| 00:00 | Welcome students. This is the uh topic for starting which is on Chapter |
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| 00:06 | covering functions and structure of the pro a cell. I've split this in |
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| 00:13 | two parts. So there will be lecture video, continue the part to |
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| 00:19 | . Okay, so in this section forget that we have learning objectives. |
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| 00:27 | again just take these as uh you things that you should be familiar with |
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| 00:31 | . They're going through these lists. you should be familiar with in regards |
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| 00:35 | the content of the chapter. Um so but the pro periodic sell |
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| 00:45 | course it has its own unique structures separate from eukaryotic cell as you |
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| 00:51 | the eukaryotic cell is much larger. put different types of specialized organelles, |
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| 00:59 | of membrane structures. So it's it's different in that aspect. So we're |
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| 01:03 | to focus strictly on what the carry cell uh looks like and and the |
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| 01:10 | functions of the structures within it. , so one of one of the |
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| 01:17 | you hear, of course you always cell wall typically associated with archaea and |
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| 01:22 | but and cell envelope. And so the what's the difference between these |
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| 01:27 | So the cell envelope is really what is the chemical structure slash composition uh |
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| 01:38 | the inner or cytoplasmic sometimes called plasma ? Right, so the plasma membrane |
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| 01:45 | membrane is what defines itself because it everything. But then you may have |
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| 01:51 | beyond that. And that's what we to as the cell envelope. |
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| 01:56 | And bacteria and archaea can differ in nature the chemical makeup composition of that |
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| 02:02 | envelope. Okay. Uh every cell far as I know on planet earth |
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| 02:08 | defined by that what we might call membrane or cytoplasmic membrane. But then |
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| 02:14 | envelope is what's what's beyond that for particular species. Okay. So we'll |
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| 02:19 | with um kind of the basic chemical of of of a bacterial cell |
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| 02:26 | We're looking at coal as an Um without question in any cell, |
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| 02:34 | the opponent in the in the highest is going to be water. |
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| 02:40 | All things are basically comprised of 70% . So as a percentage of total |
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| 02:47 | , water is going to be the prevalent. That shouldn't be surprised. |
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| 02:51 | when we go beyond that and measure take water out of the equation and |
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| 02:54 | at the proportion of other constituents of , what's gonna make up the large |
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| 03:00 | are gonna be basically what I call of informational uh components so related to |
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| 03:08 | synthesis. Uh DNA replication. So certainly all approach proteins are gonna be |
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| 03:16 | proteins that do the work of any . And we're gonna be in in |
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| 03:20 | numbers. And of course then the that make up synthesize, help synthesize |
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| 03:24 | proteins, ribosomes uh which are made of different RNA molecules. Transfer RNA |
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| 03:31 | . These are things are involved in protein synthesis as well. So these |
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| 03:35 | gonna make up a large basically almost quarter of the of the components in |
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| 03:41 | precarious cell. Um The um ribosomes are are in large numbers because they |
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| 03:55 | protein synthesis occurs. So probably one the number one functions in any cell |
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| 04:00 | the production of ribosomes to generate all proteins it needs. Okay, so |
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| 04:07 | the kind of these informational molecules and um comes cell envelope molecules molecules make |
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| 04:18 | the cell envelope. So um pepper like, can we talk about that |
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| 04:24 | little bit, that's the constituent that up the cell wall of bacteria. |
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| 04:30 | Of course remembering fossil lipids, remember lipid bi layer is comprised of fossil |
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| 04:35 | um lipid policy sacrifice. Now now sacrifice is going to be unique to |
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| 04:46 | we call gram negative bacteria. Okay will learn that the cell envelope of |
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| 04:50 | positive bacteria and gram negative very And they're going to differ in in |
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| 04:56 | proportions and types of molecules in And play sack arise is the type |
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| 05:01 | you find in gram negatives. You find that in gram positive cell |
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| 05:05 | So that's why we see that. wouldn't see that constituent. And if |
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| 05:08 | were looking at say a bacillus organism is a gram positive. Um And |
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| 05:15 | amount of petrol glide can will vary on whether it's a gram negative or |
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| 05:19 | positive bacteria. So some of these may vary in terms of percentage depending |
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| 05:24 | the particular bacterial uh envelope we're talking . Okay other things of course your |
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| 05:32 | molecules of metabolism in cells, there's kinds of metabolic pathways being uh that |
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| 05:39 | working. And they of course have various reactions and products as part of |
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| 05:44 | organic inorganic ions are prevalent. So like sodium chloride ions um uh and |
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| 05:56 | types of canines and um airlines as . And poly means these have these |
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| 06:03 | varied functions. You don't really need to know this but probably means uh |
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| 06:09 | make maybe like 1/10 of the total . They are involved in many |
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| 06:13 | A lot of them have functions in to D. N. A. |
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| 06:16 | of stabilizing it. Others have functions kind of self signaling. So it |
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| 06:20 | a variety of different functions there. , so that's kind of the chemical |
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| 06:26 | chemical makeup of pro periodic cell. again, there's going to be different |
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| 06:32 | somewhat between types. Um So if look at kind of a model of |
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| 06:37 | bacterial cell, um again that the cell membrane, the plasma membrane or |
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| 06:45 | membrane, everyone to refer to it of course what defines any cell. |
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| 06:50 | . And that's going to contain all constituents within. And so of course |
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| 06:56 | comprised of fossil and there's going to protein is associated with the membrane within |
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| 07:01 | and associated externally internally to it. So it has functions, you know |
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| 07:07 | in maintaining having being a barrier you generate ingredients and molecules across the |
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| 07:13 | So we'll talk about some of that we go on the cytoplasm itself. |
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| 07:18 | course we just mentioned the various components the cell. So of course that's |
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| 07:22 | contained in the cytoplasm. The difference cytoplasm and side is all is the |
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| 07:27 | is always the acquis portion of the . Cytoplasm is basically everything that's within |
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| 07:33 | inner membrane. The site is also specific for what's the what's the quiz |
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| 07:39 | of that uh nuclear oid uh that's the DNA is contained. So we'll |
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| 07:45 | this later. But then the nuclear is not a membrane bound structure. |
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| 07:53 | . It's basically an area that's occupied the bacterium's chromosome. Okay. Um |
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| 08:00 | there is it's not a nucleus it's an area occupied by the bacteria's |
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| 08:05 | Okay so while again uh those that it, most bacteria do then don't |
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| 08:13 | archaea very and but archaea have something different than pepper that I can uh |
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| 08:19 | mention that later as well. But uh so of course uh so envelope |
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| 08:26 | vary whether it's a gram positive or negative in the mouth of like |
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| 08:32 | Okay. And with gram negatives you there there's actually another layer beyond |
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| 08:38 | So you have the inner membrane the wall material lit up people like in |
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| 08:44 | you have this outer membrane and it lots of lipid and sugar material called |
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| 08:50 | . So very different from the envelope gram positive. And we'll go into |
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| 08:55 | on that shortly as well. There be a plasma one or more |
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| 09:01 | These are uh circular segments of N. A. Uh They can |
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| 09:08 | on their own um uh separate from chromosome being small. They may be |
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| 09:16 | can be 5000 to 10 or 50,000 base pairs. Um But carrying you |
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| 09:25 | a few genes so it's gonna maybe from one to ken jeans is |
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| 09:31 | So but these can be transferred between and we'll talk that's something we'll talk |
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| 09:36 | in unit two. Uh is how can be transferred as a process called |
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| 09:43 | . No um inclusions, inclusions comprise number of different structures. Most of |
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| 09:52 | are things are involved in like food Granules, energy storage Granules, um |
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| 10:00 | structures related to a certain particular Photosynthetic bacteria may have certain structures that |
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| 10:06 | don't. So this is kind of we lump into, you know, |
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| 10:09 | or specialized structures kind of under that . Okay. And then of course |
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| 10:15 | gonna vary from species to species and their capabilities are. Uh So external |
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| 10:22 | . So you see the appearance of appendages. So pillai and embry, |
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| 10:27 | can cook cover the cell uh essentially same thing that made it the same |
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| 10:35 | component. Um But there can be a difference between those. Uh generally |
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| 10:43 | those are about attachment but in some it can be attachment plus motion. |
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| 10:49 | , flagellum of course are all about and so there can be different arrangements |
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| 10:54 | flagellum as well. Single or groups in different arrangements around the cell but |
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| 11:01 | all about motility. Okay then you this purple covering coming into view. |
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| 11:10 | the capsule. Okay so not again everything you see here, everything you |
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| 11:15 | under cytoplasm a cell will have a cell. Our keel cell will have |
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| 11:22 | very very variations maybe that they may may not have a cell wall if |
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| 11:28 | do it may be a novel of gram positive, gram negative. Um |
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| 11:34 | um external structures that may or may have uh may or may not have |
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| 11:39 | or may not have a capsule. somebody's gonna be variables that are gonna |
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| 11:42 | constant. Okay um the capsule is a structure that you find in pathogenic |
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| 11:49 | causing bacteria. The capsule kind of the periphery of the cell that that |
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| 11:59 | can hide it from your immune So oftentimes things like the meningitis |
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| 12:04 | a very thick capsule streptococcus pneumonia that pneumonia has a very thick capsule. |
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| 12:09 | you'll find these not uncommon among different and virulence factors. So this and |
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| 12:18 | coming to to play later in the as we talk about medical microbiology but |
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| 12:23 | factors um are features that enable a to cause disease and very often it's |
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| 12:31 | like it can be things like a a gelatin capsule um things of that |
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| 12:38 | can be virulence factors among others. , the Okay, so in terms |
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| 12:46 | so memory structure, so you likely were exposed to this previously an intro |
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| 12:53 | . So I'm not gonna spend that time on it. But just recall |
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| 12:57 | the uh fossil lipid bi layer, ? Called the fluid mosaic model. |
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| 13:03 | let me just real quick show you little video here. So here's a |
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| 13:11 | a basic, very basic the membrane . So you see the the fossil |
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| 13:16 | come together making up the lipid bi . Uh of course then chemically they |
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| 13:24 | a what we call a semi permeable . Not everything can just freely flow |
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| 13:30 | . Okay, so you have things things like gasses like oxygen can freely |
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| 13:38 | flow through other things that may be or charged because this this is a |
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| 13:46 | core in this membrane and hydrophobic means water. So a curious water cyber |
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| 13:54 | called polar molecules charged molecules these will have will not be able to diffuse |
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| 14:00 | that membrane very easily. So you them help in the form of proteins |
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| 14:05 | as channels to get through. And so as well there's can be |
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| 14:11 | on the periphery. Okay, external Okay. To provide other functionalities. |
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| 14:17 | so that's what um and that's what the proteins do in a membrane that |
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| 14:25 | in the membrane. It's a they that membrane, its functionality is the |
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| 14:30 | that's involved in a lot of metabolic . So a lot of your process |
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| 14:35 | cellular respiration. A lot of those are in or associated with the |
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| 14:41 | Okay. Um so uh membrane in is about you know, it creates |
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| 14:48 | barrier between the external internal environment of cell uh interface. What the what |
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| 14:53 | bacterial cell will sense from the outside be translated into a signal internally. |
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| 14:59 | that conversion of a signal outside being and then a function occurring in the |
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| 15:08 | . That's going to be happen through , other proteins in the on the |
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| 15:13 | or within the membrane. Um other of proteins as as you saw involved |
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| 15:18 | transport. Someone have structural functions um involved in communicate Torrey functions and some |
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| 15:26 | be real as factors. So attachment example. So um uh so bottom |
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| 15:34 | is the function member. It has going to basically be due to the |
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| 15:39 | . It has the selective permeability aspect the protein comes from the lipid bi |
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| 15:44 | . Right. And so that will transport of materials as well. And |
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| 15:50 | talk about that shortly. So hop are pro carry out specific um they |
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| 15:57 | of analogous to cholesterol in our And so they have kind of that |
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| 16:02 | structure you see there in the yellow helped to reinforce the integrity of the |
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| 16:09 | . They interact with the with the acid chains of the fossil lipids to |
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| 16:16 | . You know, we we draw uh fossil lipids like this where we |
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| 16:21 | a polar head group, right? is analogous to this portion of the |
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| 16:28 | . Okay. And then we have fatty acid chains which are going to |
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| 16:35 | hydrophobic. Okay, Water, water . And so when they come together |
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| 16:41 | form this array where the tails come and the polar heads are facing towards |
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| 16:47 | sides of the membrane, external Um And so again those fatty acids |
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| 16:53 | very hydrophobic. It's going to exclude molecules that are that are water |
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| 17:00 | Right? So that's where proteins come to provide a chance for them to |
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| 17:04 | in. Um So in terms of and types of of membrane lipid |
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| 17:15 | So we see the common types political . These are differentiated by length, |
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| 17:22 | asset change the number of carbons. By the type. Is it? |
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| 17:28 | it um a straight chain with no bonds, what we call saturated or |
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| 17:34 | it unsaturated containing double bonds? As see here? Because that will then |
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| 17:39 | for kinks to occur in chains. this can affect the fluidity of the |
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| 17:45 | . Ah And so the the cells adjusts, you know, the levels |
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| 17:51 | saturation, whether there's lots of double and lots of kinks versus more straight |
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| 17:56 | saturated based on you know, temperatures acute for that. So it will |
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| 18:01 | the fluidity of the membrane by affecting interactions between these uh fatty acid chains |
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| 18:10 | each other. So either packed very together or maybe not so much. |
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| 18:16 | that is dependent on kind of the often the queue for that to |
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| 18:21 | So the bottom line is for the to maintain an optimal membrane integrity so |
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| 18:28 | doesn't fall apart uh and so that proteins in there can still be functioning |
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| 18:34 | well. So there's an optimal level membrane fluidity which everything works optimally or |
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| 18:41 | best as it can. Um The what you don't want to happen is |
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| 18:45 | membrane to freeze or the membrane to conditioned so hot that the membrane falls |
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| 18:50 | . So it still has to adjust parameters so it can maintain that membrane |
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| 18:57 | whether it's increasing decreasing saturation or um length is another way to do |
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| 19:05 | And also um bacteria is disability to cyclists cycle ization of fatty acid chains |
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| 19:13 | form these. This creates a more straight structure where the financial change can |
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| 19:22 | together. Okay, if needed. bacteria has some unique adaptations, especially |
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| 19:28 | that particular ones that live in high . So your thermal files right. |
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| 19:32 | high temperature hypothermia files like uh temperatures excess of 80 C. So um |
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| 19:40 | has to be some kind of mechanism to maintain membrane integrity as such high |
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| 19:46 | because that kinetic energy of high temp force those those molecules to come |
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| 19:53 | And and uh and and obviously member function that way. Um And so |
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| 19:59 | have a membrane molecules that are based the ether linkage. What you see |
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| 20:08 | the box there is um bacterial lipids that linkage which tends to be a |
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| 20:17 | bit more susceptible to cleavage, but especially high camp, but the archaea |
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| 20:25 | live with these high temps have these link types and they connect in the |
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| 20:32 | you see there. So there you're the based on what's called a prion |
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| 20:37 | that forms these glycerol night ether molecules you see there and these will combine |
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| 20:47 | actually memorized to form very long And you see that they're very long |
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| 20:54 | chains. Okay, so that will the membrane possible to pack really close |
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| 21:01 | and allow them to the membrane to together during high temperature, which is |
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| 21:06 | these archaea bacteria live. Okay, and further it can it can also |
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| 21:12 | what's called cycle ization into these cyclops a little bit different from the bacterial |
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| 21:19 | which are this propane type of structure is a pen tain type structure, |
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| 21:25 | similar principle, it's kind of a chain. They can pack together very |
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| 21:32 | . And so a membrane that's constructed these kinds of molecules that you see |
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| 21:37 | uh here here here, that's a that can function at high temperatures because |
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| 21:47 | the fossils are kind of packed together and the membrane integrity is maintained |
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| 21:53 | um transport. So we're all familiar , you know, diffusion and principle |
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| 22:00 | diffusion. Um The uh passive process the movement of molecules passively means is |
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| 22:10 | by the direction of the concentration Remember that molecules diffuse passively without the |
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| 22:19 | of energy by moving from an area high to low concentration. They will |
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| 22:24 | that um spontaneously. And so um a passive process doesn't require energy. |
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| 22:32 | But there's two mechanisms there in terms of what kind of molecules being moved |
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| 22:37 | one that's kind of a relatively small non polar type molecules like oxygen or |
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| 22:42 | . 02. You see there, won't need help getting through a |
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| 22:46 | Uh They can freely pass through between the fossil lipid bi layer without |
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| 22:53 | Also, other other small polar molecules water can actually pass through Okay. |
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| 23:02 | some other types, but for things sugars, amino acids that are that |
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| 23:08 | bigger that are more polar molecules. markets that are charged, these cannot |
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| 23:14 | pass through or or diffuse very, slowly that it doesn't help to |
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| 23:20 | So they need to speed things And as the presence of proteins, |
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| 23:24 | channels transport proteins that will facilitate Hence the term facilitated diffusion. |
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| 23:30 | So its diffusion simple diffusion but facilitated the molecules need help getting through |
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| 23:36 | But that too is all based on a passive process monkeys moving from high |
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| 23:42 | low concentration. And then of course osmosis, right? That's the movement |
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| 23:46 | water. So a member of water going to move toward the high solid |
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| 23:52 | . Right? So selling remember the hyper tonic? Right? So hyper |
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| 24:00 | uh selling hyper tonic a cell that's tonic. Okay. Has a higher |
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| 24:07 | of solitude than it does outside. then water will move toward that high |
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| 24:12 | side to hydrate those salutes. And bacteria precarious in general tend try to |
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| 24:20 | a hyper tonic interior so water does in right slightly. Okay. So |
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| 24:27 | doing that we create osmotic pressure and bacteria have a cell wall. Most |
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| 24:32 | have a cell wall and that will them. So as the water comes |
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| 24:36 | they expand. But the cell wall of helps to um pressing against the |
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| 24:41 | membrane or rather that cell wall helps kind of maintain integrity. Right? |
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| 24:46 | it's a way for the bacteria actually to maintain their shape as well. |
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| 24:51 | . Um Now not. Yes there passive diffusion processes but um I need |
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| 25:01 | for a second. I should say missed aqua porn's. So I did |
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| 25:07 | that water can flow through by simple but there may be times when the |
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| 25:13 | of water needs to be sped Okay. And that's what aqua porn |
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| 25:17 | Aquaponics basically protein channel specific for Okay. So the bacterial cells under |
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| 25:23 | stress into rid of water or take water very rapidly to survive. Then |
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| 25:28 | porn's will be synthesized and putting the to facilitate that quicker diffusion of |
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| 25:36 | Okay, so that's that's kind of functions of Aqua porn, czar, |
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| 25:40 | so active transport. So of you know yourselves in nature, any |
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| 25:45 | in nature are going to be at mercy of in terms of salutes that |
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| 25:51 | need of what's in the environment and concentration is present in the environment. |
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| 25:55 | it's not going to be that all salute needs, so to speak are |
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| 25:59 | to be set up in a way they can all be come in or |
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| 26:04 | out passively. Okay material have to ions. They'll have to take them |
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| 26:12 | uh against the gradient, right? from low to high. Right, |
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| 26:18 | that involves an active transport process. . And so active requires energy. |
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| 26:26 | , and the abc transporters and group I've talked about in your chapter |
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| 26:33 | And those pages but I put it because it's relevant to transport which is |
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| 26:37 | we're talking about now but you know terms of transport uh you know nutrients |
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| 26:44 | , nutrients obviously have to be transported . So I've so far used the |
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| 26:48 | of gasses of course aerobic respiration and . The cells give off co two |
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| 26:54 | those that inspire and taking the water course. But things like amino acids |
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| 26:58 | sugars and nutrients need to be taken as well. And so abc transporters |
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| 27:04 | a very common way to do that well as group translocation. So with |
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| 27:11 | transporters you see the energy requirement there in a teepee utilizing process. And |
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| 27:18 | um these are very common for transport amino acids, various sugars. Uh |
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| 27:25 | so it will have a specific um protein that will bind that sugar and |
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| 27:31 | bind to the specific transporter and then binding plus a teepee. And analysis |
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| 27:38 | that channel and the solid comes Okay. But again these are these |
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| 27:43 | scenarios where the solute concentration out here low and in here it's high. |
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| 27:53 | we're going against the gradient. Uphill energy for that. Okay, similarly |
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| 27:59 | group translocation, this takes advantage of property of um that salute diffused independent |
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| 28:07 | each other. Okay so we have a substrate that is coming to the |
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| 28:14 | through a specific channel here we're looking glucose and mantle. And the entry |
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| 28:21 | the each solvent molecule is chemically transformed so glucose to glucose six |
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| 28:31 | So there's a substance associated with the protein carrying a phosphate group that will |
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| 28:36 | to the glucose. And now we've a different products. So glucose coming |
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| 28:43 | glucose six phosphate is what results so can continue to to diffuse in because |
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| 28:51 | not glucose. That's a committee inside cell it's glucose six phosphate. So |
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| 28:58 | movement will not come to equilibrium. other words equalized on both sides. |
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| 29:04 | then stop moving. But because glucose being transformed into glucose six phosphate, |
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| 29:10 | can continue to diffuse in because glucose not accumulating inside the cell is continually |
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| 29:16 | transformed into glucose six phosphate. And then glucose continues to diffuse in in |
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| 29:23 | scenario. Okay. And in actuality the um glucose six phosphate feeds right |
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| 29:33 | black colossus and sailor respiration. Um self cells can continue taking glucose and |
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| 29:41 | it for energy as they need as as it keeps being transformed. |
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| 29:46 | same from Mannitol Mannitol. We see same thing. Mantle's another carbohydrate that |
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| 29:51 | be used as energy and it's automatically into Mannitol one philosophy. And then |
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| 29:56 | into the pathway. So again, , Mannitol and glucose here are can |
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| 30:02 | come in as long as they keep modified to something else and that and |
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| 30:07 | allows for their transport. Okay? so I in gradients and serve a |
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| 30:15 | of different purposes. One of the ones here is as an energy storage |
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| 30:20 | , right? So you see here proton pump, we call it. |
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| 30:25 | this is an energy driving process that see here. Okay. Expending energy |
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| 30:31 | we have low concentration here high So we're driving them out. |
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| 30:36 | That's going to take energy to do . Okay. And energy is coming |
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| 30:42 | the hydraulics of https. And so so what's the what does this serve |
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| 30:49 | sell? Well, it's it's a we're basically storing energy here. And |
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| 30:54 | how how can I say that? because we're accumulating protons on one side |
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| 30:59 | the membrane. Okay. And that's to have a membrane membrane allows you |
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| 31:03 | create two sides if you will, you can create a concentration gradient. |
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| 31:08 | ? So in this case it's an process. So we're low inside |
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| 31:13 | external. Okay, So that those of protons represents a storage of |
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| 31:22 | And if we give those protons a to come back into the cells, |
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| 31:28 | their charge. You're not going to pass through the membrane. So but |
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| 31:32 | you can draw them in. Which they will freely do. |
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| 31:36 | They will diffuse in. Right. you give them give them a chance |
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| 31:40 | they will gladly diffuse from high to . Right? They'll pass that passive |
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| 31:44 | process. Look, but we have give them a pathway to do |
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| 31:47 | Okay, so just hold on to idea. Well, I'll show you |
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| 31:50 | other one. So, here's Okay, so the sucrose transport occurs |
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| 31:59 | mechanism again, that would that requires because we're pumping sucrose in. It's |
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| 32:08 | to come in from low to So that too is an active |
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| 32:11 | So what happens is we couple both . Right. So we'll take the |
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| 32:19 | gradient proton pump that's pumping protons And we'll have a transport protein that |
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| 32:26 | also accommodate the protons. So that the sucrose transporter has dual capabilities. |
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| 32:33 | can transport sucrose and protons and protons down their gradient now. Right. |
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| 32:38 | the protons are coming this way, by the sucrose transport protein. And |
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| 32:46 | if it takes energy to pump the out against the gradient, then it |
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| 32:53 | is a release of energy as they down the gradient. So, a |
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| 32:59 | process, a passive diffusion is coupled a release of energy as well. |
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| 33:06 | . And so that energy release as go down their gradient can be used |
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| 33:11 | pump protons in. I'm sorry, in that's going against their gradient. |
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| 33:16 | you basically uh use one process to the other. Okay. And this |
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| 33:22 | a much more efficient system. Because what's the alternative? The alternative is |
|
| 33:26 | go back here if the alternative is with sucrose by itself, is to |
|
| 33:33 | expand an A. T. Okay, or one or two of |
|
| 33:37 | to do this process. But we have to so doesn't have to do |
|
| 33:41 | because it's it's using the energy from transfers to do this. Okay. |
|
| 33:48 | moving down their gradient coupled to this , it helps sucrose come in, |
|
| 33:53 | energy release. So coupling energy processes releasing process with the energy requiring |
|
| 34:00 | Right? So with the expenditure of . T. P. To form |
|
| 34:04 | proton gradient. That's all we Because we can then use the energy |
|
| 34:08 | this proton gradient to fuel the entry sucrose. Right? And this this |
|
| 34:13 | this is a basic concept that happens the time in all living things, |
|
| 34:22 | a energy releasing process with energy requiring . It's basic thermodynamics and it's what |
|
| 34:30 | energetic. Right? And that's what everything in life. Okay. To |
|
| 34:35 | these two processes together and it's done different ways. This is one |
|
| 34:39 | Okay, But there's multiple ways. has done uh basically how life |
|
| 34:45 | Okay. And this is one way it happens. And proton and proton |
|
| 34:50 | are very common to do lots of for cells. Okay. Whether it's |
|
| 34:56 | , it can be movement of the . Um uh lots of lots of |
|
| 35:02 | of a TPS as we'll see in . So that's a very these are |
|
| 35:06 | that are very important for that reason permanent weak acids and bases. |
|
| 35:13 | so uh so these apply to um we gasses weak bases. These uh |
|
| 35:26 | partially dissociate. If you remember that from chemistry um the something like hydrochloric |
|
| 35:37 | will completely disassociate the hydrant irons and ions. Okay, just strong as |
|
| 35:45 | what strong acids do. The arrow all the way to the right, |
|
| 35:49 | getting nothing but protons, nothing but ions. Okay, that's the definition |
|
| 35:55 | a strong acid. Similarly strong base the same thing. They completely disassociate |
|
| 36:01 | products the weak acids week basis. not they only partially dissociate. So |
|
| 36:07 | you end up happening is in your tube. You'll see uh here's a |
|
| 36:12 | weak acid. You'll see this form form and this form in your test |
|
| 36:19 | , weak base. You'll see all these constituents in your test tube. |
|
| 36:24 | , Because you only have partial Okay, so all those constituents, |
|
| 36:31 | products and reactions are present in the tube because we're only having partial |
|
| 36:35 | So what is this place of parole is in markets like this? External |
|
| 36:40 | the cell um that the neutral Right? The the uh weak acid |
|
| 36:50 | this example. Right. Or the base? That's the component that's neutral |
|
| 36:55 | . Right? And can diffuse through membrane. Right? So here's our |
|
| 36:59 | acid diffuse that that form diffuses and in the cell we have partial association |
|
| 37:06 | that can generate production of protons. , ph is a function of hydrogen |
|
| 37:19 | concentration. Okay, so that weak comes in partially dissociate protons increase in |
|
| 37:27 | and the acidity increases ph drops similarly a weak base. Uh Basic enters |
|
| 37:35 | characters a proton from water and now form the ph rises right? The |
|
| 37:43 | iron concentration goes down and hydroxide iron goes up and become basic. Okay |
|
| 37:51 | , so bacterial cells kill cells will to deal with this uh counteract that |
|
| 37:58 | through buffers um to to maintain an internal ph Okay. Um you |
|
| 38:08 | memory impairment, weak acids bases are different types of preservatives and food have |
|
| 38:13 | properties. So like citric acid is common food ingredients. Uh amino benzoate |
|
| 38:19 | , papa P. A. A. Is when you often see |
|
| 38:22 | foods breads for example it's it's meant act as a preservative and acts that |
|
| 38:28 | because these chemicals are weak acids and have this effect themselves. This can |
|
| 38:35 | to inhibit growth basically what it does as a preservative. Okay so the |
|
| 38:48 | procreate cell envelope. So we're going slowly get here into into cell wall |
|
| 38:55 | and uh cell envelope differences and people and so forth. So the bacteria |
|
| 39:02 | killed in the membrane has can have on the species, depends on what |
|
| 39:07 | it is uh can have different levels beyond the inner membrane. Okay. |
|
| 39:14 | from cell wall what's called s layer membrane or variations of it can be |
|
| 39:22 | more complex than that micro bacterial species we'll look at here for example. |
|
| 39:27 | it could even be very simple. there's bacterial types that lack of cell |
|
| 39:32 | altogether. So um so we look we're gonna look at two major groups |
|
| 39:40 | in terms of bacteria and their envelope that were distinguished by the gram stain |
|
| 39:48 | positive gram negative and taxonomic lee. we'll talk a little about bacterial taxonomy |
|
| 39:55 | on semester but there's two major groups are called firm acute and proteus |
|
| 40:00 | Your firm acute group are your gram , propio bacteria are gram negatives. |
|
| 40:08 | Just in general. The grandstand in is um one that it's been around |
|
| 40:15 | a long time but still has value application. Um It is it can |
|
| 40:22 | a initial uh mechanism to begin to bacterial type. Um It can be |
|
| 40:33 | or presumptively diagnostic in cases depending on sample the patient's sample. Uh If |
|
| 40:41 | had strep throat you're luckily had a swab and that throat swab was streaked |
|
| 40:46 | blood auger. And you look for certain type of reaction on blood agar |
|
| 40:51 | that can be presumptive of strep Uh Do a grandstand. So if |
|
| 40:55 | see gram positive cox I. And and they produce a certain reaction on |
|
| 41:01 | harder then it does presumptive that the has strep throat similar. You can |
|
| 41:05 | it with other bodily samples uh at time that may be signaling infection. |
|
| 41:11 | the gram stain of morphology can lead to the proper isolate with the identity |
|
| 41:18 | the isolates. So it has value it is still used to this day |
|
| 41:22 | those purposes. Um regardless. Uh let's look at a little bit about |
|
| 41:28 | structure and function. So for mature have it. And again archaea that |
|
| 41:35 | it's not called pepper. The Black archaea. They have what's called pseudo |
|
| 41:40 | . Black and one of the sugars slightly different but regardless for those that |
|
| 41:44 | it, it serves as a barrier protection support. Uh it is porous |
|
| 41:52 | most things can pass through it um an envelope you'll have as you may |
|
| 41:59 | different, you'll have different levels of and and specificity as you get to |
|
| 42:05 | inner membrane which is going to be more selective than will be, |
|
| 42:09 | a a cell wall around it. , um the base structure. So |
|
| 42:15 | see the term memory there, that's of an older term but you still |
|
| 42:21 | it, they both refer to the thing, Mirian is peptidoglycan and what |
|
| 42:25 | is is basically a polymer sugars to bicycle rides. So that's the glide |
|
| 42:30 | part of the term refers to that , the sugar part that refers to |
|
| 42:34 | peptide part, protein asia as part the of the cell wall dissect |
|
| 42:40 | And you don't need to memorize the structures of these things, but it |
|
| 42:44 | help to memorize kind of how it's out in terms of structure wise. |
|
| 42:48 | so you'll have a a synthesized as single polymer. So they put the |
|
| 42:54 | together in the city close to label this G in the pseudo moronic |
|
| 43:00 | em right. And the cross bridging you see occurs between peptide chains containing |
|
| 43:10 | amino acids and when they're in when you're selling ceramic assets are in |
|
| 43:17 | , they will link up through cross and they connect themselves and that serves |
|
| 43:22 | help maintain the integrity of that um wall. Okay, it must have |
|
| 43:29 | cross bridging or off the wall becomes amenable to to breaking down and the |
|
| 43:36 | can lice. So it's important to those cross bridges in there. Um |
|
| 43:41 | also referred to as a secular. as I mentioned, it wraps around |
|
| 43:45 | cell is a rod safe, sell sell uh as mentioned earlier, will |
|
| 43:52 | to try to keep itself hyper So cell flows water flows in and |
|
| 43:56 | it does, the memory will swell press against that uh cell wall creating |
|
| 44:02 | osmotic pressure. Okay, so it to maintain the shape of the cell |
|
| 44:07 | well. Okay, um the now about bridging, so this is a |
|
| 44:16 | animation that will show you how this . So there's our chain play |
|
| 44:23 | I'd uh look like hand chain there we can close up at some of |
|
| 44:28 | connections. And so you see here peptide sequence. Okay, Ellen |
|
| 44:34 | tannic acid, di amino malic acid an unusual amino acid, it's common |
|
| 44:41 | the to the pepper look like. uh and it's actually at that particular |
|
| 44:46 | acid where the connection occurs. Um and and to al means, |
|
| 44:52 | what happens is and here's the moronic . So the peptides are always linked |
|
| 44:58 | the moronic acid portion. Okay, so they will in proximity to each |
|
| 45:03 | , they will connect as such and terminal valentine is what will leave. |
|
| 45:11 | that occurs and then this occurs. now we have the cross bridging is |
|
| 45:15 | . And um so but again that operating essentially kind of holding that whole |
|
| 45:21 | together among other things as well. so it's critical to have that. |
|
| 45:27 | so uh you know and for that the cross bridging that's that's there's lots |
|
| 45:34 | enzymes involved in synthesis of the cell synthesis of the sugars uh linking the |
|
| 45:41 | together. Uh production of the peptides the peptides together. So lots of |
|
| 45:48 | the bacteria has to synthesize this. so those are all potential targets for |
|
| 45:54 | because of course we don't have cell like this or at all. And |
|
| 46:00 | these antibiotics won't affect us but they target certain of these types of |
|
| 46:06 | So your penicillin of course, is many of these targets these talks the |
|
| 46:13 | that creates these cross bridging and banco is another one that that binds that |
|
| 46:20 | allergy. Okay so if you bind example let me just go back a |
|
| 46:27 | . If you bind here the bank mice and binds here then it's going |
|
| 46:34 | prevent that enzyme from bringing those substrates and linking them. So you don't |
|
| 46:40 | the cross bridging effect. Okay so now of course bacteria have devised evolved |
|
| 46:47 | to get around these issues beta lacto among them this is enzyme resistant types |
|
| 46:54 | that can actually just destroy the penicillin in activating it so destroy penicillin. |
|
| 47:01 | can't affect the cross bridging enzyme vancomycin . Um but you can um that |
|
| 47:09 | resistant to make a mess and have acquired mutations that um created a change |
|
| 47:21 | that they didn't have a terminal. had they have a different molecule |
|
| 47:27 | I think I've seen lactate has been for Halloween for example in some of |
|
| 47:31 | mutants. And if you change the terminal molecule there is not a lien |
|
| 47:37 | something else. Then uh the bank my son won't recognize it and Vancouver |
|
| 47:44 | buy it and do anything. So offers resistance sent by the bacteria to |
|
| 47:49 | antibiotic. Um The other thing to is the peptide sequence there. The |
|
| 48:00 | tannic acid, malic acid alkaline. that's a fairly common sequence. But |
|
| 48:05 | are bacterial types that have the cross but maybe don't have the same amino |
|
| 48:10 | or sequence. Okay, so I wanted to mention that um synthesis of |
|
| 48:16 | like and as mentioned is the extension the chain uh like and change the |
|
| 48:22 | of the sugars. And so you this complex there. So looking at |
|
| 48:28 | we're actually looking at a gram Okay, I know we don't know |
|
| 48:31 | that is yet. But the gram has an outer membrane that you see |
|
| 48:36 | uh inter membrane regardless um synthesis since gonna be very similar to gram positive |
|
| 48:43 | negative. And so you see the like hand change indicated by the arrow |
|
| 48:47 | this multi protein complex that's carrying out synthesis. And then this molecule called |
|
| 48:53 | . R. E. B. talk about that in the part two |
|
| 48:58 | this chapter three material. That's a a bacterial psycho skeletal element. Your |
|
| 49:05 | with these kinds of psycho skeletal features eukaryotic cells, things like acting um |
|
| 49:12 | tubules, um intermediate filaments. These these are the site of skeletal elements |
|
| 49:19 | learned about intro bio. Well, have have some of this as |
|
| 49:24 | M. R. E. Is actually was shown to be kind |
|
| 49:28 | analogous to act influence that ourselves And so you see the M. |
|
| 49:33 | . E. B. Here comes and forms kind of like a a |
|
| 49:40 | for this complex to synthesize. Um wall material. Okay. And the |
|
| 49:47 | . R. E B is a that will complain arise you can add |
|
| 49:51 | units to increase its length and it of acts as a way to get |
|
| 49:56 | occurring along along the path of that . R. E. B |
|
| 50:02 | Okay. Kind of guiding the complex synthesis of it. Okay, so |
|
| 50:06 | see several in the rod shaped it looks like this. So you |
|
| 50:10 | different points where synthesis of materials occurring it's that complex here is being added |
|
| 50:18 | these threads of this M. E. B material. Okay. |
|
| 50:23 | so that sets up so in different types whether it's a rod or |
|
| 50:27 | You can have differences. And how peptidoglycan synthesized. Okay and so you |
|
| 50:34 | here kind of different zones around the of the cell, in this |
|
| 50:40 | in that direction. Okay um in in the cock see you have it |
|
| 50:48 | along the what's called the equity of cell if you will the middle, |
|
| 50:53 | where it occurs. Okay uh you have growth maybe just at one end |
|
| 50:58 | see here. Okay uh that's for types of that's the way it |
|
| 51:03 | But I mean the submissions that carried are gonna be the same but they |
|
| 51:08 | have may have a different mechanism of they where where synthesis occurs in the |
|
| 51:15 | . Okay and so um the but key here is that is synthesized you |
|
| 51:24 | as as as a polymer. The. Okay so comparing gram positive |
|
| 51:31 | gram negative bacteria. Okay they sell of these two types here. You |
|
| 51:36 | the basic differences between one and the . Okay so um the um on |
|
| 51:48 | left the grand positive envelope um one has well it has a very thick |
|
| 51:57 | and that's the thing that you feature is the thickness of it compared to |
|
| 52:03 | gram negative. Right. So much uh material. Uh Tycho acids are |
|
| 52:12 | then we'll talk about that here in second but coke acids um span the |
|
| 52:18 | of the peptidoglycan layer only found in positives. Okay, not in gram |
|
| 52:27 | . So will span the length and as reinforcements. So you'll have the |
|
| 52:31 | bridging plus the tai kok acids which as a as a as a further |
|
| 52:38 | support for that structure which is necessary it's so thick and gram positive and |
|
| 52:45 | to the inner membrane you may And then you may see an S |
|
| 52:50 | as well uh basically protein carbohydrate in that kind of acts as a a |
|
| 52:57 | if you will around the south the gram negative you see on the |
|
| 53:06 | , that has multiple layers. We have the inner membrane of |
|
| 53:12 | But then we have optical I can then we have an outer membrane. |
|
| 53:17 | . And so the outer membrane has lot of lipid material in it. |
|
| 53:22 | , It has transporters in it as . Right. We have the creation |
|
| 53:27 | because of the layers we have what's called a pair of plastic space |
|
| 53:32 | the middle there where that contains the wall. So um so, gram |
|
| 53:38 | envelope is quite different in that Okay, now, the Grand positive |
|
| 53:45 | to speaking, not as not as features to to go over. |
|
| 53:50 | other than cold gasses will help to the cell wall. Okay, and |
|
| 53:54 | see the structure there. Um They served to to help maintain the integrity |
|
| 54:02 | that cell wall within within that to cell membrane. Now the slayer is |
|
| 54:11 | of a net if you will a net of protein could be glycoprotein which |
|
| 54:16 | sugar and protein. Together it's it's porous. Um It's not as well |
|
| 54:24 | . Uh Here's a kind of electron kind of illustrating a model of what |
|
| 54:32 | might look like. Um But the slayer again is not um not a |
|
| 54:40 | is known about it. Uh There some evidence that for those that have |
|
| 54:44 | , it may even be a may be serving an attachment uh can |
|
| 54:50 | protection. Perhaps uh problem with S is that if you culture cells in |
|
| 54:56 | lab and maintain them in the lab contend to lose the S. |
|
| 55:01 | And so for that reason it can to become kind of difficult to figure |
|
| 55:07 | what it does but when the experiments been done it's kind of thought they |
|
| 55:11 | this kind of protective uh function uh for some types of attachment. Maybe |
|
| 55:20 | maybe a function of it as Okay. Um There can even be |
|
| 55:26 | know among archaea can have an Layer and you know have an inner |
|
| 55:32 | an S layer. Nothing else. you'll see some of these variations as |
|
| 55:36 | . Okay and the gram negative envelope um a thinner cell wall as we |
|
| 55:44 | much thinner layer of. Technical I uh it is anchored within that space |
|
| 55:51 | what's called the marine lipoprotein that you here. Okay, so that anchors |
|
| 56:00 | couple of light can in the in uh para plastic space to that inner |
|
| 56:11 | of the outer membrane. It does the uh here's the cross selecting peptide |
|
| 56:18 | there. So um but again we this outer layer, right this outer |
|
| 56:24 | layer up here. Okay. And you can even see within that outer |
|
| 56:31 | layer that both sides of it, know one side of the membrane and |
|
| 56:36 | other side that they actually can differ some places. So you see these |
|
| 56:40 | large uh these right here molecules um what's called lipid, a material attached |
|
| 56:52 | a court policy. Sacha ride attached a long strand of what's called an |
|
| 56:57 | polish Sacha ride. Okay, so very complex structure. Um and so |
|
| 57:04 | we look a little closer at Okay, the outer membrane is porous |
|
| 57:09 | a lot of different chemicals. Um I said before, the the ferocity |
|
| 57:16 | specificity tends to increase as you go in. So the inner membrane is |
|
| 57:20 | to be pretty selective and what allows but um and and for that reason |
|
| 57:27 | have differences in membrane proteins in the membrane versus the inner membrane. |
|
| 57:34 | Um and again, it's specificity maybe not specific in the outer membrane and |
|
| 57:39 | specific certainly in the inner membrane as pass through the and here's kind of |
|
| 57:46 | up structure of this. What we out here in this outer membrane. |
|
| 57:53 | and so um the lipid a material comprises this portion um is linked to |
|
| 58:04 | core policy Sacha right here and then a old place sack right out here |
|
| 58:10 | is a large repeating units of sugar um Can be 30 or 40 or |
|
| 58:20 | units long. Um The it has it can have produced an immunological |
|
| 58:31 | Okay that that that portion that's sitting the outer membrane uh the body can |
|
| 58:38 | produce an immune response to that and where the term oh engine comes |
|
| 58:42 | Okay. We've all heard of Equal . 0157. That's the pathogen strain |
|
| 58:48 | can cause food poisoning um uh has implicated a number of different outbreaks uh |
|
| 58:56 | Chipotle and the produce used lettuce for regardless. So the uh the old |
|
| 59:05 | refers to that old policy Sacha And we have characterized hundreds if not |
|
| 59:12 | of E coli strains and related strains salmonella based on the engine. And |
|
| 59:18 | it's a it's a it's a way to identify them. You can identify |
|
| 59:21 | by that particular having that particular um to the engine and identified that way |
|
| 59:28 | the H engine can also be produced immune response and that's due to the |
|
| 59:34 | of bacteria that has it. Okay that too is actually e coli uh |
|
| 59:40 | can identify equalized through O. And . Engines at least medically important |
|
| 59:46 | Um and now the end of toxic so that that occurs as a result |
|
| 59:52 | the lipid eight material. Okay. only when the gram negative cell dies |
|
| 59:58 | china. So the gram negative cell . If it licenses then the material |
|
| 60:03 | released. Okay. Um and potentially gram negative is can produce this effect |
|
| 60:12 | . Uh the lipid a material okay um produce an immune response by the |
|
| 60:21 | . The problem with it is it say if it's a gram negative infection |
|
| 60:25 | kind of spread throughout the body and the blood. If those cells die |
|
| 60:30 | can release a lot of this material once that travels throughout the body and |
|
| 60:35 | a super hyper immune response and it the body and you can actually go |
|
| 60:40 | shock. So we'll talk more about in the last part of the |
|
| 60:46 | But the end of toxic effects is something to consider if one has a |
|
| 60:50 | negative infection. Okay. And among more well known maybe more important gram |
|
| 60:58 | infections or things like uh meningitis is of those um plague um of course |
|
| 61:07 | the equally strains that cause foodborne disease and others. So infectious gram negative |
|
| 61:14 | are which have to be aware of terms of this this endo toxin effect |
|
| 61:18 | uh can cause problems in persons infected these this toxin effect. Again only |
|
| 61:26 | negatives with this the para plasm that just to mention that, remember that |
|
| 61:31 | have of course now, a layer between that's in between the inner and |
|
| 61:37 | membranes that we call it para plasm it too can contain, you |
|
| 61:41 | particular types of proteins, enzymes and that you won't see in the outer |
|
| 61:50 | or inner membrane. Um Oftentimes they're shuttle proteins that help molecules get from |
|
| 61:57 | outer to the inner membrane. So can see uh some different constituents in |
|
| 62:02 | that you won't see any other Um No a typical types of cell |
|
| 62:10 | . Um Mycoplasma, so we're gonna about to hear the term michael um |
|
| 62:19 | . Okay, so make sure you confuse yourself. Um here. |
|
| 62:27 | so mycoplasma do not have a cell there, bacterial type that lack of |
|
| 62:32 | wall. These mycoplasma species are asking pathogens um and actually infect your own |
|
| 62:41 | of the lungs and cause respiratory Um pneumonia is actually a type of |
|
| 62:47 | , But they do lack of soul there are small, they have among |
|
| 62:51 | smallest genomes of bacterial types, like the 500,000 base parasites. Archaea are |
|
| 63:00 | as I mentioned, they those that a cell wall uh will be similar |
|
| 63:05 | not identical to the pep look like . It's what they call pseudo pep |
|
| 63:10 | like. An or pseudo mirroring, say roughly among archaea uh can give |
|
| 63:18 | percentage, I must say that it's 50 50. Some have some half |
|
| 63:22 | half soul half don't but it's not common as it is in bacteria I |
|
| 63:29 | say. Um Now the micro remember michael bacteria is different from |
|
| 63:36 | Okay so micro bacteria do have a envelope that contains pep level. I |
|
| 63:41 | . Okay so your familiarity with this is tuberculosis, leprosy. And um |
|
| 63:49 | often times when you when you grow whether it's on solid or liquid |
|
| 63:56 | the way it grows and the appearance provides can sometimes be a clue as |
|
| 64:03 | as to you know their their chemical in some cases particularly their cell |
|
| 64:08 | And that's certainly the case for And so you see there in liquid |
|
| 64:13 | is the tube that's on these two on the right here, right here |
|
| 64:22 | has growth occurring just at the air interface. It's all concentrated right there |
|
| 64:29 | the air liquid interface on the right a colony and a very unusual looking |
|
| 64:33 | . If you were to stick your loop into there it would have like |
|
| 64:38 | very kind of crusty texture to Right? So very unusual. And |
|
| 64:44 | all relates to the nature of its envelope. Okay, so here you |
|
| 64:49 | a cross section of a cell envelope micro bacteria. There is the peptic |
|
| 64:56 | counter So they do have so Okay. But they but they mostly |
|
| 65:01 | these other constituents which are rich in . My colleague acids write very long |
|
| 65:10 | chains. Uh carbon chains of these kind of waxy lipids, they call |
|
| 65:18 | colic acids interspersed throughout that envelope along fossil lipids. Um And and of |
|
| 65:26 | attachment there. So the cell wall like can and the folic acids are |
|
| 65:32 | of linked to each other through this on these Robin on chains which is |
|
| 65:37 | type of carbohydrate that you see Okay. And provision for a very |
|
| 65:44 | kind of envelope in these cells. this material is very very hydrophobic. |
|
| 65:49 | they kind of tend to stick together they grow and that's why they look |
|
| 65:54 | they do whether it's in liquid culture of sticking together, repelled by water |
|
| 65:58 | a degree and kind of sitting at top there on a on a plate |
|
| 66:01 | have kind of that waxy crusty appearance that reason. Okay. It's the |
|
| 66:07 | also for you don't really use the stain on these types of bacteria. |
|
| 66:11 | what's called acid fast which involves applying but then using heat to drive it |
|
| 66:18 | the into the cell. And uh but this very thick um envelope uh |
|
| 66:27 | why they grow rather slowly and why can be difficult to treat with antibiotics |
|
| 66:32 | . E. Tuberculosis. Um because that thick envelope slows down diffusion of |
|
| 66:39 | into the cell. So it makes them having to grow slower because the |
|
| 66:45 | of nutrients is slow getting across the . But as well those that are |
|
| 66:51 | like tuberculosis are more resistant to antibiotics the antibiotics have a hard time getting |
|
| 66:58 | there as well. So um it's of the unique things about this this |
|
| 67:02 | type, this this unusual envelope. now structure is external to the salon |
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| 67:11 | . You just see the three the examples here. So capsule, a |
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| 67:15 | layer and a biofilm. Okay. the the capsule and slam layers are |
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| 67:22 | of individual bacterial cell types. The is a result of as a feature |
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| 67:28 | a collection of microorganisms that are part the biofilm. Okay. The capsule |
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| 67:34 | a is a is a um assemblage to play sax player. Typically it |
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| 67:41 | be a place aka right and maybe tenacious and well depending on the species |
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| 67:45 | it's very well stuck to the It's it's a it's a gene encoded |
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| 67:52 | uh component. Okay. And uh as I mentioned earlier can be a |
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| 67:58 | factor. It tightly bound to that surface um covers basically the components on |
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| 68:05 | periphery. Uh for pathogens you know can it can hide proteins and the |
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| 68:12 | and things that normally the cell could to immunologically but because they're covered with |
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| 68:17 | capsule, they resist that effects are as easily detected. And as well |
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| 68:23 | not as easily figure sanitized by cells try to buy our own cells like |
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| 68:30 | and neutrophils and things that uh that job is to eat the so to |
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| 68:36 | , ties. They encapsulated cells tend kind of resist this and artist easily |
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| 68:41 | ties. So a lot of your pathogens will have a capsule for that |
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| 68:46 | . Uh The contrast that with the there so slam there is not a |
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| 68:51 | encoded component, a slime layer is a byproduct of metabolism. Um and |
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| 68:59 | example growing up lots of sugar or like that, it'll exude some of |
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| 69:03 | material and kind of it'll just kind hang on to the cells, so |
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| 69:08 | speak. Um And and as as of a looser assemblage, I mean |
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| 69:16 | know that in itself can afford some sell some protection just by having this |
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| 69:20 | around its surface. But again, it's typically something that's just a product |
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| 69:26 | their by part of their metabolism metabolism secreted out. Okay, the biofilm |
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| 69:32 | course is Is part of the process we'll talk about. We'll talk about |
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| 69:37 | in Chapter four. But biofilm is assemblage of of bacteria. Uh and |
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| 69:44 | not a random process. It's a a gene uh controlled process initiated by |
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| 69:53 | but one of the one of the of that is to produce this this |
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| 69:58 | eggs. Op ah Limmer material which place Zachariah generally partially protein in nature |
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| 70:05 | is kind of the glue that holds all together and that of course is |
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| 70:11 | by the cells and is external so can kind of put it in this |
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| 70:14 | this category. Okay so um so are the main things about topics for |
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| 70:21 | first part. Um So you know kind of a self check if you |
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| 70:28 | you if you get this uh the basic you know just just draw draw |
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| 70:32 | rod shape on your paper or your bacterial shape paper and then kind of |
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| 70:37 | if you can go through and okay are the different components? Um Could |
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| 70:43 | label it? Could you could you define the functions of some of these |
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| 70:47 | these structures? Um That's that I it's really yourself checked to see do |
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| 70:53 | really understand this? Okay and of the the basics of things like I'm |
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| 70:59 | I'm assuming you already been exposed as bio the transport the osmosis and active |
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| 71:06 | . Um The of course certainly the the cell envelope difference between gram negative |
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| 71:14 | positive and understanding that and what that's um compare and contrast those two types |
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| 71:20 | gram negative gram positive and some of ones that don't fit that mold your |
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| 71:24 | bacteria, mycoplasma archaea. And then in this section the structure is external |
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| 71:31 | a cell wall or cell envelope should capsule slime layers biofilm. Okay but |
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| 71:38 | do do know that you know that envelope? Okay and how it's different |
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| 71:43 | cell wall, Right. Cell envelope or may not have a cell wall |
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| 71:46 | on the species. Okay. So two things are mean different. An |
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| 71:51 | can contain a cell wall. But it doesn't have to so don't |
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| 71:56 | think those terms are synonymous with each . Okay. Um Alright. So |
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| 72:02 | will conclude the part one and part . We'll finish up the rest of |
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| 72:06 | of the procuring of cell structures and . Thank you |
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