| 00:10 | Student, so you'll understand. Uh Welcome folks. Uh I'm just |
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| 00:39 | . I had I found out one my colleagues who teaches either this one |
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| 00:46 | that auditorium across the hall who was victim of these tiktok crank things, |
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| 00:54 | ? Yeah. Funny if if they're here, I got victimized a couple |
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| 00:57 | years ago. You're gonna hear a of expletives coming out. I'm out |
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| 01:02 | violence because I will not tolerate it I will throw them out. All |
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| 01:07 | , So just, you know, see it don't be shocked, but |
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| 01:10 | not happening again. It's ridiculous. , um whether I'm 60 years old |
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| 01:17 | not, I can still get piste enough. It'll get does anybody disagree |
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| 01:22 | that approach? Okay. We'll All right. Now, back to |
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| 01:30 | . Okay, you can start. right. So today is heavily uh |
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| 01:40 | . So it's a flipped class. ? So you guys have your prep |
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| 01:43 | . Um today is gonna be basically questions. Probably get through 10. |
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| 01:49 | get through 10, 10 or probably most of them. So, |
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| 01:53 | , uh so in between the questions even as part of the slide |
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| 01:59 | they'll be graphics, graphics and stuff will pop up to help explain these |
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| 02:06 | as we go through. Okay, it's questions a few questions about recapping |
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| 02:12 | topic, if you've got questions absolutely away, but around the questions will |
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| 02:18 | the discussion and go through um those one which is today of chapter three |
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| 02:26 | part two, which is um Okay. So, um so a |
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| 02:35 | announcements. So I sent this out the email already. Alright earlier uh |
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| 02:41 | quiz. So weekly quiz will open . So open monday friday through monday |
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| 02:46 | remember if you're in lab Alright you got a quiz in there and that's |
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| 02:52 | today through sunday. So thursday sunday friday when you're here you just don't |
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| 02:57 | confused with the deadline. Okay smart there the first one of those is |
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| 03:02 | monday. Um Okay so that's all time. So in terms of the |
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| 03:06 | so remember that the session I. . And the academic honesty it's a |
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| 03:14 | could uh email a session I. . To somebody outside the room that |
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| 03:20 | an absolute violation back in the honesty . You rate rules. Okay And |
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| 03:28 | why would you want to help somebody there? It's not gonna benefit |
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| 03:31 | Right so and I and the software has waiting to see what's going on |
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| 03:38 | so it can be detected. So don't do it. How is it |
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| 03:42 | to benefit you to do That is ridiculous. So just do your own |
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| 03:46 | and and if you know if they come to class they can't come to |
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| 03:51 | . Okay just the way it is just it's ridiculous don't even go |
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| 03:56 | Right okay so Um so as we through uh there'll be 30 seconds per |
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| 04:05 | but someone a little bit more. there's not a whole lot of reading |
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| 04:09 | lot of the slides but we're Um it certainly makes for a different |
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| 04:14 | at least I think more interesting for of us. I hope so. |
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| 04:19 | we've got to start with a couple things for you and one so I |
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| 04:25 | want to mention a couple of Um uh I'm not gonna go into |
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| 04:31 | all the uh proposed hypotheses of how originated on earth. Okay. But |
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| 04:40 | was having talked about spontaneous generation last , certainly a an event that occurred |
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| 04:48 | how they typically term it is a biotic um evolution Okay, occurred. |
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| 05:01 | that was basically the using the molecules would have been present during this |
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| 05:08 | Uh They would have um interactive For more complex types of molecules, |
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| 05:17 | , amino acids, right? And done these experiments um simulated early earth |
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| 05:24 | . They've seen the production of wife's in these mixtures. Okay. Um |
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| 05:30 | then that a bionic, remember a means without life. So, a |
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| 05:34 | evolution um gave way them to at point uh molecules that make up |
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| 05:41 | for example with its self assembled into membrane maybe perhaps, you know, |
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| 05:46 | in casing uh D. N. . And so you bring along the |
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| 05:52 | of the cell at some point. . So so antibiotic evolution to biotic |
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| 05:58 | . Okay. Like I said, lots of ideas about how this |
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| 06:03 | Um they are actively trying to do in the lab in different ways. |
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| 06:08 | have created synthetic cells in the Um They've they've taken a bacterial cell |
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| 06:14 | they basically just emptied it out right behind the shell of the memory. |
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| 06:20 | then they have constructed D. A. Of specific sequences to code |
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| 06:26 | what they thought. What they think um the essential molecules needed to begin |
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| 06:32 | and they generated a cell that could reproduce. So it's not beginnings of |
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| 06:39 | in the same way as what we're about here but it is something similar |
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| 06:44 | that. Okay. So have they life as it might have begun on |
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| 06:49 | Earth? No but they're doing all of things that are kind of all |
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| 06:53 | it. So it's not the point it's not a crazy idea that this |
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| 06:57 | have happened. Right? So um so first life is precarious. So |
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| 07:03 | takeaway here is life on earth of has been dominated by have been around |
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| 07:12 | longest on this planet. Okay. we occupy like one little snippet down |
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| 07:20 | right in the whole scheme of we're like one little blip at the |
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| 07:24 | . So but we've had these pro out sweetly gold for roughly six million |
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| 07:32 | because we've you know um the last ancestor. And we've had microbes the |
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| 07:40 | way we've had these microbes in and for six million years. So certainly |
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| 07:46 | involved with us uh and provide lots benefits to us as it evolved and |
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| 07:52 | maybe some of those things later. you know something to think about, |
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| 07:56 | that these microbes in and honest aren't that's new, right? They've been |
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| 08:02 | with us for millions of years as . So it's no wonder that they |
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| 08:07 | provide us all kinds of certain things we haven't even begun to think about |
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| 08:11 | . Okay. Anyway, so the significant thing here, cyanobacteria right? |
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| 08:17 | formation of 02 in Iran. So to this. So basically here this |
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| 08:24 | all anaerobic anaerobic environment. Okay. 02. Okay so um the evolution |
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| 08:37 | cyanobacteria which are photosynthetic bacteria, photosynthesize plants and algae produce oxygen. The |
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| 08:46 | of oxygen was huge for a number reasons. one and oxygen using metabolism |
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| 08:52 | evolve. So aerobic metabolism uses more than anaerobic metabolism. More energy means |
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| 09:01 | make bigger cells bigger organism multi So that that allowed those types to |
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| 09:08 | eukaryotic cells and multicellular animals etcetera. , increasing complexity. Oxygen also created |
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| 09:17 | atmosphere on right prior to that life to begin in the sea. |
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| 09:22 | but bombarded by UV light. Um water can provide protection from that. |
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| 09:29 | , so you create an atmosphere ozone layer shields us from UV light. |
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| 09:36 | and and now life can come out water on earth so on. So |
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| 09:40 | know it the formation of oxygen The kick started a lot of different |
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| 09:46 | . Okay so um now in terms evidence certainly there's evidence for this from |
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| 09:54 | . We can very similar to some our own we have on this |
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| 10:02 | These are actually sign of bacterial types . Um similar to what you see |
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| 10:08 | the fossil records, Hop annoyed is feature that's in uh precarious membrane. |
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| 10:16 | much like us, we have cholesterol our membranes, kind of help stabilize |
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| 10:22 | membrane. Uh They have ha paranoids . But it's a molecule that has |
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| 10:27 | found in um fossil evidence uh dating billions of years. So there are |
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| 10:35 | of evidence that that certainly allow us think that pro carrots have been around |
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| 10:40 | longest not to mention their metabolism. ? So on this early earth environment |
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| 10:49 | would have been very unstable, very , violent volcanic eruptions, um uh |
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| 10:58 | , light, uh etcetera. And the presence of not having oxygen around |
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| 11:05 | a very reduced atmosphere, meaning very rich atmosphere. Okay, compounds like |
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| 11:12 | would have been prevalent. Okay, oxygen is a very reactive species oxidizes |
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| 11:21 | . Right? So, when the of oxygen didn't have an environment that's |
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| 11:24 | like this. Okay. And these provide energy sources from metabolism, we |
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| 11:31 | right the right, we talked about before. Okay. And so um |
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| 11:38 | uh in terms of how that's so that trans source here would have |
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| 11:44 | oxidized those electrons then the electron transport to an except er right, so |
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| 11:52 | us it's oxygen that serves this role becoming water. Right? For anna |
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| 11:59 | . They can use things like Okay, gets reduced to nitrite. |
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| 12:06 | ? And then basically they're breathing with . We break below two and then |
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| 12:10 | can breathe with something like this. that's how they get energy. So |
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| 12:14 | that the energy is used to the energy is used to fix |
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| 12:18 | 02. Okay, so that's your um autotrophs. Right. Little |
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| 12:25 | Same thing. Okay, so, this this is believed to be the |
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| 12:30 | of microbes metabolisms around in early Okay, so, um so that's |
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| 12:39 | I wanted to say about origins. kind of summarizes all the stuff we |
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| 12:43 | about. So any questions? We're switch gears. Go to chapter |
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| 12:53 | Okay, so remember we're gonna be on quicker questions. Okay, so |
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| 12:59 | we're gonna do is discuss. That even a question. I get |
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| 13:05 | Okay, so check the three. we're doing two parts part one is |
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| 13:10 | approach is kind of from the Okay, so we start with like |
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| 13:17 | membrane. Right? The nature of what's around the membrane then kind of |
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| 13:23 | inside the cell. We do that Tuesday. Okay, so we'll cover |
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| 13:28 | basics of of would possess very much many other cells. But they're going |
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| 13:36 | be some unique features. You don't other things like plasma for example, |
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| 13:41 | capsule. Um life in reality. there'll certainly be some unique features for |
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| 13:48 | . So, very easy check to if you're getting this very simple blank |
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| 13:54 | of paper, draw your favorite bacterial . Right, Okay. How can |
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| 14:01 | fill this in? Do I know the parts of the program itself? |
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| 14:07 | and then proceed to label it. it out, whatever. Right. |
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| 14:12 | then um that's a good check to that you really are You got |
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| 14:16 | Okay, So, let's begin with question one. Okay, So, |
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| 14:25 | is about the definition of the term envelope. Right? What what does |
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| 14:31 | refer to? Okay. So, at your choices there? Combination of |
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| 14:40 | . Right? Okay. That's Right, hold on. There we |
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| 15:40 | . Okay. Sorry. Okay. . Let me put the uh turn |
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| 15:46 | down a little bit. Um Let put the timer on. Okay. |
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| 15:52 | about that. I don't know what that. All right, counting down |
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| 16:15 | 98. All right, So, see everybody answered. E if you |
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| 16:30 | . Uh d you're correct. The envelope is you have to say |
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| 16:38 | member, define yourself any self. ? The envelope is What's out |
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| 16:45 | Anything. There's nothing out there that's we call referred to as the |
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| 16:54 | Yes. What what's beyond the 7000 . Because they I can't see what's |
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| 17:08 | anything. Anything because you're limited. be anything. Right. Because |
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| 17:15 | I'm gonna have outer membrane can black negative. You can have a You |
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| 17:21 | have a cell wall. you can nothing. Okay. Yes. |
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| 17:28 | Anything that's external to the psychopathic What's out there that defines the envelope |
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| 17:35 | a second. It can it can absolutely you can be a bacterial cell |
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| 17:43 | RKO cell that doesn't have anything out . Just think about it as what's |
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| 17:51 | the psychopathic membrane. What's in the nature? Was that there was anything |
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| 17:55 | there is nothing out there? The memory. Yes. Right. |
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| 18:05 | So just relocation. What's going on there and stuff? I can't be |
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| 18:18 | there'll be something out there. But just talking about what's kind of the |
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| 18:21 | is that? Is that celebrated positive a typical type of cell that they |
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| 18:25 | . What's going on out there isn't wall. Does that not like |
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| 18:29 | Well, all together, that's what focusing on with the envelope. |
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| 18:34 | I can't explain it any simpler than a society. Remember what's going on |
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| 18:38 | here? That's the Yeah, because are bacterial types. Mycoplasma that lack |
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| 18:46 | cell wall completely. So that doesn't a cell wall of course also um |
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| 18:57 | the member himself but not in the area. Alright let's just go, |
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| 19:06 | , so um Alright. If the the terms in terms of quantity molecules |
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| 19:12 | cell the most abundant molecule is what the bacterial cell. Mhm. |
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| 19:50 | Put the timer on. Okay. up from 10. Yeah, it's |
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| 20:20 | to be water. So as with living thing, 70% water. |
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| 20:25 | Water is gonna be the most Yes the inner membrane. Well it |
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| 20:34 | . So we'll talk about that inner is the same thing as cytoplasmic membrane |
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| 20:39 | negative. They distinguish between the inner because they have an outer membrane but |
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| 20:44 | inner membrane is basically the cytoplasmic When you say specifically. What's the |
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| 20:55 | of what's beyond it? Yeah. . Yeah sure. Um Okay so |
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| 21:02 | . So in terms of constituents. um pro informational molecules I guess I |
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| 21:09 | them proteins. R. N. . D. N. A. |
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| 21:12 | , these are about 25%. Um your lipids and including pepto like |
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| 21:22 | these comprise oh maybe about 5% or . This is kind of the nature |
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| 21:28 | the cell wall uh passive membrane. . Uh then after that the amounts |
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| 21:36 | less Saudi molecular that are present in cytoplasm, various types etcetera. So |
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| 21:43 | certainly on the numbers basis, water going to be the most predominant um |
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| 21:48 | . N. A. Is It's essentially in bacteria, a single |
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| 21:53 | stranded molecule. Okay so but we're here about on the on the michael's |
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| 21:59 | basis. Okay so um so if look at the light can. Okay |
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| 22:09 | these values here are for e coli . See here in their average values |
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| 22:17 | most of these things are about the from bacteria bacteria but some differences. |
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| 22:21 | of the differences actually right there. like cancer staff the caucus has significantly |
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| 22:27 | . So if you look at its have more of a detective like hand |
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| 22:33 | . And why is that this staff to? Oy it's what? Yeah |
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| 22:44 | . So gram positive will always have pepper. Like an okay because just |
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| 22:49 | a thicker layer. So uh so will have slightly more elevated amounts of |
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| 22:55 | of that material. Okay so um so let's now let's talk about a |
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| 23:03 | bit more about the nature of the . Right? So we'll talk about |
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| 23:15 | liquid. So we have liquid culture e coli okay incubating at 34 |
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| 23:22 | Right? Uh If you increase the temperature of 42 what would happen? |
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| 23:28 | here's here's what we look like. what the member looks like. 30 |
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| 23:32 | G. C. Okay so there's be a change upwards okay. To |
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| 23:41 | you have two choices what looks like . Or B. And of course |
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| 23:47 | . Coli will adjust not gonna sit and just take whatever. Okay it |
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| 23:54 | adjust accordingly. Okay and so focus two things. Okay this these and |
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| 24:09 | interactions the proportions of those interactions. ? You have one type here. |
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| 24:18 | type here. Right. And you differences below what's the more likely scenario |
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| 24:25 | to do? Keep this in Right you sell wants to survive. |
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| 24:33 | . It will um do change in way to enable. Excuse me membrane |
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| 24:45 | to continue. Right. It's essential membrane must be functioning. So holds |
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| 24:51 | cell together. South things are transported back and forth. So it's critical |
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| 24:58 | the survival. So, of course going to adjust temperature right? To |
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| 25:03 | membrane kidney and function. Okay, keep all that in mind as you |
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| 25:09 | a choice. Remember in high temp high temp more kinetic energy stuff bouncing |
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| 25:19 | . Right. What's gonna minimize that around between these molecules? All |
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| 25:36 | Okay. Um who answered? A , what do you think? |
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| 25:53 | Yes. Right. Okay. let's go back. Um the elevated |
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| 26:04 | uh fluidity will get worse. more linkages definitely can in and |
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| 26:10 | Right. So, how we're gonna that? The only way is to |
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| 26:16 | the nature of the fossil living by . Right. So there's two parts |
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| 26:23 | of course, right? There's a that likes water. Right? These |
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| 26:28 | like to interact with water molecules and polar molecules. This part does not |
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| 26:37 | hydrophobic. Right? So, the they stick together is through interactions that |
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| 26:45 | both to come together. Right? a polar part of the molecule |
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| 26:51 | Remember like likes like fats like fat molecules like polar molecules. So, |
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| 27:00 | create more interactions between these fatty acid . Because the only way to stick |
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| 27:07 | is by hydrophobic interaction and it's maximized having points of contact all throughout the |
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| 27:14 | of the chain that facilitates it. make them straight pack them together that |
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| 27:21 | of hydrophobic interactions will help keep that together right now. It's not all |
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| 27:26 | nothing. Don't make it all. that's what we call saturated versus |
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| 27:30 | Right? These are more unsaturated with little legs sticking out if you |
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| 27:39 | Okay these things. All right. bonds are coming in creating the |
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| 27:45 | Okay these that's more saturated when you the chains of flat. Okay removing |
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| 27:53 | bonds making it saturated, make them let them get all those interactions stick |
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| 28:00 | . Okay and so as the temperature the proportions all about proportions. So |
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| 28:06 | not for nothing. The proportions of to unsaturated increase to keep them straight |
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| 28:15 | together, maintain fluidity. Okay opposite if you go begin to freeze right |
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| 28:23 | you can compress and lose function that . Right? So he also is |
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| 28:29 | operable and begin to freeze great Through space. Okay so there's gonna be |
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| 28:35 | optimal at normal temperatures quote right? 34. So now it's gonna have |
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| 28:42 | optimal ratio at which the membrane that . So it tries to maintain that |
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| 28:47 | temperature goes up by altering the proportions saturation, it can also make the |
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| 28:53 | longer or shorter Um introduced double bonds take them away all depending on 10% |
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| 29:01 | . The same thing. It's not unique to bacteria. Same thing happens |
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| 29:04 | all things plants that grow in cold the same thing with their membranes. |
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| 29:11 | , so um any questions about So maintaining that member of the function |
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| 29:20 | it's not just all about the fossil but proteins to proteins are stuck inside |
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| 29:26 | . Okay let's take a look here china. So here is your fossil |
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| 29:31 | bi layer and there's gonna be various . Here's your hop annoyed. These |
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| 29:36 | not just the cholesterol, they kind fit in there to maintain the integrity |
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| 29:41 | the membrane. Um but you have types of proteins like this. Many |
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| 29:46 | them transport proteins or it could be enzyme. Right, This thing is |
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| 29:50 | enzyme. Okay, so the functionality the membrane is due to the |
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| 29:56 | Think of mitochondrial membranes were all that of respiration occur. Right versus cytoplasmic |
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| 30:04 | . That's you know more about Maybe binding molecules will have. |
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| 30:08 | you know, it's relatively like a to 1 ratio of proteins to fossil |
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| 30:13 | . Okay, so the proteins in are very critical of course it helps |
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| 30:19 | and other functions. Okay, so got to keep everybody happy there. |
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| 30:24 | . Especially proteins. Okay, so uh so this is just showing a |
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| 30:30 | of different types of they move this of maddie acids um and you can |
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| 30:39 | their their uh confirmation saturated, saturated. That's just you know the |
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| 30:52 | occur as a result of temperature changes often. You can also have this |
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| 30:57 | in bacteria and archaea as a Ization occurs. You can get a |
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| 31:03 | propane. These help to straighten it and reinforce it a bit. |
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| 31:10 | so with our Kia Okay. They what are called ether link um |
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| 31:16 | So you see the difference here between ester linkage in the back. That's |
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| 31:20 | we have as well. Okay. so the ether linkage of archaea tends |
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| 31:26 | be more stable. Okay. And these are very straight chain type |
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| 31:32 | These cholesterol by ether molecules and can be combined into powers. They can |
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| 31:39 | like 60 carbons long. Right. are adaptations for our keel profiles and |
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| 31:48 | thermal files like super elevated tip. right, so you gotta really keep |
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| 31:52 | memory together at the high temp and kinds of membrane molecules help you do |
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| 31:59 | . So, files. So um the And there they too can form |
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| 32:11 | cyclic types of compounds in the chain to kind of help keep it |
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| 32:17 | increase the length. Kind of stabilize in fact. And I believe the |
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| 32:22 | Ization is kind of a the feature I don't think that are already do |
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| 32:28 | are fatty acids. Okay, so now, all right, any questions |
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| 32:37 | that. Okay. Yeah. Um a combination of both. Both kind |
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| 32:50 | work together. So saturation and cycle kind of had the same effect or |
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| 32:56 | together for the same thing to kind keep the change tight and close |
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| 32:59 | So I'd say bo is kind of happened. Yeah. Um Alright, |
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| 33:07 | now we get into a little bit transport and moving the molecules. So |
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| 33:11 | a look at this. Um So got a bacterium in the pond And |
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| 33:20 | concentration there .1 External is .5. it's but maintaining that concentration uh in |
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| 33:35 | of the external concentration of sodium. how is it doing that? Um |
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| 33:47 | the answer may or may not be there. So, the context here |
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| 33:59 | um So, of course, certainly about growth medium that we'll talk |
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| 34:05 | Chapter four. You got to bring into heat for example. Right. |
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| 34:10 | so various times transport processes are involved getting your pumping ions out and other |
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| 34:18 | . So, there's purposes for different these functions. And so it |
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| 34:23 | you know, transport. Obviously many them require help through the use of |
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| 34:28 | proteins. All right, let's count from three 21. Okay, |
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| 34:42 | they hit help. Okay, what the process going on here? Active |
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| 34:48 | course. Right. It's all about and don't obviously all these slides are |
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| 34:55 | be posted after class. So, you're not getting almost written down, |
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| 34:58 | don't need to because it will be . Um So, it's active transport |
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| 35:03 | on. And so, remember the of molecules all relates to um concentration |
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| 35:13 | . Right, going up and Right, So here we are obviously |
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| 35:18 | from a an area of low concentration high. Okay, and that's what |
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| 35:25 | call uphill going uphill needs energy and energy in to do this. |
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| 35:30 | so it's gonna have some kind of using process to pump sodium ions |
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| 35:34 | Okay, um you go the other downgraded release energy. Right? So |
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| 35:42 | microbes in the environment certainly we're going be at the mercy of their surroundings |
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| 35:47 | terms of optimal concentrations of salutes. they'll have to pump in. Someone |
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| 35:52 | have to be will come out and on the relative concentration gradients. They |
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| 35:59 | flow in without having use energy, some may have to flow with the |
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| 36:03 | of energy. Just just depends on what's going on. Okay, so |
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| 36:10 | let's look at this question. So is um again more transport uh |
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| 36:20 | So we talk about the movement of , right? Osmosis, right? |
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| 36:27 | where you use the terms hypo and tonic uh diffusion, movement of molecules |
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| 36:33 | the membrane, um group translocation type , bases. And then uh the |
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| 36:44 | below I put into this to introduce concept that we're going to see over |
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| 36:51 | over again in unit two. And so the protons down here are |
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| 36:58 | if you can't see it, they're out. Okay. And you can |
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| 37:04 | the other ones here happened in these . Okay, evaluate if that might |
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| 37:16 | sense. Okay. Right, let's count down from 10. |
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| 37:49 | let's see what we got, which false. Okay, um if you |
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| 38:02 | go through some simple diffusion. Um we got the molecules without eating any |
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| 38:09 | . That's simple diffusion. They don't a transport. So things like gas |
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| 38:16 | option C. 02 typically just pass and out of the self help water |
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| 38:21 | can. It's small enough uh that can do that too. Um contrast |
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| 38:29 | facilitated diffusion where you need help. . Um group translocation. That definition |
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| 38:36 | true. It's movement based on like was coming in, they immediately gets |
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| 38:43 | and that's about the concept of solute move independent of each other. |
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| 38:50 | I'll show you the side on the page here in a second member and |
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| 38:54 | gasses basis. That's true as Those can create problems. Internal ph |
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| 38:59 | go up or down disrupting um cell . And so these can be uh |
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| 39:05 | inhibitory yourself, these kinds of Right. And e is meant to |
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| 39:11 | a concept. We're going to talk a lot even to which is this |
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| 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 |
|
