stranded copy the strand. Okay and we get A

22:37 so we can stop right there. the plus strand. Okay Is we

22:46 directly we copy that. Okay now gonna tell you why. So you

22:52 here right this is already A. R. N. A.

22:57 Do we have to go why do have to go any further any

23:02 And it does it doesn't stop Okay so go back to what I

23:09 earlier. Okay a virus is it attaches to a host cell.

23:19 so that plus genome enters to Okay right there. And so is

23:26 gonna be enough? Because remember what's end game makes lots of viral

23:31 Each has its own genome proteins around . Right so is this entering the

23:38 ? Is that enough? No? so yes even though it can and

23:46 is translated. Okay it's not enough . And so that's why now unfortunately

23:55 easiest solution would be because it gets little complicated. The easy solution would

24:01 let's if we need more copies let's that into a plus. Okay can

24:08 work? No because you copy a strength it's just a complimentary base

24:15 So you can't that doesn't work. it has to go into a minus

24:21 mode first. Okay and so this basically what's gonna see underneath here.

24:29 so we go from minus our name two plus. Okay. Yes it

24:36 make sense but it's just the base rules. That's really what the

24:40 This whole thing right, complementary right. We don't make a direct

24:45 copy of the strand. Make the cop whether it's a plus to make

24:50 minus it might be a copy until . Right. And so that's why

24:55 has to go this wrapped. Because again, you think of the

25:00 right. They make lots of copies genome stuffed into. Okay, so

25:08 of our couples not enough mass Okay, so with the minus RNA

25:15 . Okay, they can do it one step. Right here is minus

25:22 plus. Okay. And but again you think all right, we're gonna

25:28 lots of viral particles. Right. we need to make lots of copies

25:34 this because that's the kind of virus is viruses exiting the host has to

25:40 a minus genome because that's the kind viruses right way to do. It

25:46 to make you have to make more of this as well. Right,

25:50 a minus RNA. But this table only really focusing on how do we

25:56 to the plus? Okay, here , here, here and here.

26:02 I'm just thinking long term. this this minus RNA virus is gonna

26:06 to make our particles. So we pockets of the genome as well.

26:10 , so again, we'll go through this in uh let me talk about

26:17 virus life cycles on right through this thursday. Okay. But I just

26:27 to throw it out there now. kind of get it in your get

26:30 gear screening on. Right. And um any questions? It's gonna think

26:42 it absorb it. I said we'll through this all again on thursday.

26:48 so the retroviruses. Okay uh other unique box if you will.

26:55 So um they're RNA genome is copied D. A. Okay. And

27:03 so the reason for that is why has. What's that we talked about

27:13 time. I think HIV is one those types that does what and it

27:21 the host. Okay so if you're do that you gotta be D.

27:27 . A. Okay. And so actually does that with reverse transcriptase making

27:33 minus D. N. A. . And then it actually uses host

27:37 polymerase to make the double strand. that's what can get integrated to the

27:42 chromosome. So I have to go that step because that's what viruses do

27:48 . You're gonna do that the host double stranded DNA. So you've got

27:53 make a form of that. So what it does. Okay of course

27:58 that it can produce it can use our right to make M.

28:06 And A. And then make viral . Okay so um so looking at

28:14 types, right again you need to this tape. Okay. But just

28:19 you you know diseases that you know diseases that you may be aware of

28:26 papilloma virus. Right. Um chicken DNA viruses, single stranded DNA viruses

28:34 so much in humans but parvovirus you pets uh cats and dogs. Um

28:44 is a bacterial virus here. Um certainly by the RNA viruses. Lots

28:50 that are familiar. Okay. Um west Nile is endemic in this part

28:57 the country. Um Yellow fever and . If you go uh I've seen

29:05 for get vaccinated. You're entering these in latin America especially dengue fever,

29:12 fever. Um Certain countries the polio here minus RNA. Or a lot

29:18 them. Okay flu Ebola. Uh , mumps, rabies familiar with all

29:27 . Right. These are all types coronaviruses. Okay so um retroviruses.

29:34 know those types HIV among them. then these groups this group kind of

29:41 different these are messy plant plant These para retroviruses. Okay so they

29:49 a form of of reverse transcriptase so don't integrate the post genome. Okay

29:57 they have this kind of different way replicating. So they produce an

30:00 N. A. From their uh . N. A. And then

30:05 they basically transcribe. Okay and then is A plus RNA. We can

30:11 viral proteins with that. Okay. reproduction replication and but to make its

30:19 . N. A. It copies R. N. A. Using

30:22 type of birth transcriptase. Okay. make D. N. A.

30:26 it's kind of so retro viruses go you see here right. And this

30:32 what the pere retrovirus does. What see here. Okay. RNA.

30:36 DNA. This one's DNA RNA. to DNA. Retroviruses. Our

30:41 And D. N. A. R. N. A. Back

30:45 Arnie. Okay so it's just a different. Okay um I'm not sure

30:50 they involved that strategy but um these viruses are very used a lot in

30:58 in genetic engineering as vehicles to transfer into plants and things for biotechnology purposes

31:08 yeah a little bit different in terms how they do their replication. Okay

31:15 um. Okay. Alright. Almost done. So the large so I

31:24 put this in there to some very . So we saw the size range

31:31 viruses 20 to 900 nanometers. So is something that's much larger. Micron

31:37 more than that. Okay. These things that typically amoeba large proto

31:46 Okay. But they do have their . N. A viruses they do

31:52 you know a lot of D. . A. One point over a

31:56 base pairs in this one. Um of protein coding genes. Obviously they

32:01 have uh rudimentary metabolisms, right? some amino acids a little bit of

32:09 and lipid metabolism. I'm not sure extensive it is but certainly more so

32:14 your typical virus. Uh Now what these where I come from? It's

32:21 that maybe they were a cell at time that's now just lost a lot

32:26 these functions. And so it has dependent on affecting another cell type because

32:32 that. But are still maybe in to be, you know, maybe

32:39 functions will be lost as time goes . I don't know. But it

32:42 have been something of that kind of . Okay. Um they're not I

32:49 know proportionally how many of these there if there are a significant number but

32:55 they are. I think they're found marine environments typically. Uh But then

33:00 is it is you see here a that's infecting another virus. Okay,

33:08 that's so um the so what can virus beginning from viruses affecting?

33:18 obviously it's getting some function. So these large viruses and they do have

33:25 metabolisms that viruses don't have. So was kind of a mind bender saying

33:34 virus infects another virus. Okay, , it's not something that's very prevalent

33:39 you know, it's it's it's out . Okay, so any questions.

33:48 So last thing we're gonna talk about is just on equality. So I

33:53 earlier last time most of that of viruses were there was no redeeming

34:02 Okay, so other than causing Right. Although they do have certainly

34:06 use in the lab um as a to transfer genes and whatnot. But

34:14 it is shown to be quite um their activity. Okay. So they

34:25 marine environments that have been seen affecting and plankton uh that they can control

34:34 of marine organisms uh microbes in the . And in doing so when you

34:43 control the numbers of populations that allows to kind of thrive as well.

34:49 have one dominant species. You will a lot of diversity. Right?

34:54 if you kind of viral infections can of affect certain types of lower population

34:59 or certain types, you don't get imbalance right? You get more

35:04 And they've seen that. Okay. so when they speak of this viral

35:09 , right? It's a mechanism really byproduct of infecting cells. Okay.

35:17 um of course if you break this you infected cell and cell rises and

35:22 really is the nutrients available to others others to use. And that's kind

35:26 their contribution here. Is that plus kind of controlling population sizes. So

35:32 can see here in this um little here. Right. So we have

35:38 specific to bacterial um put synthesizers, environments, those specific for uh uh

35:48 like algae and plankton. And so infecting them, the that material becoming

35:55 for others to use nutrients, carbon in etcetera. Um but then also

36:02 other micro types to flourish that maybe wouldn't. Okay. And and of

36:08 they don't the viruses themselves don't take population is down to zero.

36:16 Because they're looking all right, So be some types that will be resistant

36:20 the viral infection. Okay, So not talking about taking these things down

36:24 zero. Just reducing numbers. And over time some of the cell types

36:29 resistant to the virus and then it back and forth. And so but

36:33 a way to control numbers. It's way to provide nutrients to the ecosystem

36:37 well. Okay, so um and same thing happens in our gut.

36:43 have viruses that are good that are bacteria in there and and creating the

36:50 pipe controlling population sizes as well. , so so That wraps up part

36:59 . Okay. Life cycles. We'll with bacterial life cycles. And then

37:11 don't understand because in fact the Celtic not as complex right for themselves are

37:18 complex as you carry out. so um any questions before.

37:27 Alright. So this is just a of we talked about before.

37:32 viral life cycles. And so the attachment the genome. So the variations

37:44 didn't step uh so much variation in beginning because recognizing the host and whatever

37:52 type it is about interacting with each on the surface uh genome entry should

37:58 the entire captured which is comedy. animal viruses. Uh bacteria viruses will

38:03 need a genome uh for sentences assembly part of the process. Um And

38:10 is then here is where you can exits where you can have the

38:15 Maybe those that have envelopes, envelopes around them or not. Okay so

38:20 go through specific examples of bio types and see some of the variations in

38:27 steps. Okay so uh let's get question here. Okay so this is

38:35 uh fade out fade or bacterial Um And this is asking about uh

38:45 is following is or are not part the life cycle of a lighting

38:51 Little paralytic page. Okay what's So we're gonna have what they were

39:01 about bacteria or viruses there there's different in terms of how they conduct their

39:10 . Lighting is one of those. let's go ahead and go forward from

40:10 54. Okay. Alright so look the two. Right So E.

40:28 D. Yeah so E. And . Jack. Um So certainly

40:36 B. C. So nature of lighting viruses eventually effect then pretty quickly

40:45 after killing. Uh Of course in middle make lots of viruses. Okay

40:53 let's look at bacteria phage life cycles specific to bacteria. Um Whether you're

41:01 little virus or what we call elissa virus of course ends with recognition.

41:09 . And so bacterial viruses typically have kind of structure. Right? Looks

41:14 the your book calls them tailed Other books call them complex viruses because

41:20 have they have typical capsule structure but they have these other parts to

41:25 Right. And so this actually compresses you see here and in the process

41:32 that D. N. A. bacterial is very common. That that's

41:37 that's the only thing that gets in genome. Everything else stays outside.

41:42 it essentially becomes the protein parts have basically what they call ghosts because they

41:48 have any more just a protein shell husk on the outside of the

41:54 Um Now athletic fage license page. so very versus wait another term for

42:06 pages is what they call virulent. . Try it again here. Same

42:19 virulent. Sorry, try one more . Okay. All right.

42:35 I. R. U. E. N. T. Okay

42:38 there's another name for little viruses um temper. So temper temperate to kind

42:44 go run hot and cold. So stage has a period. It can

42:52 short or long where it's kind of into the host chromosome. Just sitting

42:57 . Okay. Not doing anything. . That's the nature of a license

43:02 stage. Okay so um a pro is what that is called profane.

43:12 what you think, you know, into the host. Okay. And

43:17 gonna show you on the diagram. kind of combines both. So even

43:22 you're a less energetic page and just out eventually you're gonna go into a

43:27 cycle because ultimately you want to make particles. Okay. And the only

43:32 to do that is to go into light cycle. So for less hygienic

43:36 license is part of it as well someone. Right And it's the

43:41 The state of the state of the basically determines how fast it will go

43:46 lighting cycle. Okay, so let's at this here. Um Okay so

43:58 with the little page the try to this move out of the way and

44:07 try it this way. There we . Okay so the light cycle um

44:12 really gonna comprise this part here. so you see the itself um

44:19 I'm sorry. So then we begin right down the host chromosome. Okay

44:28 so our approach and our proteins are um and so very common in in

44:34 virus life cycle. You'll have viral designated as early and late. So

44:41 genes expressed early in the process. later in the process because there's different

44:46 of the lifestyle. You need some proteins early on kind of maybe it's

44:52 enzyme it needs made for it to . Um Later in the cycle it's

44:56 be proteins needed to kind of assemble exit the cell. So it makes

45:01 to kind of differentiate those in terms very important cycle cycle. So you

45:10 see that the host genome eventually is degraded. Right? And so the

45:18 will actually use those nucleotides for fires use those nuclear times to replicate.

45:25 uh you see the assembly of viral and then um exit. And so

45:31 these lighting stage 52 500 particles per okay can be produced. So it

45:39 very rapidly. Um and so you have E coli suspension add a drop

45:49 lighting faith to it 30 minutes. looks clear as water because the cells

45:55 be obliterated and because as soon as exit of course they want to affect

46:01 and more self. Right? It's happen very quick fashion these bacterial

46:06 Okay. And that's that's it for faith. That's all it does.

46:10 what you see in the dash Okay. Um Nice sergeant will at

46:18 point have that as part of the but it also has this part.

46:23 . And so the genome is basically can see it in purple here.

46:32 integrated into the chromosome. Of course cells unaffected. Right? Obviously it

46:39 affected over here. Right? All resources being used eventually to sell

46:44 It kills it. But over here viral genome profile page right, is

46:51 hitching a ride in the chromosome as cell replicates obviously. So there's

46:59 Okay, so obviously all sorts of , you know now how fast these

47:06 grow? Cells grow so many thousands upon thousands themselves. Now carrying each

47:15 a copy of the genome. so that's like a ticking time

47:20 Right? But at some point it's to enter life cycle. That's the

47:26 way to make our apartments. So it will go back into that

47:31 . It's not just it's everything It's not all at once. But

47:36 potentially all the cells that are carrying profane can go into the you get

47:45 lot of faith produced during this So what is the what is the

47:52 thing that kind of controls? Well I stay in misogyny or do I

47:57 into the light cycle? Okay, um if I go into the logic

48:04 , okay, I'm gonna have I'm be creating these. Let me try

48:10 more time here. Going to be um these right here right by particles

48:20 they will want to go right and more cells. Right? So and

48:29 that's the way for the buyer to itself, right to make lots of

48:33 that can then grow and infect more . Make more virus particles. So

48:38 , so knowing that. Okay, that's the success of that. The

48:47 of that requires what when these dudes out, what's got to be around

48:56 hostess? Of course. Right, it's gonna want to do this

49:01 Right? Going to light cycle when potential is there to have lots of

49:06 soldier. Okay, so knowing Alright uh let's look at this

49:14 Okay, I'll come back to Alright, so I hear that.

49:25 right here there it is. okay, there's the question. So

49:33 look at that. Okay, so would promote that was already on its

49:40 , some caffeine or something here. um let me erase this. Okay

49:48 what with the presence of abundant nutrients , promote less so ginny or promote

49:54 cycle? Always virus the traditional Okay, counting down. Okay,

50:46 down. Okay, so it would um so as I mentioned right if

50:55 guys come out okay and they want seek and make sure lots of pushed

51:03 to infect what's gonna make the host happy and lots of nutrients, lots

51:10 nutrients, lots of growth, lots hosts, correct? Right. So

51:17 abundant nutrients would promote going to the cycle. Okay. Um it's wouldn't

51:30 sense for the virus to go to strategy particles if the chances are one

51:37 the poster. Right? In fact would be the case if there were

51:42 know if there were a lack of that it needs to help the host

51:46 are growing that much. Um And the opportunities if it didn't go too

51:52 excites the virus did. But then something that host host, they're too

51:58 . Okay so better to wait. are, it certainly happens to your

52:03 . Right, when you have a they attract attract bacteria viruses that infect

52:09 allies and other bacteria and they see after you've had a meal that there's

52:16 rise in these um landing page, page is the one that does

52:22 Okay and um there's between meals there's reduction right? The virus is kind

52:29 staying staying in that in that estrogenic . Okay then when you get the

52:35 meal is kind of burst you see more of these um landing page appearing

52:40 they've gone to life cycle with the of nutrients between taken in in the

52:46 to grow. Okay. Um Does make any questions about that?

52:53 Okay so. Okay. Yeah. yeah I think this depends obviously they're

53:23 different different viral types. And so herpes virus yeah it forms the blisters

53:31 you're stressed right? But but I'm sure. Yeah so so it's also

53:38 talking about a that on the skin mucous membranes in your mouth and what

53:45 talking about a completely different environment different . And so I think that's probably

53:49 you want to see differences like So but exactly because even with um

53:56 so because of that some of the virus and we're talking about bacterial growth

54:01 ? Which is going to be different herpes virus affecting your own skin cells

54:06 or epithelial cells whatever are gonna be different scenarios in terms of environment.

54:13 it's good question. Good question. other, Yeah you talk about just

54:29 lighting cycle. So life cycle. So we're talking just about the athletic

54:37 like page. Yeah so with bacteria course you have you have lots of

54:56 they're gonna grow. Okay and so you are a Lysa genic virus.

55:03 ? You have two strategies. Okay can stay as a like login or

55:07 can stay go to lighting cycle. . And so their strategy is tied

55:12 really the state of the host Okay. So if you have abundant

55:16 , the host is gonna grow Crazy. Right? That's gonna be

55:19 trigger for the virus to say okay it's time because I can affect lots

55:23 faith come out lots of hosts to . Right? So if it's uh

55:29 lighting virus and does it doesn't do ? Oh geez okay. I mean

55:35 gonna be um uh yeah that that can be limiting for it too.

55:41 I mean like virus does what it it doesn't have any an alternative.

55:45 in fact it's going to go through cycle and kill the cells.

55:50 Now if if if the population it infecting had lots of nutrients and lots

55:56 cells. Right then it's it's a for it. Right? Because now

56:00 doesn't apply to the infection that has of cells in effect or maybe it

56:04 . Right, so there's been a words to infect. So yeah there's

56:09 both ways but for a lot of that only has only one choice in

56:13 make viruses get out and kill Right. So does that make since

56:20 . All right because the lights a one the land of one has a

56:23 of different options here. Okay. and questions. Okay. So

56:32 13. Okay. So we got of age. This is a lie

56:39 . We have faith ages which led psychologically. So m. 13 is

56:45 of a third category. Okay. it's what we call a slow

56:53 Okay. And so it's a type can infect doesn't doesn't form a profile

57:00 . So it doesn't it's not a in the sense of a landing

57:06 It doesn't stays outside of And so can see it. Uh here.

57:14 again, it's a filament. This of age. All right. And

57:20 only the genome enters what you see here. Okay. And it stays

57:24 stays in the in the site is doesn't go into the host genome.

57:29 . And so um but as it as you see here. Okay,

57:37 going through the copy genome. McGraw assemble etcetera. Right? And it

57:43 . Alright, so that's okay on host. Remember there's a continuum

57:51 Right minded virus where the host cell not going to survive at all.

58:00 it can be a complete uh my for the varsity is hanging out indefinitely

58:07 soldiers is healthy and happy keep growing in between. So as long as

58:14 not putting too much of a strain the hook. Right? You're doing

58:21 own kind of thing replicating. Doing . No rain the host. So

58:25 live with that. You can actually along and divide function. Okay.

58:31 would be happy if it wasn't in but it can still survive nonetheless.

58:36 obviously it's gonna have a very different time right? With the virus inside

58:43 minus not the virus of course. . So but that's that's what

58:49 13 does it? Has this slow what slow release means the a life

58:55 that doesn't produce a lot of viral at once. And that doesn't put

58:59 strain on the host. The host still survive and replicate although not as

59:05 as I could without it but nonetheless still replicate. Okay. And so

59:11 what is comparing this with the latex ? Okay. But this M.

59:19 maybe have that the writing phase does was it almost guaranteed of What is

59:32 was M. 13. We must it's not gonna run out of this

59:38 . So it's gonna be So you every generation, right? You see

59:44 cells. Right? And so and be others. But but yeah so

59:50 this this charity means there'll be right? I wouldn't say it is

59:55 , maybe it runs in the area in that kind of blows through all

60:00 they're my host. It has. then what they're gonna do.

60:04 But with M. 13, you less less amount of reproduction. But

60:11 know I always got a host, can be short of infecting a

60:14 Okay so you know different different Okay um Alright so we um so

60:27 course with viral infections and how viruses their thing. Obviously host also has

60:35 right We have mechanisms to counteract a infection. Okay so um and so

60:44 uh and us you know anything that to a viral infection has this as

60:53 option? Okay simply changes occur to surface protein that the virus uses to

61:02 interest. So that's that's a common . Genetic resistance is common among many

61:07 kind of life form that succumbs to infection. So bacteria no different.

61:13 restriction enzymes that's gonna be uniquely Right? You are aware of restriction

61:21 from the D. N. Technology right? How we combine make

61:27 DNA markers using the scissors. The in the nucleus. Is that cleave

61:32 . So uh and of course the used. Common technology all come from

61:40 . Maybe some form of the ones it's those uh they know the bacteria

61:47 use this as their defense against Right? So they modify their own

61:52 modify their own D. N. . Right on on the side of

61:56 scenes typically and by manipulating them and that protects their D. N.

62:01 . From the effects of their nuclear . The viral DNA. Okay.

62:08 one is an example. Right so cut it will recognize the sequence um

62:14 these staggered cuts. Right? So like so okay so it just breaks

62:25 of D. N. A. again if you if you have your

62:28 a zines are methylated right here here the enzyme won't attack it by bacterial

62:37 is protected but the viral DNA is sensitive to it. Okay. Um

62:42 there's hundreds of these things. Different of in the nucleus is now the

62:46 that's I guess the more recent in of discovering as a quasi bacterial immune

62:55 is this CRISPR your knowledge? This probably through more through genetics and using

63:02 as a tool to to fix basically D. N. A. Genes

63:09 humans used of course in that research that purpose. Um But was found

63:16 bacteria as a way in which they kind of remember in a way previous

63:24 infections. Okay. And so CRISPR for these sequences that are put together

63:32 are basically a catalog of prior viral . Okay. So I'm just gonna

63:37 this in kind of bids on the slide here. Okay so we start

63:43 course with viral infection of the And then the first part of the

63:49 is this cast protein this short for . Um so it has a binding

63:57 it can have cleavage ability and so binds to this viral sequence.

64:04 And cleaves out a segment. Okay a segment of nuclear tide clean out

64:11 this viral. Okay then uh that the catalog for that virus. Okay

64:24 gonna store it take that sequence and it in its genome. Okay.

64:29 uh bacterial viruses are generally mostly just . N. A viruses. Right

64:37 we're talking about taking a segment of DNA. Putting in the host

64:41 Okay. And that's what this CRISPR is. It's part of the

64:47 the segment of the host chromosome. it's taking that is occupied by these

64:52 spacer sequences they call them. But of these are Pryor cane originated from

65:02 viral infection. Think of each time virus affects it and it goes through

65:10 process. Okay that it has a a little book on that virus.

65:18 puts it on the shelter library. so that all these are like books

65:23 the previous viral infection. Okay so got that catalog in this part of

65:27 genome. Okay. And so it mobilized right when an infection occurs.

65:37 so we transcribe it into our A. Okay. And then we're

65:41 take those and kind of chop up that they call it. Right process

65:48 transcript into segments. We call the sequences. Okay so again these are

65:54 RNA forms of those DNA segments of viral infections that restored in the

66:03 And now we have RNA forms of little segments. Okay we're going to

66:08 which one of these. Which one these? This one this one this

66:14 is going to be homologous. It's be complementary to the virus that's infecting

66:20 now. Okay and so um if a match right that's what's going

66:26 So you see that cascade protein and with the christmas sequence. We see

66:33 there's a binding take them off. it means that there is that that

66:40 was indeed in this sequence it was by this virus before because it has

66:48 sequence that is complementary to. Okay so the binding leads to basically inactivation

66:55 the virus the viral infection stops. of course the strategy works if like

67:02 said if there was a complimentary segment that region if there wasn't then then

67:10 will likely succumb to that. Um but but that's so it is

67:17 of like a that's what they call , a pseudo quasi new system because

67:22 new system army adapted we have a to we know you know we've been

67:29 by a particular agent before. Right . Your system recognizes it and then

67:38 antibodies to the time is so much way. It's the same thing.

67:44 . Um Any questions? Yeah. . Yeah I think so because it's

67:56 not in terms of the components but in the maybe the function of it

68:00 because you can remember previous viral infection it's stored into that sequence. We

68:07 do the same thing but in a way but it is re recognizing um

68:14 . And so we have a record in our immune system. That's something

68:19 talk about later in the semester. I should go okay of course.

68:26 has a very specificity this caste That's how it's used in human genetics

68:34 kind of fix um mutated genes because able to recognize we can engineer it

68:42 recognize specific sequences. So we can it to recognize a human gene and

68:47 you can use the editing function to of cut out the bad parts put

68:52 place a really good part and hopefully the gene. There's been some uh

68:57 with this. I don't think it's mashed mass market problem. Anyway,

69:03 certainly one of those things uh definitely the future. Um Now you've probably

69:10 about this in genetics class as So here let's look at this

69:14 Okay uh we're gonna switch from transition bacterial viruses, viruses. Okay this

69:23 kind of the intro here. Okay count down from 87. Alright so

70:04 get yeah it's gonna be genome type . RNA. It kind of determines

70:10 we'll go in the cell. Okay um okay so mm bars lifecycle.

70:22 we talked about focus on the Metro is within a hope. How many

70:29 cell types are infected? Right. so we look at broad versus

70:33 Uh this picture showing the binding for virus is on uh preparatory sell these

70:43 are actually present. These are involved binding to cell. So it uses

70:49 to to infect. Um the uh replication cycle? Right? So we

70:58 talked about D. N. A type in large part determines where it

71:03 when it infects a cell. And D. N. A viruses.

71:07 What's so again in the context of viruses And I was strictly talking about

71:13 viruses. Um The where is of they in fact eukaryotic cells and all

71:20 complex structures in eukaryotic cells can be part of the life cycle. So

71:26 the D. N. A virus likely to go? Where the facts

71:30 that like herpes virus or coronavirus? were elected go in the cell because

71:38 it has options right side. Pro cell where there's no structures inside but

71:44 is important eukaryotic cells, right? the nucleus? You're right uh Environment

71:54 . N. A. Is going the nucleus. But what's it going

71:56 find in the so when you replicate ? Right, your chromosomes do this

72:04 the nucleus. Right. They copy . So the DNA proliferates to do

72:11 is in the so that's why DNA typically go there because that's where they'll

72:15 the DNA polymerase to copy their Okay. There's some that do carry

72:19 own but many do not. And very often that's why that's the reason

72:24 going from nucleus is that's what it that we can copy its genome.

72:29 . Um are the viruses we talked this before. Again, that's a

72:35 a virus enzyme, viral enzyme is a host enzyme. Okay, so

72:42 gonna have to have that either express . Uh have the gene for that

72:48 their genome. Okay. Retroviruses we know they're different to integrate into the

72:56 genome. So they're gonna have a transcriptase to do that. So um

73:02 with bacterial viruses, yes, genome everything stays outside. That's pretty much

73:10 standard for bacteria viruses stages. And virus is different strategies. Okay,

73:17 what you see here. So this process is the mechanism by which that

73:23 is released into the cytoplasm. so there's three ways to do

73:29 Okay, so we can basically uh so you see the viral approaches here

73:40 to suffer. And then that envelope uh meld with the self pleasure.

73:51 here is the actual state police. . Um and then genome Captain broken

73:59 GM is released. Right? A or endo zone. Okay, so

74:07 see I believe on a virus and will fuse first commonly use this receptor

74:17 one cholesterol and ourselves enters the same receptor mediated endo psychosis. And so

74:24 virus exploits that receptor and then the forms around it and excuses for the

74:33 own. That's what will digest resolve Captain releasing the genome. Okay.

74:41 for a DNA virus like this guy it can again it can form a

74:48 around it but instead of being released the outside of it it goes to

74:55 nucleus. Right? That's where the first nuclear members. That's typical for

75:03 . Okay. Um but methods of confusion at the time of membrane or

75:12 information or part of the two common of course, whether releases here or

75:22 depends on the virus or DNA Ok folks look finish it there and

75:29 it up next time. Thank Yes. So they initiated by without

76:11 ? Yeah. Yeah, monday, . But that doesn't work. Let

76:31 know if it does work. This a prior infection. Now when it

77:08 this process it will have one of segments that will be able to buy

77:13 it. And so it does and will inaccurate. So basically this process

77:19 successful stops the virus infection, it go any further. Right? It's

77:28 . Right, correct. So it's us if we have were vaccinated,

77:32 ? And so we get vaccinated with virus. So so that now your

77:41 remembers. Right? So next time get infected with that same virus.

77:49 , so it's the same thing. question I answered the wrong thing on

78:01 last question because I put that in proteins. Okay, so like okay

78:17 last part. One more time. it's so I didn't think it was

78:21 because I was like oh bacteria just be DNA or RNA as well.

78:26 why does the genome type matter? because we're talking about the virus.

78:34 the animal virus most bacteria viruses are . N. A. But for

78:38 animal viruses the it's um so we're about the type of life cycle.

78:44 where does it go in the cell effects. So are the viruses do

78:48 typically go to nucleus? They do things outside the nucleus where DNA viruses

78:52 go to the nucleus for you Because preliminary typically and things like that.

78:59 that's what that's referring to. And what it goes one way or the

79:02 is going to be really what kind um does it have? We'll determine

79:07 . Okay so that's because we're talking animal viruses and their structures in eukaryotic

79:13 . Now animal virus can have different . Unlike bacterial virus. And the

79:20 that chooses is mainly the type of , yes. Okay so think of

79:27 less of RNA and DNA and more . Yes. Yes. Yes it's

79:34 of it's kind of yeah it's about does the virus need. Again there's

79:39 exception to these things next time but an RNA virus doesn't need. So

79:45 the point of going to the nucleus virus does for the most part so

79:51 has to go there. Right so kind of what this is. But

79:56 there's there's exceptions because the virus actually . But we're talking about for most

80:04 . this is how it works. always gonna be exceptions, fortunately,

80:10 , okay, okay, so I 11 30 12 30 monday,

80:21 That doesn't

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