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00:10 Student, so you'll understand. Uh Welcome folks. Uh I'm just

00:39 . I had I found out one my colleagues who teaches either this one

00:46 that auditorium across the hall who was victim of these tiktok crank things,

00:54 ? Yeah. Funny if if they're here, I got victimized a couple

00:57 years ago. You're gonna hear a of expletives coming out. I'm out

01:02 violence because I will not tolerate it I will throw them out. All

01:07 , So just, you know, see it don't be shocked, but

01:10 not happening again. It's ridiculous. , um whether I'm 60 years old

01:17 not, I can still get piste enough. It'll get does anybody disagree

01:22 that approach? Okay. We'll All right. Now, back to

01:30 . Okay, you can start. right. So today is heavily uh

01:40 . So it's a flipped class. ? So you guys have your prep

01:43 . Um today is gonna be basically questions. Probably get through 10.

01:49 get through 10, 10 or probably most of them. So,

01:53 , uh so in between the questions even as part of the slide

01:59 they'll be graphics, graphics and stuff will pop up to help explain these

02:06 as we go through. Okay, it's questions a few questions about recapping

02:12 topic, if you've got questions absolutely away, but around the questions will

02:18 the discussion and go through um those one which is today of chapter three

02:26 part two, which is um Okay. So, um so a

02:35 announcements. So I sent this out the email already. Alright earlier uh

02:41 quiz. So weekly quiz will open . So open monday friday through monday

02:46 remember if you're in lab Alright you got a quiz in there and that's

02:52 today through sunday. So thursday sunday friday when you're here you just don't

02:57 confused with the deadline. Okay smart there the first one of those is

03:02 monday. Um Okay so that's all time. So in terms of the

03:06 so remember that the session I. . And the academic honesty it's a

03:14 could uh email a session I. . To somebody outside the room that

03:20 an absolute violation back in the honesty . You rate rules. Okay And

03:28 why would you want to help somebody there? It's not gonna benefit

03:31 Right so and I and the software has waiting to see what's going on

03:38 so it can be detected. So don't do it. How is it

03:42 to benefit you to do That is ridiculous. So just do your own

03:46 and and if you know if they come to class they can't come to

03:51 . Okay just the way it is just it's ridiculous don't even go

03:56 Right okay so Um so as we through uh there'll be 30 seconds per

04:05 but someone a little bit more. there's not a whole lot of reading

04:09 lot of the slides but we're Um it certainly makes for a different

04:14 at least I think more interesting for of us. I hope so.

04:19 we've got to start with a couple things for you and one so I

04:25 want to mention a couple of Um uh I'm not gonna go into

04:31 all the uh proposed hypotheses of how originated on earth. Okay. But

04:40 was having talked about spontaneous generation last , certainly a an event that occurred

04:48 how they typically term it is a biotic um evolution Okay, occurred.

05:01 that was basically the using the molecules would have been present during this

05:08 Uh They would have um interactive For more complex types of molecules,

05:17 , amino acids, right? And done these experiments um simulated early earth

05:24 . They've seen the production of wife's in these mixtures. Okay. Um

05:30 then that a bionic, remember a means without life. So, a

05:34 evolution um gave way them to at point uh molecules that make up

05:41 for example with its self assembled into membrane maybe perhaps, you know,

05:46 in casing uh D. N. . And so you bring along the

05:52 of the cell at some point. . So so antibiotic evolution to biotic

05:58 . Okay. Like I said, lots of ideas about how this

06:03 Um they are actively trying to do in the lab in different ways.

06:08 have created synthetic cells in the Um They've they've taken a bacterial cell

06:14 they basically just emptied it out right behind the shell of the memory.

06:20 then they have constructed D. A. Of specific sequences to code

06:26 what they thought. What they think um the essential molecules needed to begin

06:32 and they generated a cell that could reproduce. So it's not beginnings of

06:39 in the same way as what we're about here but it is something similar

06:44 that. Okay. So have they life as it might have begun on

06:49 Earth? No but they're doing all of things that are kind of all

06:53 it. So it's not the point it's not a crazy idea that this

06:57 have happened. Right? So um so first life is precarious. So

07:03 takeaway here is life on earth of has been dominated by have been around

07:12 longest on this planet. Okay. we occupy like one little snippet down

07:20 right in the whole scheme of we're like one little blip at the

07:24 . So but we've had these pro out sweetly gold for roughly six million

07:32 because we've you know um the last ancestor. And we've had microbes the

07:40 way we've had these microbes in and for six million years. So certainly

07:46 involved with us uh and provide lots benefits to us as it evolved and

07:52 maybe some of those things later. you know something to think about,

07:56 that these microbes in and honest aren't that's new, right? They've been

08:02 with us for millions of years as . So it's no wonder that they

08:07 provide us all kinds of certain things we haven't even begun to think about

08:11 . Okay. Anyway, so the significant thing here, cyanobacteria right?

08:17 formation of 02 in Iran. So to this. So basically here this

08:24 all anaerobic anaerobic environment. Okay. 02. Okay so um the evolution

08:37 cyanobacteria which are photosynthetic bacteria, photosynthesize plants and algae produce oxygen. The

08:46 of oxygen was huge for a number reasons. one and oxygen using metabolism

08:52 evolve. So aerobic metabolism uses more than anaerobic metabolism. More energy means

09:01 make bigger cells bigger organism multi So that that allowed those types to

09:08 eukaryotic cells and multicellular animals etcetera. , increasing complexity. Oxygen also created

09:17 atmosphere on right prior to that life to begin in the sea.

09:22 but bombarded by UV light. Um water can provide protection from that.

09:29 , so you create an atmosphere ozone layer shields us from UV light.

09:36 and and now life can come out water on earth so on. So

09:40 know it the formation of oxygen The kick started a lot of different

09:46 . Okay so um now in terms evidence certainly there's evidence for this from

09:54 . We can very similar to some our own we have on this

10:02 These are actually sign of bacterial types . Um similar to what you see

10:08 the fossil records, Hop annoyed is feature that's in uh precarious membrane.

10:16 much like us, we have cholesterol our membranes, kind of help stabilize

10:22 membrane. Uh They have ha paranoids . But it's a molecule that has

10:27 found in um fossil evidence uh dating billions of years. So there are

10:35 of evidence that that certainly allow us think that pro carrots have been around

10:40 longest not to mention their metabolism. ? So on this early earth environment

10:49 would have been very unstable, very , violent volcanic eruptions, um uh

10:58 , light, uh etcetera. And the presence of not having oxygen around

11:05 a very reduced atmosphere, meaning very rich atmosphere. Okay, compounds like

11:12 would have been prevalent. Okay, oxygen is a very reactive species oxidizes

11:21 . Right? So, when the of oxygen didn't have an environment that's

11:24 like this. Okay. And these provide energy sources from metabolism, we

11:31 right the right, we talked about before. Okay. And so um

11:38 uh in terms of how that's so that trans source here would have

11:44 oxidized those electrons then the electron transport to an except er right, so

11:52 us it's oxygen that serves this role becoming water. Right? For anna

11:59 . They can use things like Okay, gets reduced to nitrite.

12:06 ? And then basically they're breathing with . We break below two and then

12:10 can breathe with something like this. that's how they get energy. So

12:14 that the energy is used to the energy is used to fix

12:18 02. Okay, so that's your um autotrophs. Right. Little

12:25 Same thing. Okay, so, this this is believed to be the

12:30 of microbes metabolisms around in early Okay, so, um so that's

12:39 I wanted to say about origins. kind of summarizes all the stuff we

12:43 about. So any questions? We're switch gears. Go to chapter

12:53 Okay, so remember we're gonna be on quicker questions. Okay, so

12:59 we're gonna do is discuss. That even a question. I get

13:05 Okay, so check the three. we're doing two parts part one is

13:10 approach is kind of from the Okay, so we start with like

13:17 membrane. Right? The nature of what's around the membrane then kind of

13:23 inside the cell. We do that Tuesday. Okay, so we'll cover

13:28 basics of of would possess very much many other cells. But they're going

13:36 be some unique features. You don't other things like plasma for example,

13:41 capsule. Um life in reality. there'll certainly be some unique features for

13:48 . So, very easy check to if you're getting this very simple blank

13:54 of paper, draw your favorite bacterial . Right, Okay. How can

14:01 fill this in? Do I know the parts of the program itself?

14:07 and then proceed to label it. it out, whatever. Right.

14:12 then um that's a good check to that you really are You got

14:16 Okay, So, let's begin with question one. Okay, So,

14:25 is about the definition of the term envelope. Right? What what does

14:31 refer to? Okay. So, at your choices there? Combination of

14:40 . Right? Okay. That's Right, hold on. There we

15:40 . Okay. Sorry. Okay. . Let me put the uh turn

15:46 down a little bit. Um Let put the timer on. Okay.

15:52 about that. I don't know what that. All right, counting down

16:15 98. All right, So, see everybody answered. E if you

16:30 . Uh d you're correct. The envelope is you have to say

16:38 member, define yourself any self. ? The envelope is What's out

16:45 Anything. There's nothing out there that's we call referred to as the

16:54 Yes. What what's beyond the 7000 . Because they I can't see what's

17:08 anything. Anything because you're limited. be anything. Right. Because

17:15 I'm gonna have outer membrane can black negative. You can have a You

17:21 have a cell wall. you can nothing. Okay. Yes.

17:28 Anything that's external to the psychopathic What's out there that defines the envelope

17:35 a second. It can it can absolutely you can be a bacterial cell

17:43 RKO cell that doesn't have anything out . Just think about it as what's

17:51 the psychopathic membrane. What's in the nature? Was that there was anything

17:55 there is nothing out there? The memory. Yes. Right.

18:05 So just relocation. What's going on there and stuff? I can't be

18:18 there'll be something out there. But just talking about what's kind of the

18:21 is that? Is that celebrated positive a typical type of cell that they

18:25 . What's going on out there isn't wall. Does that not like

18:29 Well, all together, that's what focusing on with the envelope.

18:34 I can't explain it any simpler than a society. Remember what's going on

18:38 here? That's the Yeah, because are bacterial types. Mycoplasma that lack

18:46 cell wall completely. So that doesn't a cell wall of course also um

18:57 the member himself but not in the area. Alright let's just go,

19:06 , so um Alright. If the the terms in terms of quantity molecules

19:12 cell the most abundant molecule is what the bacterial cell. Mhm.

19:50 Put the timer on. Okay. up from 10. Yeah, it's

20:20 to be water. So as with living thing, 70% water.

20:25 Water is gonna be the most Yes the inner membrane. Well it

20:34 . So we'll talk about that inner is the same thing as cytoplasmic membrane

20:39 negative. They distinguish between the inner because they have an outer membrane but

20:44 inner membrane is basically the cytoplasmic When you say specifically. What's the

20:55 of what's beyond it? Yeah. . Yeah sure. Um Okay so

21:02 . So in terms of constituents. um pro informational molecules I guess I

21:09 them proteins. R. N. . D. N. A.

21:12 , these are about 25%. Um your lipids and including pepto like

21:22 these comprise oh maybe about 5% or . This is kind of the nature

21:28 the cell wall uh passive membrane. . Uh then after that the amounts

21:36 less Saudi molecular that are present in cytoplasm, various types etcetera. So

21:43 certainly on the numbers basis, water going to be the most predominant um

21:48 . N. A. Is It's essentially in bacteria, a single

21:53 stranded molecule. Okay so but we're here about on the on the michael's

21:59 basis. Okay so um so if look at the light can. Okay

22:09 these values here are for e coli . See here in their average values

22:17 most of these things are about the from bacteria bacteria but some differences.

22:21 of the differences actually right there. like cancer staff the caucus has significantly

22:27 . So if you look at its have more of a detective like hand

22:33 . And why is that this staff to? Oy it's what? Yeah

22:44 . So gram positive will always have pepper. Like an okay because just

22:49 a thicker layer. So uh so will have slightly more elevated amounts of

22:55 of that material. Okay so um so let's now let's talk about a

23:03 bit more about the nature of the . Right? So we'll talk about

23:15 liquid. So we have liquid culture e coli okay incubating at 34

23:22 Right? Uh If you increase the temperature of 42 what would happen?

23:28 here's here's what we look like. what the member looks like. 30

23:32 G. C. Okay so there's be a change upwards okay. To

23:41 you have two choices what looks like . Or B. And of course

23:47 . Coli will adjust not gonna sit and just take whatever. Okay it

23:54 adjust accordingly. Okay and so focus two things. Okay this these and

24:09 interactions the proportions of those interactions. ? You have one type here.

24:18 type here. Right. And you differences below what's the more likely scenario

24:25 to do? Keep this in Right you sell wants to survive.

24:33 . It will um do change in way to enable. Excuse me membrane

24:45 to continue. Right. It's essential membrane must be functioning. So holds

24:51 cell together. South things are transported back and forth. So it's critical

24:58 the survival. So, of course going to adjust temperature right? To

25:03 membrane kidney and function. Okay, keep all that in mind as you

25:09 a choice. Remember in high temp high temp more kinetic energy stuff bouncing

25:19 . Right. What's gonna minimize that around between these molecules? All

25:36 Okay. Um who answered? A , what do you think?

25:53 Yes. Right. Okay. let's go back. Um the elevated

26:04 uh fluidity will get worse. more linkages definitely can in and

26:10 Right. So, how we're gonna that? The only way is to

26:16 the nature of the fossil living by . Right. So there's two parts

26:23 of course, right? There's a that likes water. Right? These

26:28 like to interact with water molecules and polar molecules. This part does not

26:37 hydrophobic. Right? So, the they stick together is through interactions that

26:45 both to come together. Right? a polar part of the molecule

26:51 Remember like likes like fats like fat molecules like polar molecules. So,

27:00 create more interactions between these fatty acid . Because the only way to stick

27:07 is by hydrophobic interaction and it's maximized having points of contact all throughout the

27:14 of the chain that facilitates it. make them straight pack them together that

27:21 of hydrophobic interactions will help keep that together right now. It's not all

27:26 nothing. Don't make it all. that's what we call saturated versus

27:30 Right? These are more unsaturated with little legs sticking out if you

27:39 Okay these things. All right. bonds are coming in creating the

27:45 Okay these that's more saturated when you the chains of flat. Okay removing

27:53 bonds making it saturated, make them let them get all those interactions stick

28:00 . Okay and so as the temperature the proportions all about proportions. So

28:06 not for nothing. The proportions of to unsaturated increase to keep them straight

28:15 together, maintain fluidity. Okay opposite if you go begin to freeze right

28:23 you can compress and lose function that . Right? So he also is

28:29 operable and begin to freeze great Through space. Okay so there's gonna be

28:35 optimal at normal temperatures quote right? 34. So now it's gonna have

28:42 optimal ratio at which the membrane that . So it tries to maintain that

28:47 temperature goes up by altering the proportions saturation, it can also make the

28:53 longer or shorter Um introduced double bonds take them away all depending on 10%

29:01 . The same thing. It's not unique to bacteria. Same thing happens

29:04 all things plants that grow in cold the same thing with their membranes.

29:11 , so um any questions about So maintaining that member of the function

29:20 it's not just all about the fossil but proteins to proteins are stuck inside

29:26 . Okay let's take a look here china. So here is your fossil

29:31 bi layer and there's gonna be various . Here's your hop annoyed. These

29:36 not just the cholesterol, they kind fit in there to maintain the integrity

29:41 the membrane. Um but you have types of proteins like this. Many

29:46 them transport proteins or it could be enzyme. Right, This thing is

29:50 enzyme. Okay, so the functionality the membrane is due to the

29:56 Think of mitochondrial membranes were all that of respiration occur. Right versus cytoplasmic

30:04 . That's you know more about Maybe binding molecules will have.

30:08 you know, it's relatively like a to 1 ratio of proteins to fossil

30:13 . Okay, so the proteins in are very critical of course it helps

30:19 and other functions. Okay, so got to keep everybody happy there.

30:24 . Especially proteins. Okay, so uh so this is just showing a

30:30 of different types of they move this of maddie acids um and you can

30:39 their their uh confirmation saturated, saturated. That's just you know the

30:52 occur as a result of temperature changes often. You can also have this

30:57 in bacteria and archaea as a Ization occurs. You can get a

31:03 propane. These help to straighten it and reinforce it a bit.

31:10 so with our Kia Okay. They what are called ether link um

31:16 So you see the difference here between ester linkage in the back. That's

31:20 we have as well. Okay. so the ether linkage of archaea tends

31:26 be more stable. Okay. And these are very straight chain type

31:32 These cholesterol by ether molecules and can be combined into powers. They can

31:39 like 60 carbons long. Right. are adaptations for our keel profiles and

31:48 thermal files like super elevated tip. right, so you gotta really keep

31:52 memory together at the high temp and kinds of membrane molecules help you do

31:59 . So, files. So um the And there they too can form

32:11 cyclic types of compounds in the chain to kind of help keep it

32:17 increase the length. Kind of stabilize in fact. And I believe the

32:22 Ization is kind of a the feature I don't think that are already do

32:28 are fatty acids. Okay, so now, all right, any questions

32:37 that. Okay. Yeah. Um a combination of both. Both kind

32:50 work together. So saturation and cycle kind of had the same effect or

32:56 together for the same thing to kind keep the change tight and close

32:59 So I'd say bo is kind of happened. Yeah. Um Alright,

33:07 now we get into a little bit transport and moving the molecules. So

33:11 a look at this. Um So got a bacterium in the pond And

33:20 concentration there .1 External is .5. it's but maintaining that concentration uh in

33:35 of the external concentration of sodium. how is it doing that? Um

33:47 the answer may or may not be there. So, the context here

33:59 um So, of course, certainly about growth medium that we'll talk

34:05 Chapter four. You got to bring into heat for example. Right.

34:10 so various times transport processes are involved getting your pumping ions out and other

34:18 . So, there's purposes for different these functions. And so it

34:23 you know, transport. Obviously many them require help through the use of

34:28 proteins. All right, let's count from three 21. Okay,

34:42 they hit help. Okay, what the process going on here? Active

34:48 course. Right. It's all about and don't obviously all these slides are

34:55 be posted after class. So, you're not getting almost written down,

34:58 don't need to because it will be . Um So, it's active transport

35:03 on. And so, remember the of molecules all relates to um concentration

35:13 . Right, going up and Right, So here we are obviously

35:18 from a an area of low concentration high. Okay, and that's what

35:25 call uphill going uphill needs energy and energy in to do this.

35:30 so it's gonna have some kind of using process to pump sodium ions

35:34 Okay, um you go the other downgraded release energy. Right? So

35:42 microbes in the environment certainly we're going be at the mercy of their surroundings

35:47 terms of optimal concentrations of salutes. they'll have to pump in. Someone

35:52 have to be will come out and on the relative concentration gradients. They

35:59 flow in without having use energy, some may have to flow with the

36:03 of energy. Just just depends on what's going on. Okay, so

36:10 let's look at this question. So is um again more transport uh

36:20 So we talk about the movement of , right? Osmosis, right?

36:27 where you use the terms hypo and tonic uh diffusion, movement of molecules

36:33 the membrane, um group translocation type , bases. And then uh the

36:44 below I put into this to introduce concept that we're going to see over

36:51 over again in unit two. And so the protons down here are

36:58 if you can't see it, they're out. Okay. And you can

37:04 the other ones here happened in these . Okay, evaluate if that might

37:16 sense. Okay. Right, let's count down from 10.

37:49 let's see what we got, which false. Okay, um if you

38:02 go through some simple diffusion. Um we got the molecules without eating any

38:09 . That's simple diffusion. They don't a transport. So things like gas

38:16 option C. 02 typically just pass and out of the self help water

38:21 can. It's small enough uh that can do that too. Um contrast

38:29 facilitated diffusion where you need help. . Um group translocation. That definition

38:36 true. It's movement based on like was coming in, they immediately gets

38:43 and that's about the concept of solute move independent of each other.

38:50 I'll show you the side on the page here in a second member and

38:54 gasses basis. That's true as Those can create problems. Internal ph

38:59 go up or down disrupting um cell . And so these can be uh

39:05 inhibitory yourself, these kinds of Right. And e is meant to

39:11 a concept. We're going to talk a lot even to which is this

39:17 of combining coupling, pairing, energy process and energy required process that happens

39:27 the time in metabolism. Right? here we have a proton green is

39:33 very common way bacteria used to to different purposes. Okay, so think

39:41 almost kind of think of it as battery if you will. Okay,

39:45 by pumping protons, you're basically increasing amount of potential energy out there.

39:54 . And you can find is that ? By allowing them to flow back

39:58 their gradient. Right? So that release energy. Okay, so you

40:04 use that for different purposes in this we're using it to fuel the output

40:10 sucrose because that's an uphill process, ? That's requiring energy. So let's

40:15 come up to the energy releasing process protons going down. Okay. This

40:20 actually what you call a this example an anti poor ones going one

40:26 one the other way. Okay, , the alternative here is that they

40:31 do it this way. Well then just um make this the sucrose and

40:37 teepee using process. Well, that's that's not as efficient. Let's just

40:42 the proton gradient to help us do . It's expanding morey tps.

40:48 proton gradients are used all the Whether it's to help transport molecules,

40:55 energy to make a Tps is Right? So even to make a

41:00 . P. S that in itself energy. Okay. That comes from

41:06 radiation. Um moving the foot general proton gradients. So use all over

41:11 place for different purposes because it's already of energy, right? That we

41:16 couple to energy using process. we see that time and again,

41:21 talk about metabolism in the next Okay, so the false answer here

41:26 a okay, so water moves to high solid side moves to the hyper

41:35 side? Okay, basically to have those molecules. Right? That's that's

41:40 movement of water. So for that cells certainly bacterial cells Kia plant cells

41:50 to keep themselves slightly hyper H Y E R. Time. So a

41:57 of water that helps helps maintain their integrity. Right? Plants have a

42:03 cell wall, bacteria and have a wall. So water flows in,

42:08 that membrane against the cell wall and kind of helps keep shape integrity of

42:15 . Um So, if you look some of these uh concepts here,

42:20 here. So yeah, here's your of simple diffusion facilitated those most.

42:28 , so the direction these molecules move and these are examples are strictly based

42:35 the set up of the gradient. high to low Right. Um of

42:42 , active transport processes. We use to move markets public gradient.

42:47 So uh mentioned water can move by through a membrane. Uh Not as

42:59 as it could have been had Okay. But if a cell finds

43:05 finds itself under osmotic stress, whether needs to get rid of water fast

43:11 needs to take in water quickly, can speed things up by using Aqua

43:18 . Okay, these can be quickly in the membrane and that will facilitate

43:22 rapid transfer of water right? There be times maybe the cell find themselves

43:27 an environment that's very low salt outside it concentrates in the cell and it

43:31 too much coming. Maybe these So you can facilitate rapid transfer transfer

43:38 the appearance of these opera porn's which specific for water. Okay. These

43:44 two mechanisms um the translocation mentioned in question. So we have glucose that

43:54 gets trans converted into glucose six So these two species well independent of

44:01 other. Right? So as long you keep converting glucose and you go

44:06 yukos keep moving in. Okay? that weren't the case, if you

44:13 have this happening and that was just coming in like so well, it

44:22 only keep moving in until when when it start moving when they're both equal

44:28 right now for the movement. So gets converted and that allows it to

44:33 coming in. Okay. Um so uh this is basically this formation of

44:41 six phosphate is the first step So it goes right in to

44:47 Similarly with mannitol, the same Okay, so down here a teepee

44:53 very common way, bacterial transport uh other types of molecules that specificity to

45:02 where you'll have a binding protein that with it and then combined with the

45:11 part of the transporter here. And it can be an energy driven

45:15 as you see here to bring in self against this gradient. Okay.

45:21 both of these are very common mechanism bacteria and archaea. And so lastly

45:29 membrane Permian we get these are these be problems problems with um because so

45:41 you recalled you know with strong acids ? Hcl when this um dissolves it's

45:54 engine nine's and chloride ions nature And it's just these are what you

45:59 in solution. You don't see this all it's completely dissociated, right,

46:05 with a weak acid base, partly associates. So you're always gonna see

46:11 three species in solution or similarly over if it's a weak base. Okay

46:19 so one of those that's the problem This one right? That guy uncharged

46:29 so they can slip through the Okay then once inside the cell right

46:35 can disassociate. And so that's when gets sitting inside the cell or if

46:39 a weak base gets basic inside the uh internally so tries to keep ph

46:47 plus or minus half a unit. okay and it gets too much bubble

46:52 and still has to counteract that um buffer is in the cellar. Typically

46:58 acids. These acts to counteract the of acid and base. Um As

47:04 as it's not too much you know too much anything can't can't counteract

47:08 But um this mechanism is really how lot of food preserving this world.

47:16 you may look at a food label you typically see something like citric

47:20 very common food additive. Another one P. A. B.

47:25 For para amino said you see those often as food additives. And so

47:32 have this feature being able to be of these membrane primitive gasses. They

47:37 hit a growth so they get inside cell affect ph and inhibits the growth

47:42 the organism. So it's kind of to be a um you know retard

47:48 spoilage of things. Um Any I'm sorry. Any questions?

48:00 Oh so it had to be hyper cell interior water moves in. Yeah

48:08 moves out. So you remember the hypersonic are relative to each other.

48:14 it's high platonic inside the cell. it's hyper tonic outside. So we're

48:19 to move that way. Not into cell. Okay so those two terms

48:23 always relative to each other. Yeah it's. Oh you're right yeah good

48:40 . Yes introductions inter. Right you're . Interest sailor. Right you're

48:49 Very good. Um Okay. Any questions? Okay so um let's

49:00 Okay so now to sell wall or of it or features of of those

49:09 have it. So I put these putting these two terms in here.

49:14 just just taxonomic names. Right when to them as positive as you can

49:21 there is a big tax group. I've seen these terms pop up on

49:32 an M. Cat or other professional I've seen from accused rodeo bacteria.

49:36 we're gonna throw it in there. you say you've seen it before.

49:41 um but back to the gram stain protects you native. Um there's been

49:52 for since 1900 I think. And it's still hands utility today. It's

49:59 used to this day. It can like initial step in identification right?

50:06 can kind of one or two categories positive gram negative. Although not every

50:12 thing stains gram negative positive. Some variable. Some don't stay with it

50:20 in the nature of the envelope. but many do many do stay with

50:26 uh the gram positive gram negative. and um it can be diagnostic

50:33 So there's not only a used for fee to identify but uh medically medically

50:41 types. It can be diagnostic. it all depends on the nature of

50:46 sample you're getting from the patient right the throat swat is a sample of

50:52 fluid that bathes your spinal for um it from a um a lesion due

51:02 uh some other type of disease. you can look at it and go

51:06 the morphology and what's the gram So a throat swab that gives you

51:13 coxon chains use pre presumptive that streptococcus , strep throat. Right? You

51:19 treat it accordingly with specific antibiotics. a gram negative diplo caucus which is

51:26 it looks like two beans stuck together diplodocus shape and gram negative coming from

51:34 fluid that's negative for meningitis. So a number of these medically important

51:40 you can diagnose simply through gram stain morphology and the microscope. Okay,

51:46 the point is there's still definitely used this today. It is still done

51:50 clinical laps. Okay. Um So gonna be a number of questions that

51:57 to this picture. Okay. So So don't do not. I had

52:08 but then I found out 123456. options on on the app at least

52:13 didn't find it. So so so have the letters here A through

52:19 Indicating different labeled structures. Okay. you have your choices A through

52:25 So just don't confuse this A. A with that they're not related.

52:32 . A. Through F. Or just the choices you're gonna punch on

52:37 about. Okay, they're looking for A. Okay. Timer's going

53:25 counting down 54. Cut to So structure A. Is,

53:40 It is LPS layer. Okay. Let's look at the next one.

53:50 . G what is G. Is to the black black threads black

54:06 Mhm. Okay. Alright, calm . Uh It is B. That

54:57 correct. Tai kok acids and let's a look at this one. We'll

55:04 all this here shortly. Alright so it up a little bit. So

55:09 label represents lipoprotein. Okay, represents protein. Okay, so again,

55:25 , focus focus on these. If you think it's aged then pick

55:58 . I think we got one more this. Mm hmm. Yeah,

56:23 is. Uh that is liberal right? That is correct. This

56:30 there. Okay. And finally. , um which contains in a seal

56:41 acid. Okay, Okay. I'm start counting down from three.

57:22 Okay, so, yep, it g Okay, so um I think

57:31 all figured out by now. I'm that the type one is the

57:38 What negative? Of course? negative gram positive. Can I?

57:46 um and then uh this is the one. Is is not clear

57:51 but I'll post this as well. of it as like a checklist here

57:57 of all the different structures and the . Okay, so, you

58:03 it's kind of use it as a . What where when it is.

58:11 um a little bit of recap here so all of course is not like

58:21 plant cell wall. Similar in that have to provide protection. Was maintaining

58:27 in the cell. It kind of hand in hand with hypersonic interior water

58:32 in pressing against that cell wall integrity . Think of a balloon in a

58:39 box, right? You put more up against that box helping to reinforce

58:44 . So kind of similar principle. , so the structure itself. Pepito

58:52 like hand sugar. Right? So peptide combination um it's synthesized as a

59:00 strain palmer that wraps around the Okay. Much like this.

59:07 where? of course this would be rod shaped cell obviously that would be

59:11 inside here and um the the two sugars nsc was posted in Tennessee.

59:20 acid. This is the one where cross bridges form. And so that's

59:28 the peptide sequence comes in. right here these so these are all

59:35 between the ceramic acid residues. And of course the number of antibiotics,

59:44 targets are different parts of synthesis of cell wall. There's a lot of

59:49 involved in synthesizing this enzymes and many those targets with different antibiotics like penicillin

59:56 amoxicillin, ampicillin etcetera. Okay. so what the state so don't think

60:04 the people of like and it's like like a brick wall around the south

60:08 actually very flexible. Is it's Okay, it's quite porous. Um

60:15 the cross bridging is really uh maintains integrity of the cell wall. So

60:22 you interfere with the cross bridging then whole thing kind of destabilizes right

60:28 What actually ends up happening is the of plastic membrane underneath begins to bubble

60:34 right and can actually lice. Okay that's really the action of antibiotic that

60:41 . So authentic sis is to basically lights the sell by destabilizing that cell

60:47 . Okay so um the we mentioned osmotic pressure and helps to maintain

60:55 Um Okay so the connection. So unique. So the peptide sequence

61:01 It can vary from species to It may not be I'll be identical

61:07 there will be some sort of a sequence that the cross bridge. This

61:11 a common sequence. Um The acid an unusual amino acid version. Okay

61:20 it's where the connection is made. cross breeding occurs so it looks something

61:24 this. So what you have before cross bridge forms one of the strands

61:30 to al means here. Okay and the connection is made, one of

61:38 terminal airlines is let go now you across bridge. Okay so as mentioned

61:46 so penicillin uh there's a target for wall synthesis. Um There's gonna be

61:53 . Banco mason is one that will uh actually bind here. So Vanco

62:02 sits here and in doing so prevents cross bridging from current, basically blocking

62:09 action of the enzyme to be able bind and create the cross bridge.

62:13 and so that of course weakens the wall and cell death. Um uh

62:20 counteraction how bacteria evolve resistance to Right? Well the penicillin, one

62:26 the ways is to simply just have enzyme that breaks apart penicillin. penicillin

62:36 very there's a lot of rings to . And so the kind of leaves

62:41 rings and destroys the penicillin. Um one mechanism um What what might be

62:49 mechanism that soviet commission sits here and cross bridging. How might a resistant

62:59 . What might it evolve to counteract any I. D. You so

63:06 have a single mutation and this might in the bacteria and this is what

63:10 it to be resistant to cross bridging somewhere else. So it changes some

63:23 kind of chemical. Right? So could be I think I've seen certain

63:27 will have a mutation instead of having een at the terminal allen it's a

63:35 lactic acid. Um And that of is not recognized by bank of so

63:40 can't sit there. And so um not become resistant. Okay so um

63:50 and the sure of the cell walls we have negative side by side.

63:59 starting from the bottom up right this gonna be comin structure. So we

64:05 to the inner membrane here because the negative has an outer membrane.

64:11 But this is the cytoplasmic membrane. . And so uh but then of

64:18 differences occur as we go up. so the grand positive right will have

64:25 thick layer of peptidoglycan, several layers um but reinforced by these strands of

64:37 a gas. It. Right so anybody's familiar with construction and making a

64:44 you often put rebar long uh metal in the concrete and reinforce it very

64:51 to what's going on here. Okay that not only reinforces the pepper like

64:56 but allows it to connect to the membrane? So kind of holding it

65:02 place as well. Okay beyond that can have an s layer. We'll

65:07 about that in a second. Um and then you may have other

65:13 these sugar molecules out here. Um now gram negative. I look

65:19 this as kind of oreo cookie is very negative. The ramp positive is

65:26 oreo cookie with the lid off. , so you saw the white layer

65:30 one cookie but you're missing. The negative has all of it.

65:37 So they have the inner membrane outer . And that space in between which

65:41 what we call the para plasm or plasmid space. That's just the space

65:47 between these two membranes. Um that area can have different types of enzymes

65:55 proteins in it as well. Um it also contains the petrol of like

66:01 Okay, which again is very much compared to gram positive. Uh It

66:08 is connected held in place to the membrane as you see here by these

66:16 lipoproteins. Right? So that's what it with the cell wall of gram

66:21 to memory, right? In this the outer membrane. And so uh

66:27 if you look at both halves of outer membrane, they're both different.

66:33 ? You can see on the inner you have muscle lipid molecules of

66:38 But on the outer half in addition that you have these L.

66:43 S lam lps for lippo party Okay. Um as well as of

66:51 fossil olympics but clearly different from the side of the membrane and of course

66:56 that helped transport. So um generally the outer membrane molecules at eight transport

67:05 not as specific as it is when get to the inner membrane a little

67:10 more selective. So um but nonetheless different. Um look to it from

67:19 to grant positive. Okay. And um looking at uh so all in

67:29 is fairly porous. Uh remember the was somewhat porous. It does have

67:36 transport proteins. It's just not as . Um the antitoxin effect. Okay

67:44 we're looking at uh this portion of LPS there. So this is what

67:49 looking at here is basically let's go one. Is this part?

67:57 This part and specifically this part it's the lipid a material as we see

68:04 . Okay so that part can have we call indo toxin activity.

68:11 And so that's an issue for you basically every gram negative potentially has

68:19 But the ones that are concerned are that are infectious disease causing gram

68:24 Okay because in the course of treatment have such an infection and you administer

68:32 that will kill the cells. Well that's now you risk a potential of

68:37 these these molecules. Right? Because are part of the cell membrane outer

68:42 and they're only released when the cell and license. Okay now generally that

68:48 of effect is of most concern if infection has advanced it's like gotten into

68:58 that means it's in your blood and these this endo pox and interact with

69:04 immune system selves. And and if traveling through your blood that means it

69:09 encounter many many more immune system selves it would if the infection will localized

69:16 a certain part of your body and sitting there okay involving more of your

69:22 system selves, it creates a super response. You throw out all kinds

69:27 chemicals called cytokines and these these different in your body and the bottom result

69:33 your body gets overwhelmed and you can into shock and die. Okay again

69:39 most serious when it's a gram negative has got into your blood if you

69:43 it before that point it's a local . Generally no problem but he can

69:50 serious depending on if the infection gets . Okay, so as a consideration

69:54 different antibiotics you can use to counteract effect without having to really send a

69:59 . So it may it may come that depending on how severe the infection

70:03 . Okay um now these other components . The old policy Sacha ride.

70:10 , so this is an example of old palace aka ride here repeating units

70:16 various sugars. Okay um also shown . Okay, now the the also

70:26 the old engine. Right? We'll about H engine next time which relates

70:30 the and the importance of these is really in identification of medically important.

70:41 really of like E. Coli salmonella similar foodborne agents that cause foodborne

70:50 Like 157 is one of the famous . I I call it the Chipotle

70:54 . Coli because chipotle linked a number outbreaks uh laminated lettuce I think um

71:02 to 157 it's it's a pathogen. And you can quickly identify it based

71:08 the type of O engine. This has 0157. So there's numbered

71:14 Uh it's true and we have antibodies these different engine versions and we figured

71:20 out a long time ago but we those antibodies that we can rapidly identify

71:25 types of pathogens. Okay. Um so the H. Is just the

71:29 that that that interacts with the jell . Okay so um another thing about

71:36 outer membrane. So as mentioned before para plastic in the space between me

71:40 remember you can have its own unique with specific enzymes and things. But

71:46 negative gram positive. So when you're at effects of say like antibiotics or

71:56 antimicrobial agents, okay you always do a gram negative gram positive because they

72:02 have different can have different responses. that outer membrane can be a depending

72:10 your chemical nature of the antibiotic it penetrates right? Um in some cases

72:18 there's always gonna be sometimes there will differences And so um I need to

72:22 aware of you have a gram positive negative infection because the choice of antibiotic

72:26 be influenced by that. Okay so now the S layer so the S

72:37 Is um think of that. Well one it's it's been hard to pin

72:47 functions of it because it's a feature the cell loses once you've cultured

72:53 So you think you're looking at a culture and then you have to kind

72:57 maintain it transferring it periodically to fresh and in that process it can lose

73:04 DS layer. So that's kind of to be a problem and trying to

73:08 down the function of it. But of the s there is kind of

73:11 a net a net of proteins around cell wall. Okay, it's

73:18 Okay. But there is some evidence suggest in some types that may assist

73:25 maybe attachment. In some cases they see maybe it can be a virulence

73:31 that important causing disease. But these are here and they're not it's not

73:37 a widespread thing. So uh still elusive and trying to nail down the

73:42 but nonetheless it is visible as you see from electron micro graphs but in

73:47 of kind of determine functional structure has proved elusive in many cases due to

73:53 feature of losing this. Okay But , it is a feature of gram

73:58 . Okay? Um are there any ? But please stop, Please?

74:09 stop. So, um, so pick it up and finish up and

74:14 get into part two Tuesday. So a good one books. We'll see

74:20 next

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