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BIOL 2301 Human Anatomy & Physiology I - 2301_lecture05_0906
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00:07 All right, Welcome back. I you guys had a good long
00:11 Good long weekend. Huh. That's meme this morning. Labor Day is
00:16 day of remembrance of all the things forgot to do over the summer.
00:20 don't know. It kind of feels what I did. My kids actually
00:25 still sleeping in today. They have An extra day for some reason,
00:29 don't understand. So they got stabbed night, watch movies, swim,
00:34 like a bunch of animals. I'm to bed at like 9:00. Please
00:37 me get up and time on my . So, today, what we're
00:42 do is we're gonna kind of, gonna feel a little bit like we're
00:46 around, but we're not. Um we're gonna do is we're going to
00:49 finish up where we left off, were talking about translation. And really
00:54 we're trying to do is we're trying get to the point with how do
00:56 make that protein? And that's were were kind of not going into a
01:00 of detail, but we were just of like, hey, these are
01:02 things that are involved. This is we're gonna end up with. And
01:06 there, what we're gonna do is gonna talk a little bit about what
01:08 are in terms of of their And so that should be pretty
01:13 And the reason we're interrupting here with instead of just moving on to the
01:18 thing is we were going to start at how do materials get across the
01:26 because remember that's kind of where we off, we talked about the plasma
01:30 and then we kind of said, right, we're gonna go deal with
01:32 translation transcription. And now we're coming to the membrane and we're gonna ask
01:36 questions about it. Like All If this membrane is a barrier between
01:40 inside the outside, how do things across that membrane? That's what we're
01:44 look at through kind of the rest the lecture. And so, this
01:48 side right here is just kind of extension of that translation. Alright.
01:54 I know it's been five days but doesn't matter. We didn't really have
01:57 weekend for this class because I thursday Tuesday, right. And so
02:02 thursday we said, look we had message this M RNA ribosomes come up
02:07 then you get tr names that come and help extend this protein.
02:12 most proteins in the body. Not because there are really two different types
02:16 proteins, but the ones that we're in, not the structural protein,
02:20 the functional proteins are what we refer as globular proteins. Now. Why
02:24 you think they call them globular? they look like globs. That's how
02:30 we are in biology. We name for what they look like or for
02:35 they do. So over here is example of a globular protein. It's
02:40 we would say it's been folded, been shaped and arranged And the only
02:44 that can happen is if you have that comes along and helps its shape
02:48 . Because remember we have all those acids that are sticking out all over
02:51 places, you're adding one amino acid a time as you extend that
02:56 And so something has to help twist and bend it into the right
03:00 Remember what happens when it's not in right shape, when it's in its
03:04 form, it's incapable of performing as was designed to do. So we
03:10 something to come along and what that is is we call them chaperones,
03:16 is again, strange why that They just picked it all right.
03:22 again, the specific proteins here are so important. But I wanted to
03:25 of describe the process for you because is kind of kind of interesting.
03:29 what you have is you have some that come along and help bend and
03:32 it. But what you ultimately do you have this structure that's kind of
03:36 a a martini shaker. You the martini shaker is you've you've seen
03:43 movies like where they have sophisticated that's that thing, you know,
03:47 shaker and you put things in and shake it up and you pour your
03:50 out and it's like, oh that's what this is literally like,
03:55 have the cage, you have a , that cap comes along and then
03:59 you do is a little bit of on the inside and out pops the
04:01 of protein. We don't know how works. But that's how it
04:07 So all the globular proteins, how know how to shape every single
04:11 Because each of them have unique special . How it knows. We don't
04:15 . All right. But everything needs have this type of chaperone in order
04:21 it to get shape. Now remember we talked about the proteins that they
04:26 basically strings of amino acids. And when you look at a protein,
04:30 it has a three dimensional shape because been folded there are different levels of
04:36 . When you look at a The first level is the easiest
04:40 Alright. And that's basically just the of Amino acids. If you look
04:44 the amino acids and see these sequences like the word. The letters in
04:48 word. Every protein is a unique , right? Because the sequence is
04:56 . That makes sense. So, is the primary structure, right?
05:01 first order. So like here you see at the very end this would
05:04 the the interment, that would be c terminus. I don't know why
05:07 picked the c terminus. But you see I have fennel, alan and
05:10 and Syrian system. But all those acids, If you started reading from
05:15 one to that one would account for this protein happens to be. And
05:20 primary structure. Now we talked about amino acids amino acids had this this
05:27 group. This variable group that sits to the side and each of those
05:31 groups has unique characteristics. Remember we about that and I said you don't
05:35 to memorize the unique characteristics because there's many amino acids you don't remember 20
05:40 we use. And each of those chains that are, those variable groups
05:46 different sizes. And what ends up when you get these different sizes and
05:51 charges and different characteristics is that you creating some unique shapes. This is
05:58 is referred to as a secondary So based on that primary structure,
06:03 start getting some unique patterns that start . And so for example, I'm
06:09 gonna go to this like basically the thing you get. So they're they're
06:13 showing you what those are groups They're just showing like for example,
06:17 will happen is you get these bends twists that form what are called alpha
06:21 is now the helix is a type secondary structure that is repeatable. If
06:27 go back to the previous slide, can see them over and over and
06:30 again. It's basically because of the of the amino acids it causes those
06:35 over and over again. The second is the beta sheet here, you
06:39 see again, here's the beta Now, these both of these things
06:42 being kind of held together by these that are different, unique types of
06:46 that we're not going to talk about it's unimportant for us, right?
06:50 they're kind of held in position and the beta sheet which end up as
06:53 end up with these flat areas. if I go back again, you
06:58 see here's here's an example with a bunch of flat areas in it.
07:02 so those unique shapes within the context that larger protein now have unique interactions
07:11 the surrounding environment. Just look at hand. Can you do the same
07:16 with your hand? Or can you with your hand? The same thing
07:21 your feet? Can you draw with feet? Now, I've seen people
07:27 are missing their arms, who can right there, famous artists who can
07:32 with their feet. But almost 100% us can't do that right. If
07:37 try to write your name with your , it would be kind of
07:41 wouldn't it? You'd be lucky to a straight line. You'd probably break
07:44 pencil. Right? Why is I mean, they're both the same
07:49 of limbs. They have the same of origins which we're going to learn
07:52 when we talk about the bones. because these have been shaped to be
07:58 to grip and grasp and be able find work. Whereas your feet not
08:03 much, your feet are designed to you long distances, everyone, you
08:08 , anyone can do a handstand. you walk on your hands about how
08:15 ? Like 10, 15 ft? ? Some some of you who have
08:22 it probably can me. I just over, Right. But the rest
08:26 y'all, you know, you but couldn't do the entire campus, You
08:31 walk all the way around the could you know? But you can
08:33 it with your feet, right. you could do it, I'd say
08:37 on your head. But that's just euphemism, right. The same thing
08:43 is that these little bits and the alpha helix and the beta pleated
08:48 or the beta sheet are unique structures allow for unique parts of the protein
08:55 do things. And then the sum the secondary structure which is dependent upon
08:59 primary structure. So, primary structure secondary structure. Secondary structure begets tertiary
09:07 . The tertiary structure is just the name we say for the entire shape
09:13 the protein. All right. you can imagine all the parts of
09:17 protein are the some of the alpha is the beta sheets and the other
09:21 structures that we never discuss which is upon that primary structure in the first
09:27 . And so when we look at functional protein, what we're looking at
09:31 its tertiary structure and is being held that folded position because of a whole
09:36 types of chemical bonds of which we're going to concern ourselves. Alright,
09:41 , when you look at a protein ask why is it doing what it
09:44 ? It does what it does because the secondary structure is being held in
09:49 by the unique little chemical bonds so it has its active regions capable of
09:55 with other active regions of other proteins whatever it needs to. Alright,
10:00 acts with other molecules. Now, molecules some proteins go one step
10:09 so not all proteins go one step . Some do. And this is
10:13 we call the quaternary structure. This the fourth level quaternary structure is when
10:19 get two or more polyp peptides or and they come together they aggregate together
10:25 they form this larger macro molecule. again, they're being held together by
10:30 series of chemical bonds again which we're going to concern ourselves with. But
10:34 might even bring in things that are proteins, what we call prosthetics.
10:39 , So think when you lose a and they give you an artificial
10:42 we call that a prosthetic. All . And so if you're a peptide
10:48 you have something that's not a protein to you, that's a prosthetic.
10:53 so here this is an example of quaternary structure. What we're looking at
10:59 hemoglobin. You all heard of It's the thing in the blood that
11:03 oxygen found in the red blood All right so it has a globe
11:10 unit or global. Excuse me, globulin unit. Globulin, globulin
11:15 And they got this kind of messed . It should be alpha,
11:18 beta beta. But again, artist screws these things up. Alright.
11:24 then in the middle of these we this little tiny pigment called him.
11:29 our prosthetic unit. And so that which if you go back at that
11:34 right there is supposed to be a molecule. Right? So this is
11:40 globulin and four he seems kind of to and held together to create that
11:46 structure which we refer to as Now again I'm not gonna ask you
11:50 this is. It's just hemoglobin is always the example they use in every
11:54 solitary textbook. Okay so you'll see like 1000 times if you ever take
11:59 class where they're talking about protein Alright so proteins have shape. Those
12:08 are dependent upon those three levels of . And if it's a complex,
12:13 fourth level of structure and it allows that structure allows it to do the
12:18 things it does. And it all with that gene in the D.
12:23 . A. That gets transcribed into . That gets modified and then read
12:31 translated into that amino acid sequence of primary structure and then ultimately folded to
12:37 to do the things that it Okay, so far so good.
12:45 now again, we're jumping back. is kind of a reminder I kind
12:49 mentioned this already is the production that cell does all those structures that have
12:57 plasma membrane are part of this larger called the indo membrane system. And
13:02 I was in school, when I in y'all seats, they didn't talk
13:05 this, they didn't kind of connect the dots together. But now we
13:09 connect all the dots. It's oh, this is a series of
13:14 that work together to do some unique . And so, this little list
13:19 here, we've talked about protein right? We've talked about metabolism and
13:26 a little bit. When I say , that's making things right. We
13:31 really talked about the movement of lipids that's okay, we're not really gonna
13:34 with that. We said, the er makes lipids and if you think
13:38 it, if I'm making fossil lipids they're traveling the entire distance, that
13:42 be an example of movement of Alright, But ultimately these structures that
13:48 nuclear membrane, the er so rough smooth the golgi and the vesicles in
13:54 them as well as the plasma membrane directly or indirectly connected to one
14:00 Because as I'm making these proteins in materials, I'm moving that plasma membrane
14:07 into the plasma membrane and while I things in through a process called induced
14:13 , I'm taking plasma membrane away and it back the opposite direction. So
14:18 all interconnected because of that activity. watched that video on blackboard a couple
14:28 do you remember seeing these guys? mean they literally are, it's like
14:34 decided to make something for cells. , yes. Just kind of does
14:39 kind of weird walking looking thing. carrying vesicles and so I want to
14:43 kind of show you if you haven't the video, you're not required
14:46 I'm not gonna pull things from and , tell me what you saw in
14:48 video, but it helps you visualize actually going on this out. Because
14:52 often what you see are those electron graphs, those black and whites that
14:56 been showing you and it looks like whole bunch of black dots with a
14:58 bunch of gray dots and a little of a little bit of white area
15:02 it. So at least with that you can kind of get a
15:05 of what's going on. And so we're looking at here is a
15:10 it's called motor protein. Right? there's different types, there's connections and
15:15 . Um and their movement is dependent energy in the form of a teepee
15:21 hence they're called motor proteins. And they do is they move stuff and
15:25 what they're doing is they're moving large . I think in the video you
15:28 them moving a testicle and in one , I think it shows another one
15:33 on mitochondria. But I can't It's been a while since I watched
15:36 video. But in essence remember those are not just floating around like So
15:43 I go back over here, that vessel, cool right there or right
15:47 is not just floating between this point that point it's being moved and carried
15:54 motor proteins. So everything has rhyme reason inside a cell. It's not
16:00 things going wherever they feel like. , everything has purpose and part of
16:05 is being directed by these proteins along tubules. And the video actually shows
16:12 those micro tubules. So, what does It ensures that materials that you
16:17 producing are going the right direction. , for example, if I'm making
16:21 protein that needs to be secreted out the lumen of an organ, like
16:25 your bloodstream or say into the digestive . It's going towards the a pickle
16:30 of the cell and not towards the lateral side because we have things directing
16:36 . All right. So, this what we're saying is that things have
16:41 and reason they're moving to where they to go. All right now,
16:47 they get to where they need to , they don't necessarily just immediately merge
16:53 the membrane. I like that your talks about this at your level because
16:58 swear to you up until probably graduate , I did not understand this
17:03 Alright, so, what this is to show you is that when that
17:07 rise to the membrane, it doesn't emerge and release its material instead,
17:12 held in place until the signal comes . And this right here really does
17:16 really good job of showing it. each of these lines represents part of
17:21 lipid bi layer, right? So got layer one and layer two.
17:25 look what happens is that we're So you can think about these these
17:29 are called docking proteins. Snares is name. And again, you can
17:34 a bunch of geeks sitting around trying figure out what they're going to call
17:36 proteins. And they come up with craziest acronyms to come up with a
17:41 right there. That's just what we . Alright, so their snares,
17:47 ? So we have a B snare is on the vesicles. We have
17:49 T snare which is on the Right? And so, what,
17:53 know, you create a dock inside directed to where it needs to
17:56 and it sits there and it's almost to burst open. But it needs
18:01 signal to come along. All And that signal is usually in the
18:05 of calcium, right? And what does is that it causes those snares
18:11 change shape and it basically rips open vestibule at the surface. So then
18:16 can release your materials. Alright? , it's just ultimately this really unique
18:24 really elegant system of design where things going, where they need to go
18:29 , being released when they need to released so that the cell can do
18:33 it needs to do exactly when it to do it. All right,
18:38 deal. Well, next slide, do not write down anything. I
18:42 want to show it to you this how crazy it is. Alright,
18:46 , it shows you all the all the materials, everything that's involved
18:50 this process. So, here you see the different shapes and stuff represent
18:55 proteins as part of the snare. then what do you need? You
18:59 calcium to come in. So here am close that position. I'm not
19:03 to release the stuff, but I'm ready. And then when calcium comes
19:08 , that changes the interaction between everything the testicle opens up, that testicle
19:12 with the membrane. Everything that's involved recycled goes up to the next
19:17 The whole process repeats itself. I everyone to flex real quick,
19:25 relax, relax, flex quick. , every time you do that,
19:30 are thousands and thousands of action tons tons but lots and lots of
19:36 of neurotransmitter causing you to flex that and the reason you're able to do
19:42 is because those vesicles are lining up incredibly fast rates to be ready for
19:48 next flexion. Right? Your muscles move until you think about it.
19:54 , there has to be a signal goes from the brain to the
19:57 And right there at that neuro muscular there are hundreds if not thousands,
20:02 vesicles already lined up with others lined behind them, ready to go pretty
20:09 . It's because of those little proteins there. So, here we are
20:17 the inner membrane system, Here's our apparatus, here's our vesicles, there's
20:21 plasma membrane. And what we're trying do is we're trying to ask
20:24 right? What can we do with that have been processing the Golgi?
20:29 ? What are we doing in the ? Anyone can remind me pass
20:33 Yeah, we're sorting and moving proteins where they need to go and what
20:38 picture horribly does because again, you , artists, it's basically saying,
20:43 , there are three paths path number . All right. And it's kind
20:48 a shared path path number one is got material that needs to be
20:52 that soluble protein that you usually that soluble protein, soluble protein is
20:58 the water and the environment. this is material that is gonna be
21:01 out into the external environment. that's number one. So inside the
21:06 , I'm gonna sort it and I'm put it into a vessel that is
21:08 to merge with the plasma plasma membrane then I'm gonna release that soluble material
21:14 outside the cell. Number two. can be a receptor now notice the
21:20 in which that receptors pointing. It's into the golgi when the vessel forms
21:26 pointing into the vestibule. And the for that is when that vesicles merges
21:31 the plasma membrane, it turns inside right. It basically opens up.
21:34 so the inside of that vehicle is the outside of the cell.
21:39 that's number two. If I am plasma protein or sorry, if I'm
21:44 plasma membrane protein, then I am to be sorted. I'm gonna be
21:49 the surface of the testicle and then gonna merge with that plasma membrane and
21:53 gonna be facing the right direction when merge with that plasma membrane. That's
21:59 two. Number three was of course can form a license zone. So
22:03 are enzymes that are gonna be used destroy other things. And so I
22:08 this slide up here not to This is exactly the same slide that
22:11 saw previously with a different picture, think. All right. And it
22:15 shows you what's the purpose of the zone. It acts like the stomach
22:18 a cell. All right. That kind of our our analogy.
22:24 So I can go in and I eat foreign materials, like big nasty
22:30 bacteria or something. Or I can through a process of intake. In
22:35 words, I'm targeting specific proteins. want in or non specific proteins and
22:40 can intake them in or I can myself with a damaged organelles to destroy
22:45 in an orderly fashion to ensure that damaged organelles doesn't cause the cell
22:51 And so the lice ISO acts in way. And so it's just a
22:56 . But what it has in there a whole bunch of enzymes that are
23:00 for chewing up other stuff. that's not too hard. But inside
23:09 cell. Remember we said there are proteins as well in order for the
23:15 to do the things it does it proteins just circulating in the site is
23:20 okay. Do you remember me saying a little bit kind of sort of
23:23 . Okay. What happens when those go bad? How do I get
23:27 of those? I can't pick to them up by a license. Um
23:32 license um merged with other vesicles. answer is I've got another biomolecular
23:41 Alright. The protea ozone, this our last little protein that we're going
23:45 deal with the protein ozone the biomolecular here. If I had to come
23:50 with an analogy I'd call the garbage of the cell. Now you could
23:55 another stomach of the cell but I've used digestive system. So garbage
24:02 You have a protein you don't want it's broken misfolded or you're done using
24:07 . All right, so just it's unwanted protein. So, what you
24:12 is you take this other little A little tiny flag and you come
24:16 and you mark the protein that you want. The little tiny flag.
24:19 called ubiquitous. It's called ubiquity in it's everywhere. Hence ubiquitous. Ubiquitous
24:26 . Yeah. You see everything is when we name it. All
24:30 So, you can see here, have I done? I've taken my
24:32 . I don't want I put a bunch of ubiquity on on this says
24:35 and destroy this. And that ubiquitous the flag that says, okay,
24:39 grabs it and says you go over to the protozoan. Protozoan says All
24:43 , bring it and it goes in . Oh, maybe paper shredder might
24:48 another good one. Right? And sits there. And what you'll end
24:51 with a whole bunch of amino And what do you do with those
24:54 acids? Recycle them, attach them a T. RNA. Go make
24:58 a new protein. Alright, If ever accuse you of not being
25:03 And then I recycle stuff all the . All right. So, this
25:12 that the cell does what it's designed do this process of breaking things down
25:19 is gonna cost energy. Everything costs , right? Just like everything costs
25:24 . There's nothing free in this All right. So, but this
25:29 you to maintain proper cellular function. so, cells that are controlling what
25:35 being made when it's being made how use it and then getting rid of
25:39 when you're done is part of normal functionality. Alright. So, I
25:46 that's where we stop with in terms the types of parts and pieces.
25:50 . So, we're all happy. there any questions about any of the
25:53 that we've covered? You can go as far as you need to?
25:57 , go ahead. Mhm. He fevers are Mhm. All right.
26:16 , the question here is you're trying connect two dots? The question has
26:19 do with All right. When we a fever temperature rise, a positive
26:24 loop. Alright. So, what do is we set a new set
26:27 and the idea here is um our know that when infection occurs that are
26:34 work within a specific range of All right. And we know that
26:39 proteins of most infectious agents work at different temperature now. How does it
26:44 this? This is just years and and years of trial and error and
26:48 . Right. So, what we're do is we're gonna raise our temperature
26:51 we're But we're gonna raise it outside range of the survivability for,
26:54 a bacterium or virus or something. it's gonna be within our range in
26:59 . All right. So, the was Alright, But what about my
27:02 membrane, my plasma membrane when temperature is gonna become more and more
27:07 Why don't I basically fall apart and into goo? Is that kind of
27:11 you're going with that? Oh, why is it more fluid?
27:17 So, whenever you're whenever you're dealing temperature, remember think of temperature as
27:23 . Alright. And I know this not always an easy concept to
27:27 but if you add in temperature to you're adding in energy. So,
27:32 you add energy to molecules, they to move more frequently, right?
27:36 start bumping into each other more And so what's gonna happen is that
27:40 that are close together are gonna start more frequently and they start moving apart
27:46 greater rapidity and so that ultimately results greater fluidity. Can I help?
27:53 . I thought you were gonna go why don't I fall apart? The
27:55 is the cholesterol. Well, I you should all know that at this
28:00 . Okay. Anyone else? Yes. Mhm. Yes. All
28:22 . So, the question is and making sure part of the reason me
28:26 it so that they can hear. number two is just to make sure
28:28 understood the question. And you'd be very often. Some kind of
28:32 You know, like someone asked me question like three times another class and
28:35 thought they were saying purple and then not saying purple. It had nothing
28:38 do with the color at all. . So, the question is all
28:41 . I've got a membrane. And I add a vestibule to that
28:44 Does that cause the plasma membrane get ? And what is the long term
28:48 of that? Well, you can about like this as I'm adding
28:51 There's also other processes are taking place I'm taking away membrane. So,
28:56 speaking, the size of the cell its normal activity doesn't increase or decrease
29:03 any sort of significant value. Now, does that mean that sells
29:08 increase in size? No, I , cells do increase in size
29:11 And in fact, if you've taken 1 1 of the very first things
29:15 try to teach you when they start with cell theory is that there is
29:19 specific size that if a cell gets large, it becomes non functional that
29:23 volume relative to the surface area. you there's a certain ratio. Once
29:27 get past that ratio cells start miss functioning. And so what does that
29:33 it causes you to Create two Because now you can get back down
29:38 that ratio. And this is probably multi organ multi cell organisms came came
29:44 ? But with regard to just adding and taking away its roughly equal roughly
29:52 else? That's a good question. . Does that mean it's gonna find
30:06 . When we go back Alright. you're asking a complex question, she's
30:11 what's calcium doing? How does How does it do its thing?
30:14 right. So what you can see is that calcium plus this other agent
30:19 complex and come in and they're trying show you can see the little tiny
30:23 squares here. They're binding to specific . I think this is Mark 19
30:30 market. I don't know. Oh it is. I can't even see
30:34 it says. Yes, synaptic synaptic man. Yeah. You see I
30:40 even know the names of some of things because it's not important for
30:42 right? I'm not working on Not that important. But the idea
30:46 that it comes in and binds to causes a change in the shape.
30:49 calcium because it has a charge it's to specifically um are groups and that
30:56 cause a shape change in the protein you change the shape of a protein
31:00 its activity. And so that's what does by changing the shape, It
31:04 its interaction with that. Which causes among all the other members of the
31:10 the snare which causes you to kind tear the the vesicles outwards so that
31:15 materials can come. In other what you're doing is you're deforming the
31:20 shape of the vest. Ical. ? So you can think about
31:23 My best school wants to be Right? And what it does is
31:27 basically force it this direction and once get past a certain angle, it
31:31 to flatten out. So that's really of what it's doing there.
31:38 going back anyone else? Yeah. , due to signal? Uh so
31:53 that's kind of going beyond what we to talk about in the class.
31:56 I'm not, I'm not. She's questions. Alright. My skeletal muscles
32:00 to neural signals and I have to about what about cardiac muscle?
32:04 cardiac muscle, there's two different types muscle cells. One we're going to
32:08 about this a little bit. one is has an auto rhythmic function.
32:13 other words, it actually contracts on own independent of any sort of neural
32:19 and very early on in development. one of the first things you'll actually
32:23 even before the heart forms, those start appearing and they're already in pre
32:29 and uh and relaxation. And what do is they end up forming the
32:34 . The other part of the heart muscles that are different than our skeletal
32:39 but behave like our skeletal muscles. respond to the contraction signal coming from
32:44 ones that are actually creating that Right? So it's a contract.
32:49 sell and another rhythm cell together. . Yes. So the question
32:58 do the cause your own action Yes. And we'll we'll get to
33:00 and just to point this out, they limited by just with that?
33:04 your heart go up when you run ? Right? So they respond to
33:09 signals, but they're not they're not upon neural signals to contract, which
33:17 kind of cool. Ready for the stuff, boring stuff. Alright,
33:29 call this boring stuff because this is I fell asleep when I was in
33:32 seats. All right. So, I fall asleep, it's gotta be
33:36 . Actually. That's not true. usually fall asleep on most of my
33:38 . Don't tell my parents. what are we gonna do? Is
33:43 gonna ask the question. All Remember what I said, is we
33:45 this plasma membrane? How do we the plasma membrane, Right? Because
33:49 one side of the plasma membrane, have water on the other side we
33:52 water. And the plasma membrane is up of lipids. So, it
33:55 as a barrier to prevent water soluble to move back and forth. It
34:00 no effect on the lipid soluble substances lipids don't stop lipids, they attract
34:05 , right? That's like that. the easy way to think about
34:08 All right. But before we get , we need to understand a little
34:12 of language. And so here we're look at the question of diffusion.
34:15 is stuff you kind of already Look, if I take a whole
34:18 of molecules and put them into an because of the kinetic energy each of
34:23 stores. They're gonna start running into other. The And they run into
34:27 . And what they're gonna do is gonna spread out evenly, ultimately given
34:31 time, they will spread out so that all the molecules that you
34:36 in are equidistant from one another, ? Kind of like when you walk
34:40 a classroom, you walk in, the first one, you're like,
34:42 , I can get wherever I want go, and then you sit down
34:45 the next person walks in, I don't want to sit next to
34:47 person, and so you kind of out evenly until finally, you're kind
34:52 stuck with having to sit next to , all those introverts in here,
34:55 what I'm talking about? The extroverts kind of looking for you,
34:59 It's like, oh, there's somebody can go talk to before class.
35:07 , I'm an introvert too. anyway, so diffusion is simply the
35:13 of those molecules down their concentration Alright, until those molecules are equally
35:22 , right, they reach a state equilibrium, so they're evenly distributed within
35:27 environment. So the more the steeper gradient, in other words, the
35:34 molecules you have in one place versus other, like, see there's zero
35:38 here, there's lots over there, faster the rate of diffusion.
35:42 so things gonna move. So the way to think about this thing about
35:45 on a skateboard. If I put skateboard in this room and step on
35:48 , am I gonna move anywhere? , because the room is flat down
35:52 , alright, instead of stairs, a ramp if I get on the
35:55 on that lower part right there, I gonna have speed, Will I
35:59 able to go down the slope? , because there's a slight ramp
36:03 And so now the steepness of the right, is at I don't know
36:09 10°, something like that. And then at the next portion of the
36:12 the next portion of room is even , it has a higher um
36:17 And so the speed at which I down that top portion would be greater
36:21 the speed that I go down that , which is greater than this flat
36:25 . So the steeper the gradient, faster the rate of diffusion.
36:31 number two temperature. And remember I think of temperature as energy, it
36:37 the kinetic energy of a substance. if I have something that's called a
36:42 of molecules, the rate of fusion that in that uh fluid is going
36:46 be fairly slow. I like to of ice T. Vs. Sweet
36:51 , right? Everyone here knows how make sweet tea, if you're in
36:54 deep south, you better know how make sweet tea, right? You
36:58 tea or you take water, you it, you put your tea bag
37:01 and before it gets cold, what you do add your sugar?
37:06 Because that's energy. You put those crystals in there and they're like,
37:10 and they start falling apart and they elbowing each other out of the way
37:14 that sugar distributes equally. You go the restaurant and they say we have
37:18 . U. R. T. you have to put the sweetener and
37:20 dump in your sugar, what's that gonna do right down the bottom?
37:25 you sit there and you go damn . And then you have to sit
37:28 and you add kinetic energy by right, That's what you're doing is
37:33 adding in kinetic energy. So temperature kinetic energy. The more temperature you
37:40 , the greater kinetic energy, the the rate of diffusion because the molecules
37:44 bumping into each other and try to out until there's equilibrium. Now,
37:52 that definition, let's look at a now. Alright, so here's our
37:56 , there's our lipid bi layer. if we have lots of stuff out
37:59 , if our substance is lipid Alright, because our lipid bi layer
38:05 lipid and you can see here here's gradient there's lots there's little It says
38:10 I have lots out here and I'm soluble, I will move through the
38:16 down my concentration gradient. All right in saying that that molecule which is
38:22 soluble is gonna be pretty unhappy because in watery environments on both sides.
38:27 the rule still stays the same. right, You cannot slim the more
38:32 have over here on the left over there, you're going to drive
38:35 in the direction towards where there's less it. Alright. Because things are
38:40 to reach that equilibrium. They're trying reach that balance. If I have
38:45 that's water soluble, it can't pass that lipid bi layer. It needs
38:51 . Alright? So if I'm wall , I can pass through the wall
38:55 I'm not wall soluble, I can't through the wall. What do I
39:01 ? I need help. What kind help? A door. Alright.
39:06 so that help means it's facilitated. facilitated by to pass through this door
39:14 through this wall by a door. so facilitate diffusion simply means I have
39:20 that allows me to pass through. so we can use channels or
39:24 This is a channel. These two right here represent carriers. So,
39:29 channel is simply an opening that passes through the membrane. Right? So
39:37 you can see I have an opening passes all the way through.
39:41 I can open and close that just I can open and close that
39:45 Right? But if I look through , I can pass all the way
39:48 , right? It is a complete between those two points. A carrier
39:54 the other hand is not gonna be to both sides simultaneously. The example
40:00 like to use I think we talked this already. Haven't We know the
40:04 class? I've done it all at upper level. You ever been to
40:08 hotel or an airport where they have rotating door, right? You have
40:12 go up to the door and you there and you have to time and
40:14 jump in and then it's like and you go through the other side.
40:19 a point when you're in that circle you're neither open to the inside or
40:23 outside, right? And if you about it too long, it might
40:27 you panic because you're now trapped, ? Especially if you have luggage that
40:31 gotta sneak out with you, But that's kind of what a carrier
40:35 . There's a point where it's open one side, then there's a point
40:38 it's not open to either side and there's a point where it's open to
40:42 other side and I can now be . All right. So when you're
40:47 about carriers, that's what you're gonna now over here is gonna be different
40:53 this one right here, we're gonna to that that's still a carrier,
40:56 we're gonna deal with that in just second. Oh, I guess on
40:59 next slide. So when we're talking these three, what we're looking
41:04 we're looking at concentration gradient. So are moving down their concentration gradient either
41:10 the process of simple diffusion using a basically a passageway or I can use
41:15 carrier and none of these because the says passive. None of those require
41:21 . All right, But if I to move something against its concentration
41:26 I want to move something where there's to where there's more It's gonna require
41:31 . Think about a ball. If put a ball on a shelf
41:35 that ball will want to roll off shelf. It naturally wants to go
41:40 , you know, because of the of gravity. But if I want
41:44 put a ball on the shelf from floor, I have to use energy
41:48 to bend over and pick it up I gotta lift it up and I've
41:51 to apply energy to set it up the shelf. Right? So,
41:55 requires it requires work and energy and what active transport does. Active transport
42:03 the expenditure of energy to move things an area of low concentration to an
42:09 of high concentration. All right, others are just moving down their their
42:15 down there gradients. So I can energy directly. If I use energy
42:22 . So, that would be the is of a T. P.
42:27 that's going to be called primary active . I used energy Now, every
42:33 I use energy like this, this pumping. I'm pumping things from low
42:37 high. Right? And so very you will see these molecules named as
42:43 . Alright, so they have a pump. We have calcium pumps.
42:47 have the sodium potassium 80 P. pump. Alright, so when you
42:51 the word pump, just think, I am using energy to move things
42:55 low to high and when I pump into a substance like into a reservoir
43:01 if I take ping pong balls and them into a closet, I have
43:06 stored up, right? Because I'm things to where there's more and when
43:10 have more versus less, which way those things want to go? They
43:14 to go from more to less. so there's potential energy and now I
43:20 use that potential energy. So what doing is I'm actually creating a concentration
43:27 that can drive things forward. Now active transport takes advantage of that potential
43:34 . I have something on the outside wants to get in right? And
43:39 it's gonna do is it's going to me to move something against its own
43:44 . It's a shared movement. The I use all the time and it's
43:49 the best. But I think sometimes connects. When I went to school
43:56 went to school in New Orleans went Tulane when I went to school in
44:00 Orleans. Every bar near the university a ladies night and they all had
44:06 right? Because let's just build the students because we can't right now,
44:13 you were a lady. If you inside, I mean you could go
44:16 and out the bars all you wanted write. But you still have to
44:20 for your drinks. Guys, on other hand, had covers unless they
44:25 in a lady with them. And so what we would all do
44:30 we'd go hang out outside the bar we're interested in going into and then
44:34 wait till someone showed up. You , like usually a bunch of girls
44:37 be a bunch of guys, a of girls, we'd say,
44:39 if you go in with me, will I do? I will pay
44:44 your drink so I can get in free. Right? And so that
44:49 kind of a co means of getting the bar for me as a
44:56 I don't have to pay a cover for her, she can get in
44:59 she gets her drink for free. ? And that's kind of what secondary
45:03 transport is. One can get in fine without any sort of help.
45:07 this other one wants to get And so together when they go
45:11 I'm using that free energy to move one that requires energy to get
45:17 That kind of makes sense? we're gonna see this in deeper detail
45:21 little bit later, but that's I to distinguish. So notice in secondary
45:25 transport. Am I using energy No, I'm not burning a.
45:30 . P. I'm using the potential from the director from the primary active
45:37 . So primary uses a TP directly create gradients of potential. Energy,
45:42 energy is then used to move other or to drive other things. But
45:48 , whether your secondary or primary you're something upstream or uphill, Alright,
45:57 energy. Right? That kind of sense. Kind of. It's not
46:02 best. But because we haven't looked some specific examples, it's gonna be
46:05 little bit confusing and I understand All right. I think we've got
46:09 examples here in just a bit. think we'll see. All right
46:15 these things are simple ideas that are Complexly. That makes sense. I
46:22 that makes sense. Alright, so . Remember diffusion is simply moving things
46:26 high to low concentrations. So what some of the parameters that can affect
46:33 rate of diffusion? Alright, the size matters, the size of
46:38 solute can affect the rate of The bigger the size, the slower
46:42 diffusion. Easy way for me to this. Think about being at a
46:45 at a sporting event or at a , was it bad bunny was performing
46:51 go to bad bunny, Was it ? Was it like hard to move
46:55 like. Alright. Now, imagine a four year old to the bad
47:00 concert. All right. Just bear me. Alright, right. If
47:06 weren't holding that child's hand, would child be able to move through the
47:09 a lot easier than you. They would literally run between everybody's legs
47:14 that child would be long gone and forever. All right, your big
47:23 are small. Big things have harder moving around other big things. Small
47:28 have no problem moving around big So the smaller the substance, the
47:33 the rate of diffusion, the bigger substance, the slower the rate of
47:36 . That's an easy one. Membrane . You can look down here.
47:41 , membrane thickness, This is also you this is D for size of
47:45 . All those things represent over Alright? So, if I have
47:50 to pass through, that's really, small, I can pass through it
47:54 quickly. Right? So, crossing threshold from this side of the room
47:59 that side of room. Not a crossing across the street, that's a
48:04 bit thicker. Right? Takes more . So the thickness of the membrane
48:09 which I have to pass has an on the rate of diffusion. Now
48:14 , generally speaking, that doesn't Right? Your thicknesses, your
48:17 your thickness. But the guy who discovering all this stuff. Oh,
48:21 , I found a characteristic, So matters surface area matters. Alright.
48:28 many people do you think we can through that door at the same
48:32 2? I like that. That's good answer. People argue with
48:34 It's like, no, I can three through there. Yeah, if
48:36 turn sideways and you maybe walk like alright? But to maybe if you're
48:41 size, maybe 1.5. Right? yeah, so if I want to
48:46 more people through that door, what I have to do besides make people
48:51 ? Make make the opening bigger, ? So if I increase the surface
48:56 through which that material had can I can pass more material faster.
49:00 surface area matters. The greater the area through which I passed. The
49:04 the rate of diffusion, the smaller surface area, the slower the rate
49:09 diffusion magnitude of the concentration grading. already talked about if I have lots
49:14 have little, that's gonna be a steep slope. But as I bring
49:18 two things close to equilibrium, I'm slow down the rate of diffusion right
49:23 they're equal, we mentioned temperature. then lastly, viscosity, I should
49:29 just temperature. The higher the the faster the rate viscosity refers
49:34 kind of, the thickness of the . In other words, what's the
49:37 environment? Kind of has to do density and a whole bunch of
49:40 But you can imagine the thicker the , the slower or harder it is
49:45 move through it. So, um it's not represented up here. So
49:51 call that rate of fusion flux. , So the flux, you can
49:58 here over here from here to This would be fast. And as
50:02 move from here to there, it's slow down, the flux slows down
50:07 eventually you'll get to a point where reach equilibrium and whenever you're at
50:12 those materials don't stop moving. What what that means is that the material
50:16 moving from one side to the other equal liberated. So as we're at
50:24 point right here, these molecules are moving that direction, but these molecules
50:28 kind of moving that direction, so is an opposing flux and so when
50:34 reach equilibrium, the flux in both is the same and this is better
50:39 probably in this picture, you can here, I've got molecules moving this
50:43 , I've got molecules moving that direction you can see them moving in opposite
50:48 . So the difference between the direction one way and direction and the other
50:54 what we refer to as the net and that's usually what we're talking
50:57 usually what we're measuring when we're talking the diffusion, Because just like when
51:03 guys are leaving this room, I everyone, there's there's roughly 400 people
51:07 and all 400 you're trying to leave room while you got students outside trying
51:12 get in and you know that one , you've seen them, right,
51:16 the ones that's fighting against the grain in, right? Even though the
51:20 of people are moving out, there's those three people that are kind of
51:24 their way in net diffusion still says moving out of the room, but
51:29 still got those three people moving or two people or whatever it
51:33 Alright, so equilibrium simply is when flux is the same in both
51:39 particles that will always be moving lastly bulk flow. And this is a
51:45 that's uh easy to describe. I , in terms of example, but
51:50 to kind of visualize if you don't an example when you breathe in,
51:54 are you breathing into your body? . Is kind of not a trick
52:01 , but it feels like it, ? It's not oxygen. What are
52:03 breathing in air? That's Yeah. it's it's not a trick question,
52:09 it feels like it, right? not. I'm not. And
52:12 whenever we ask questions, they're not to be like, is this
52:16 It's it's air now here, it a little bit harder. What is
52:21 oxygen, nitrogen, carbon dioxide and and then about a billion other different
52:29 that are so small that we don't bother thinking about it, Right?
52:32 it's mostly nitrogen. All right. , what is out of all of
52:38 gasses? Which is the one that actually want oxygen? Alright, So
52:43 I breathe out, what am I out air, right? Made up
52:50 nitrogen, oxygen. Carbon dioxide water a whole bunch of other stuff.
52:59 differences is in the air that I'm out in the air that I'm breathing
53:03 has made slight modifications to the gasses we're breathing in and out. So
53:09 I breathe in I'm breathing in more . But I use some of that
53:13 and I make carbon dioxide. So I breathe out, there's more carbon
53:17 coming out and less oxygen right You know that and it kind of
53:23 like he's being mean and Trixie, ? But I'm not I'm just trying
53:27 demonstrate. So when I breathe I'm not selecting specifically oxygen to breathe
53:34 , I have to breathe in all gasses. So what we call that
53:39 that fluid movement into the lungs is flow because all the gasses have to
53:45 in and when I breathe out, not just breathing out the carbon
53:49 I have to breathe out the oxygen I haven't used yet. So I
53:53 breathing out via bulk flow in your as the fluids are circulating,
54:00 So you can just think of your and circulation. I have carbon
54:04 I have oxygen. I've got And and so there's gonna be certain
54:09 that sells one, they're gonna want and they're gonna want to get rid
54:13 carbon dioxide, but all those materials together in the body that's bulk
54:21 But when we look at one specific that's not bulk flow, we're looking
54:25 when we say bulk flow, we're at the sum of all the things
54:29 together and what direction are they Okay, so when we breathe in
54:34 breathing air that would be bulk breathing out. That's bulk flow.
54:39 thing I want to diffuse across my when I breathe in is auction.
54:42 I'm diffusing air out, what part specifically material trying to get rid of
54:47 dioxide. So it sounds trixie, both flow refers to all of it
54:52 and the direction it's moving. So you breathe in air, you
54:56 out air permeability. A membrane that the passage of any given substance is
55:09 to be permeable to that substance. a membrane disallows the movement of the
55:17 through it, it is said to impermeable to that substance. So,
55:22 wall, for example, allows gamma allows for all sorts of types of
55:29 to pass through it. Really, small things. They passed just through
55:36 . It's impermeable to me. I go running towards that wall.
55:42 , I'd say get your phones out that would be like the King and
55:47 of Tiktok Professor makes acid self in . All right. Our membranes are
55:56 we call selectively permeable, meaning something's permissible to some things, it's not
56:03 then it determines at times which things going to be able to pass through
56:07 . So this right here, just of shows you kind of a general
56:10 , how you gonna look at it asses are membranes are permeable to
56:16 you don't have to have channels or to allow gasses to pass through their
56:21 tiny molecules that just kind of float the two points. They just diffuse
56:26 fine hydrophobic molecules. Remember things that lipid soluble passed through the membrane.
56:34 fine, small polar molecules like ethanol membrane can't stop them. They're
56:40 small, they sneak between the lipids while they technically don't want to go
56:47 , they're not gonna stop that the doesn't stop them. But when you
56:51 to larger molecules and charged molecules, are the things that we disallow were
56:58 to them. So, if I to get, for example, an
57:02 acid into a cell or glucose into cell, I'm gonna have to use
57:07 of those transport mechanisms to make it . If I want to get an
57:11 into the cell, I'm gonna have use one of those transport mechanisms.
57:15 gonna have to use facilitated diffusion for to happen. Here's a word that
57:26 the crap out of everybody I learned osmosis before. Yeah, one person
57:35 nodding their head the rest of your , I'm gonna duck down. I'm
57:38 pretend like So, if I asked what's osmosis, you guys would be
57:42 to answer me, right? Because seen it. Yeah, that's that's
57:45 uh Alright, depending on which sort class you're taking osmosis comes with different
57:52 . It's the same thing. It's how the words that they use.
57:55 right. So, in chemistry, they like to do is they say
57:57 the movement of water to a higher concentration, right? In which case
58:02 it's very, very confusing in they'll actually go through and describe how
58:07 actually works, which gets it even . Right? And what I'm gonna
58:12 here is I'm gonna try to make life really, really easy so that
58:15 will never be confused by osmosis ever . Alright, So, we know
58:20 diffusion is. Right, diffusion is a substance from an area of high
58:23 low concentration osmosis is simply the movement water from an area of high water
58:30 to an area of low water In other words, osmosis is water
58:35 . Alright, Now, why do chemists make this so confusing because water
58:42 to be the environment in which the that they're interested in are doing their
58:46 , so, they're more interested in salute than in the water.
58:51 But I want you to consider I know this is gonna be a
58:53 bit hard to see. All Everyone see the box, just
58:58 Sure, it's kind of sort Okay, I'm gonna put a membrane
59:01 here. All right. If I a solution, a solution is a
59:05 of water plus something. Alright, just say it's 70% water.
59:13 I'm gonna put water over here as , and I'm gonna have a
59:17 We don't know what the solute we don't care. It doesn't
59:20 All right. So, if I'm water, how much should I
59:25 30%? That's easy. easy Alright, let's say over here,
59:32 50% salute. So, how much do I have? All right,
59:36 , okay, so they focus down and they say water moving to a
59:40 solute concentration. I say don't confuse . Make your life easy. Look
59:45 . High water to low water and all. That's all osmosis is.
59:54 . So don't let this term where talking about salute confuse you.
60:02 now, water can move through a through the plasma membrane just fine.
60:07 we already said plasma membrane doesn't stop movement of water. Water will move
60:12 its water concentration gradient. Alright, an area where there's less water or
60:19 salute. Right? It can also a channel. The channels that we
60:26 on cells that allow water to pass . Have these very clever names called
60:30 porn's see what we did there. . Using a fancy word for
60:36 Aqua por water pour. And the . N. On any word that
60:41 protein. So, we got aka . So, we got another
60:45 Alright, now water has inherently all have inherently hydrostatic pressure. I'm gonna
60:55 your bottle for a second because it's front of me and it's easy.
60:58 see the water in here? You tell it. That's right there.
61:02 . Where does this water want to out? That's that's the answer we're
61:08 for. It's out. Alright. is a volume of water in there
61:12 has pressure and that pressure is being in all directions to its container.
61:18 reason the water doesn't leave the container because the pressure opposing the water pressure
61:26 greater than the water pressure. But could squeeze this. You know,
61:30 I wanted to I could create greater on the inside cause the water pressure
61:33 the inside to burst beyond the Right? But that would be an
61:38 pressure on the outside. But water a natural pressure applied to every one
61:43 the containers that you have here. if the pressure inside the container is
61:47 than the actual inward pressure than the is going to escape, that pressure
61:52 referred to as hydrostatic pressure. See name hydro water. So hydrostatic pressure
62:00 the water pressure of the fluid Alright, The osmotic pressure is a
62:05 of hydrostatic pressure. Alright, And this pressure is is it's an opposing
62:12 . All right, now, I you to envision for a moment of
62:15 car. You guys know what a car is. How many people can
62:18 fit in a smart car? I one. I see one You guys
62:23 trying look you and your friends are to go down to that new club
62:29 , right? How many people? got a smart card and there's 14
62:33 you. How are you gonna get there? No, the train doesn't
62:37 no more. Start shoving him in car. Like it's a clown
62:44 You never done that man. You start shoving people in, shoving people
62:48 . I bet you you could fit eight people into a smart car.
62:53 , I didn't say comfortably. You're comfortably. How do I get down
62:56 comfortably? You can get a but we don't afford limits right
63:01 what you do? You shove people the smart car, right? Because
63:04 can pick up the smart car and in your pocket later. All
63:08 And you just keep putting people keep pushing and pushing in and finally
63:11 gonna get that one person right where push them in and the pressure inside
63:17 car is so great ! That out a person on the other side.
63:22 just found the osmotic pressure. If was a container. Alright, look
63:28 our things here. The red dots water. The little gray area just
63:33 where the fluid levels are. All on this side. How many water
63:38 do we have? You don't need count them. Lots of little How
63:42 on that side lot. All Now, remember actually I got this
63:49 . Red dots are not water. dots are salutes. So the gray
63:55 here represents how much water is Alright now this membrane in our little
64:00 here is supposed to be permeable only the water not to the salute.
64:06 water is trying to move to where is less water because there's lots of
64:10 less or more water less water water gonna start moving, it keeps moving
64:15 direction as I move water into this over here. What's gonna happen to
64:21 pressure? It's gonna go up, happens to the volume? It goes
64:26 volume and pressure are related, And there's gonna be a point where
64:30 pressure as a function of the volume so great that the next molecule that
64:35 over kicks out another molecule back to other side. And what you've done
64:40 is you've reached equilibrium. Alright. so it looks weird because like wait
64:46 second, that volume is much much than that one. Yes. But
64:49 terms of the the as close to as you can possibly get. In
64:54 words, I've reached that point where not allowing anything else in this
64:59 even if it wants to go that , it can't because the pressure is
65:02 high, that's all osmotic pressure it's the hydrostatic pressure that opposes movement
65:08 that environment. Just like that smart . I can only fit so many
65:13 in that smart car. The next I push in forces the person
65:19 So if it was eight, six your friends are gonna have to ride
65:23 train. Okay, that kind of sense. What's that? Oh
65:29 sorry. You have to get an and it's a busy night so it's
65:33 to cost you a lot. It of makes sense. So osmotic pressure
65:38 a hydrostatic pressure that opposes movement into fluid. That's what we're looking for
65:50 . Now, those of you who going into nursing, you could care
65:52 about all this stuff. This is you care about ethnicity. It's dependent
65:56 osmolarity and osmotic pressure. But you'll this more frequently. Tennis City.
66:02 City simply is the ability of a . So it's water plus stuff
66:06 Cause the cell to gain or lose through the process of osmosis. Person
66:14 to you dehydrated into the, into er do you just stick them and
66:20 pure water into their body? I mean they're dehydrated. You think
66:24 that'd be fine. But what happens you create an environment that's mostly water
66:29 I've tilted the osmolarity in such a that I've got lots of water
66:35 Very little water inside the cells. water rushes into the cells causes the
66:39 to and that's not good for When cells start popping, you can
66:45 say no. That's bad. All . So when we look at a
66:50 , we ask the question how much is in there. All right.
66:55 I have hypo hypo means less tonic to the salute. So, I
67:00 less salute than the cells. If I'm isotonic, I am same
67:08 as the cells. And if I'm tonic I'm more solute than the
67:14 So teutonic refers to salute here Think of Visine. You guys ever
67:20 Visine on the other side of I drops. They usually have like a
67:25 saline solution. And basically they're So they don't cause your eyes,
67:32 know, dry out there basically acting your tears. And so you're wetting
67:38 eyes in the same way when you up and you're dehydrated. They gave
67:43 they give you a hip atomic Right? And so what it
67:48 it slowly add in water into your as opposed to rushing it and causing
67:54 to lice. So hip a tonic solute. So water is going to
68:02 in. But it's gonna cause let's where are we? Hype atomic.
68:07 hypersonic is going to cause the cells expand. Water moves into the cells
68:11 . Nothing happens. Um hyper tonic water is going to leave the cells
68:17 cause them to shrink. Alright transport back to where we were here.
68:28 we've talked about the different mechanisms so , we have simple diffusion we have
68:34 diffusion and a whole bunch of different . Right? And so we want
68:37 come back and we talked about osmosis is a type of diffusion. So
68:41 coming back and we're looking here at diffusion. So when we look at
68:45 transport proteins, when you look at channel proteins and carrier proteins are put
68:48 place because they are plasma membrane proteins trans membrane proteins. So remember they're
68:54 through that process of creating something in membrane at the level of the er
68:59 then moving it up through the golgi ultimately to a vehicle that comes and
69:02 to the surface. So that's how get there. Alright, so that
69:07 protein um I should point out um see. Oh yeah very often what
69:13 see with these transport proteins that have an open and closed confirmation. So
69:17 pathway right here that door I can through it is the channel. What
69:23 of channel would you say? Open closed? Open. C. That's
69:26 . And if I take that door allow it to shut it is now
69:30 does that make the channel disappear? it's still there so it opens and
69:34 . Alright. So channels are simply that can open or close but always
69:40 a path that's always open to both . With the exception of that opening
69:45 portion carrier proteins will only be open one side. Then they exist in
69:50 state. Where it could be I mean where it's close to both
69:53 and then opens up to the other . So it moves between those three
69:57 Now. How do we open and a channel. Well, what we
70:02 these channels when they have these things open closed. We call those
70:06 We don't call them doorways calm And the gates are have specific And
70:11 is the ugly term modality. A modality simply is the thing that
70:16 it to open or close. All . And so, these are just
70:21 of modalities. This is not the list of modalities, but for
70:25 you can have a voltage gated voltage gated channels. This looks in
70:29 of charge. It says what is charge around the membrane? Alright,
70:33 this is dependent upon the ions that in the fluid outside the cell and
70:38 fluid on the inside of the You change the balance. That causes
70:44 in the shape of the molecule which the gate to open. That was
70:47 little bit more difficult to visualize. one I think is the easy one
70:51 visualize the ligand gated channel. A is simply a molecule that binds to
70:56 molecule where they come up with the Ligon. I don't know. All
71:01 , but that's what it is. can think of it as a key
71:04 I have a key, I can and close the gate. Right?
71:08 that's what religion is a little tiny that binds to and opens and closes
71:11 gate. Alright. So this one kind of the easy one. Usually
71:15 some sort of chemical messenger. Chemical is just a chemical that's floating through
71:20 blood. That then serves to act that key makino sensitive. That's when
71:28 twist the membrane or twist or change shape of the molecule that causes the
71:34 to change shape. You ever been , stabbed, poked anything like
71:41 right? You feel that pain, ? What you've done is you've opened
71:45 closed a mechanic sensitive channel which allows ions to move in, which creates
71:51 signal that then goes your brain that , hey, um you've been poked
71:54 stabbed or pinched or whatever it Alright, so this changes to mechanical
72:01 surrounding it and then thermally gated. an easy one. Changes in
72:07 Right? So again you change the that changes the shape of the molecule
72:12 response. So it opens and How many do I got here?
72:21 . Okay. Primary active transport we've mentioned requires energy directly. So this
72:26 a pump action. Uh This is example that you're seeing here is one
72:31 the most common type uh sodium potassium P. Ace. So, what
72:35 doing is I'm gonna take three So, we have lots of sodium
72:39 the outside of the cell. Very sodium on the inside of the
72:41 You can look at the little green . All right. And basically says
72:45 going to move the three sodium from to where? There's more of
72:51 And in order to do that, gonna expend energy to do it.
72:53 in the form of a T. . So, that's where I pumped
72:56 three. And then when I open to the other side, the three
72:59 leave and it creates a binding site potassium to potassium come in and then
73:04 pumped to the inside. So, have low potassium here, high potassium
73:09 . And so you can see I'm exchanging these two ions but at the
73:15 of energy and I'm moving them both the opposite direction. They naturally want
73:19 go sodium naturally wants to come in I'm pumping at the opposite direction.
73:25 naturally wants to go out. But pumping it into the cell and as
73:28 result, I'm now creating potential energy now sodium wants to find its way
73:33 into the cell because of that concentration . And so it's going to use
73:37 channel or it may use something like secondary active transport mechanism, which is
73:42 next slide. Here's another simple This is the proton pump,
73:46 I've got lots of protons out I've got a few over here at
73:49 expensive, expensive energy. I'm moving out from this environment to that one
73:56 it's gradient. Alright, I promised the example of the secondary active
74:03 So here again, is that sodium 80 P. S. I got
74:07 and lots of sodium out here. little sodium out there because I pump
74:10 in direction that they don't want to sodium now wants to come in.
74:14 can come in but it won't be to come in unless it brings into
74:18 with it. Glucose wants desperately to inside cells because it's useless outside of
74:22 cell. Right? But it can't in cell because to pump it in
74:28 be to expend energy. Glucose is , Right? You fought really,
74:35 hard for that glucose molecule. You want to expend more energy.
74:40 So, what do I do? pump it? And I'm using the
74:45 energy. The sodium glucose says, um I want to go in.
74:50 I go in with you? I said, I can't go in
74:52 you go in with me. And they lock arms and through this
74:56 They do it together what these two do. And it's actually we got
75:02 little bit more time. So, no rush. What these two slides
75:06 not memorize them. All right. I want to point out with this
75:10 in the next one is that these mechanisms appear over and over and over
75:18 . Right? So, when I back here and I showed you this
75:23 . All right, you're going there's sodium potassium probably saying I gotta
75:27 this. Alright, Yeah, you of do. But if you understand
75:30 mechanism, you understand this mechanism, difference is I'm only pumping one
75:34 not two things against their gradients. when I come back and look at
75:38 , I can see there's my sodium pump. This artist does some simple
75:42 . All pumps look like bells. at that pump. It's pumping calcium
75:47 protons. Same thing that we saw there. Very similar here. There's
75:53 same pump. It's being used on organ L over here. Here's that
76:00 pump. So, that same thing a structure is used over and over
76:05 over again. Alright, well, about channels? Alright, well,
76:10 got a potassium channel. There's a channel. There's a vulture gated calcium
76:14 , voltage gated sodium channel over Chlorine channels. Alright. So,
76:21 matters at this point? The Right. How does that opening and
76:26 ? All right. What if I'm things? What if I have to
76:29 transport? I'm using secondary active Right? So, I think over
76:34 this one. Yeah. So, the example of sodium and or glucose
76:39 amino acids. We just saw But there's other ones that are like
76:44 . They might have more. They be going in the opposite direction,
76:48 both of them, or they might exchanging. But the mechanism is still
76:54 same. I'm using potential energy to that kind of exchange. So,
77:00 doesn't matter right now to memorize each every single one of these carriers.
77:08 understanding conceptually how they work. You concept? Because here's the big
77:15 There are over 400 sodium channels. if you know how one works,
77:22 know how they all work. I two more slides here will be
77:25 It should be really easy because I I have what I have three
77:30 You know, I'm gonna talk until have. All right, The last
77:36 bit is how do I move big across that membrane? This is where
77:41 vesicles come in. If I'm pulling into this uh pushing things out of
77:47 cell, I've made something. This a process of exhaust psychosis. We've
77:51 seen this, we've seen it described . Alright, again, moving things
77:56 energy. So that's why exocet But what I'm doing is I'm secreted
78:01 large proteins out of the cell. can't use the channel, I can't
78:05 a carrier because channels and carriers can carry small molecules. Big molecules require
78:10 things. If I want to bring into the cell, I'm gonna call
78:16 process endo psychosis. And there are types of video psychosis depending on what
78:21 looking at. So, for we have to go psychosis, psychosis
78:25 the cell eating where I extend my out and wrap the thing I'm interested
78:31 and then it's now stuck in its and I can then attack it with
78:34 license zone pinot psychosis here, The in vaginal weights. It basically folds
78:42 and then kind of creates a vesicles in pinot psychosis, there's nothing specific
78:48 going after, I'm just pinching off the extra cellular fluid happens happens to
78:53 in it is what I capture. then the part that we're most interested
78:57 is how do I target something? , I need to have a
79:01 So I have a plasma membrane a trans membrane receptor that's pointing outward
79:06 bind to that. And if I'm it's something I'm trying to capture,
79:10 binds to it and then those things together and then that cause once you
79:14 that accumulation that's going to cause the to close in and now you've captured
79:20 and then you can process whatever it that you've captured. It's a very
79:24 mechanism. So pinot psychosis is not membrane receptor mediated is Alright, I
79:33 you one extra minute go team. , I'll see you guys on
79:39 Remember we have a test next Hey, how you doing?
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