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BIOL 2301 Human Anatomy & Physiology I - BIOL2301 lecture04_0125
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00:04 All right. It looks like everything up and running. Um We finally
00:09 some sunlight y and then it's gonna cold, then it's gonna rain.
00:18 right, today, what we're gonna is we're going to talk about the
00:24 and that's also what we're going to doing on Tuesday next week. Is
00:28 Thursday? Yeah. So Tuesday next . All right. So what we're
00:32 at here is just kind of the picture and overview and really the easiest
00:36 about the cell or learning about the is draw yourself a picture. Do
00:41 remember that first day of that, uh biology class you took in high
00:46 and they pulled out the microscopes that like 50 years old and they
00:49 look in the picture and draw what see and you drew a picture of
00:52 cell and it was like this little blob thing with dots in it.
00:55 so that's what you drew. that's, that's OK. You can
00:59 like that. All right, you need to do the stuff that you
01:02 up here, which is 3D and not an accurate representation. But the
01:06 here is part of learning. Some this material requires you to actually get
01:12 hands busy and draw things out so you have a visual representation. Other
01:16 just a bunch of words, the itself actually is pretty straightforward. It
01:21 three parts to it. And really of these parts, the nucleus kind
01:25 falls into this category of organelles that gonna get to in just a
01:28 But you can think about it this , the cell is a specialized compartment
01:33 the body that does something special. know how we keep coming back to
01:36 theme of compartmentalization. So this might something that you kind of like,
01:40 wait, maybe I should be paying about compartments and what they do.
01:44 so the way that we create this is by creating a or having a
01:49 membrane, the plasma membrane in this is this pink thing here, it's
01:53 serve as that barrier that divides the of the cell from the outside of
01:57 cell. Later on. I think the next lecture, we're gonna spend
02:01 a bit of time talking about the membrane. We're gonna have a little
02:04 of time talking about it today. I'll be honest when I was in
02:07 seat, when people started talking plasma , I got bored out of my
02:11 and I fell asleep usually in most my classes. So if you do
02:15 I understand because it's not all that until you put into perspective of what
02:19 actually does. The second thing is stuff inside the cell. This is
02:24 cytoplasm. All right, the cytoplasm all the material that the cell uses
02:30 do its job. And so what has within there is the organelles which
02:34 compartments inside the compartments. And what have is also the cytozole. All
02:40 . So the cytozole is the the goo that does, that contains
02:45 that aren't specifically hidden inside the And then the last thing and we
02:50 of just set it off as something because this is what humans like to
02:54 . We like to identify things go special and put a big giant star
02:57 it. But one of the organelles called the nucleus and the nucleus is
03:02 the control center for that cell. when we say control center, it's
03:07 acting as a brain. But what does, it contains that hereditary
03:10 the chromosomes and within the context of chromosomes are all the genes that that
03:16 is using to have the instructions to all the machinery that that cell is
03:20 use, so it can do its . And so that's why we consider
03:24 special. Now, when I say the genes and all the uh hereditary
03:29 , that is a lie. Because we are gonna see a little
03:33 later here that some of the DNA not actually inside the nucleus and it
03:37 everything all screwed up and stuff like . But the simple thing is,
03:41 just think of the nucleus having all DNA. All right. So this
03:46 our frame of reference. And so gonna start with the cytoplasm and I
03:51 see that it is recording. by the way, if you do
03:54 on and try to find a recording Tuesday and it's like, oh,
03:57 no sound. And what happened? that, that's Doctor Wayne being an
04:01 . That's why I said you gotta for that little orange light because I
04:03 press the button. But if there a video missing or if it gets
04:07 up or whatever, you can always the previous semester. Like the fall
04:12 semester. Uh 23 has a really lecture for that for that class.
04:17 just same place you go. Just for the previous semester. All
04:22 Now, back to our story We have the cytoplasm cytoplasm, as
04:27 said, is the material encased within plasma membrane if you think of the
04:32 where you live. All right, it be a house, a dorm
04:36 or an apartment, your space is by the walls and the door that
04:41 you in and out of that But everything inside that is your
04:45 even if it's shared with a All right. And that would be
04:50 equivalent of the cytoplasm. So all furniture uh is the stuff that's in
04:54 cytoplasm. Well, inside your inside the apartment, ho home or
05:00 room. Right. And that's kind what we have here is when we
05:03 about the cytoplasm, we're talking about the stuff. All right.
05:07 within the cytoplasm, we have three things that we define within it.
05:13 right, the cytosol is the All right, we have up here
05:17 fluid. So that's water, plus solutes, the things that are dissolved
05:22 it, plus some other materials. it'd be like for example,
05:26 there might be some sugars, there's things that are just too numerous and
05:30 worth naming for our purposes in this . So when you think about
05:34 it's like if I put a pin a cell, the stuff that would
05:38 out the water, plus the stuff the C is all. All right
05:42 suspended within the cytozole are the organelles the organelles. As we said,
05:47 are specialized compartments that are used by cell to do the things that the
05:53 does. So we refer to as metabolic machinery. All right. So
05:58 like the factory portions of the We're gonna go through all the important
06:02 . And then the last thing are are called inclusions. And these are
06:06 things that was like, well, too small or sorry, they're too
06:09 to be a uh dissolved substance, ? So it's not a protein,
06:15 not necessarily a sugar or something like . It's too big to be
06:18 but it's too small to be an . So we have to include
06:21 So we're gonna call it an All right. Now, what do
06:26 look like? Well, this could like glycogen, for example, it's
06:29 a molecule but it's not something that's in there. It could be like
06:33 . Um If you're looking at for example, you know how flowers
06:37 pretty because of all the cute little . The reason they're pretty and they
06:40 the cute little colors because they have of pigment inside the C is all
06:45 right. That would be the All right. And then some cases
06:49 might even see crystals. All And again, not so much in
06:54 , but they do exist in some . We'll see a picture a little
06:57 later showing you like what one of kind of crystals kinda look like?
07:01 right. So what we wanna do we're gonna ignore the side of off
07:04 now, we're gonna ignore the What I wanna do is I wanna
07:07 in on these organelles because these are interesting things, these are the things
07:11 tell the story of the cell. so there are different types of
07:15 They fall into two basic categories. textbooks are really bad. Because people
07:20 write chapters or these textbooks aren't experts everything. And so they don't know
07:25 to call half of these, these of organelles. So the first group
07:29 the easy one. They're the membrane organelles. So they consist or
07:33 they're, they're contained, the materials them are contained by a, the
07:38 material that makes up the plasma So it's a lipid bilayer. All
07:43 . And so what we're gonna see that they're actually continuous. But what
07:47 doing is we're creating a unique compartment the cell, do something unique.
07:53 which is why we're able to define that mem or what that organelle
07:58 All right. And again, we've used this example, but it's easy
08:01 come back to in your apartment, your dorm room, in your
08:04 you have a bathroom, you have kitchen, you have a living
08:07 you have a bedroom, each of are uniquely defined because they have a
08:12 job, right? And so keeping it simple. If the bedroom
08:18 for sleeping, it's for sleeping because has the materials necessary for sleeping,
08:23 instance, a bed. All And so when you look at an
08:27 , it is defined by that one that's contained by a plasma
08:32 But two, it has all the it needs inside it to do the
08:37 types of chemical reactions that it is to do. All right. And
08:42 gonna walk through each of these as go along. All right.
08:45 the examples of these, of these bound, we're gonna starts with the
08:50 that we separated already called the nucleus the nucleus. The next one would
08:54 the endoplasmic reticulum from the endoplasmic We have the goi apparatus, then
09:00 have peroxisome and I think is Oh Yeah, the mitochondria and the
09:04 are also included in this. All . And we're gonna learn what each
09:07 them do. And I'm gonna give simple definitions. Like I just told
09:11 , the nucleus is like a what like a brain? Is it a
09:17 ? It is not a brain? right. So we're gonna give you
09:21 to help you best understand what it even though it's not a perfect
09:26 All right, the next group you'll see listed as uh um the uh
09:34 membrane, the lacking a membrane or say something along those lines. And
09:39 , that's incorrect. The best way refer to this other group of organelles
09:44 you call them biomolecular complexes. And just a fancy word for saying a
09:48 of molecules that have been jammed together act together. All right, if
09:52 see another one like uh uh membrane or membrane uh organelles or something like
09:59 , that's just bad writing. All , that's not what they're called.
10:03 would look at you funny and people the field would look at you
10:07 All right. So what these are I said, there are lots of
10:11 that have been jammed together. So see them listed as macro molecules.
10:15 large molecule complexes, they have a function, just like these have a
10:20 function, but they're not bound by specialized membrane to create a compartment.
10:26 found within the cytosol and materials are to them or they're shifted to a
10:32 to do the things that they're designed do. And some examples of this
10:35 be ribosomes, the centrioles as well the molecules that make up the
10:41 All right. And when you hear side of skeleton, you already picked
10:44 skeleton, don't you? I hope do. All right. So that's
10:48 another example. We're calling it a of skeleton because it acts like a
10:52 , but it's not quite a So we start with the eye of
10:58 kind of looks like an iron and is the nucleus. All right.
11:02 so you'd see this structure and you're , well, isn't this the
11:05 No, it's not. This is actual nucleus and it has stuff on
11:08 inside. And if you look carefully , you can see that there's kind
11:11 this little blackish grayish stuff that's sitting the edges that is there on
11:17 All right. And it's representing some the nuclear material that's in the
11:23 Now, what we are talking about is a structure that tends to be
11:26 largest organelle in the, in the . It's very obvious when you look
11:31 a cell, like I said, you're back there in ninth grade and
11:34 took the biology class or maybe you a sophomore, you looked in a
11:37 , you saw a picture of a that looked like a blob that you
11:39 really identify, but at least it a big giant.in it that you could
11:44 , right. That's why you see . It's so big relative to the
11:48 of the stuff in the cell. , the purpose of the nucleus is
11:53 it contains all these hereditary materials, DNA. And so what we say
11:59 that this is a place where DNA occurs. Now, when you hear
12:03 replication, what we're talking about here taking a cell and actually creating a
12:08 another cell from it. But to that, both cells have to have
12:12 same DNA. And so this is we're going to make that DNA.
12:16 not its only job. It contains the hereditary information. So this is
12:21 storehouse for all the instructions that the needs to do its function,
12:26 And so within this, you're gonna the chromatin, you'll have a
12:32 And then structurally there is a barrier the nuclear envelope that is kind of
12:38 relative to the other organelles, which call the nuclear envelope. All right
12:43 , this picture here shows you that envelope. Now, if you're not
12:48 , you have a lot of DNA each of your cells. Uh The
12:53 genome contains within it about 33,000 And each of these genes don't encode
12:58 one protein. They can be rearranged , and uh modified during the process
13:03 making RN A. So you actually more proteins than you actually have genes
13:09 . And we'll get into that a bit, but not a lot.
13:12 because it's not really so important for guys. But one of the things
13:15 might ask yourself if it's like, I have 33,000 genes, how does
13:19 cell figure out which genes to And where wouldn't you kind of like
13:23 know that? And the answer is that it's all organized. The hard
13:30 is we don't know how it's but it is organized. And part
13:35 that is because of this nuclear envelope the nuclear envelope right here. So
13:41 can see there's two layers to there's an inside layer and then there's
13:44 outside layer, the outer membrane or outer layer is continuous with the next
13:50 . All right, the next organelle the endoplasmic reticulum. So just kind
13:55 set that over to the side. get to that in just a moment
13:58 interested in what's going on inside. you can see here on the inner
14:01 it has this weird lattice work and lattice work is what contains and monitors
14:08 not monitors but, but, but to organize the DNA so that the
14:14 and the materials inside the nucleus know to find the genes it needs.
14:18 right. So that's what this blue is representing. This chromatin here is
14:24 DNA and this white stuff is supposed represent the machinery or the,
14:31 the molecules that help organize that. right. So that would be the
14:34 lamina. And then whenever you make A because RN A is made in
14:41 nucleus and then it's sent out of nucleus, you need to have a
14:44 to go out and you have to a way for things to come in
14:47 the nucleus as well. And so gonna have nuclear pores and those nuclear
14:52 are very specific to what it allows and what it allows in these are
14:56 just doors that things can wander in out. So in the cartoon,
15:01 kind of draw it as a basket really what this basket does is it
15:05 to make sure that the things that moving in and out have the right
15:08 or the right a molecular sequence associated it to allow it to go in
15:13 go out. So it, it's of a regulator of what is allowed
15:18 move across that membrane. All And that's what you're kind of seeing
15:22 this picture. All right. So space membrane is a nuclear envelope.
15:31 helps organize the chromatin, the DNA it regulates the movement of materials both
15:36 and out so that the nucleus can appropriately. Now, we have the
15:42 giant ball in the center. And can see here here's an electron micrograph
15:46 you can see that you have this stuff and then you can see over
15:49 that is the nucleolus, it's like eye inside the eye. And for
15:54 most part, we're still not 100% what the nucleolus is responsible for.
15:58 one of the things we do know it's responsible for is making a type
16:02 RN A called ribosome RN A ribosome A is used to help make
16:09 Yes, ma'am. They cross both them. So, so it's
16:16 it's a structure of proteins that basically a, a path. And so
16:22 crosses from the, from the inner and goes and opens up on the
16:28 . Yeah. So what we're gonna is we're gonna take these uh these
16:33 ribosome sub units and we uh put together and it helps to form the
16:38 , which we'll talk about in just moment. All right now, as
16:42 learn more and our technology gets we can actually learn more. I
16:46 probably put it that way as technology better, we're able to identify and
16:49 experiments better. And so we're starting discover that nucleolus is actually more functional
16:54 just making our RN A. But our purposes, you can just say
16:58 prominent structure helps to make uh Ribozel A that should be good enough to
17:04 . And so with the nucleus containing nuclear material, and it allows it
17:08 make RN A which will use as sets to um do all the stuff
17:15 the cell. We need to take RN A and send it someplace.
17:18 so one of the places that we're send the RN A is to the
17:22 called the endoplasmic reticulum. All The other place it's gonna go,
17:27 RN A goes, goes to the . All right. Now, there
17:30 two different types of endoplasmic reticulum. have one that has bumps on
17:35 So when you look in a you can actually see it looks kind
17:38 bumpy or fuzzy and then the other of endoplasmic reticulum doesn't have the
17:42 And so it's relatively smooth and that's it has the two names rough versus
17:47 endoplasmic reticulum. But when two things are very similar, look very
17:52 that means we're gonna have different And so what we do is we
17:55 , OK, well, what are functions? So if the rough endoplasmic
18:00 has bumps, what are the bumps the bumps are ribosomes? All
18:04 So this is trying to show you poorly what the, what this looks
18:09 . All right. So you have the surface, these little tiny
18:12 these ribosomes, these great looking things here. Those are the ribosomes.
18:18 what happens is is we're gonna use endoplasmic reticulum to make proteins that go
18:24 organelles or that are going to be or put on the surface of the
18:31 . All right. So if I a protein that I want to serve
18:34 a marker or want to serve as receptor or do something on the
18:38 it's going to be made while that is being pushed into the endoplasmic
18:45 If I have something that needs to secreted, that means it needs to
18:48 put inside a container and then that is then going to open up to
18:52 surface and the materials inside the container gonna be relieved. So this is
18:56 being done through the rough endoplasmic So those little bumps represent where that's
19:02 . And so you can see here's an opening, this is the
19:05 I'm making. Here's the ribosome, describe this process. You've never heard
19:09 it. We'll get to it in a moment. But what it's doing
19:11 it's inserting the protein. And so we have something that's inside the endoplasm
19:18 , we'll deal with the next step the next slide, I think.
19:21 . OK. The smooth endoplasm curiculum a little bit different. All
19:26 It has different jobs depending upon which of cell you're looking at. So
19:30 example, in muscles, this is we store up a bunch of calcium
19:35 the purposes of muscle contraction. That's of cool in the liver. It
19:41 up a whole bunch of enzymes for . So it basically breaks down things
19:46 are poisonous to you. It allows the synthesis of lipids, it allows
19:52 to make steroids. So, depending the cell and where you're looking,
19:56 gonna see more or less endoplasmic or endoplasmic reticulum. So, for
20:02 in the uh adrenal glands that sits the kidney, that's where a lot
20:07 your steroids are made, right? you heard of? Um,
20:11 I'm not gonna go into them, basically, that's where a lot of
20:14 are made. So you have inside cells inside the adrenal gland, lots
20:18 smooth endoplasmic reticulum and they just pump steroids. So, depending upon where
20:23 are smooth endoplasmic reticulum will have a role. But generally speaking, you
20:28 think it's not making proteins. it's making things that deal with
20:33 It can serve as a storage house it can serve as a place where
20:37 gonna detoxify, break things down. right. And when we go through
20:43 different systems, we'll probably point out is where that's happening. Now,
20:49 to the rough endoplasmic reticulum, I'm a protein, the protein, we're
20:53 gonna say it's a secreted protein because can see right here it's completely inside
20:57 rough endoplasmic reticulum. What do I with that? It's inside this
21:02 What happens next? Well, I'm pinch off a portion of the rough
21:07 reticulum. So now I have a in essence inside are the proteins.
21:13 gonna try to secrete. I've got plasma membrane that now is gonna be
21:18 and moved to the next structure, is the Golgi apparatus. The Golgi
21:23 , when you look inside or look a cell looks like a bunch of
21:26 that have been stacked on top of other. All right, it has
21:30 side that faces the rough endoplasmic reticulum it has a side that faces towards
21:36 plasma membrane of the cell. The that faces the rough endoplasmic curriculum is
21:41 the cyst face. It is the side of the Golgi apparatus. So
21:46 little organ or that little vesicle, little bubble that contains that protein is
21:51 be pinched off the ref endoplasmic It floats over it. It's not
21:55 floating, it is moved over to Golgi and it is received by that
22:01 facing side and then that uh vesicle with the cyst facing side. So
22:08 you can see these are representing those and what it does is it merges
22:13 that first pancake layer and then within of these pancake layers, there are
22:19 machinery inside the goi apparatus is responsible figuring out where that uh those molecules
22:25 supposed to go. It does modifications the molecules to help them be
22:30 The way you can think about the G is that it is like the
22:34 office. Have you ever wondered when take a letter? I know you
22:38 go down the post office all the . If you take a letter and
22:41 it to the people at the post , somehow it magically arrives at its
22:46 . How does it do that? there are people in there that
22:52 actually, it's machines that sort And that's the same thing that's going
22:56 at the molecular level inside a Here's a protein we want it
23:01 I made it specifically so I could it out of the cell goji.
23:05 figure out how to make that happen it has all the machinery to make
23:09 happen. So these molecules will be and tagged, modified, sorted and
23:16 move from layer to layer to layer layer until ultimately they arrive on the
23:22 side. This trans face and a will be pinched off and it will
23:26 sent to where it needs to Why? Because of the proper
23:31 that's part of that protein. Now , how we're not worrying about that
23:37 you wanna know, change your major biology, major work your way all
23:40 way up to cell biology. A of work and then you learn stuff
23:44 that. But for us goji, does it do? Acts like the
23:49 office sorts proteins. All right. , those vesicles when they get pinched
23:55 from the trans face, there's a bunch of different things that can happen
23:59 it. Right. One of the that it can do is that it
24:03 a new vesicle, a new All right. And this vesicle,
24:08 new organelle that forms from this vesicle called the lysosome. And you can
24:12 right here in the little cartoon, drawn a picture of that lysosome in
24:17 cases, it'll just be transported someplace . So it could be transported to
24:21 plasma membrane. It could be transported used as storage and become a storage
24:26 , all sorts of different things. what I wanna do is I wanna
24:29 on this lysosome for a moment. we have a nucleus that's kind of
24:33 a brain. We have the endoplasmic which makes stuff. We have the
24:39 apparatus which serves like a post office sorts of things. And the first
24:43 that comes from this goji is this and the lysosome is like a
24:49 It is not a stomach, it like a stomach. All right.
24:53 , in our little cartoon over what we're looking at is we're looking
24:58 a phagosome. All right. This a type of cell that eats things
25:02 the one that you may have heard is a macrophage. Have you ever
25:06 of the cell? A macrophage? really, really good cells in your
25:09 . They hunt down all the bad . They kind of wander around your
25:12 and they look for bad things. if they find them, they grab
25:15 , they in, in ingest it then they destroy whatever it was that
25:19 wandering around your body. So for , if this is a macrophage,
25:23 of the things that macrophages do is look for bacteria. So you're out
25:27 playing outside or walking along the you trip and fall, you skin
25:32 knee. One of those little tiny find their way into your body.
25:35 does your body fight that bad boy ? All right, that's what it's
25:41 and you can see what it It actually there's, there's some really
25:45 videos on Google or on youtube. If you look up neutrophil eating or
25:49 macro or chasing bacteria, you'll And they literally do this. They
25:53 hunt it down and they'll chase it then they reach out and what they'll
25:58 is they will engulf that bacterium. that's what this picture is trying to
26:02 you is like this isn't supposed to here. So what I'm gonna do
26:05 I'm gonna extend my plasma membrane and gonna wrap around and I'm gonna trap
26:09 bacterium inside a vesicle. So this be an example of another membrane bound
26:14 is a vesicle. All right, , we're interested in the lysosome,
26:20 is sitting over here when you see word lice, you should think
26:25 So, lysosomes contain within them enzymes allow them to break stuff. And
26:31 particular, what lysosomes do is they materials that would be harmful to the
26:38 or to the cell. So in case of the macrophage, it's hunting
26:41 bacteria. It's saying, let's trap bacteria, let's merge this vesicle containing
26:48 dangerous bacteria with the lysosome. So what we're seeing in this part.
26:52 then what we'll do is when we that, all those enzymes that are
26:56 the lysosome are now capable of sitting chopping up the tiny bits of the
27:01 so that we end up with a of particles that aren't harmful, which
27:05 can either break down further or uh reuse or what we can do is
27:09 can then shed them and, and them. So that's in essence,
27:13 going on here. All right. the lysosome has enzymes that help break
27:20 materials that could be harmful to the . This is why I say it's
27:25 of like a stomach. All you can eat things which is called
27:31 . Cell eating. I can absorb and I can then break them
27:35 Now, many enzymes, as we in the last class are dependent upon
27:40 things, temperature. Do you remember ? And ph, all right.
27:46 , we're not gonna adjust temperature all much in the body. So our
27:50 is more or less constant. There's exceptions to that rule that we don't
27:54 to get into. But Ph, all over the place and one of
27:58 things that you'll see with the lysosome they have on their surfaces. A
28:03 of proton pumps. If you're not , that's when H plus that's a
28:07 proton pumps. And what they do they pump protons into the cell or
28:12 , into the lysosome. And in so it drops the ph, it
28:16 it very, very acidic. And the enzymes in that lysosome are
28:21 very, are, are very active very acidic environments. And so what
28:26 doing, it's kind of like your . This is why I like to
28:29 it's like your stomach. So if don't know the ph inside your stomach
28:32 a ph of two. All It's very, very, very acidic
28:37 else in your body is between six eight. But stomach really, really
28:40 . And what you do is you in proteins in there and then they
28:45 because remember we talked about denaturing and and then that allows the enzymes to
28:49 in there and chop it up and how you get all the little tiny
28:53 . All right. So the digested are gonna be removed or used.
28:59 , here's the fun part. What if you take a lysosome and break
29:04 on accident. All right, we to think for example, that our
29:09 are well controlled and our enzymes only those things that the body wants to
29:14 . Now, enzymes just recognize They don't care where they come
29:20 So most of the enzymes in our are contained actively to ensure that they
29:26 destroy you. And the same thing true inside a cell. We create
29:33 compartment. Remember talking about compartment, create the compartment so that we can
29:38 the acidic environment plus the enzymatic activity that the cell itself doesn't get eaten
29:45 its own enzymes. If it if you rupture a lysosome, then
29:50 enzymes can now start breaking down the outside the lysosome. And what we
29:55 when that happens, we call that digestion or autolysis. All right.
30:02 that would be breaking the cell It's a bad thing. All
30:07 The other type of digestion that you see with organelles like lysosomes is something
30:13 autophagy. All right now, autophagy really, really popular right now because
30:17 like, oh, if we can out the process where autophagy occurs,
30:21 can deal with cancer, maybe we turn it on and destroy the cells
30:26 we don't want around. But what is there is a normal process where
30:31 broken organelles inside the cell are taken the lysosome and then what they're
30:38 what you do is you take that organelle and you break it down using
30:42 lysosome own activity. Right. So can see why this might be a
30:47 that cancer researchers are trying to figure . Right. It's like,
30:51 if this cell is misbehaving, why I destroy the things that are making
30:54 misbehave? All right. Now, haven't figured it out yet. It's
30:59 very popular for about eight years and not getting anywhere with it. So
31:04 happens. All right. So this one type of organelle that can be
31:09 through this process nucleus to the endoplasm , endoplasm reticulum to the golgi.
31:15 have the lysosome so far you guys me? Not particularly hard. Is
31:20 literally you draw the picture? You the little thing and say this is
31:23 it does. We have another type organ. Now, it's called
31:28 This is a weird one because it derive from the gold G. All
31:32 . Instead, it is derived directly the rough endoplasmic reticulum. The other
31:39 that can happen. So this is to show you here is the endoplasm
31:41 . It's like, oh look I am there. I'm getting my
31:44 . But one of the things I do is I can take tiny
31:47 what would be a pre peroxisome and bring those two things together and I
31:51 a bigger one and that would be process of, of fission. This
31:56 that self arising proxy zone. All . So, they've derived in one
32:00 two ways, either directly from the partic, not the golgi or they're
32:04 arising by merging together. All Now, this is another one,
32:10 organelle that contains within it. A of enzymes. The specific types of
32:15 are oxidase and catalas. And their is to take something that's toxic and
32:21 it down and make it into something toxic. And ultimately taking that small
32:25 that's less toxic and turn it into . Now, there's a long process
32:32 in all of this. But in , what we're dealing with is we
32:35 molecules that are called um free radicals free radicals in essence, are molecular
32:41 bonds. They have an electron that out there and it's just looking for
32:44 electron. So what it will do it will merge with other molecules and
32:48 them to disrupt kind of break them , which causes more free radicals,
32:52 causes more problems, which causes more radicals. And you can see where
32:55 becomes problematic. All right. So they, what cells do is
32:59 I don't want free radicals floating So what I'm gonna do is I'm
33:02 trap this bad boy and merge it a perox zone and then this oxidase
33:08 gonna take these free radicals and I'm keep uh attacking this free radical until
33:13 break it down into something called hydrogen . You guys heard of hydrogen
33:19 Right. Have you played with hydrogen at home? Yeah. Ok.
33:24 dyed your hair blonde, right? your hair or maybe you had like
33:28 , a cut or an ingrown toenail you're like pouring it on there and
33:31 like to watch the fizzy stuff, ? That's not particularly harmful. It's
33:36 very low doses. Don't drink a of hydrogen peroxide. Very, very
33:40 , but we can brush our teeth it. Right? Ok. With
33:47 step, you can convert hydrogen peroxide water is water dangerous to you.
33:52 , it is. Don't drown in . All right. Too much water
33:56 . Very little water. That's Ok. So what we do is
33:59 take that hydrogen peroxide from the free and we convert into water and that's
34:03 process of neutralizing that I just described you can get rid of water.
34:08 easy. All right. That's not only thing this does. Um,
34:13 of the things we do is we a lot of fatty acids in our
34:15 . Fat, fatty acids are a that stores up lots of energy
34:20 very efficiently. So our body is , really pro fat. You'll,
34:25 you get older you'll learn this All right. I mean,
34:29 I got, I got mine. right. So what we can do
34:33 we take those fats, we store up. But when we want the
34:36 , we gotta break the fats. so we have a process called beta
34:41 peroxisome have the enzymes that allow for oxidation to occur. Uh Let's see
34:46 else. I've again detoxification because of process up here. And I mentioned
34:51 free radicals. So we have an that's specifically designed to neutralize things that
35:00 harmful and catalyze reaction that is important energy release. Yeah, it's,
35:15 actually it's its final stage. So you take a free radical, you
35:19 keep, what you're trying to do you're trying to take a free rad
35:22 and make it stable. All And so ultimately, what you're doing
35:26 you're using this process to produce a free radical or a very harmless free
35:33 , which it would be hydrogen So, what hydrogen peroxide likes to
35:36 if you can imagine it's a oh an oh and it's come together and
35:39 very unstable. So it falls apart creates a very uh a free radical
35:44 . But what you can do is the catalas is you can uh change
35:49 the oh which is a free radical H2O. So the oh is kind
35:54 the recipient at the bottom end that harmless free radical versus a very dangerous
35:59 radical that might occur otherwise. All . Right. Right. So
36:10 what you're trying to do is you're to remove a dangerous molecule that can
36:15 almost irreparable harm to the, nuclear material of the cell. All
36:21 . And again, I don't want to get hooked hooked up on
36:24 but proxy, yes, we're, detoxifying. Whereas a lysosome removes large
36:32 , cellular material, bacteria, So big things would be an easy
36:37 to think about it. It's a question. It's like, why do
36:40 need all these different things? Why they sell it? That's because that's
36:43 you're asking, right? We're gonna another one in just a moment
36:46 It's like, really because there are types of things that the body has
36:50 deal with. All right, the one, you guys ready for the
36:54 one, mitochondria, mitochondria, you learned a long time ago are the
36:59 plants in the cell. This is you make a TP if you've ever
37:02 to do um uh glucose metabolism, learn that this is the, the
37:07 that's at the very bottom end that's for oxy phosphorylation. Basically, you
37:12 in sugar on the other side uh sugar and oxygen and on the other
37:16 , you're gonna get water and carbon and a whole bunch of energy.
37:19 right, we're not gonna talk about we get there because reasons. All
37:23 . But this is what's really, kind of cool about this. What
37:26 looking at here is a very, ancient uh relationship between a cell that
37:34 another cell. All right. So have their own DNA. So remember
37:40 said, all our DNA is in nucleus. And I said, I
37:43 . Well, this is the example why I lied. So what happened
37:46 ? You can imagine a long time there was a single cell organism.
37:49 came along and I said, here's something I wanna eat and it
37:52 this bacterium or other organelle, not , other cell, but instead of
37:57 cell being digested, they created a a relationship where that cell that was
38:04 actually produces energy for the cell that it. And so now we have
38:10 , this shared relationship so that one doesn't get destroyed provides energy and the
38:16 one protects it from the surrounding right? So it's a commercial
38:22 All right. Now, this is weird part, all the mi mitochondria
38:27 your body. And again, this kind of a lie, but just
38:30 with it because it's easier to say this way than to try to explain
38:33 it's a lie. But all the in your body came from your
38:37 So everyone has a lineage through their , great, great, great,
38:43 , great, great, great, , great, great, great.
38:44 take it all the way back to beginning of time, grandmother,
38:49 That's your mitochondria. That's your shared or your your, we all share
38:54 same heritage. We're all humans, ? We're all humans. No,
38:57 in here. They're not gonna admit . Right. We all share the
39:00 mitochondrial DNA. All right. And passed on from mother to daughter,
39:05 to daughter. Why? No dad ? Why? No dad? Mitochondrial
39:09 ? Because when the sperm and the come together, it destroys all
39:13 the mitochondria from the dad. So, which is how it
39:19 All right. So these are self , they replicate based on the need
39:26 the cell for energy. So if look at a cell and it has
39:30 bunch of mitochondria, what can you about that cell? It needs lots
39:35 energy. All right. So muscle , heart cells like that. Lots
39:39 lots of mitochondria cells like your skin , not so much. OK.
39:46 mitochondria make energy, they have their DNA capable of self replication. All
39:52 . And then the little fun, kind of side fact, they all
39:55 from your mom. So those are the the big picture of all the
40:01 bound organelles. And so now what wanna do is I wanna shift,
40:05 gonna move into the non membrane right? No, no, the
40:10 complexes. And so I've already mentioned ribosome, but we're gonna look at
40:14 in a little bit more detail And what we're looking at is a
40:17 or a model of what a ribosome , this is where protein synthesis
40:22 So when we talk about cells and function and the work that they
40:25 we're asking really what kind of proteins there? What is it using to
40:30 the work? And so to get proteins, we have to make the
40:34 . And so the ribosome is where make the protein. All right.
40:38 so you can see there's two units , we have a big unit and
40:40 small unit that's actually referred to as large and the small. And that's
40:43 as much uh biochemistry as you prob need in this. All right.
40:49 , as part of this, what can see, they've drawn 123
40:53 These three sites are, how we the parts that make that we
40:57 the nucleic acids, um the um nucleotides, how we deliver them uh
41:05 to the or actually not the how we deliver the amino acids to
41:10 extending protein chain. So we have binding sites for TRN A that are
41:15 the amino acids. We're gonna talk that more. In the next
41:19 There's also a site that allows us bind up the type of RN A
41:23 we're reading. So remember we talked the, all the instructions being in
41:27 DNA, but RN A really is copy of the instruction for a particular
41:31 . So that's what's also being bound . And so you can see a
41:35 actually has three different types of RN associated with it. You have the
41:39 , which is made from ribosome RN . But because we're making proteins,
41:43 going to have a different type of A. And we're also going to
41:46 the MR RN A, the memory A or the messenger RN A,
41:50 memory messenger RN A that contains the set, but the ribosome is not
41:56 TRN A, it's not the MRN , it's just this structure up
42:00 the RN A and some protein that's with it. Now, I think
42:05 is cool. You guys are probably like boring picture. What we have
42:09 are the pictures of ribosomes in their . So ribosomes can consist or exist
42:15 a couple of different places. First is on the endoplasm curriculum,
42:21 And we call that what rough er . So what we're looking down here
42:28 is that rough endoplasmic reticulum, you see the cistern, this is the
42:34 right here on the outside. Those the ribosomes you can probably see now
42:38 they called it rough because you can you expect it to be nice and
42:42 , but there's a whole bunch of everywhere on this structure. All
42:48 we also can find it in the itself. So the purpose remember of
42:55 rough endoplasm reticulum is to put uh inside a vesicle for function inside that
43:03 or to insert them into a membrane to uh secrete them out of the
43:10 , right? But the cell itself has a whole bunch of protein.
43:16 needs to make, to function itself you would find in the cytozole.
43:22 that's what you'd find over here. so all these big bumps that you're
43:26 at those are ribosomes and if you carefully, you'll even see that there's
43:31 changes that are coming off it, is a protein that is being
43:37 So I'm gonna go back like eight or however many it was there we
43:42 . So you can see here, that long protein chain that's being formed
43:47 this process. Now, granted the we're looking at is showing us out
43:52 the cytosol, not up against the reticulum, but it is showing you
43:57 you can see under an electron If you look and then the message
44:02 , you can see the line that's between all those things. So I'm
44:08 an RN A, the ribosome is and it's running across the length of
44:13 RN A and there's many of them along the length I'm making protein,
44:19 is kind of cool. All So, ribosomes exist in two basic
44:25 . They can be called free If they're free ribosomes, they're circulating
44:29 the cytozole or they can be bound , which means they're bound up to
44:34 endoplasmic reticulum. All right, where are, tells you what kind of
44:39 they're doing, what kind of proteins making proteins that are functioning inside the
44:43 or proteins that are gonna function inside vesicle on the surface or be
44:49 Now, there's a third place that can also find um RN A or
44:54 ribosome that's gonna be inside the mitochondria makes its own proteins. And
44:58 a ribosome will do its job. I can be a free ribosome inside
45:02 cytozole. I do my job, make my protein, I get released
45:06 then I can go back to another inside of Z side of all.
45:10 inside the C of all. Or can shift over to the uh mitochondria
45:15 I can be shuttled over to the curriculum. So ribosome isn't specific to
45:20 it's gonna work. It's named for it's doing its job. So it's
45:24 of like working at a oh, don't know, clothing store. So
45:28 could be at a register or you be folding clothes or you can be
45:32 doing inventory, you work inside the and that's kind of what arrives
45:36 It works where it's told to So, ribosomes involved in protein
45:46 All right, that good. We the next type of membrane bound organelle
45:52 the cyto or non membrane bound. mi the macro molecules biomolecular complex is
45:58 cytoskeleton. All right. Now, you hear cytoskeleton, you can think
46:03 terms of I am I have structures are responsible for creating the shape of
46:08 cell every cell in your body has unique shape and that shape has a
46:13 functionality to it. All right. as we go through, you'll start
46:16 it's like, oh yeah, this definitely looks different than the last cell
46:18 looked at. All right. And , we are doing macro structures.
46:22 remember we have to go through all different levels when we're talked about these
46:27 . So the cytoskeleton is basically a of fibers that provide shape to the
46:32 . And that shape can be uh movement inside the cell as well.
46:38 it can act as kind of like muscle. So cytoskeleton can be skeletal
46:42 muscular for the cell. All So this is kind of what we're
46:46 here, it supports, maintains the , it allows certain types of
46:50 whether it's movement of structure or actual of the cell. All right.
46:56 It positions the organelles. One of things you look at when you look
47:00 a picture of a cell, we don't show you all the stuff
47:03 inside the cell, we just show the interesting things like, look,
47:06 the organelles. Oh look, this is filled with stuff called cytosol.
47:11 what we don't show you is that is literally filled up with this network
47:16 material. All right, this cytoskeleton helps to maintain the shape. So
47:21 organelles are held in place. They're just floating around like things on a
47:27 pool, they are positioned where they to be. Um it uh provides
47:34 for motor proteins, which we'll talk a little bit later. Um And
47:38 also uh interact with materials um outside we'll briefly describe. Now in our
47:46 picture here, we're showing you three types of fibers. All right.
47:51 so these are the ones we're gonna on. And this is kind of
47:54 picture showing you the kind of the of those fibers. But these pictures
47:58 here aren't particularly good. These pictures a little bit better. So if
48:07 look at the cells in your do you think that they're red and
48:09 and blue? No, it would pretty cool, right? What we're
48:15 at here are cells that have been with an antibody to that particular molecule
48:22 they have attached to them a little dye and when you shine light on
48:26 at a specific wavelength, it lights , it's called immunofluorescence. And so
48:30 can use different dyes that react at wavelengths and you can take pictures and
48:36 what you do is you use that things that lit up and you colorize
48:39 . So each of these different picture we're looking at are colorized images and
48:43 just kind of cool. All And so in the picture that you're
48:46 here, the molecule that we're most in is the one that's been dyed
48:50 . All right. This is a . It is the smallest of the
48:57 that we're interested in. All And what it is you can see
49:00 here it's two twisting uh uh chains act in molecules. All right.
49:07 so what they do is if you two strings and you string them together
49:10 twist them, it makes it a stronger structure. And that's why this
49:14 exists in this form. Now, filaments, their job is to bear
49:20 . So when you pull on the uh uh a chain like this,
49:26 not gonna break, it's basically it opposes that, that stretch their
49:33 job. You can see here it on the edges, right? You
49:37 how it sits out here on the , there's another cell way back
49:40 but this is like on the edge the cell. So its job is
49:44 primarily play a role in determining the of that particular cell. It's not
49:49 it does. Acton is usually partnered another molecule called Mycin. Acton and
49:56 work together to slide across one another allow you to cause contraction and
50:04 So when you think about a muscle , we're talking about two fibers,
50:08 playing a role in causing that And this is what allows movement.
50:14 very often acting as paired to allow . All right. So you can
50:19 contraction in the cell like you can the whole cell contract like in a
50:24 cell or what you can do is can create a localized contraction which will
50:28 the cell to move itself, which kind of cool. So I like
50:33 uh I'll, I'll save my s that story for another time. Um
50:37 anyway, this process is cytokinesis. cell kinesis is movement, cell
50:42 So, acting microfilament play a role movement and cell structure. It's a
50:51 cool picture, isn't it pretty? . All right. What we're looking
50:55 here, these are the intermediate Here's a real helpful thing. Intermediate
50:59 in the middle. So it is middle sized one that we're interested
51:03 All right, these are uh different of intermediate filaments that exist. They're
51:08 in a family of molecules called If you want to know what keratin
51:13 stuff that makes up fingernails, the that makes up hair, the stuff
51:17 makes up your skin and makes it tough. So all those things are
51:21 of tough, right? Would you your nails are tough? Yeah.
51:26 . So it's a tough molecule. what it is is that it is
51:30 bunch of little tiny fibers that have wrapped. So this is a
51:33 much stronger structure than you can imagine that is right? Just by virtue
51:39 the number of strands that are involved how thick it is relative to the
51:44 . Now, you can see here has a very uh fixed arrangement inside
51:49 cell. So you can imagine what you think is inside that big giant
51:52 right there where there are no the nucleus, right? And so
51:56 can see it's excluded from the but it surrounds that nucleus. And
52:00 all these fibers expand all the way , to the edges of that
52:05 And what they do is they resist . All right. So um how
52:11 of you guys have a sibling? right. Are you a younger
52:14 Younger siblings? Ok. Older All right. I can do it
52:18 way. Torture e torturer. Did you guys ever give Indian Burns
52:26 your younger siblings? You know what Burn is? Ok? So there's
52:31 names for it but Indian Burns are you grab someone's arm and you take
52:36 you twist in opposite directions, It's a lot of fun,
52:40 I, I was a torturer. was in a torture. You ever
52:44 pink bellies? Yeah. See the aren't gonna do pink bellies guys do
52:49 bellies. We take your little brother little sister. Usually a little brother
52:52 they're the ones that need to be . You hold their arms down,
52:55 put your legs over their arms and go there on their belly,
52:57 belly, pink, belly, No, no. OK. We
53:03 . That one's an easy one. people know the Wet Willie when you
53:06 that ear gross. Yeah. And there's other fun games we'll talk about
53:11 little bit later. Like the, not touching you game. Did you
53:13 play the, I'm not touching you . You can't be mad, not
53:16 you. OK. Just making sure on the same page. All
53:19 So the reason I bring up the burn, all the Indian burn,
53:24 I said, if we grab someone's , you twist in the opposite
53:27 When you do that, notice that skin doesn't come falling off your
53:31 it feels like it, but nothing tears away. It just hurts.
53:36 the reason it doesn't tear away is each cell is attached to another cell
53:41 a specific type of junction, which talk about in the next lecture.
53:45 what's on either side of that junction these intermediate filaments? And so when
53:50 cell pulls on another cell, what doing is you're pulling on the intermediate
53:55 and these intermediate filaments go all the around the cell like it is like
53:59 see in this picture. And so you're doing is you're dispersing the
54:04 the pull on that cell to all other points and those points are attached
54:08 other cells which have these things in , these intermittent filaments which are attached
54:13 other cells which are attached to other . And so the tension that you're
54:17 in each cell is reduced because it's among all the cells that are in
54:21 network came. That's what the intermediate do. When I say they resist
54:28 is they disperse the forces so that cells aren't being torn apart by that
54:35 . All right. Now, when talked about these, these aren't particularly
54:41 structures, they are broken down and . All right, when we talk
54:45 these are gonna be broken down and these for the most part stay once
54:50 built. All right, they're kind a, more of a permanent
54:54 So, intermediate filaments, more permanent and micro filaments less so. So
55:01 leads us to the last one. , it's color coded. So you
55:04 see here the green, the blue actually a dye that stains the
55:09 the DNA in the nucleus. And why you can easily find the
55:12 But you can see, I've got microtubules that are arranged inside the
55:18 They're very large in diameter, they're hollow in structure. And what you're
55:22 is you're taking this molecule called See, I've told you already,
55:27 named things simply for what they do for what they look like, it's
55:30 tubulin because it forms tubes, Very, very basic, very boring
55:37 stuff. So what we do is form these tubes and this becomes this
55:42 structure that is non compressible. All . So what you can't do to
55:47 cells is you can't squish them real because they have this network that basically
55:53 the squishing from occurring. All So they also help to determine the
55:58 shape. They help determine where organelles gonna be. These tubules are dispersed
56:03 the cell. And so they serve highways for molecules that move organelles around
56:10 move other materials around called motor Um I think after today's lecture,
56:17 a video that's posted on canvas that's of the cell And it basically it
56:21 have posted before class. I don't my post tomorrow after class, but
56:26 can always just go look it up it shows these molecules walking along the
56:32 . And in this particular case, video, it shows that motor protein
56:38 a vesicle from the golgi to the membrane. And when you look at
56:44 things, you're like, this can't this is made up. No,
56:47 is what they actually look like and is how they move, you
56:50 and granted it is a video someone cartooned it out. But
56:55 it's not like I think this is , what it look like.
56:58 it's based on actual uh evidence. right. So you can imagine I
57:05 need a microtubule for a period of and then I change my mind and
57:08 don't need any more so I can it down. And so that's what
57:11 do. It also plays an important in cell division. It is also
57:16 component of cilia and flagella. So we talk about psyllium flagella in a
57:20 of lectures, the inside of these are uh microtubules. Now, microtubules
57:28 derived from a structure called a All right, this whole thing is
57:33 centrosome. All right, within the zone, we have two structures that
57:38 called centrioles. All right, they an old timy name. Uh If
57:42 go and look in older books, see things called basal bodies. All
57:46 . So centrioles and basal bodies are same term. They usually refer to
57:50 positioning, but you'll see them And so within the context of the
57:56 zone, we have these structures that made of microtubules, you can see
58:00 they're uh these triplets. So 123 there's nine of them and then they
58:04 them into uh uh dimers that then and that's from which we build these
58:11 . So they start here and then them. This, this green material
58:16 called the PC M. That's the from which you build. It's where
58:19 tubulin is actually found. So these are near the nucleus. So if
58:24 go back here, you can where do I expect the centrioles to
58:28 ? Well, they're probably sitting they're probably sitting there, they're pro
58:32 clearly sitting there, see how dark is and or how light it is
58:36 that point. So centrals are where those microtubules are coming from. And
58:42 during cell division, those centrioles in centrosome split go to the other other
58:47 . So remember when you're drawing the the steps of mitosis and you drew
58:50 centrioles and they went to the opposite . That's what you're breaking right there
58:54 that structure and those two things are out to the opposite sides. And
58:58 you pull the DNA apart during uh cell division, right, during
59:05 those are microtubules that are doing All right. So this kind of
59:11 all the the organelles that we're really of interested in, right? So
59:15 had the membrane b brown organelles. started with the nucleus, endoplasmic
59:20 plural Golgi lysosome, peroxisome, And then we jumped in and we
59:26 with the ribosome and we dealt with cyto skeletal elements, but that isn't
59:33 the self, we just make a of things without understanding context and
59:37 It doesn't make a lot of So, are there any questions so
59:41 about the organelles? They say you guys? OK. OK.
59:46 here one. How about back Are we good or are we doing
59:50 for a math class that's coming up because come on, we do
59:55 don't we? Yeah. Actually, sat at around class when I was
59:59 teaching award committee, I was in , a business class saw one guy
60:03 porn and I saw because I was in the back and I said,
60:06 , it, it happens. And then, um, I was
60:10 a law class and I saw people shoes. Yeah. So,
60:15 it just warms your heart to know when you're going to law school that
60:18 future attorneys are not focusing in on lesson. But instead of trying to
60:22 out which loafers are the best. I give you a hint that it
60:27 a guy that was shopping for Not a woman. Yeah, I
60:31 like I buy shoes. It's just I have to look for the same
60:36 every time. It's like. All . All right. I asked
60:40 Are you guys good over here? . OK. Cool. All
60:44 So now we go to the plasma . All right. Plasma memory remember
60:48 as that barrier. All right, a lipid bilayer. You can see
60:52 right here. See the fossil right? They're arranged. So that
60:56 we have the hydrophobic region out hydrophilic hydrophobic, water hating, hydrophilic
61:03 loving. OK. So the heads outwards. So phospholipids are not the
61:10 lipids that you're gonna find here and the plasma membrane isn't just made
61:13 of lipids. There's also proteins associated the plasma membrane. All right,
61:18 regard to the proteins, what we is we have uh uh cholesterol.
61:23 let's see, we've got a cholesterol in there here. We got the
61:27 . You can see right here. have Glycol lipids. All right.
61:30 , don't let these things scare you confuse you glyco sugar lipid.
61:35 it's a sugar lipid. That's what means. And so basically, it's
61:38 acid tails with the sugar jammed on top. All right. And if
61:42 notice in this picture, what we is the sugars are on one
61:45 So, here's the glycolipid, there no glyco lipids on this side,
61:49 we do have cholesterol jammed into that . We also have these proteins and
61:53 different types of proteins. All Uh We're gonna just name them as
61:57 class of proteins. We have proteins are jammed into the membrane when they're
62:01 into the membrane like that we call integrated. All right, or integral
62:07 . All right. And there's different of integral proteins. If they're affiliated
62:10 associated with the membrane, we refer them as peripheral. Now, this
62:14 not a good cartoon of this, peripheral would be more likely associated out
62:20 than jammed in this, in that . OK. And what you can
62:25 here is that there are also There's a picture of one right
62:29 There's a picture of one right Here, we can see a protein
62:32 there's the glyco portion, the sugar attached to it. All right.
62:38 sugars are always found on the There are no sugars on the
62:43 different types of proteins. Those that in the membrane are integral those that
62:48 on the surface of the membrane are . Now saying that when you look
62:54 a picture like this, everything looks , like it's all glued together and
62:58 no movement. But the truth is because of the molecular interactions, what
63:03 have is we have a membrane that very fluid. All right, we
63:08 to it as the fluid mosaic And the way you can think about
63:11 , it's like a water bed. lipids are not connected, they're just
63:17 one another. They're ranged because of op paic characteristic that they have,
63:23 . So some of they're just kind floating around. And so they are
63:28 with one another and they don't flip , they don't move, they only
63:34 on the one side because of those . So if you're a lipid out
63:39 , you can move anywhere within that for the most part, as long
63:44 you're facing outward, you rarely You flip out and go the opposite
63:48 and vice versa. All right. the molecules that are associated with the
63:53 if they're not attached to something. you can see down here this light
63:57 stuff that would be cytoskeleton, there be proteins affiliated with that cytoskeleton and
64:03 they are, they're anchored and they move. But for the most
64:06 you, if you're not anchored to cytoskeleton, you're free to move to
64:09 you need to go. So this the example I like to think of
64:13 . So when I was a grad , the lab down the hall from
64:17 , they worked on a type of protein, a plasma membrane protein called
64:22 integra. And what Integris do is allow things to attach to other
64:27 So it allowed the cell to uh adhere to like the wall of a
64:32 vessel. All right. And what want to do is they were studying
64:35 Integris. And so what they did they dyed them, you know,
64:37 used an antibody to dye them and they put them in zero G.
64:41 were, they had a grant from to see what would cells do at
64:44 G. So they put the cells the centrifuge, they're on a plate
64:49 uh these are uh like macrophages and . And so they can move wherever
64:53 want to do. And it was , what would happen if you put
64:55 at zero G? So they spun centrifuge and it goes to zero
64:58 Are the cells going just float Because the endocrine, no, they
65:02 moved around just fine and they made of these things. And what would
65:05 really cool is you'd see these plasma , they would come to the edge
65:09 the cell while the cell was moving it was like a tank tread,
65:12 was like disconnect from the, the plate, you know that in the
65:17 and it would like the protein would run all the way to the other
65:19 of the cell. It would be , and then it would attach itself
65:22 then the cell would just kind of like a tank tread along the
65:26 And it was the wildest videos that , that you could see. I
65:30 , because it's how cells move because had the freedom to make that
65:35 they moved to where they needed to , right? So the plasma and
65:39 is fluid nature mosaic, meaning not is evenly spread out the proteins and
65:46 lipids move to where they need to within the context of which side unless
65:50 anchored in place. So now we to do some applied knowledge. We've
65:57 learned about a couple of different types fats, right? We learned about
66:01 , right? We learned about right? OK. So what we're
66:07 at here is if I take a and I apply heat to it,
66:11 solid fat will do what it'll That's what we're looking for. All
66:15 . And if I take a liquid and put it in the fridge,
66:18 I cool down the temperature, what's happen to that fat, it's gonna
66:21 solidified. All right. So we the nature of fats what they
66:25 All right. When we think about temperature, I want you to think
66:28 them in terms of free energy So more temperature equals more energy,
66:35 temperature, less energy. Now, example I used on Tuesday when I
66:40 talking about fats, as I when molecules are, are not
66:44 but just molecules. When we apply , it's like being inside what a
66:49 pit. So you're starting to throw elbows, right? And so that's
66:52 you can kind of see in that picture up there, those molecules have
66:56 associated when they're starting to throw their . And so what happens is the
67:00 begin separating from each other and that's it becomes fluid. Now, you
67:04 imagine what would happen to you. your cells did that, would you
67:11 ? Like the wicked witch of the ? What would you think? I'm
67:15 you're nodding your head going. that's what would happen. Do you
67:18 ? Like the wicked witch of the ? Nope. Not even here in
67:22 , right? And when it gets , you'd imagine, although it feels
67:26 it, that you would be right? But that didn't happen.
67:31 the reason it doesn't happen is one we talked about the fatty acid
67:35 right? If I kick my leg , you can't get close to
67:38 right? Because there's now a So that's one of the things that
67:42 for fluidity of a, of of a membrane. But if I'm
67:45 not close together and I heat things , then you'd imagine things would melt
67:48 lot faster. That's not very So the the the the relative saturation
67:54 important. That's number one, do have lots of saturated tails or no
67:59 very few saturated tails? More the closer the the fossil lipids get
68:04 , the less fluid my membrane So I put in some tails.
68:09 now I have a loosey goosey more fluid. All right. But
68:15 higher temperature that becomes problematic. I these gaps. And so this is
68:19 cholesterol becomes important. All right, in our membranes helps us to adjust
68:27 fast the membrane is gonna melt at temperatures and whether or not it's gonna
68:31 up at cold temperatures. All And so in the bottom part of
68:34 picture, this is what we're looking . I was really trying hard to
68:38 a sip here. So what you here, you can see, I
68:44 no saturated bar or no unsaturated I have my, my, I
68:48 have some unsaturated. And so you see this is more fluid than that
68:52 just like you see up there. if I put cholesterol in there,
68:57 that's gonna do is it fills in gaps that where you'd have that unsaturated
69:04 . So it would be similar to something like this because I filled in
69:08 gap itself. So instead of the spreading apart, um where I'm increasing
69:14 temperature, I've actually already filled in gap. So it becomes more
69:19 um more solid at higher temperatures. cholesterol creates an environment where a fluid
69:27 doesn't become too fluid at higher Go ahead. No. So the
69:35 that we concern ourselves with cholesterol is of, of how it can create
69:41 inside uh the blood vessels. And what will happen is is when there's
69:46 surfaces, things like fats will actually kind of bind and stick and then
69:52 will create other things to stick to , which will create other things to
69:55 to it. And eventually what you up with this hard clump of materials
69:58 prevent the flow of blood through And the way you get the blood
70:01 it, make the heart work you have to push it harder.
70:04 then that makes, that's where the come in is the too much
70:09 Okay. Now, the opposite is as well. All right. So
70:13 I have a very stiff membrane, I insert cholesterol in there, it's
70:17 throwing in an unsaturated tail right Those, those, those those uh
70:23 phospholipid that wanna get close to that . And so I create something that's
70:27 fluid in nature, right? So the temperatures drop, I remain
70:34 so at high temperatures, I remain solid than I normally would at low
70:39 , I remain more fluid than I would. So your cells have an
70:42 to survive along a broader temperature. than they normally would without the cholesterol
70:51 the unsaturated fats. And that's good for you. Right. I
70:58 come summer it's gonna hit that Remember? Feels like you don't,
71:04 love that one? Feels like Yeah, you're not gonna melt.
71:09 if you went up to Buffalo where minus 30 right? You're not gonna
71:13 sitting going oil can because your cells freeze up at those temperatures. It
71:19 up at a lower temperature. Mhm. So it's flash freezing your
71:31 . Well, it's not flash freezing it's freezing the cells. And so
71:34 this point now the materials inside the that water is freezing and when water
71:40 it expands and that's killing the So that's part of the, that's
71:45 of the prospect. Yeah. it, it doesn't, in the
71:53 doesn't increase, it just doesn't solidify the normal temperature. But you've got
71:58 right idea. The idea is if is the normal range in which my
72:01 can survive without the cholesterol, having allows me to survive at higher temperatures
72:07 at lower temperatures. All right. I expand the range in which my
72:11 can live uh in terms of the in temperatures. And the reason is
72:17 at lower temperatures, I don't create uh structures like what you see up
72:23 under, underneath the bee or above bee and at higher temperatures, I
72:28 get quite so fluid because I've jammed the cholesterol in those spaces and this
72:36 over here prevents them from getting close . That's why? OK. Did
72:41 answer the question? Did I, I clarify your question or court?
72:46 . Yes, me too. what happens if the cells get too
72:59 ? Basically, uh, before they start rupturing other bad things are gonna
73:05 . You're dealing primarily with proteins. wanna hear here. This is not
73:09 human biology thing. This is a thing. You guys like scorpions?
73:13 , you should be shaking your Uh, uh, all right,
73:17 can survive at really, really high and they can survive at really low
73:21 . You can actually freeze a uh, at minus 80 degrees.
73:25 think so. And so that it up and then you can take it
73:28 and let it thaw up and it's fine. So they're just freaky
73:33 old ancient scary things. But the I bring them up is because they
73:37 do have a temperature sensor sensor in bodies. So, when the temperature
73:41 too hot, so you can imagine in the desert, it's 100 and
73:43 degrees. What do scorpions do? , I don't want to burst the
73:47 or melt or whatever that scorpions would , they actually bury themselves under the
73:52 away from the heat. Now, you get hot, what do you
73:56 ? You turn on the crank up air conditioner and stay inside, especially
74:00 in Houston. But yes, you sweat. Um But that's the idea
74:04 that you, we respond to the in our environment by trying to avoid
74:10 environment. But what would happen if put you in an oven? The
74:16 thing that would happen to a steak anything else? You, your,
74:19 proteins would, would uh cross link you'd be cooked. So that's why
74:24 doesn't happen, you know. All , we're getting down to the last
74:29 bit here and we may end We'll see. So I've already mentioned
74:32 before is the sugars are found on side, we have a special name
74:36 that structure. It's called the Glyco . And what's interesting about the glyco
74:41 is that it's one of the ways your cell uses to identify cells that
74:46 in the body versus cells that don't in the body, what we call
74:50 identity. All right. And so glycolic, the sugars that are attached
74:54 the outside of the cells are unique yourself. And that's even true for
74:58 twins, identical twins do not have same sugars on the surface of their
75:04 . So this includes the sugars that on the outside of fats as well
75:08 the outside of protein. So collectively glyco Cali is both these two
75:12 All right. Now, in terms what is the plasma membrane, why
75:15 we even care about this? Why you boring me about this stupid plasma
75:20 ? Well, the answer is that it serves as a barrier from the
75:23 or the outside of the cell. creates that unique compartment so that you
75:28 a structure that does unique chemical So a muscle contraction is depend dependent
75:35 the chemical reactions that are taking place that muscle cell. All right,
75:40 I didn't set that space apart, wouldn't have the environment to allow for
75:44 interaction to occur, it would be just everywhere else in the body.
75:48 that's one of the reasons why it's to have it. All right,
75:52 is what we say to is selectively , meaning it chooses what goes in
75:57 what goes out of the cell. this again allows for the uniqueness of
76:02 internal environment. One of the things it does is it establishes an electrochemical
76:09 and that's just a fancy way for , because it's selective for the ions
76:13 are going in and out of What it does is it chooses how
76:18 create differences from the inside and the of the cell. And when I
76:22 differences in charge, I now have means by which to create flow of
76:28 , right? So I can create and so I can create electrical currents
76:32 can make things happen. So your , your muscles are dependent upon electrical
76:38 and it's because of this selectivity and these unique gradients that allow us to
76:44 . Now, we're gonna go in lot of detail about this later because
76:47 of our class is based on electrochemical . And so when we get to
76:51 , we're gonna talk about in more . But that's one of the things
76:54 we're dealing with. The last thing that it uh uh puts a whole
76:59 of receptors and other molecules on the . And this is what allows cells
77:03 talk to each other. All So you can create tissues and organs
77:09 cells need to communicate and the means which they communicate first. If I'm
77:14 this unique environment, I'm, I'm those molecules, those those chemical
77:20 But I'm creating an ability to talk another cell because I have a way
77:26 talk out of the cell and the to talk into the cell. All
77:31 . So those are the proteins that gonna be associated with the plasma
77:35 What do I have? I have slides here. I think we're good
77:40 we come back. What we're gonna is we're gonna start here with the
77:43 dogma. We've already mentioned it. this is gonna be where our starting
77:47 is, have a great weekend, warm or cold or whatever it
77:53 I don't know, it's just changing 30
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