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BIOL 2321_Microbiology for Science Majors - 2321_2_21_24_CH 03
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00:00 Of a recap here. So we're chapter three, we are looking at
00:03 cell and this um a lot of here. So we are gonna extend
00:09 little bit into Monday as well to this up. Um W what we'll
00:16 up with is kind of the stuff , it's not shown here but the
00:21 uh Granules storage, Granules, that of stuff we leave till Monday just
00:28 little bit, then we'll get into , which is um check for.
00:34 . So um all right. So went through the cell kind of the
00:38 the approach here is kind of somewhat from the outside into a degree.
00:44 it's like, what's the envelope made ? Right? We look at uh
00:48 transport proteins. Uh Yes. sorry. Yes. Question.
00:58 Oh I sent out three times. sent an email, right? You
01:02 to look on your, you you have a number associated with,
01:08 are you seeing your points on Are you seeing your points on canvas
01:12 clicker points? Then you're good. don't have to worry about it.
01:16 , that's Yeah. If you're not your points, then that you may
01:18 on that list. That's the Yeah. Any other. OK.
01:26 yeah, if you're not seeing your points, then that's a red flag
01:29 you probably are on that list. . Uh If you're seeing your
01:33 don't worry about it. All So uh so memory structure, we
01:38 through that and uh transport processes uh uh for, for the most part
01:46 last time focused on cell wall of negative to gram positive. OK.
01:52 through this uh one thing I wanted mention, I really kind of didn't
01:56 at all. Uh this refers to to Prokop, OK, hop
02:05 All right. So these are like uh molecules very similar to cholesterol.
02:09 have, you have cholesterol in your . Pro carrots have this version of
02:15 , which is called the hyoid. really just to kind of help stabilize
02:19 fossil lipid bilayer. Um Is what does. Um The thing about honos
02:25 you can do those are molecules that have been um able to be
02:32 Uh they leave like a chemical signature . So they found these things in
02:37 fossils, which is evidence of being to tie a prokaryote to a timeline
02:43 an evolutionary type of scale here. . But aside from that there,
02:47 they are pro specific cholesterol molecules that in the membranes. OK. Um
02:54 oh The other thing I didn't mention much was or at all, I
02:59 is this ester linkage uh thing. the ester linkage, ether linkage.
03:04 that's the difference between uh IKEA and are linked to the glycerol via these
03:19 linkages, right? These um archaea membrane molecules lipids that are these of
03:28 type that you see in the adaptations those that live in extreme temp.
03:35 . They have the ether linkage, ? So s significance of that the
03:39 linkage is one that's a little more than an extra linkage. ETRA linkage
03:43 is more susceptible to being hydrolyzed the , the east linkage less.
03:48 OK. So all the more important you're one living at 80 degrees centigrade
03:54 up to really keep those um membrane intact. OK. Uh Talk about
04:04 . OK. Um OK. Any about this stuff, either transport or
04:12 membrane structure. Yada yada. All right. Here are the questions
04:18 , this is uh so we talked the gram positive gram negative cell
04:22 OK. So we went through that . So let's just kind of look
04:25 this question and then finish that up again. Let's look at it real
04:30 . There's a couple of things to regarding the cell wall and it's kind
04:35 some atypical cell envelope types. Oh Do that first. OK.
04:43 you can answer sorry. Mhm. this up a little bit here.
05:19 come down from 15. Yeah. . 321. OK. And positive
05:43 cell, lax this component. Let's . So if it's g what,
05:50 is it lacking? What are the it's lacking? Hi buddy B is
05:58 . Y what's the other one? . F right. F so ga
06:07 had to think about it for a myself. Uh A uh B and
06:10 . Right. So again, here go side by side, we went
06:13 this last time. So kind of , you know, a real easy
06:16 on this is can you just draw positive gram negative? So all label
06:21 stuff, right? So knowing these , um so you know, gram
06:28 , very thick pep I can compare to the gram negative. Gram negative
06:31 that outer membrane right layer with the S and um that old polysaccharide,
06:40 um uh lipid a material which can create the endotoxin effect. And uh
06:48 lot more going on that you might by comparison to the gram negative and
06:52 grand pos, right? So the positive with its thick wall tyco acids
06:57 really kind of the if you're familiar road construction in which we all probably
07:02 having seen Cullen Boulevard, you they put the uh those metal bars
07:06 rebar, right? And then they the concrete. So think of the
07:10 metal bars here is the Tyco gasses this material. OK. Um And
07:17 course, these differences and do do to differences in responses to antibiotics and
07:25 septics disinfectants because of the the chemical and you know, allowing passage of
07:31 molecules more easily than others. And that can have an effect on
07:36 , if the antibiotic or whatever treatment effective against it. Ok. You
07:42 run um run both representative gram negative positive types when analyzing the effects of
07:50 to figure out, hey, is , is this chemical gonna be a
07:53 and a septic disinfectant or antibiotic? have you? So that always plays
07:58 role here? OK. Um Any questions about that gram positive gram
08:06 . So W OK. So S OK. Your book talks a little
08:13 about this. Um I wanted to some actually a better picture of this
08:19 this, of what it actually It's somewhat, still be not mysterious
08:26 they're can be difficult to work with it's one of these features that can
08:31 lost on when cultures are grown on plate, material strains grown on a
08:37 . They can tend to lose some . Um uh And, and the
08:43 is one of them. OK. of that is uh motility is another
08:49 that can be lost when you're, you're, when you're maintaining it in
08:53 lab because you maintain these things are typically rich, really rich medium.
09:02 ? But you know, if you're la you know, nutrient augur,
09:05 ? That's a very rich medium. . And so the still doesn't have
09:09 go far to get food. So it's a, if it's
09:14 then its motility isn't really so much because it's in a buffet,
09:19 Doesn't have to move. So that's feature that you kind of lose,
09:21 lose over time if you're maintaining it the lab. So if you run
09:26 to maintain that motility, you need grow it in a different way.
09:30 it's just the point here is that things that the micro may have in
09:35 that it needs to survive may lose because it doesn't need it. You
09:40 , if it doesn't, it's not are efficient, right? They don't
09:44 to keep doing an activity or something wastes energy if they don't need
09:48 So they may lose that characteristic over . OK. So that's that can
09:52 um with other characteristics as well. layer OK? Is thinking of it
09:59 kind of a a net, maybe net of protein around the envelope.
10:06 . Um It can be glycoprotein as . I got this off the
10:12 OK. Internet uh showing you So the yellow is the um S
10:19 components of the S layer. So in arch uh many of which
10:24 have a cell wall, it's the layer covering around their membrane, that
10:31 of is in many cases essential to . OK. Um So you see
10:36 kind of here, it can be in the membrane or be kind of
10:39 to one side. Uh the orangey . This material here can be a
10:47 type material on the surface like a layer or something. And it can
10:52 uh on top of that um there's gram negative, it's covering the outer
10:59 , right. Um Here is this what the, the kind of the
11:04 right? Here's the s layer with yellowish. OK. So uh functions
11:08 this thing, OK. Um It's porous, it's fairly porous that you
11:15 . Well, instead of just uh book doesn't really give all the
11:18 And I, I'm not gonna ask to know all these things, but
11:21 to uh it, it depends on species you're looking at some have different
11:26 . So protection against uh pages, are a bacterial virus that attaches.
11:32 it can have protection against that resistance the low ph not sure how that
11:38 . Um uh adhesion could have some , sticking to surfaces and cells um
11:45 the membrane. So they found, know, different of these functions um
11:51 various species, doesn't mean it's that across the board, but for what
11:56 studied. So they have um you , more often than not it,
12:00 it does have a nest, there it can be about sticking to
12:04 stick to the surface or another cell something like that, but it can
12:08 these other functions. OK. um and both like the, the
12:14 picture. Um Actually let me show picture here. You might think um
12:21 , that you only have it Here's the s layer shown here that
12:26 grand positives have it. That's not case S layers can be gram
12:31 gram negative Aria. What have OK. So just kind of ignore
12:38 you just see it in the grand . It can be across the
12:42 OK. All right. Yes. at this question here. OK.
12:51 , um, all right. So have a cross section sewing three different
12:56 . You can probably guess. Uh are OK. So which would be
13:03 likely, which would likely be most to osmotic shock, right? So
13:10 of uh you know, water coming a cell, right? What's
13:16 what's gonna help it out? There will be some degrees of difference
13:23 depending on the species on the OK. Some of the analogy was
13:34 balloon and a cardboard box, 22. OK. Let's count down
13:54 . OK. Uh People pick b . So what is, so we
14:01 that's a cytoplasmic membrane, obviously it's . So which is the gram
14:09 Hey, yeah, grandpa. Gram positive. And I'm assuming you
14:15 this is gram negative? OK. this structure is what? So
14:25 OK. All right. And of , the cell wall here in the
14:31 negative. OK. So let's go to our cardboard box analogy. Uh
14:39 is gonna, which is gonna be thicker cardboard box, cardboard box is
14:44 sell. All right. So our box is bigger here. Thicker,
14:49 ? Our balloon fills up with Ok. Our cardboard box, which
14:55 our gram positive with a thicker cardboard our gram negative box with the thinner
15:01 cardboard, thinner cell wall. The expands which was going to be more
15:06 to that. A that's why a the correct answer. OK. The
15:12 membrane is just a membrane. It's that same thing as a cell
15:17 OK. So because the gram negative an outer memory, it doesn't mean
15:21 know, it's, it's, it's to resist that Mastic uh stress.
15:28 . So it's the thickness of of the light hand the cell wall
15:32 serves the purpose there. OK. Any questions about that? OK.
15:39 the thickness of the cell wall is matters here in terms of this
15:42 OK. So OK. Synthesis. there's a lot of components in cell
15:49 synthesis. OK. Uh As mentioned , many of these are are targets
15:54 antibiotics. So um it does, , it, there's differences, the
16:01 of how it goes together is the . But you can see differences in
16:05 mechanics of the process, depending on you're a rod shape or a,
16:10 circular coccus shape. Uh It it can happen a little bit
16:15 All of the components are identical. . So Mreb is one of those
16:20 we'll talk about here in a Uh It's a cytoskeleton element. Um
16:26 its involvement is in helping um facilitate wall synthesis specifically in uh a rod
16:35 cell. OK. So you see little archy things here are the
16:44 the little blue Bobs here are basically OK. And so, uh in
16:52 rod shaped cell, they're being synthesized along the length of the cell and
16:59 connect up OK to form the intact wall. Um And so it just
17:06 of shows the differences here. So we're seeing over here is this,
17:11 right. So E coli and bacillus both rod shaped, right? So
17:14 have this kind of uh I think this kind of piecemeal synthesis that then
17:19 up OK. The uh streptococcus and obviously round shaped. OK.
17:28 So it occurs um from the middle . OK. And begins to expand
17:34 that central point. OK. Other um these are types that it kind
17:41 um synthesis occurs at one end or other, right? Kind of not
17:48 norm typically. But that's why these shapes that are kind of branching shapes
17:53 irregular forms because they have kind of this odd growth pattern. OK.
18:00 Typically those types, aino uh big word um have kind of these
18:09 forms almost just got fungus. Uh The other ones are uniform,
18:14 have uniform bras, uniform brown shaped . OK. Um But yeah,
18:20 coccus is kind of just begins in middle and kind of just expands from
18:24 . OK? The rod shapes kind throughout the whole length you have synthesis
18:29 they meet up. OK. Um so, and we'll learn the Mreb
18:37 of it as kind of a scaffold you will, this is uh contained
18:43 here. Uh They all cells, cells. FTSZ it's a cell
18:53 cyto skeletal component we see in circular cells. OK? We'll talk about
18:59 two things here in a second. . But they, they, these
19:02 skeletal elements help to facilitate their, roles in helping um cell synthesis.
19:10 also in the division where the cell into two, that's where you see
19:15 cyto skeletal um components come into OK. Uh Like I said,
19:21 talk about those here in a All right. All right. So
19:25 a to E so we're gonna finish one here with kind of some having
19:31 through, you know, your grab and you grab negative, what else
19:34 out there, right? And what the other kind of envelopes we
19:37 So that's kind of where we're going ? OK. Open. Mhm um
20:25 is one true answer. OK. if you picked f pick something
20:29 OK. And it's for a Oh, on that when I said
20:35 it's OK. Remember, unfortunately, can't be with you tomorrow. To
20:39 those out for you. All let's count down here. 876.
20:57 . Who answered D as in D as in dog, you answered
21:04 as in dog? Got to go the list. Ok, let's go
21:07 the list. That's always fun. see. You answered D Trey.
21:13 know you're here. Why did you ? D oh, we, we
21:22 you answer D because, because right, they don't, they don't
21:31 a so well, correct. You correct. No cell wall. What's
21:36 gonna do? Right. Penicillin, . He Glycan synthesis doesn't do,
21:40 doesn't have a cell wall, don't it. So it's gonna have no
21:44 on mycoplasma. OK. So that's true statement. OK. Everything else
21:50 . OK. So, um we'll through these right now. All
21:57 So mycoplasma, OK. The, are, uh, don't, you
22:02 this, but those are respiratory They're among the smallest, if not
22:07 smallest uh bacterial types. Um don't lack ac they lack a cell
22:14 . They are um cause respiratory illnesses. They actually get into your
22:19 of your lungs, um cause a of pneumonia. Um IKEA,
22:25 They, it's probably, whereas most then not have pep Ian cell
22:34 it's probably everybody get 50 50 50 archaea have a, have, have
22:41 cell wall have built roughly OK. that do, it's very similar in
22:48 structure, but there is some That's how we call it pseudo.
22:52 Mmmurien, it's kind of an old that you refer to. Uh that
23:00 to the cell wall. Uh I think it's used as much anymore,
23:03 uh but they, they call the um type of that pseudo,
23:10 Pseudo Marion is its form um So don't confuse because they start with
23:16 same four letters. Uh don't confuse and mycoplasma, right? They're completely
23:23 . Ok. Uh Mycobacterium causes tuberculosis among others. Um the but they
23:33 a very unusual envelope, right? do have pep glycan, right?
23:39 we see that right there, But it's dwarfed by the amount of
23:47 material, OK. Um which is hydrophobic. Uh The these my colic
23:56 are um uh I'm taking organic you've gone through lipid structure. These
24:04 kind of lipid. There are their particular chemical structure. Uh We
24:09 know wax, right? Wax is sticky kind of uh very water
24:14 right? Wax your car, keep water beads on it, right?
24:19 these kind of envelopes, the cells to stick together, stick to each
24:23 . OK? It gives them some features when you grow them on a
24:28 or in liquid as you see um they tend to grow at the
24:32 liquid interface. So on the left would be something like an E coli
24:36 throughout gives you like a uniform cloudiness . We call it the one over
24:43 the cells are kind of sticking right? They're, they're aerobic,
24:47 ? So they kind of tend to to each other and up near the
24:51 of the liquid. OK? On plate, they kind of have that
24:54 if you put your loop in there it looks like a a candle wax
24:58 touching it in there. OK. the other thing is having this really
25:03 envelope, OK? Is the two , it slows diffusion of molecules into
25:14 . OK. So they have to through that thick envelope into the
25:19 through the cell memory. That means carelessly take a longer time to
25:25 right? The Kodak can grow in to 18 hours. These take 36
25:32 48 hours to get really good growth even longer. OK? Because it
25:36 a while for stuff to to fuse , get in also means that then
25:41 try to administer antibiotics, those take while to get in as well.
25:46 a mycobacterial infection is one that is typically gotten rid of in a 10
25:54 course of antibiotics. It takes months. And so things like tuberculosis
25:59 often chronic diseases, right? Um again, all due to this really
26:07 unique type of cell envelope, Um All right. So then
26:14 with the end of part one are of some. So what can be
26:23 to the cell envelope, right? now we're at the outer, outer
26:27 periphery of the cell is there stuff can still be out there? And
26:31 answer is yes. OK. So shows you kind of in this relative
26:37 diagram here, we can have a , right? We have a slime
26:42 , right. So our cells can together and form a biofilm,
26:45 This is material that's all external to envelope. OK. So the capsule
26:53 which you you're a lab you saw last week, I think.
26:58 Um so the capsule versus a slime , OK. The slime layer,
27:04 capsule is a gene encoded feature, ? A a non pathogen can,
27:13 acquire a capsule by a gene inherited what we call horizontal gene transfer.
27:21 worry about it. Now, we'll about it later. But the point
27:23 it's a gene encoded feature, You express the gene, you form
27:28 capsule, OK? It's very tightly to the cell envelope as you
27:34 OK. Pathogens are the ones that have these things, right? Meningitis
27:40 . You were vaccinated for the streptococcus pneumonia, very thick capsule.
27:46 it helps to basically cover up, up the antigens on the cell
27:52 So your immune system can't really see that well, right? They
27:55 they don't, they're not as antigenic call it. Ok. It also
27:59 them less able to be phao right? So these, it's
28:03 that's what we call the vir It enables it to cause disease.
28:07 . So more often than not a that uh a pathogen has that for
28:12 reason, enables it to um avoid immune system. Ok. Um Because
28:18 slime there, by contrast, then really a by a by product of
28:23 cells metabolism. Ok. Um Oftentimes you can grow certain cell types on
28:31 medium, very rich with a lot sugar. Ok? And they will
28:37 it, of course to grow, the excess is processed and excreted and
28:41 kind of hangs around the cell. ? You know, you're probably
28:45 dealing with a cell with a slam it has like a looks like snot
28:48 your plate basically. OK. So using this extra cer sugary type of
28:54 and it kind of just loosely hangs the cell. OK? So it's
28:58 a gene encoded thing, OK? a by product, it metabolism
29:02 And, but so it's kind of random thing, you know, sometimes
29:05 may be a lot, sometimes very , it just kind of hangs off
29:08 cell. Uh it can lose Um But if it does have
29:14 you know, you could envision that ? It could be some kind of
29:18 for it, right? So uh it's just not a consistent structure always
29:25 . So that one that forms the will always have a capsule,
29:29 Just a slime layer. It's a thing just based on your metabolism,
29:33 available to eat, that influences the of the slime layer. OK?
29:40 Then biofilms the, we'll talk more that next week. But for now
29:45 a biofilm forms. Um because it's cells collectively are synthesizing this what's called
29:55 polysaccharide material exo meaning outside. So synthesizes this stuff and it's kind of
30:01 glue that holds it all together. . So, but it's a
30:07 typically sugary protein ish kind of uh . Um But again, it's
30:13 it's on the outside, right? periphery of all these are are external
30:18 the salon. OK. Um Any about that? OK. Alright.
30:28 Part two. OK. So let's here. This will take us into
30:34 Klett elements. OK. So while mulling this over, um you've have
30:44 through the stuff, stuff we're going , you've gone through in the context
30:47 the periodic cells. You did Neutro Bol, right? Chapter
30:51 I think the intro bum anyway. and so you remember they are cytoskeleton
30:57 is really big thing. OK. how you um uh mitotic spindle moves
31:05 microtubules, right? Those are pyo elements, um chromosomes moving right?
31:11 pulling it apart. Uh A flagellum microtubules, you have um intermediate filaments
31:18 anchor organelles in place. Uh What's other one? Um things like
31:25 Acton myo, those are cell skills in your muscles, right? So
31:31 extensive network of things, bacteria IKEA compared to UK O it's relatively new
31:41 . Last 1015 years, we found they have some of these things.
31:47 . Just not, it's not the network like you see in the eu
31:51 on cell. But nonetheless, they a role really in, in and
31:58 cell division, which is kind of their role is at. Ok.
32:04 , let's see. Uh, there certain, so a is certainly
32:09 Ok. So my material says Smith only one of these three. That's
32:14 . It actually turns out that uh cells round ones only have one of
32:19 three. OK. Uh If just , that's true. OK. Some
32:25 may possess only two. that is as well. So rod shaped cells
32:31 two of them. There's one type has all three. OK. So
32:35 is true and um one of the in August microtubules. Yes. Uh
32:46 true. OK. Uh So there , it's a little bit different than
32:50 it works, but bacteria can't have flagellum. It just works in a
32:55 way. OK. So none of are false. You get all true
33:01 . All right. So we'll go this and its first C scale to
33:06 here. So this is only for purposes. I don't expect you to
33:11 off the components of the UK on . So just only for comparison,
33:17 . Just to show the extensive network various um of these filaments.
33:23 So this was found in mutants or in prokaryotes in this particular bacterial
33:33 bacillus sulu a rod shaped, Using like um fluorescence um A and
33:42 other techniques. But they found here's normal nonm strain rod shaped,
33:48 Little, little white line. Here kind of when the cell is
33:52 the septum cells will divide. Um here of course, is a mutant
33:58 is a blob sorry, a rod . OK. So it was found
34:02 uh these proteins, MRE proteins are in the mutant. So it's uh
34:09 . Well, that must have something do with being a rod having these
34:13 proteins. OK. So, and we saw that, you know,
34:18 cell wall synthesis, right? These molecules have a role there.
34:23 So what IC all pro cells as as I know they will have this
34:30 , right? They'll have that And it will be lined up in
34:37 middle of the cell. It, typically forms uh during cell division just
34:42 to the cells dividing forms because it facilitate the the splitting of the
34:49 Um That's what acceptation acceptation is that of the cells uh into two.
34:57 . Uh Because in the middle we it determines kind of the cell
35:01 OK. Um The and also uh believe it also plays a role in
35:09 the DNA replication too. We'll talk that at the end. So E
35:13 will have that right? You see in the middle here, plus
35:20 um, Mreb. All right. we have it here that, and
35:25 these are the MRE Ds, Again, facilitating cell wall senses.
35:33 . And then lastly, these, , comma shaped, typically called vibrio
35:38 . Ok. Um, they have rods, but they're, they're curved
35:43 basically. And so they're gonna have two elements plus the one that makes
35:49 curve. That's what the crescent It's, it's in larger concentrations on
35:56 side of the cell, which kind makes it curve like that.
36:00 So um that's the one that has three. So you can see how
36:04 types of, there's one others there's two of these, the common
36:08 type has all three. OK. yeah, uh it's about um um
36:13 really facilitating cell division and um so , OK. It can have a
36:20 a degree help it shape. But a lot of that's, you
36:24 , really due to um so envelope um osmosis water coming in can
36:29 But this can have a little bit a role there too. OK.
36:34 OK. So subdivision acceptation, So a ab per cell once it's
36:43 hatched, so to speak. Once it's been split and now it's
36:49 its own. OK. The life that cell will be actually to um
36:55 comes up kind of small. And then it kind of expands.
37:00 . As it goes to life, life OK. And, and as
37:04 gets bigger, it will then then cell devices, right? So
37:09 that, that process the 1 to , that's septation. OK. And
37:16 how that occurs is through this controlled by a thing called a diva
37:24 Zoe. OK. So that so that's basically the that cell
37:31 this apparatus we've seen already. Here. So they call the whole
37:38 A Dibos because it's gonna bring about , right? So on a circular
37:44 cell like this, right? It in the middle. So the FTSZ
37:50 see there, right? That's in middle of the cell. That's what
37:55 gonna facilitate this, right? So gonna have, oh for God's
37:59 that's um going to OK. That going to uh bring together uh both
38:09 , right? So, acceptation is on the outside, going in
38:14 And then completes itself. So it's wall synthesis occurring here. OK.
38:20 um so the plane of the right? Is it perpendicular or whatever
38:30 brings about the different morphologies, So, streptococcus in this plane can
38:35 diplococcus or streptococcus chains, uh two you get tetrads, et cetera.
38:42 it's several planes, that's your you know, in all directions.
38:46 it looks like cluster of grapes. . Um So a couple things.
38:53 this again is a cell wall OK. So think about this is
38:57 hit for an upcoming question, quick . OK. That um as I
39:03 before, these are targets for cell uh targets for antibiotics, right to
39:09 cell wall synthesis, right? ampicillin, amoxicillin, blah,
39:13 blah. OK. So uh antibiotics have their effectiveness can equate to cell
39:24 . OK. And so think about , when is this process of cell
39:30 synthesis? OK. Most active, ? Once it's actively doing this,
39:36 happening here? Well, we have of several synthesis. OK. So
39:41 that in your memory bank, we to that question. OK. Which
39:45 right now. OK? I thought was far down the road. All
39:48 . Here we go. Which bacterium going to be most susceptible to
39:54 OK. So a slow or non streptococcus, it's gram positive,
40:01 A fast growing staph aureus also gram , a fast growing E coli grab
40:09 . So now you gotta think in of OK, difference between the gram
40:14 and gram positive and the difference between fast and not growing fast.
40:20 And let me do that. And , let's see. OK. So
40:36 put up, there's a cell actively , right? So if you look
40:44 a population of bacterial cells and they're dividing, you're gonna see a bunch
40:48 these. OK? And so it's look like there's a fast growing
40:54 the slow growing population, right? pro proportions forces of cells, they
41:00 in singles, not really growing very or rapidly growing. OK? Then
41:05 have to ask yourself, there's uh which, which has the most
41:12 of targets, right? So think all that when you're answering this question
41:19 let me pause. OK. Now I mean, I think I mentioned
41:27 . No, I did not, in um not specifically penicillin but,
41:33 you didn't have to wait is I get the fast versus slow growth
41:38 what may work better there. But about the gram negative gram positive
41:42 OK. So what role would that ? That's maybe where Chat G BT
41:49 in, right? Google it, ? So hopefully those who have the
41:56 answer I do. OK. Um right. So let's move ahead.
42:02 ahead. So OK. So this kind of weird here. Let's open
42:09 up a little bit. So 104 B OK. Uh Yes,
42:20 OK. So I think myself, right. So fast versus slow.
42:25 . So obviously, you all know , the one with the most targets
42:28 is the fast growing one, Because all the cell wall synthesis is
42:32 occurring here, right? And all ones that are in, they're in
42:35 process of about to divide, That's where all the active cell wall
42:38 is occurring, right? So that's going to um penicillin's gonna chew that
42:43 right? Chew up the enzymes components , that carry that out,
42:47 So OK, so we take fast , over, slow growing is everybody
42:51 ? With that no problem. So then it's like the positive versus
42:55 , right? It really didn't, mentioned that outright in terms of penicillin
43:01 . So penicillin actually has a harder getting through a gram negative,
43:08 easier because uh think of the gram , right? The the pepto glycogen
43:11 right there, right? And so the it can be the components of
43:17 can be directly attacked. OK? the gram positives are more susceptible to
43:22 and gram negatives. OK? Um , but the growth is a,
43:27 a, is a thing because not the growth factor in terms of the
43:30 of penicillin, but also in the in antibiotics that inhibit uh protein
43:37 Um and other and DNA replication, ? Because those are gonna be more
43:43 and the cells are actively dividing. so, you know, it can
43:46 that many antibiotics are more, more their best effect when the cells are
43:51 growing versus not growing so well. we know that because one strategy that
44:00 have some do is to say, , here comes antibiotic, I'm not
44:06 grow. And that's a strategy that's they call persist. Um They just
44:12 , all right, I'm not gonna , right? And they're less susceptible
44:15 the effects. OK? And um uh because you take an antibiotic,
44:22 not gonna be in your system right? It, it,
44:26 you lose it right, you expel eventually and So that's when, when
44:31 happens, that's when these persist begin grow. OK? And so that's
44:36 sneaky strategy, right? Actually, of brilliant. Right. So,
44:40 I tell you, it's, it's , it's a war right? Between
44:44 and pathogens, right? We always to uh keep on top of
44:47 right. So, anyway, so , growth phenomenon as we'll talk about
44:52 week has a lot of different aspects it just beyond, you know,
44:57 it food and see how fast it it goes. It's a lot more
44:59 it than just that. OK. is, this is one of the
45:03 phenomenon here. OK. Uh Any about that? Yeah. So,
45:10 OK, so here's a before and question. So just answer it and
45:15 we will probably not gonna see this until the beginning of next lecture.
45:20 let's see what you can do We're gonna cover these topics, uh
45:29 , but probably not, probably won't the polar aging, but we'll get
45:33 other one then. OK, you're sure of your best shot.
45:42 And we'll go through these topics and we'll see the question again on
45:56 OK. Thank you. All Let me pause for a sec and
46:22 go to one. OK. Uh , all right, that looks
46:34 OK. The consensus was, oh , I got, I need to
46:41 a picture of it. I get data in my computer. All
46:43 So 111 for F OK. We'll we'll come back to that Monday.
46:51 . You don't need to know that the exam anyway, so don't worry
46:53 it. So not for exam one least. So nucleoid. So we
46:58 about this last time, right? um so number one get this in
47:02 head. A nucleoid oid oid is a nucleus. OK. Nucleoid represents
47:11 area, an area in the OK. If a nucleoid is bounded
47:17 anything, it's bounded by the cytoplasmic that defines the cell. But there's
47:25 , there's no covering if you that comprises a nucleoid. It's just
47:32 area in the cell that the chromosome . That's it. OK?
47:37 and you can see there it's like uh whitish splotchy areas in the
47:43 right? All of this stuff right is the chromosome but that's the nucleoid
47:50 that's what we call call the OK. So uh important in there
47:55 this when we get to this in few slides is the origin,
47:59 The ori that's where replication of the originates, same as in your
48:06 except you have linear chromosomes and you multiple a because you got a lot
48:11 DNA to copy, right? A cell doesn't have as much. So
48:17 of these is enough. OK? And you see that here. So
48:24 see this would be um where that thing would form, right? So
48:36 was formed during uh prior to replication you see it's kind of right where
48:43 origins at, right. So, in the middle of the cell,
48:47 ? It's attached on the underside OK. So it's gonna have different
48:51 . Parts are gonna be um exposed open and the parts are coiled
48:55 That's what the um S uh DNA does is coil it up.
49:01 Um Because parts of DNA are being and other parts are not,
49:05 So if you're gonna express DNA, gotta open it up, get access
49:09 it. OK? Um So there's , you know, parts on uh
49:17 uncoiled parts are coiled, et OK? Uh Of course, it
49:21 a binding protein. So you kind have to uh help maintain its
49:25 you don't want it to break or like that. Um Size range I
49:31 this before. So, yeah, coli has like um is on the
49:35 side, it has about 4 million pairs that mycoplasma we talked about this
49:41 the lower end, it'll have much . So it makes sense, smaller
49:46 , less information can be stored in . OK? Of course. Um
49:50 chromosome itself is also big, so have to cool it up so it
49:53 in the cell as well. Um So the picture may be a
49:59 deceiving here, right? So the , right? Because you're seeing the
50:02 and you're seeing this boundary around right? It's not an organelle.
50:06 . This is just a cytoplasmic membrane the cell, right? Just a
50:11 simplified drawing obviously here. OK. , um OK. Now there are
50:22 laundry list of reasons why prokaryotes can so fast and evolve, adapt rather
50:33 . OK. And this is one those is a small size,
50:38 Just to keep up with so small helps if you want to grow
50:42 Two is this phenomenon, the that and translation occur virtually simultaneously.
50:54 Um We don't have that you you carry out um compartmentalize the
51:03 Uh being a um I'm trying to transcription transcription occurs in the nucleus translation
51:14 the nucleus, right? So it's , right? So don't occur
51:18 don't have that problem in the pro no nucleus, no nuclear membrane.
51:24 . So it can all occur at same time, right? Um So
51:29 this graphic here, black strand is chromosome DNA. OK. The blues
51:38 coming up rrn A messenger RN am A transcripts. OK. The red
51:47 are ribosomes, OK. Then little strands are uh protein polypeptide.
51:59 Um OK. So let's focus on left. All right. So here's
52:03 segment of DNA corresponding to a OK. So uh we'll talk about
52:09 process in unit three. OK. Nevertheless, so only summarize copies DNA
52:18 for an MRN A and because there's separation of transcription and translation um that
52:29 this becomes available. MRN A, essence, when a specific part becomes
52:35 . So down here is what's don't worry about this. Now,
52:41 , it's part of unit three, makes sense to mention it here.
52:46 RBS is what's called a ribosome binding . It's not long, maybe 30
52:55 or maybe 20 bases. I think at the A at one end.
53:00 so I remember when you talk about acids, right? You have what's
53:04 the five prime and three prime. . And so it's on that five
53:11 end where this ribosome binding set And so being there means a ribosome
53:16 recognize it and then a ribosome can . OK. And so it does
53:22 begins to move, right. So we get the translation part of the
53:27 uh process. So I, so this moves, then of course,
53:32 it's unoccupied and another ribosome combined, moves another one combined moves and so
53:37 , right? So you get a string of ribosomes all along the
53:43 OK. Like you see here. obviously, uh the polypeptide length is
53:50 because this one, the the three end is almost done synthesizing. So
53:56 protein is almost made this one at five prime is just started. So
53:59 short, right. So the point is that this, well, the
54:05 here I have a question, this, what's the implication?
54:10 The cell can produce lots of protein quickly. OK. Remember proteins are
54:18 are the the thing that makes life the functioning, functioning of various
54:24 thousands of proteins, right. So when a material culture is growing lots
54:29 cells being produced, that re represents of protein synthesis. And if you
54:33 do it in a way that's very . Like this is you can facilitate
54:39 growth. OK. So being small transcription translation coupled together, two reasons
54:48 others, why you can grow so under the under the right conditions?
54:54 course, right? Because remember all all boils back down to metabolism,
54:59 ? What what foods available and it it, how much is available,
55:03 cetera, right? But certainly these also factors in why it can grow
55:08 fast. OK? This stuff over , OK. Which is which is
55:13 don't care that much about but I'm mention it. OK? Um it
55:19 to do with the proteins over OK? These things OK? That
55:26 you know what's different about them compared these is that these are at the
55:35 . OK. So of course, know, I would say that probably
55:39 proteins made in the cell work in , in the cytoplasm. But you
55:44 have several that can uh be in membrane or are excreted outside the
55:50 So, so you have to like proteins to go in different, you
55:57 , either outside or the membrane or stays in the inside is all and
56:01 way to differentiate is through these signal particles, right? This is what
56:07 um you see here, OK. the protein being that's made, there's
56:13 part of it, a sequence that recognized by these proteins that bring them
56:19 the outside or into the membrane, ? And so the ones that work
56:23 a inside don't have that. So just function in the cytoplasm. But
56:29 that have that particular sequence, they're , directed to the surface and complete
56:36 process there. That's all it OK. You had a similar
56:41 Does anybody remember what's the organelle in cells? That is like the traffic
56:46 saying you go here and you go goi apparatus. I think that's
56:52 OK. Um uh So yeah, you have to direct proteins of different
56:57 to go to different places. And for pro Kario, it's not as
57:02 , it's really working the inside or membrane, more or less.
57:07 Um Any questions about that? Mhm . So, and again, with
57:16 , uh the apparatus components involved in or, or targets. OK.
57:22 like rifampicin among others. Um And , imagine when this is the most
57:28 , right? Cells are actively right? Um OK. So this
57:33 just uh again, just to reiterate of the uh we're gonna talk about
57:39 , get replication, but we're not into the details of it like you
57:44 intro bio, I don't care about fragments and blah, blah,
57:48 You already know all that. So more just kind of looking at a
57:51 of things for specific. OK. , so we look at cell
57:57 OK. As you already know Uh Maybe you have nightmares about
58:03 I remember when I taught this Um The nightmare was, when is
58:08 chromatid? Not a chromatid? Remember questions, sister chromatid, blah,
58:14 blah. And yeah. OK. to worry about. That's why I
58:18 into prokaryotes. I don't have to about all that stuff, right.
58:22 uh anyway, so the process, , the mitosis process um is it
58:27 prophase metaphase anaphase telophase? Right? all about, you know, the
58:35 chromosome segregation and all that kind of , right? It's complicated, that's
58:39 chromosome. So you have to have process to do it, right?
58:43 . So that's what these mitotic phases about and result of course, is
58:49 identical cells. So we're talking not meiosis. Although mechanics are
58:54 we're focused on mitosis here. Uh Pro pro prokaryote, right?
59:00 fission, right? Pretty simple, speaking, right? Single circular chromosome
59:08 , right? Uh copy that, we still have to have a way
59:12 hold on to it to a We don't use a mitotic spindle.
59:16 not what bacteria do. OK? they can use that ore,
59:21 So there's an ori sitting there and where replication initiates, right? So
59:27 an aura right there and actually it attached to the cell right there.
59:34 ? So when that aura gets um , right? When the DNA replicates
59:39 it's stuck, right? So the can then divide and now you're assured
59:45 each one gets a copy of the , right? So if you didn't
59:49 that right? And it was something this, OK? So you made
59:58 copies of your two copies of your and they're just kind of floating around
60:02 the cell. It could be the divides and one split in two,
60:07 one half, one side didn't get , right? So you have to
60:11 some way even though it's a lot than you carry out of, of
60:14 on to them, so to right? So that that doesn't
60:19 OK. And um but it's not complicated process of involving my cuts and
60:25 that stuff, right? It's, much simpler. OK? But the
60:28 line is the same end result, ? Using in clones, right?
60:33 you don't refer to Proyas, even it's the same end result, you
60:39 call it mitosis mitosis is its own , right? That you only use
60:45 the context of eu car out You don't ever refer to a prokaryote
60:50 out mitosis completely off, right? carries out vision, binary fission.
60:55 . Um All right. Average 10 to 24 hours. Uh it
61:02 be much faster if it's, if you're a zygote going to like
61:07 development. Right. That's pretty But even that's like, I think
61:12 the fastest there is maybe six hours eight hours. But, uh,
61:17 of the cells in you right now growing that rate at that rate,
61:22 . Um, unfortunately, they only at that rate if they're what?
61:29 . Ok. That's, those represent growing cells because they don't have the
61:34 on them anymore. OK? Um forget about that. So prokaryotes,
61:40 minutes to two hours on average, faster, right? Small cells,
61:44 ? Small chromosome, right? Um of them uh trans translation combined
61:52 So all reasons why they can um so fast. OK. So the
62:00 , all right. So again, not gonna go through all the minutia
62:06 details like you've seen before. The basics you should know,
62:12 So strand separation, right? So , we're only talking about circular chromosomes
62:17 , not your, not your linear , right? So we're just dealing
62:20 a small circular chromosome. And so the ori is where strand separation occurs
62:27 in itself creates the forks, So a fork there and there in
62:36 of course, you remember the bidirectional , right? Replication occurring from the
62:42 , right? You're gonna go right? And so at each fork
62:48 a repli, OK? So the zom is contains two. I think
62:55 , I guess I didn't know if wrote it there or not, I
62:58 . So let me just uh real . So each repos, each blob
63:05 a DNA, I'll just write pol polymerase, right? So that's the
63:11 polymerase. And that's the same over right here. Here. Two DNA
63:18 . OK. So, and they're ones that bring about the synthesis,
63:22 ? So I remember one lagging strand one leading strand. OK. Uh
63:26 don't even need to know that. the point here is that each reps
63:29 two of them, one of each , each is comprised of DNA molecules
63:35 so then we um so the new occurs. And so obviously, if
63:38 , if you initiate synthesis, once open the strands and the ori gets
63:43 , right? And so remember that's of the how how the cell will
63:48 on, hold on to each OK? Because remember we still have
63:53 get one in each cell that OK. So, um and so
63:58 here, uh here you see the right? Here's our chromosome. And
64:06 and so the termination, so they're go around and meet at the terminator
64:11 and they're gonna have 22 copies. . So over here, the gold
64:17 blobs are your repos, OK? kind of like you see here and
64:22 , right? So you, you've seen right away, right? When
64:29 has become copied right? Here's your you see one here and one here
64:36 the cells, they're being attached to inside of the cell, right?
64:41 now you're holding on to both of . OK? They haven't completed replication
64:49 , but it's doing that right. here, here are the repos umes
64:52 around right now. And so here see the FTS, as you
64:57 right? They're gonna form eventually in middle here, right? That's where
65:03 septation is going to occur. The the splitting. And so
65:09 you already see that uh it's already , begin the copying of the
65:19 what will happen. So this is form into two cells, but it's
65:24 begun doing the DNA replication for when will be four cells, right?
65:29 kind of like it's thinking ahead, doesn't have a brain, of
65:32 but it's kind of, you it's, it's, it's, it's
65:35 far ahead already, right? In of that one, is this one
65:38 still, right? This DNA replicating be ready for when it goes from
65:43 , then to four right away, ? So again, why you can
65:47 so fast? Why do you think can grow so fast? Right.
65:51 um so then when we complete, , that first round started here,
65:57 ? So we're, we're completing about complete this one here, right?
66:04 this one is ready to go for it's four cells, right?
66:08 and you can see the two or or there or here or there,
66:13 means we're working on those new copies that are gonna be present now in
66:19 cells, right? So here's the uh that Z ring, the FTSZ
66:25 right here. OK. That's gonna about the section, right? So
66:31 now we formed two cells but very , right? Because it's almost done
66:36 that replication, you're gonna have So this is how you get exponential
66:41 , right? 1 to 2 to to 8, blah, blah,
66:45 . We'll talk about that next OK. Again, it, it
66:48 so fast, right? Occur under conditions. E coli does this and
66:54 cell to a million in four or hours, right? Super fast.
67:00 . Um ok. That's probably a idea. Please stop. OK,
67:04 get it. All right. All . Thanks folks for hanging around.
67:10 Good luck. Don't overthink my Ok. Ok.
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