| 00:02 | Alright, y'all here we are in very wet Tuesday, continuing our discussion |
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| 00:08 | channels and other fun stuff. And what we're doing is we're looking at |
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| 00:14 | some just kind of specifics about the structures that allow ions to move |
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| 00:19 | and forth across memory. That's how gonna start, because that's where we |
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| 00:22 | off last week. And then what gonna do is we're gonna move into |
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| 00:27 | signal works in the cell. In words, how do cells talk to |
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| 00:32 | other? That's kind of the big going. And so here we are |
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| 00:36 | this point here, looking at pores channels and actually there's a question someone |
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| 00:39 | me at the end of class so what exactly is a poor and |
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| 00:42 | just didn't happen to get to And so a poor simply is a |
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| 00:46 | that has no gate or door and going to call them gates because that's |
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| 00:50 | we define them in biology. So basically it's an open channel that allows |
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| 00:54 | to pass through. And at some in your career you've probably heard about |
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| 00:58 | porn's Yes, Right. That's a pour, that's literally what it |
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| 01:02 | And so a water pour is just channel that allows water to go back |
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| 01:06 | forth easily in and out of the . So whenever you hear poor, |
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| 01:10 | think, oh, it's a but it doesn't have a gate. |
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| 01:13 | things move down their concentration gradients through poor. A channel on the other |
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| 01:18 | , even though it's the same it actually has a gate that regulates |
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| 01:23 | passes through it. All right. so what we do is we refer |
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| 01:27 | its modality. What is its The modality is simply the thing that |
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| 01:31 | and closes the gate. And so here's a couple of examples of |
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| 01:36 | We have chemically gated voltage gated, gated. There's thermally regulated channels as |
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| 01:41 | . So there's all different types. really you can just think of this |
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| 01:45 | a key. What is the key opens the gate that allows the things |
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| 01:48 | pass through? And so with chemically , that's the easiest one to |
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| 01:52 | You can imagine what binds to the A here. I'm gonna underline the |
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| 01:59 | again, a chemical, right? so that basically says some physical |
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| 02:07 | some little element or an actual chemical along, that serves as a key |
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| 02:11 | opens the door. That's an easy to visualize, right? Alright. |
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| 02:15 | weirder ones, the harder ones are voltage gated and hear what you're doing |
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| 02:20 | the channel itself has charges around And so when the differences of the |
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| 02:26 | on either side of that channel start , that's gonna change its interaction with |
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| 02:32 | environment and it changes shape and that's it opens up. All right. |
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| 02:36 | these voltage gated channels are really, important and valuable in understanding how muscles |
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| 02:42 | neurons work. And so you'll see come up over and over again mechanically |
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| 02:46 | i thing, they're they're kind of to conceptualize. but it's still not |
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| 02:51 | as easy as I take a chemical open the gate here. What we're |
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| 02:54 | is we're manipulating the environment around the . When you manipulate the environment, |
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| 02:59 | twisting and turning and stretching and stuff causes the channel to be affected by |
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| 03:04 | twisting the turning. So it changes and so it opens up as |
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| 03:07 | So like when you get a pinch when you feel a poke, those |
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| 03:11 | mechanically, you're mechanically manipulating cells that these types of channels that allow ions |
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| 03:17 | pass through. All right now channels pores are very, very small and |
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| 03:24 | very selective as to what they allow and there are hundreds of them. |
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| 03:30 | news. We don't need to know . All right, but they're very |
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| 03:33 | . So typically what we'll say is look at a channel and says, |
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| 03:36 | this channel only allows sodium to pass ergo it is a sodium channel, |
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| 03:42 | ? If it's a voltage gated sodium which basically pointing to its most |
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| 03:47 | Alright, so the idea here is the channel has a specific side. |
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| 03:52 | you guys have all taken chemistry. you should know the answer which element |
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| 03:56 | bigger, potassium or sodium potassium is . Yeah, I know it's kind |
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| 04:04 | scary when he throws stuff out at like that. Right? It's like |
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| 04:08 | you mean I have to remember right? So potassium is bigger. |
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| 04:12 | you think oh, when I have potassium channel wouldn't sodium be able to |
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| 04:15 | go right on through because they're both the same valence. They sit right |
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| 04:18 | the same column, right over there that far left, right. The |
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| 04:22 | is known. It's because of the of the electrical charges. So you |
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| 04:26 | think of it kind of like as magnetic field that repels and attracts and |
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| 04:30 | if you're the right size, you go through. But if you're the |
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| 04:33 | size out you go, you don't to go through. So that's why |
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| 04:37 | have that degree of specificity to All right. And notice these are |
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| 04:41 | dealing with ions very, very small . If you're bigger like a glucose |
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| 04:46 | and glucose is really small, relatively , you're gonna need something different. |
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| 04:51 | forgot I had to push the Sorry, when I go into two |
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| 04:55 | programs, you know, it doesn't . So here's that carrier and this |
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| 05:01 | of visualize is what we were talking on thursday. It's like it's never |
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| 05:04 | to both sides at the same Just like that rotating door at the |
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| 05:08 | , right? You have a binding that that particular molecule that needs to |
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| 05:14 | carried across the membrane combined to when chemical binds to that binding site that |
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| 05:21 | the change in the shape of the . And so this is just trying |
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| 05:25 | show you the different stages here. am outside here I come in and |
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| 05:29 | I'm bound. So now I change . I reorganized. Now I'm open |
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| 05:33 | the other side and now that I'm to the other side, I have |
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| 05:37 | affinity. I still have affinity but affinity. So out the molecule goes |
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| 05:42 | longer bound. So then I flip to the original shape and so this |
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| 05:45 | me to move materials in very specific . Alright, so we never have |
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| 05:50 | continuous passage and we're moving molecules in particular direction but we do it a |
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| 05:56 | slower because it's not just a channel we can just flow through down a |
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| 06:00 | . So you can imagine over here got lots of these whatever that happens |
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| 06:04 | be. And on this side I very little. And so there's that |
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| 06:09 | that's driving the molecule down its concentration . But we use this as a |
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| 06:16 | because these are bigger items. it's not always gonna be bigger |
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| 06:20 | it can be ions and we'll see example of that in a little bit |
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| 06:24 | . Now when you're dealing with carrier transport. So that would be this |
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| 06:29 | a carrier. Right? So this an example of carrier mediated transport. |
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| 06:33 | gonna have some rules that kind of with this. You have specificity not |
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| 06:37 | molecule combined, that binding site. it has to be specific. Sometimes |
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| 06:42 | molecules are very similar and they combined the same site. And so then |
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| 06:46 | you have that then you're going to up with competition? All right, |
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| 06:50 | guys ever play musical chairs? one chair. Two butts. |
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| 06:55 | so one of those butts is gonna the chair the other but is gonna |
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| 06:58 | all by its lonesome. And that's what happens here. You don't get |
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| 07:01 | share the chair. And so it's now you're kind of fighting dependent upon |
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| 07:08 | . Right? So if I have of this molecule intent of this |
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| 07:11 | that carrier is likely gonna carry this with greater frequency than this one. |
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| 07:17 | ? But if I change concentration so equal there's an equal chance that both |
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| 07:22 | molecules will pass through that particular Alright. And there's a point of |
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| 07:28 | in other words, um if I 10 receptors or 10 channel, excuse |
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| 07:32 | . If I have 10 channels and have one molecule, I can move |
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| 07:35 | molecule pretty quickly. Right? Cause 10 options. If I got to |
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| 07:39 | can still move it at the same . Once I get to 10 molecules |
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| 07:43 | 10 molecules for 10 receptors, I'm start reading reaching a saturation point because |
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| 07:48 | of those molecules now is going to fighting for one Channel. So if |
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| 07:54 | have 100 of them there's gonna be right, basically everyone wants to get |
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| 07:59 | but there's only 10 doorways into the . Right, so understand that when |
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| 08:04 | looking at these that these these mechanisms carriers were dealing with these questions of |
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| 08:11 | what is the specificity? What do have here? Oh yeah, glucose |
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| 08:14 | galactose. You guys remember those two ? Right? Can you visualize them |
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| 08:18 | exposes? Look awful lot alike. groups are switched into positions. You're |
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| 08:24 | of like, I don't know about . Go back and check it |
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| 08:26 | All right, you can actually google up and I'll show you the line |
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| 08:30 | . You don't have to do that now. But if you look at |
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| 08:33 | , you'll see, oh wait a . Yeah, there's a flip |
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| 08:35 | So they're very similar. So they they can compete for the same binding |
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| 08:40 | . Right? So that's the Notice here, the rate of reaction |
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| 08:43 | a little bit slower because of that . And then saturation. There's a |
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| 08:49 | or specific limit to which I can . All right. Now we get |
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| 08:55 | the weird stuff. The active When you see the word active, |
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| 08:58 | do you think of energy? Okay. So when we're dealing with |
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| 09:04 | usage, what we're saying is we to use energy to move something in |
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| 09:09 | direction, it doesn't want to If I put a ball on a |
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| 09:12 | , it wants to go down and the floor. Right? And so |
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| 09:16 | I gotta do is apply a little energy just touch it and that thing |
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| 09:19 | roll and fall to the floor, no other work that needs to be |
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| 09:23 | . But if I have the ball the floor and I want to put |
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| 09:25 | on top of the um uh cabinet shelf, I have to do |
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| 09:31 | don't I? Right. See what our physics one. So we learn |
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| 09:35 | , right? So energy has to applied. Now I can apply energy |
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| 09:39 | and do the work. Or I apply energy indirectly and do the |
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| 09:44 | In other words, the machinery that's the work. So, when I |
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| 09:47 | over and lift it up and put ball on the shelf, I'm using |
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| 09:51 | directly. Or what I can do I can put energy into machine and |
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| 09:55 | machine does the work. Right? , that would be an example of |
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| 09:59 | versus indirect. And so we have that are both direct and indirect and |
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| 10:05 | just refer to the direct system as active transport. We use the indirect |
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| 10:10 | active transport. Now, I'm gonna you the primary is easy, |
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| 10:16 | Sometimes it takes a little bit of moment to wrap it around, wrap |
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| 10:19 | heads around the idea. All But that's the idea. We're moving |
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| 10:23 | in a direction. They don't want go. Alright, so, I'm |
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| 10:27 | just show you pictures here to make lives simple. These are just the |
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| 10:30 | to support what we just said, potassium 80 pes pump. You have |
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| 10:35 | this one. You know when we're things on our body, like caffeine |
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| 10:38 | stuff. This might be one of things you want to consider because you'll |
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| 10:41 | it all the time, Right? here what we have is we have |
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| 10:46 | lots of sodium on the inside of cell and we don't want to get |
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| 10:50 | of it so that there's little sodium the inside. We have lots of |
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| 10:53 | outside the cell. We want to it on the inside of the cell |
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| 10:56 | we can get to our natural state of equilibrium and homeostasis where we have |
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| 11:02 | heavy on the outside, potassium heavy the inside. So this pump does |
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| 11:07 | job. So what I'm gonna do I'm gonna take three sodium, I'm |
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| 11:10 | bind to this carrier. When that . What's gonna happen is it's gonna |
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| 11:16 | shape and with a T. It allows it to change shape so |
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| 11:19 | I'm moving it and then I create two new binding sites, potassium comes |
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| 11:23 | and then it changes shape again, moves in. So at the expense |
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| 11:26 | 1 80 P. I can move move sodium out of the cell. |
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| 11:30 | gonna move potassium into the cell. , now, if you want to |
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| 11:34 | what that actually looks like. This the process, there's multiple multiple steps |
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| 11:39 | this and it doesn't matter where you um we're just gonna start up, |
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| 11:43 | see what the best place to start period. Okay, So what we're |
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| 11:46 | do is you can already see A . P. Is bound up to |
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| 11:49 | molecules. So it's ready to We've already primed the system. We |
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| 11:52 | the energy there. We just got release it. We have the binding |
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| 11:55 | for sodium sodium binds into it. causes conformational change so that sodium goes |
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| 12:00 | . The new the new binding sites created as a result, the picture |
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| 12:05 | tell you exactly what's going on. three sodium binding sites are right on |
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| 12:12 | of the two potassium sites. So can't buy them both at the same |
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| 12:16 | , right? They take up the space. That's why they always draw |
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| 12:20 | separately so you can visualize it. that's why if you ever wonder why |
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| 12:23 | can't I just do it at the time? That's why. Alright. |
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| 12:27 | as Yes, sir. Uh Well rule no, and the reason for |
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| 12:38 | is because look at what the Does it just does exactly what we |
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| 12:41 | to carry to do, right? never open to both sides at the |
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| 12:44 | time. So once I bound myself it, look what happens, I'm |
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| 12:49 | closed on both sides. And then I'm open only on the outside. |
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| 12:53 | even if I'm released from that right, I only have one |
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| 12:57 | I can only go one direction. ? So if I if let's say |
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| 13:02 | your eye can see kind of a bit what you're thinking here in |
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| 13:05 | I can go back and forth. . So if I get released, |
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| 13:08 | I buy into that site while I'm open to that side? Sure. |
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| 13:11 | I have less affinity so I'm less to. And also I have no |
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| 13:16 | . That's the only way I can . And I'm not going to be |
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| 13:19 | to create those potassium sites until both leave. Yes. In this particular |
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| 13:29 | this particular pump. Yes. Absolutely. That's correct. Alright. |
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| 13:35 | so you can see here now once potassium, excuse me. Once the |
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| 13:39 | have left now we have our potassium . Just imagine on the same |
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| 13:43 | And so now the potassium comes in wants the potassium by that's what causes |
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| 13:48 | d phosphor relation the release of the to turn it back the other |
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| 13:53 | and then these are just the opposite . Alright, So, I think |
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| 13:57 | a pretty easy example to see. , Yes, ma'am, Prime |
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| 14:05 | It's so, you can see it's gonna be in this case it's |
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| 14:09 | be to return the potassium to the to return to its original shape. |
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| 14:14 | , if you look here here, see nothing bound up. Right? |
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| 14:18 | , what have I done is I've started the movement from the opening to |
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| 14:23 | outside to now opening to the inside once I've opened back up to the |
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| 14:27 | , that's when I can prime it the fresh A. T. |
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| 14:30 | That hasn't been hydrolyzed yet. All , so the idea here is the |
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| 14:36 | ation of a teepee occurs here to me to change shape. And I'm |
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| 14:40 | trying to see actually it looks like occurring there. My my mistake. |
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| 14:44 | obviously I'm not gonna ask you that . That's a just so you |
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| 14:47 | that's a cell, bio bio kim molecular biology question. I'm not gonna |
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| 14:52 | you what are the steps I'm wanting to understand the process because we have |
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| 14:57 | of these pumps in our body. right, let me show you the |
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| 15:02 | one, you ready now as a of this, I've pumped a lot |
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| 15:06 | sodium on the outside of the I've pumped a lot of potassium onto |
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| 15:10 | inside of the cell when I moved in a direction they don't want to |
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| 15:13 | and they've accumulated. I have created energy, right? If I put |
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| 15:18 | whole bunch of ping pong balls in closet, where do they want to |
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| 15:23 | when I open the door out of closet? Right, So we have |
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| 15:27 | stacked up trying to move down their gradient, there's just no mechanism that |
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| 15:32 | know of, right? This second allows us to do that. All |
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| 15:36 | . This is where secondary active transport in. It's basically storing up energy |
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| 15:43 | a concentration gradient so that I can something against its own gradient. |
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| 15:49 | so the example that we have here there are lots of these little systems |
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| 15:53 | the body that allow us to move that wants to go into the cell |
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| 15:58 | with sodium. Now the example I use is this year's. I hope |
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| 16:02 | . Okay. I don't want to on your pencil. No, |
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| 16:04 | don't don't worry about it. I'm getting out of the way. Um |
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| 16:07 | gonna use an example that's not gonna everybody here. All right. But |
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| 16:10 | worked for me for many years and I'm just sticking with it so you |
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| 16:14 | just shake your head at me and go whatever. Doctor. Alright. |
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| 16:17 | went to school in New Orleans went late. I think I told you |
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| 16:20 | this. Maybe not. If I I went to school in New |
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| 16:23 | why do you think I picked new ? You can say I see the |
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| 16:27 | on your face. Go ahead. fun. All right. I |
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| 16:32 | it's a fun city to live There's a lot of social life you |
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| 16:36 | do and in fact every day of week, there's a ladies night at |
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| 16:41 | bar around the university. So, , if you want to drink, |
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| 16:44 | you gotta do is show up to bar that has ladies night and usually |
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| 16:48 | can get in for free and usually guy's gonna buy you drinks. |
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| 16:53 | how's that gonna happen? Well guys to pay a cover charge to get |
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| 16:56 | these places man. I don't want pay a cover charge but I can |
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| 17:01 | in free if I bring in a . Right? So what happens is |
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| 17:07 | outside the bar there are single women single guys are usually in groups and |
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| 17:12 | like, hey man I want to in. I've got a friend in |
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| 17:15 | , I want to go hang out but I can't get in, I |
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| 17:17 | want to pay the $10 cover or it was at the time. It's |
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| 17:20 | like $4 and that was still outrageous the time, you know? But |
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| 17:23 | like I want to go in if come in with me I will buy |
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| 17:28 | a drink and then we'll call it . So you see what happened? |
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| 17:33 | gets her free drink, doesn't have pay for drinks that night. I |
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| 17:36 | into the bar and I can hang with whoever I do. And maybe |
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| 17:38 | might actually get a phone number. what this system is right here, |
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| 17:44 | ? sodium wants to go on the but it doesn't have a mechanism to |
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| 17:48 | . So glucose needs to get in cell but is moving uphill. It |
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| 17:52 | do so and I don't want to energy to move energy because as far |
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| 17:56 | sales are concerned, what's glucose? a whole bunch of energy. How |
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| 18:00 | energy do you guys remember? 38 P. Yeah 34 to 38 80 |
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| 18:06 | . Alright so it's saying I don't to spend energy to go into the |
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| 18:11 | . What I'm gonna do is I'm , hey sodium I see that you |
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| 18:15 | to go in um If you take in with you we both get what |
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| 18:19 | want and that's what this mechanism It's showing you this. The potential |
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| 18:24 | of sodium wanting to move into the allows for glucose what to move against |
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| 18:30 | gradients to get into the cell. I don't spend any energy doing so |
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| 18:35 | . I mean I still use up energy now. This is true for |
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| 18:40 | whole bunch of different systems. Much your sugars and amino acids use |
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| 18:44 | So think about all the digestion that do. Think about what's in the |
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| 18:48 | that you digest, that amino acids . Not your heads go. Yes |
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| 18:53 | I eat proteins. Do you eat of things with sugars and you break |
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| 18:58 | down into glucose, galactose and Guess what if I want to get |
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| 19:02 | across the board, I'm gonna have have a system that allows me to |
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| 19:06 | it without expending energy. And this what allows me to do that. |
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| 19:11 | primary active direct use of energy. . T. P. Aces are |
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| 19:15 | be associated or part of the channel you're looking at secondary active transport. |
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| 19:20 | using the potential energy created by the active transport systems that you have. |
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| 19:35 | . Yeah. So, the active is here. Right. So, |
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| 19:39 | did I do? I expended energy move three sodium against it's gradient and |
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| 19:45 | to potassium against it's gradient. the expense was in order to store |
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| 19:50 | the ping pong balls in the I expended energy, right, I'm |
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| 19:54 | sodium over here. I'm expending Now, the energy is in the |
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| 19:58 | of stored up sodium outside the cell wants to get in and similarly stored |
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| 20:04 | potassium wanting to get out. So, you can think of |
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| 20:10 | That's a good way to think about gradient represents the difference. So, |
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| 20:15 | amount of energy you actually have stored . Yeah. Uh in the pump |
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| 20:30 | this case. Yes. Well, remember I said in this over |
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| 20:34 | in our starting position, you we have less sodium, but I |
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| 20:39 | , we have more sodium out So, we're always moving against the |
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| 20:41 | . When you're talking about a both sides are moving against the |
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| 20:45 | And so this just shows you the . So, so the end result |
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| 20:50 | , is you're gonna end up with attack um on the outside of the |
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| 20:54 | . More potassium on the inside of cell, you're gonna end up with |
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| 20:58 | sodium on the inside of the more sodium on the outside of the |
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| 21:01 | and now you have a gradient that to drive sodium back into the cell |
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| 21:06 | you have a great that's gonna want drive potassium back out of the cell |
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| 21:12 | you're using a pump, that's that the case, yes, but the |
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| 21:15 | inclination of any sort of chemical is move which direction down its gradient, |
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| 21:20 | down the gradient. So remember against going uphill. So, I think |
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| 21:25 | I get out of my bike, I want to go up a hill |
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| 21:27 | do I want to go down a ? Down the hill? That's the |
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| 21:30 | you want to go. All right , the put your hands in your |
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| 21:35 | . Do not write these things down because I know every one of you |
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| 21:39 | to memorize all of these molecules. not. You have now learned conceptually |
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| 21:46 | hundreds of thousands of molecules really just of molecules that exist in your body |
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| 21:51 | allow you to move things back and across membrane. One term we use |
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| 21:56 | called a co transporter. Co transporter to objects in the same direction. |
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| 22:01 | does this kind of look like? active transport and secondary active transport? |
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| 22:09 | moving to things in the same Alright, sometimes you'll see the term |
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| 22:13 | porter, all the salts are moving the same direction. It's a secondary |
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| 22:18 | transport system. These are all examples types of of of these coats transport |
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| 22:25 | that your body uses. This is an exhaustive list. These are the |
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| 22:29 | common ones. Alright. So, you see something pop up like a |
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| 22:33 | chlorine co transporter. You go Okay get that here. There is the |
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| 22:36 | I mentioned, the sodium amino acid transporter. Oh I'm using sodium to |
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| 22:41 | me move my amino acids. That's concept. When you see something |
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| 22:46 | you can then memorize the specific We also have exchangers here. This |
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| 22:51 | another type of secondary active transport here moving in opposite directions. So once |
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| 22:57 | sodium is moving down its gradient but acting as the pump energy to move |
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| 23:02 | calcium in the direction. It doesn't to go. Alright so sodium is |
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| 23:07 | in because it wants to move calcium is moving out even though it |
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| 23:10 | want to. Alright, you're going a second but it's the same mechanism |
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| 23:14 | we saw with the active transport. differences were not using energy directly. |
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| 23:20 | . We're using the energy of the the stored energy of the sodium. |
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| 23:24 | potential energy to drive the pump Okay. And you can see there's |
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| 23:29 | lot of different ones and typically what doing is we're gonna be exchanging a |
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| 23:32 | eye on for cat ion or an eye on for an an eye on |
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| 23:36 | we're not changing charge what we're doing changing which so happens to be inside |
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| 23:41 | outside the cell. Alright. But idea here is what are my |
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| 23:48 | Right? This case is gonna be chlorine. You're gonna see this bad |
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| 23:53 | a couple of times? I love picture? This picture. Picture makes |
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| 23:59 | excited. So does this one. ? Because this shows you everything you |
|
| 24:05 | learned again. Do you have to all these right now today? Am |
|
| 24:09 | gonna test you on every one of ? No, because you probably have |
|
| 24:12 | seen an enac channel. But what shows you is that, oh |
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| 24:17 | here's a channel Enac. You can of guess. So it's electrical sodium |
|
| 24:21 | really what it stands for and there is. There's sodium goes in so |
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| 24:24 | a volt educated channel. When I the channel, sodium comes in, |
|
| 24:27 | are often named for what they look . Here's uh well, I want |
|
| 24:33 | show, I guess they don't have up here. They have circa. |
|
| 24:36 | , Circus is a channel. You're learn it when we get to the |
|
| 24:40 | , you hear circuit and kind of you scared Like what is a |
|
| 24:43 | A circus, no circus, smooth , plastic particular calcium channel circa It's |
|
| 24:50 | , oh, those stupid abbreviations. that's what all these are. If |
|
| 24:55 | look at them, calcium channel, that a little any different than that |
|
| 24:59 | ? What do you think? it's calcium and sodium. Yeah, |
|
| 25:04 | structurally. Are they different? the cartoon even shows you and I |
|
| 25:07 | it's a cartoon. But basically, , they behave the same channels or |
|
| 25:11 | or channels. It just depends on what's the modality? Right? What |
|
| 25:15 | and closes it and what does it through? This is the picture that |
|
| 25:19 | book uses for a pump. It like a bell. Anything different between |
|
| 25:22 | two pumps. Other than the actual not even the materials ones on the |
|
| 25:26 | membrane ones on an organ L. . They behave the same way because |
|
| 25:29 | a pump when you hear the word . What do you think of active |
|
| 25:35 | ? I'm burning a TP to make happen. And what am I |
|
| 25:38 | I'm pumping calcium in in this case protons out over here pumping calcium out |
|
| 25:43 | the cell. Protons into the Right? Here's our coach transporters in |
|
| 25:50 | . C. C. Is a one. Sounds scary. But sodium |
|
| 25:55 | chlorine chlorine in K. C. . Right? proton channel. How |
|
| 26:01 | that different than those channels? It's it's just what allows to go through |
|
| 26:07 | . All right. So, my in showing you this is not to |
|
| 26:13 | is to start seeing the pattern when see the pattern. All of a |
|
| 26:18 | everything is gonna start becoming easier and and much more fun to understand the |
|
| 26:26 | when you going to learn a specific . And you're going okay? Now |
|
| 26:29 | see this is just like the one just looked at another system. It's |
|
| 26:33 | a different molecule, but it behaves same way you're golden. Okay. |
|
| 26:38 | right. I don't know how long took to get through all that |
|
| 26:42 | But now we're on the official third . Any questions so far that we |
|
| 26:48 | get? Yes. That's just kind the general terms we use. |
|
| 26:58 | And so if I went back and mean, just showed you um like |
|
| 27:02 | this exchanger, right? I we've got a driver here that's moving |
|
| 27:06 | down its gradient and it's carrying with bicarbonate against it's gradient is carrying chlorine |
|
| 27:11 | it's gradient and that is those are the opposite directions. And so, |
|
| 27:14 | we're doing here, we call this exchange because of the number of |
|
| 27:18 | right? In which direction they're So, you can refer to them |
|
| 27:21 | anti ports or you can refer to as exchangers, I think really in |
|
| 27:26 | college level books, the use the that basic term, the anti import |
|
| 27:31 | I don't know why. And then you get up to the professional level |
|
| 27:34 | , they refer to them now as . So, there's something in terms |
|
| 27:38 | the language that changes, right? co transport just means I'm moving two |
|
| 27:43 | at the same time. I just to know which way. And if |
|
| 27:46 | look at the word it will tell which way they're going to deport or |
|
| 27:49 | ports. You know, Exchanger or general co transport? No, we |
|
| 27:58 | talking or have talked about the small . Let's get to the big |
|
| 28:03 | That's all right. You know, get to the big stuff. How |
|
| 28:06 | I move big things out of my ? Alright. Because moving small |
|
| 28:11 | we have channels and carriers. But got proteins and proteins are huge. |
|
| 28:16 | monstrous. And so what we have we have what is called the Secretary |
|
| 28:21 | . So what we're doing here with Secretary pathways, we're putting things either |
|
| 28:26 | the cell or we're putting them into membrane. Right? So when we're |
|
| 28:31 | about those channels, those channels got that membrane through some sort of |
|
| 28:35 | they didn't just magically appear there. what they did was they used this |
|
| 28:41 | what is called the Secretary pathway. so the gist of it is is |
|
| 28:45 | if it's soluble something that you need secrete what you're gonna do is you're |
|
| 28:49 | be always inside the organ el and what you're gonna do is you're gonna |
|
| 28:53 | moved to a vesicles and then that will ultimately merge with the plasma |
|
| 28:58 | And then whatever that soluble protein it's been secreted out of the |
|
| 29:03 | All right. If you are a protein, something that is supposed to |
|
| 29:07 | in the membrane, what happens is you are tagged and actually as you're |
|
| 29:13 | made, you are inserted into the and then as you go along and |
|
| 29:17 | you're sorted, you're actually staying within membrane on that vesicles and eventually I |
|
| 29:22 | this one actually shows a couple of right there, the little yellow dumbbell |
|
| 29:26 | things. And then once you get there now you are in the membrane |
|
| 29:30 | the portion that is supposed to be outward while you're making it is facing |
|
| 29:35 | the organ l right, so that it comes to the surface, what |
|
| 29:38 | doing is you here's my organelles or my vehicle, I merge with the |
|
| 29:45 | . And what happens is is I up this way and so now I'm |
|
| 29:48 | the right direction. Alright, so way you can help yourself remember, |
|
| 29:54 | is like the inside of the like the outside of the cell. |
|
| 29:58 | not but it's like that. right, so we can make things |
|
| 30:04 | one of two ways I can regulate or I always make it okay regulator |
|
| 30:10 | always make it when I'm regulating something means the materials are still gonna be |
|
| 30:15 | all the time. But when it's to release it, some signal has |
|
| 30:21 | come along. So in our little over here, what they're trying to |
|
| 30:25 | you is they're trying to show you vesicles that's hanging around, full of |
|
| 30:28 | the stuff that it's going to secrete you need to have some sort of |
|
| 30:33 | or some sort of signal that comes and says it's time to merge that |
|
| 30:37 | to the plasma membrane and now, it moves to the plasma membrane then |
|
| 30:42 | can open up and release its So that would be a regulated |
|
| 30:46 | the constituent tiv is that you're always a pathway that's always turned on. |
|
| 30:52 | always making stuff, always putting things the vesicles. But the vesicles are |
|
| 30:56 | moving to the surface of the cell releasing its material. Alright, So |
|
| 31:02 | this constant production. It never slows . All right. Now, when |
|
| 31:08 | say this, I'm kind of reminded we're gonna see when we talk about |
|
| 31:13 | digestive system. For example, you produce the pancreatic enzymes are always being |
|
| 31:19 | in the small intestine. It's always the same rate until you put put |
|
| 31:23 | in your body, in which what do you think it does? |
|
| 31:27 | increases. Right. And then after food gets all digested and stuff, |
|
| 31:31 | the enzymes returned back to that original of rate. So its constituent of |
|
| 31:38 | . What do you think? It like it doesn't it? Yes, |
|
| 31:43 | it's regulated at a different area. what I want to point out is |
|
| 31:46 | this is being regulated here at this . Right, I already made this |
|
| 31:52 | . I've stored it away. I'm to release it when we're talking about |
|
| 31:56 | of your regulating up here in the . Yeah. Right. So, |
|
| 32:05 | it's it's a compare contrast between these . Right? So regulated at the |
|
| 32:10 | of secretion here, We're not regulating the level of secretion. If we're |
|
| 32:15 | at all, it's gonna be the of transcription, right? So I'm |
|
| 32:21 | more so that I release more. so that's where the levels, So |
|
| 32:27 | the difference. Like I said, enzymes never stopped being made in your |
|
| 32:31 | track. Or really, it's in small intestine. Always always always |
|
| 32:35 | Which is why you can always eat . That's why I'm always hungry. |
|
| 32:42 | right. So, what I'm trying draw us into is, yes, |
|
| 32:53 | . So, for the constituent Yeah. So, so in |
|
| 32:58 | it never stops. It can get a low baseline level, but you're |
|
| 33:03 | always making you can ramp it But if you ramp it up, |
|
| 33:06 | not you're doing it at a at level way up here. You |
|
| 33:10 | Like I said at the level of the product, not at the level |
|
| 33:14 | releasing the product. So, right , I'm just gonna give you an |
|
| 33:17 | . This will land for some of may completely miss the hormone that regulates |
|
| 33:22 | steroids. Alright? So that we're about follicle stimulating hormone and looting. |
|
| 33:27 | hormones are always being made. Always peptides and their only released when the |
|
| 33:34 | signal comes from the hypothalamus to tell pituitary gland time to release the |
|
| 33:39 | All right, So that means they're being made at a relatively constant rate |
|
| 33:46 | , we can accelerate that rate and can decelerate the rate. But we're |
|
| 33:50 | making, right? But the rate release, that's what we're regulating, |
|
| 33:56 | what were we talking about, regulated we're talking about that. When do |
|
| 34:00 | release it? It's already there, got to do is give you the |
|
| 34:06 | signal and out it comes. We get the reproductive system, we |
|
| 34:11 | to learn that one which is a lot of fun. Oh, by |
|
| 34:14 | way, I'm a reproductive biologist, I get all giddy around that time |
|
| 34:17 | year, it's like Yeah. So what I'm trying to get to |
|
| 34:22 | trying to get to vesicular transport these and we do a terrible job teaching |
|
| 34:30 | vesicular trans. Anyone here have dr for general bio or I mean, |
|
| 34:34 | intro bio. Did she get real about these vesicles? Yeah, because |
|
| 34:37 | studied this stuff and so she actually into depth but everyone else doesn't because |
|
| 34:43 | else kind of like, it's just physical and that's okay and I'm not |
|
| 34:47 | to be the world expert in all either. But what I want to |
|
| 34:50 | out here is the secular transport simply a way to move very, very |
|
| 34:54 | substances that can't pass through a So we're gonna do is we're gonna |
|
| 34:58 | it into this membrane like structure. it is made up of the same |
|
| 35:02 | , a Plaza membrane. It's capable merging with the plasma membrane is part |
|
| 35:06 | a larger system which we refer to the indo member Nous pathway or the |
|
| 35:11 | membrane system. So basically everything from er to the golgi through the vesicles |
|
| 35:16 | to the plasma membrane is kind of same system. And so when we're |
|
| 35:21 | these large peptide large proteins, we this big structure. Now they don't |
|
| 35:26 | float around. Like when you look the pictures of them, they kind |
|
| 35:28 | get the sense that they're like bubbles through like fluid and that's not the |
|
| 35:33 | . They're actually being dragged around by and dining these little tiny proteins that |
|
| 35:39 | energy to move them along specific tracks get them to where they need to |
|
| 35:44 | . So A T. P. going to be involved in this. |
|
| 35:47 | then we have specific terms we use we're describing different types of processes involving |
|
| 35:53 | for example, we have a type intake that's referred to as fagot |
|
| 35:58 | which is the term we all heard least once, right? But we |
|
| 36:02 | have endo psychosis and exocet. sis psychosis is to take in where |
|
| 36:07 | closest to take out these are more less opposite. This is a unique |
|
| 36:13 | that's specific for a specific type. when I was in college we didn't |
|
| 36:17 | these differences, they just refer to or the other but as we get |
|
| 36:21 | we get smarter or as I guess passes, we get smarter. So |
|
| 36:24 | give things new names. And then makes classes like this more complicated. |
|
| 36:29 | , so how do we do All right, Well, first off |
|
| 36:32 | have a plasma membrane that wants that want to bend. It wants to |
|
| 36:35 | kind of flat and so we gotta we gotta bend it. And so |
|
| 36:38 | have proteins that play a role in . All right. And these are |
|
| 36:42 | classroom molecules and your customers. So probably heard of classroom, you may |
|
| 36:46 | have heard of a customer. But they're basically proteins. That kind |
|
| 36:50 | do the same thing. What they is they force the membrane to kind |
|
| 36:54 | bend on itself to create that round . Alright. And so this kind |
|
| 36:59 | show you the process from endo Basically what we've done is we've we've |
|
| 37:04 | a whole bunch of molecules we want bring in using these receptors that's that's |
|
| 37:09 | in the classroom which is represented by little triangle scary looking things. And |
|
| 37:15 | it's done is bent that membrane and of pulled it in and now created |
|
| 37:19 | round vesicles. And then what they is they recycle themselves and they go |
|
| 37:22 | and can do the same thing and you have this vesicles with materials trapped |
|
| 37:26 | them that you can then use the inside or transported or whatever it is |
|
| 37:32 | you're supposed to do with it. , you can have molecules that have |
|
| 37:36 | classroom on them um to form, them off the Golgi for example, |
|
| 37:41 | the same thing and then you recycle . And I think I have a |
|
| 37:44 | of that showing you showing this as . So this can occur both for |
|
| 37:49 | or exocet. Oh sis. So first step is to create the vesicles |
|
| 37:53 | using these unique proteins. The second is directing it and again it's really |
|
| 38:00 | to get lost in the minutia Alright, but what I want to |
|
| 38:03 | you is that when we said that regulated the vesicles again aren't just floating |
|
| 38:08 | , they're transported right up next to membrane on which there are many proteins |
|
| 38:12 | are located. We call these proteins as snares and there's proteins that are |
|
| 38:20 | with the with the vesicles. Their are associated with the plasma membrane. |
|
| 38:24 | one is called the the V snare the vesicles. The T snare is |
|
| 38:28 | the targets that would be on the membrane. And basically you can think |
|
| 38:31 | it as a place where these things dock. So there's like this is |
|
| 38:35 | you need to go. So they and they sit and they reorganize themselves |
|
| 38:39 | such a way that the two membranes almost ready to open up and join |
|
| 38:43 | each other but they're not allowed to the right signal comes along to let |
|
| 38:47 | happen. So that's what's happening here we're seeing the the vessel being docked |
|
| 38:55 | it's kind of stuck in this position the right signal comes. Once the |
|
| 38:59 | comes in you see the merging of membranes materials inside the vehicle are released |
|
| 39:05 | then we have to recycle everything because cells are very very green and they |
|
| 39:09 | everything. And so what they're gonna is they use another series of molecules |
|
| 39:13 | are collectively referred to as the snaps basically say let's move you all to |
|
| 39:17 | next spot and get this going. so you imagine if I'm moving a |
|
| 39:22 | of molecules energy dependent, right, want to know where all your |
|
| 39:26 | T. P. Is going. not to move your muscles. It's |
|
| 39:29 | you have so many of these little things going on in your cells all |
|
| 39:31 | time. So snares let me direct the vesicles need to go. Let's |
|
| 39:37 | doc that vesicles until the time of is necessary and then the snaps helped |
|
| 39:42 | dissociate all those proteins so I can them and now that vesicles now part |
|
| 39:47 | the plasma membrane. Yeah. So yes, so that's kind of |
|
| 39:59 | purpose of the of the of the is to get all those parts and |
|
| 40:03 | them off to where they need to . So the V. Snare portions |
|
| 40:06 | redirected back to the golgi so that can you can actually rebuild your |
|
| 40:10 | The T stairs are redirected back to plasma membrane so that they can create |
|
| 40:14 | new docking site and then what you're is you're now ready for the next |
|
| 40:18 | to be formed. Alright now we're see this when we over and over |
|
| 40:24 | when I get when we get to muslim, I'm gonna point to and |
|
| 40:26 | do you see how they're so closely ? So closely associated? All |
|
| 40:32 | And what this picture is just trying show you again is is the different |
|
| 40:37 | of endo psychosis that we have. we have I'm gonna start with the |
|
| 40:44 | was common one, the one that's to understand receptor mediated apoptosis. And |
|
| 40:49 | just gonna make sure where this that's uh okay, that's fluid phase. |
|
| 40:54 | I think this is this is the I'm just trying to look at the |
|
| 40:59 | so you can see on the surface our side we have all our little |
|
| 41:02 | , things that look like a little upside down wise. So those are |
|
| 41:05 | receptors saying here I am, I'm looking for the thing I need to |
|
| 41:07 | . All right. And so what is is when things bind to those |
|
| 41:12 | , what that's gonna do is you're to have those receptors go, oh |
|
| 41:16 | bound. And so what they do they move and affiliate and associate with |
|
| 41:20 | other into kind of a clump. a real scientific word, right? |
|
| 41:26 | basically it's like, oh I've found . So I'm gonna go hang out |
|
| 41:28 | the things that have bound something and that is what attracts in the |
|
| 41:32 | So again, there's machinery that we're talking about. So the classroom comes |
|
| 41:37 | and that causes that flat membrane to inward and ultimately form the vesicles. |
|
| 41:45 | binding something because the fiber receptor, specificity, and what I'm doing is |
|
| 41:52 | now focusing in on bringing that thing the stuff for whatever purpose I have |
|
| 41:58 | to transport it or use it or that would be receptor mediated. |
|
| 42:05 | so, again, I have, , this is the way you can |
|
| 42:08 | lots of substances. The next most or easiest to understand is probably pinot |
|
| 42:14 | or what is called fluid phase into , which is being shown over |
|
| 42:17 | in essence, what this is, the classroom or the customers or whatever |
|
| 42:22 | shaping molecules are. The, what do is they will congregate the plasma |
|
| 42:27 | and what they'll do is they just that imagination again, and then pinch |
|
| 42:31 | whatever happens to be in the surrounding . So, what we have here |
|
| 42:37 | just random. That's exactly right, random. So you get what you |
|
| 42:41 | and you don't throw a fit, ? And what you're doing is they |
|
| 42:44 | it pinot psychosis. It's sell I'm just pinching off whatever I can |
|
| 42:48 | off, you're actually not reaching you're actually in vaginal waiting. |
|
| 42:52 | whatever happens to be in that thing I finally close off that vesicles, |
|
| 42:56 | what you get. And so it's very non specific thing, you don't |
|
| 43:00 | what you're getting. But whatever materials pick up, you can use recycle |
|
| 43:03 | move whatever the case may be. then we have this weird one |
|
| 43:07 | you know, I'm glad they're throwing to books. Just just confuse us |
|
| 43:11 | . It's called photosynthesis. It was discovered in capillary epithelium and its primary |
|
| 43:17 | is to move molecules from one side the capillary to the other. |
|
| 43:21 | And we haven't talked about capillaries. it's not very helpful to kind of |
|
| 43:24 | this without taking a little bit of . But basically what it says is |
|
| 43:28 | there are there are holes in capillaries most material can move through naturally. |
|
| 43:32 | kind of like, like the holes my fingers here. But those holes |
|
| 43:36 | still too small to move big things if I want to move a big |
|
| 43:39 | , I need to transport it across very very, very thin cell. |
|
| 43:43 | so why don't I just form a way forward by doing this. And |
|
| 43:48 | is where they discovered um uh cal in which is a one of these |
|
| 43:53 | again, shaping molecules and it creates special pits that allow you to transport |
|
| 43:59 | from one side of the cell to other. And again, remember the |
|
| 44:02 | are very, very thin. So kind of create big giant gaping pores |
|
| 44:06 | for the one thing you're trying to . All right, So it's very |
|
| 44:10 | to the receptor mediated psychosis because your for what you're trying to find. |
|
| 44:16 | at the same time it's, you , different mechanism. So they're throwing |
|
| 44:23 | book just to make us confused. ? But as I'm as we learn |
|
| 44:28 | and again, if you took the with dr Gifford, she probably walked |
|
| 44:32 | through a whole bunch of different mechanisms were very similar. So, here's |
|
| 44:35 | one. Here's another one. Here's one. You see it's the |
|
| 44:39 | What am I doing? Do I to have a receptor or am I |
|
| 44:42 | something without a receptor? All Ready for the weird or not? |
|
| 44:48 | weird one. The the one that like it'd be the easiest Vegas |
|
| 44:52 | Figo means eat so cell eating. this is different than end acidosis. |
|
| 44:59 | this is the key thing of why separated the two out with Figo |
|
| 45:04 | What you're gonna do is you're creating podia. Right? So, in |
|
| 45:08 | particular case, what we see is see the little bacterium see little red |
|
| 45:11 | with hairs on it. That's really . And what you're doing is you |
|
| 45:14 | a macrophage that macrophage says this thing doesn't belong here. And it actually |
|
| 45:20 | neutrophils, macrophages will actually follow the the chemical signal that it leaves and |
|
| 45:26 | it does is once it gets near doesn't wait for it to bind the |
|
| 45:31 | because that would be very, very to do. So what it does |
|
| 45:34 | it reaches out and extends its cytoplasm closes that side of plasma around it |
|
| 45:40 | creates a vesicles around the thing that trying to take in. That's what |
|
| 45:44 | can see here. Right? And we have our bacterium inside a vehicle |
|
| 45:49 | then we can take that vest off just do whatever we want to. |
|
| 45:52 | the case of a bacterium. Let's kill everything inside there just to be |
|
| 45:56 | , chop it up and just use the little tiny molecules that we get |
|
| 46:00 | our own use. And that's what is trying to show in this particular |
|
| 46:05 | , the type of vesicles that we're with. You can kind of see |
|
| 46:09 | that picture. See little green Those little green dots are lice ISMs |
|
| 46:19 | what do we have in license? does anyone remember from enzymes? That's |
|
| 46:24 | what I'm looking for. It's I didn't even ask what specific |
|
| 46:27 | There's a lot of different ones. . But the license um kind of |
|
| 46:31 | kind of like a stomach. Notice you kind of like like a stomach |
|
| 46:35 | a cell. All right, I'll point out this also requires a |
|
| 46:39 | cause there's all sorts of side of elements that you need to move and |
|
| 46:43 | and stuff. So again, vesicles and lots of a T. |
|
| 46:49 | This is just trying to show you formation of a life design, which |
|
| 46:53 | a form of the secular formation. here you can see there's the class |
|
| 46:59 | , what are we doing? We the material that we want inside that |
|
| 47:03 | that's already there. See it's being . And then what we do is |
|
| 47:06 | form the vesicles using the classroom. classroom is gonna recycle to allow me |
|
| 47:10 | keep making it more and more. then what I do is I take |
|
| 47:15 | and emerging and I'm forming this in zone. So in this particular, |
|
| 47:20 | , this is a pre licensed in zone. So what we're doing is |
|
| 47:23 | are creating a structure that will ultimately a license zone in this particular |
|
| 47:29 | So you're just adding more and more to it. But again, same |
|
| 47:33 | are involved, right, pinch off membrane using the class Teran transporting one |
|
| 47:40 | to another, merging it with another membrane like structure. Release the materials |
|
| 47:46 | it recycle. Do you think this energy? Yeah. All right. |
|
| 47:56 | , I'll be working right. so in terms of Exocet oh |
|
| 48:02 | what we're really what we're doing is uh I'm trying to remember here with |
|
| 48:08 | sausage toast is we're really kind of to it at this point. Not |
|
| 48:12 | release point. As in in terms the formation of the vesicles is what |
|
| 48:17 | trying to get at there. so it's not just limited to the |
|
| 48:21 | of the of the plaza memory. also there at the level of the |
|
| 48:24 | L So we're using it in both , is what I'm trying to get |
|
| 48:29 | . Anyone else. All right. we doing on time? What have |
|
| 48:34 | done? 11 48. Oh, only 15 minutes. Oh my |
|
| 48:41 | We'll see if we can get through rest of this stuff. Osmosis. |
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| 48:46 | just make osmosis Simple. Everything your or your physical physics professor told you |
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| 48:50 | wrong. Simple as most is a it's water moving down its concentration |
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| 48:57 | That's all it is. Alright, you hear the word salute, just |
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| 49:01 | salute. If you have a container has 100% of something in it, |
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| 49:05 | more salute you add what happens to water? It gets less. |
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| 49:10 | So, if you're moving to an of higher solute, that means you're |
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| 49:13 | to an area of lower water. like to focus on the solid because |
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| 49:16 | is the environment which the chemical reactions place. That's why they focus |
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| 49:20 | But what we're wanting, what we're about when we're talking about osmosis is |
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| 49:24 | the water moving to? So, just have to ask that question. |
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| 49:27 | just moving to an area of lower concentration. All right. So, |
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| 49:34 | a membrane is permeable to water and both substances will diffuse across the membrane |
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| 49:39 | equip liberate, right? But if membrane is only permeable to water and |
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| 49:44 | solid, then water is going to to quit, liberate itself across that |
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| 49:50 | . Right? So, that means I have lots of salt over here |
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| 49:53 | very little solid over there, water gonna move until it reaches equilibrium and |
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| 49:58 | it can't reach equilibrium. Right? , that's kind of the idea with |
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| 50:03 | is just think the direction in which is going. Alright, so water |
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| 50:08 | from the area higher solute concentration. ? Um see Oh yeah, moves |
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| 50:14 | Sorry, I thought from no, , no moves to Alright. |
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| 50:20 | I have an example I use with but we'll get to it when it's |
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| 50:24 | a couple of seconds here. The we use in biology when we're looking |
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| 50:29 | the quantity of the of solute in body, we refer to osmolarity, |
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| 50:34 | or osmolarity. Depending on what you're at, kilograms or mills. |
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| 50:40 | And really what you're, what we're here is basically saying, we don't |
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| 50:44 | what the solution is. Just how particles do we see and stuff. |
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| 50:48 | . And generally speaking throughout the entire , your body has a roughly 290 |
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| 50:54 | Oz moles of solute throughout the entire . All right, so that's that's |
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| 50:59 | point of equilibrium. And so just remind you when we're talking about |
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| 51:04 | that means when you put something in can disassociate, for example, sodium |
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| 51:08 | is you might have a mole of chloride when it dissociates, you have |
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| 51:12 | mole of sodium, you have a of chlorine. So that means you |
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| 51:15 | to um Oz moles of material. kind of makes sense. All |
|
| 51:21 | So, one of the things we to consider when we're looking at at |
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| 51:24 | body is what are the number of ? Alright. So, what I |
|
| 51:31 | to look at in these next couple slides and I'm like, I'm afraid |
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| 51:35 | going to spend too much time on . Is this idea of where does |
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| 51:39 | move and how do and what are trying to maintain? So, remember |
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| 51:44 | the first in that lecture on I said cells are compartments in which |
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| 51:48 | reactions are going to take place and we're in home static balance. |
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| 51:52 | When we have the right amount of so that the right chemical reactions can |
|
| 51:56 | . Do you remember we're talking about ? All right. So, what |
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| 52:00 | if we put too much water into environment? We're gonna muck up the |
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| 52:04 | between the water and the sites were with the osmolarity, which means we're |
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| 52:09 | with the chemical composition, which means cells are no longer going to be |
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| 52:12 | to function the way that they're designed function. So, your cells actually |
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| 52:16 | mechanisms in place to help you deal that. And so this is an |
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| 52:21 | of the sodium potassium pump. Doing . So, you can see |
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| 52:24 | I'm pumping it in sodium Or I'm pumping sodium out of the |
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| 52:28 | pumping potassium into the cell. The tiny arrows that you see in this |
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| 52:32 | right here represent leak channels. What you think a leak channel does it |
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| 52:39 | you things to leak. Yeah, so so when sodium is being pumped |
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| 52:44 | eventually there'd be a point where there's more sodium, but because we have |
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| 52:47 | channels, sodium sneaks back in and have leak channels for potassium. So |
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| 52:53 | does potassium do, its like, , I'm gonna leak back out. |
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| 52:56 | so we have to have the It's like a bilge pump saying, |
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| 52:59 | , water is always getting in the , got to keep the pump going |
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| 53:01 | I don't want the boat to And so you're always moving this stuff |
|
| 53:04 | that's part of the way that we that equilibrium. And so the equilibrium |
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| 53:08 | not just in those ions between the the outside, but also with the |
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| 53:12 | of water. If I kill the , those ions are gonna move back |
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| 53:17 | forth. And then water is going go in to match up with the |
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| 53:22 | that's kind of moving in because I , just by charge, what's happening |
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| 53:26 | ? I'm gaining one charge for every I'm gaining three for every two that |
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| 53:31 | lose. So there's a net gain a positive ion moving in, |
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| 53:35 | You see that So water is gonna in the in the cell's gonna |
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| 53:39 | What happens when things swell? Is a good thing? It burst? |
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| 53:43 | can burst or it basically marks with chemical composition as well. So it's |
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| 53:50 | to have these pumps and these league to ensure the balance. Now this |
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| 53:55 | an example these two things. What if I put a cell into an |
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| 54:00 | where the cell shrinks? All I'm just trying to make sure if |
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| 54:03 | pictures look right to me see, yeah. So just look at the |
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| 54:08 | here. So the outside of the is the same on the inside. |
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| 54:11 | we're in equilibrium. But if I the osmolarity around the cell, water |
|
| 54:16 | gonna want to escape right? Because osmolarity is much lower. Remember the |
|
| 54:20 | the osmolarity, the more salute you . So if I have more |
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| 54:25 | where does the water want to go to? The more solute? So |
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| 54:29 | goes rushing out of the cell. causes the cell to shrink. But |
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| 54:33 | the other way you look at, I have less water, I've concentrated |
|
| 54:37 | materials in the cell have created a different environment. Cell is going to |
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| 54:40 | functioning. So what happens we'll all channels that we have are there to |
|
| 54:46 | balance the system. In other as water leaks out of the cell |
|
| 54:51 | channels are going to open in response allow different ions to move in to |
|
| 54:58 | the water back until we reach an in terms of the osmolarity. So |
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| 55:05 | important here, malaria and equilibrium, amount of water in the cells. |
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| 55:10 | converse is true is here what happens the cell swells again create, put |
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| 55:14 | drop of cell into an environment which lower osmolarity. Water's gonna come rushing |
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| 55:17 | the cell is expected to expand. means you now diluted all the the |
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| 55:22 | machinery inside the cell, the cell function appropriately. So what do we |
|
| 55:27 | ? We have channels that allow you move salutes out. When you move |
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| 55:31 | salutes out, the water follows cell back to its original shape even though |
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| 55:36 | osmolarity is different, it's now able function because it matches the surrounding |
|
| 55:43 | That kind of makes sense. All , this is a weird one. |
|
| 55:48 | , Yuria is like you're a slow , you're right. The one you |
|
| 55:52 | jokes too and they kind of stare you for a little bit and then |
|
| 55:55 | it about a couple minutes later. you have a friend like that? |
|
| 55:59 | a little slow. Okay. Where you tell a joke and they |
|
| 56:03 | like everyone is laughing and they're just of like you can just see the |
|
| 56:06 | hamster wheel turning right? That's that's your area is. And so when |
|
| 56:11 | drop your area into an environment that's the osmolarity. Water is gonna naturally |
|
| 56:16 | towards it to reduce, you to bring equilibrium as far as osmolarity |
|
| 56:20 | concerned. but but Yuria can pass a membrane. It just does so |
|
| 56:26 | slowly. And so what ends up is that the curia will move to |
|
| 56:30 | other side of the membrane and at same time it draws the water with |
|
| 56:33 | . So you you initially see a of the cell and then you'll see |
|
| 56:39 | return back to the original shape. it kind of has this strange kind |
|
| 56:44 | behavior on how cells behave. Why do we talk about this |
|
| 56:49 | And who cares? Right, How guys work in the er I mean |
|
| 56:54 | know you got a couple of Right, so this is where we |
|
| 56:57 | asking questions even though I'm not a . Alright person comes into the er |
|
| 57:01 | dehydration. Do you give them pure ? Why? Because why? Because |
|
| 57:12 | cells will explode? Because what you is basically you're you're already dealing with |
|
| 57:15 | situation in which the environment right? low in water Or high end and |
|
| 57:22 | . So you put a whole bunch water out here. What's gonna |
|
| 57:24 | Right? It's just gonna start rushing and start cells causing them to |
|
| 57:29 | Right? So what do you give instead? Sailing? Isotonic solution? |
|
| 57:35 | . That's where that word isotonic. really refers to the osmolarity of the |
|
| 57:40 | . So hyper is a hypo those prefixes, you should already know hyper |
|
| 57:44 | high, same, high Polo. tonic parts are weird when that refers |
|
| 57:49 | the salute. So hyper high Same salute. Low salute. All |
|
| 57:57 | . And so the idea here is I am giving a solution, there |
|
| 58:03 | certain things I need to consider, what's it going to do the |
|
| 58:06 | Is it gonna cause damage to the ? Because when you have vast differences |
|
| 58:12 | water environments, water is going to to where there's less water and that |
|
| 58:18 | cause much harm. Alright, so just kind of showing here one of |
|
| 58:23 | things that are mostly the shift where water go? Well water mostly follows |
|
| 58:28 | . It will follow glucose as not so much by your area because |
|
| 58:32 | I said yuri a kind of moves it needs to go and there's an |
|
| 58:37 | , I'm gonna use a little bit . Um and I'm gonna I'm gonna |
|
| 58:40 | off on it now because I don't to confuse you all. I just |
|
| 58:43 | to just kind of run through these quickly and see if they make sense |
|
| 58:47 | you. Right, so if I an isotonic solution, here's the extra |
|
| 58:51 | , Green is intra so I add solution out here. Why does this |
|
| 58:58 | shrink? Why does it not move and forth? Why do you think |
|
| 59:05 | not a trick question? We already said it a couple of seconds |
|
| 59:08 | I so right, so it means the same salute, same water. |
|
| 59:14 | water has no desire to move in direction. It just stays where it |
|
| 59:18 | , right? And so it's gonna of stay there like that, you |
|
| 59:22 | a question or did you Okay? , see if you got the right |
|
| 59:27 | , give yourself a gold star. , what pure water? What's gonna |
|
| 59:32 | ? Alright, throwing pure water, the initial state, right, |
|
| 59:35 | I got a lot of water in . Osmolarity has now dropped. So |
|
| 59:38 | do you expect to happen? Where water gonna go? Look at |
|
| 59:43 | look at the similarities, it's gonna from left to right, It's gonna |
|
| 59:47 | from the extra cellular fluid in the fluid, right? It's gonna |
|
| 59:52 | And so while this initially swells eventually going over here to where there's less |
|
| 60:00 | ? That kinda makes sense, Because again, it's about osmolarity. |
|
| 60:05 | eventually you'll reach equilibrium. Look at osmolarity is now, okay, now |
|
| 60:11 | is over time, this is just imagine me taking a big old |
|
| 60:14 | needle because that's more fun and just right into your blood, that's your |
|
| 60:21 | cellular fluid. Got a lot of in your exercise, your fluid. |
|
| 60:23 | , where's it gonna go? You're just stay there, nope, it's |
|
| 60:27 | to go moving into the cells to equilibrium. Alright, what about |
|
| 60:34 | What is pure sodium chloride? Imagine a pure sodium chloride pellet into your |
|
| 60:40 | right, mm, get a good deer salt lick all right chop it |
|
| 60:48 | down, What's gonna happen? you don't increase the volume, |
|
| 60:52 | Because it's just pure solute. Look happened to the osmolarity now, out |
|
| 60:57 | control. Way over the above. what's gonna do? It's gonna draw |
|
| 61:04 | out and move to the environment until reach equilibrium. All I'm trying to |
|
| 61:12 | you to see here is the effect water and solute has on an |
|
| 61:18 | right? It will move itself, ? And it will try to reach |
|
| 61:26 | . Now, these substances, these are gonna move in one or two |
|
| 61:33 | across the cell or through a So, here what we're looking at |
|
| 61:37 | is we're looking at the digestive Alright, this is the interstitial |
|
| 61:42 | This is basically trying to show over this is the typical membrane. I |
|
| 61:45 | to look and see what we got . So, this would be your |
|
| 61:47 | tract. This over here would be space inside your body. Alright, |
|
| 61:53 | your digestive tract is exposed to the environment, y'all know that, |
|
| 61:56 | See, look, if I ah there's a big hole through my |
|
| 62:00 | , you can see one. I'm gonna show you the other. |
|
| 62:05 | So, if I'm moving materials from outside into a cell that's called |
|
| 62:15 | If I'm moving something from inside the out of the cell that's called |
|
| 62:21 | That's different than excretion secretion. Just in and out of the cell. |
|
| 62:28 | would be like, for example, urine and then getting rid of it |
|
| 62:33 | . That'd be excretion. Now the that things can be absorbed or |
|
| 62:39 | Or one of two ways I can through the cell or I can go |
|
| 62:44 | the cells up here. Up top , we can see the sodium. |
|
| 62:49 | absorbing the sodium here. I've got channel and then now I've got a |
|
| 62:54 | . Right? So, you can I've got this channel. I'm moving |
|
| 62:57 | this direction, but I want to the sodium levels low. So, |
|
| 63:00 | do I do is I use a and then I have another channel over |
|
| 63:03 | to allow potassium to be moving out then I'm pumping it back in. |
|
| 63:08 | , this type of movement from outside and back out would be trans cellular |
|
| 63:16 | . If I'm moving something in between cells like this is chlorine, This |
|
| 63:23 | is moving down its concentration gradient. is Paracel Euler transport. Alright, |
|
| 63:32 | drawing the chlorine from this direction? direction. What do you think? |
|
| 63:36 | a hard trick question, concentration. . The slope. Right. The |
|
| 63:41 | thing. It could be the concentration the the ion itself or it could |
|
| 63:46 | the electrical gradient as well. That's it in. Alright. In this |
|
| 63:51 | instance, it's probably just the But it might be both. It |
|
| 63:56 | be one or the other. All . So, whenever you're dealing with |
|
| 64:03 | cellular what you're usually doing is with downhill and then uphill or an uphill |
|
| 64:09 | then downhill. Okay. So notice translator transport, does it cost energy |
|
| 64:16 | moving uphill? The answer is Always gonna cost energy the whole |
|
| 64:24 | One step may not cost energy at , but the other one will and |
|
| 64:28 | comes first depends on which direction you're going. So, for example, |
|
| 64:32 | you have high acidity in your one of the things you have is |
|
| 64:36 | have cells in the kidney that move into those para tubular cells that |
|
| 64:44 | you know, your pump moving it , then you pump it out the |
|
| 64:47 | side. Right? And at the time you may have potassium being moved |
|
| 64:53 | the cell and then pumped out the side. So which step comes first |
|
| 64:58 | here's just examples of of these different of transports. So sodium we already |
|
| 65:03 | here's potassium. So potassium is going the pump and then now you can |
|
| 65:08 | it's being down its concentration gradient. type of transport is that? Co |
|
| 65:15 | ? Secondary active. Right. But of glucose inside the cell. So |
|
| 65:21 | uphill and then downhill. Yeah. important if it's taken Which 1? |
|
| 65:35 | , the sodium potassium pump? It's , one because we discovered it |
|
| 65:40 | That's that's one of the reasons. really it's because without it we couldn't |
|
| 65:45 | that potential energy that many of ourselves advantage of It was It's a it's |
|
| 65:49 | very primitive system, it's it's found every organism. So as one of |
|
| 65:53 | molecules that came to exist very early during evolution. And then so not |
|
| 65:59 | does it do that, but it you to create those unique environments internal |
|
| 66:03 | the cell. Yeah. It's it's is it literally is one of those |
|
| 66:10 | types of things where just cause. . I mean, I mean, |
|
| 66:14 | it could have been calcium and It just that wasn't the one, |
|
| 66:18 | just happened to be this one. know? Why was that selected at |
|
| 66:21 | very beginning? If I was around could tell you. But I don't |
|
| 66:25 | . But it's a fair question. sometimes we don't know the answer. |
|
| 66:29 | ? Or maybe someone does. It's not me. That's also feasible. |
|
| 66:34 | . I don't know everything I pretend do. But I don't promise, |
|
| 66:40 | again, chlorine, you can see case in case C. C. |
|
| 66:44 | doing that pumping chlorine in and then going down its concentration gradient. |
|
| 66:53 | Oh, like right here like so what's what's happening is is that |
|
| 66:59 | , you're gonna have leak channels and . So everything is being this is |
|
| 67:02 | problem with all these pictures. They show you all the mechanisms that are |
|
| 67:06 | . We're gonna talk about the eye I'm gonna actually show you this thing |
|
| 67:09 | the dark cycle. It's like the time I think in any picture that |
|
| 67:12 | show you that says, hey um see this channel here, this is |
|
| 67:16 | allows us to continue on forever. ? But you can imagine as the |
|
| 67:20 | goes in. Yeah, I can it out over there but eventually I |
|
| 67:23 | out of sodium over here eventually. what that means is there's got to |
|
| 67:26 | leaked channels on this side to allow to occur as well, right? |
|
| 67:31 | , in that case, you Yeah, there's gonna be like |
|
| 67:36 | I was I was getting a little in my head there for a |
|
| 67:40 | Alright, alright. How much time I got? Well, I'll answer |
|
| 67:44 | question. Huh. Too late. on the bottom. Uh And which |
|
| 67:52 | ? Uh Yeah, this one right . Yeah. So over here our |
|
| 67:57 | step would be using secondary active So it is a uphill first and |
|
| 68:02 | this is downhill. Yeah. And , right now today is not the |
|
| 68:06 | you're gonna go, oh I recognize of these in every one of |
|
| 68:09 | I mean, I've seen in C. C. Enough time outside |
|
| 68:12 | this class to know what it It's a co transporter. But the |
|
| 68:15 | time you see that you'll be I've got to really think about this |
|
| 68:19 | primary sodium potassium that we're concerned with of this pump system. So I |
|
| 68:24 | that sodium is the driver right, sodium is going down its concentration |
|
| 68:31 | Does that make sense? So that's driver of the other two. Where |
|
| 68:35 | potassium wanna go. Does potassium want go into cells? Yeah, because |
|
| 68:40 | know reasons, right? Actually, , it doesn't. It wants to |
|
| 68:43 | out right now, potassium wants to out of the cell so I'm pumping |
|
| 68:48 | against it's gradient. So, he to go in though. What about |
|
| 68:51 | , chlorine? A little ambivalent. truth is, is that it's it's |
|
| 68:55 | kind of sits at the at the of the cell and so it's just |
|
| 68:59 | of doing this to match the Right? All right. You said |
|
| 69:05 | got 10 minutes. This is man. I'm gonna just have to |
|
| 69:13 | talking fast. Alright with regard to to cell communication, we'll just get |
|
| 69:17 | far as we need to. I , eventually I do catch up because |
|
| 69:19 | of these lectures is is a lot . I don't know why. All |
|
| 69:22 | . But in essence, what we when we're talking about sales, what |
|
| 69:25 | talking about, How do cells talk each other? How do you guys |
|
| 69:27 | to each other? Right? You get on your phone and talk to |
|
| 69:33 | other. What's another way? Text you can do your Tiktok videos. |
|
| 69:40 | . That's a weird form of but it somehow works right. There |
|
| 69:45 | other ways that you can communicate. another way you can communicate away from |
|
| 69:48 | phone mail. Alright, meow, can yell across the room. You |
|
| 69:55 | pass a note, right? Ever notes in class or you guys too |
|
| 70:00 | to do that. You did do . Okay. Yeah. See my |
|
| 70:02 | . We don't have cell phones. we pass notes in class when you |
|
| 70:06 | caught. Oh man, brutal. . So, so in essence you |
|
| 70:11 | imagine cells that are near to each have different ways of talking to other |
|
| 70:14 | cells that are far away from each . And these are kind of different |
|
| 70:17 | . Now. The two primary forms communication are what we refer to as |
|
| 70:21 | and chemical 99% of the forms of in your body is chemical electrical. |
|
| 70:27 | like to sometimes confused with some forms chemical communication. Like when we think |
|
| 70:32 | a neuron we think oh that's electrical it's not really it's how I move |
|
| 70:36 | signal from one side of the cell another side of the cell. Just |
|
| 70:38 | happens that the cells are very, long. So for example, a |
|
| 70:43 | leaving my spinal cord going down to little pinky is as long as my |
|
| 70:47 | . So to get a signal from to the other side of that sells |
|
| 70:50 | electrical and then a chemical signal occurs go the next thing. So, |
|
| 70:55 | would be a form of chemical right? But so electrical is when |
|
| 71:01 | charges in the cell membrane are modified adjusted from cell to cell that are |
|
| 71:06 | each other chemicals. When the molecules gonna be secreted between two cells. |
|
| 71:12 | right. So, the mechanisms the one is just a Quran. You |
|
| 71:17 | see that gap junction from the previous is listed there. So, here |
|
| 71:20 | we have is we have two cells are connected to each other by a |
|
| 71:23 | of gap junctions. The molecules that this to happen are called connections. |
|
| 71:26 | form these channels that can open and between them. And this allows for |
|
| 71:30 | exchange of all sorts of different types chemicals including ions and when its ions |
|
| 71:36 | what we have is we create currents would be what type of electrical. |
|
| 71:42 | this is a type of electrical communication it can also be chemical because there |
|
| 71:47 | other types of molecules that can be . So, depending on the situation |
|
| 71:52 | either gonna be electrical or chemical. types of cells that are next to |
|
| 71:56 | other. One can have a One can have a ligand. |
|
| 72:00 | so, you see this often in immune system where two circulating cells come |
|
| 72:05 | contact with each other and their legends receptors come into contact. This is |
|
| 72:09 | is called as cell to cell And in doing so, what you're |
|
| 72:14 | is one cells telling the other cell to do right. You've heard of |
|
| 72:18 | helper cells you've heard of t uh of toxic cells. Why do you |
|
| 72:23 | I help ourselves called to help Because it helps. And what it |
|
| 72:27 | is it binds up to other like the TC cells inside the toxic |
|
| 72:31 | and tells it, you're the one needs to go and kill that thing |
|
| 72:34 | there. You kind of know how kill it. I'm letting you |
|
| 72:37 | That's okay now, that would be example of cell. A cell |
|
| 72:43 | Local signaling is of two different We have auto cringe. When you |
|
| 72:48 | the word auto Quran, what does mean? Auto means self. |
|
| 72:51 | I'm talking to myself, Have you talked to yourself? Yeah, when |
|
| 72:55 | studying, do you talk to yourself loud? Right. Have you ever |
|
| 72:58 | a note to yourself to do That's an example of the Quran signaling |
|
| 73:03 | now. You just sit there. would a cell have to do |
|
| 73:05 | Well, you got to think in of there's thousands of chemical reactions and |
|
| 73:09 | of processes are taking place. You be activating one system and that forces |
|
| 73:15 | to turn off another system and so releasing that whatever it is that you're |
|
| 73:19 | , acting back on the cell may you to turn off or slow down |
|
| 73:22 | whatever the process is that you're that would be an example of a |
|
| 73:26 | . All right. But you can here, what am I doing is |
|
| 73:29 | see, I'm secreting and I'm binding receptors on my own cell. That |
|
| 73:34 | be autocrat then we have Para it's very easy to confuse peregrine and |
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| 73:40 | a Quran. But just a Quran literally next to like the cell that |
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| 73:44 | associated with. Peregrine means the cells are around me nearby. All |
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| 73:49 | So, if she was a cell chemicals, peregrine would be you and |
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| 73:55 | and you and you and you and , but not the rest of |
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| 73:58 | Because these are her nearby neighbors. , if you guys were holding hands |
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| 74:03 | that was how you were talking to other, what would that be? |
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| 74:08 | all right. You see the difference ? So it's it's releasing the material |
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| 74:12 | becomes para Quran. All right. , the signaling molecules, in the |
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| 74:17 | of this type of signaling whether it's of character are diffusing through the interstitial |
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| 74:22 | to the nearby cells Okay, here attached then we have a long distance |
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| 74:31 | here. What we're doing is releasing signal at some distance away from where |
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| 74:34 | receptors located. You're more familiar with in terms of hormones. Right? |
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| 74:39 | I have in my hypothalamus, the releases hormones that act on a structure |
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| 74:44 | away the pituitary gland which is millimeters , which for molecules like forever. |
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| 74:49 | then molecules from the pituitary gland will on molecules in or structures or receptors |
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| 74:55 | are located my adrenal glands and my and so on and so forth. |
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| 74:58 | is a long distance. That's a lot of distance. Right? And |
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| 75:02 | what we have is the chemical is into the bloodstream so you can see |
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| 75:05 | being released into the bloodstream and then travels throughout the body and then when |
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| 75:10 | comes across the cell that has this receptor that it's going to cause a |
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| 75:14 | in that cell. If the cell have the right receptor, no response |
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| 75:19 | , Right. That's one of the things about signaling. You have to |
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| 75:22 | the right receptor. Not every cell going to respond. Okay, |
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| 75:27 | for example guys, we have estrogen our bodies. Talk to other |
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| 75:32 | right? But we have very few receptors. So our body doesn't respond |
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| 75:37 | same way to estrogen as say women . Which have estrogen receptors all over |
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| 75:42 | place. All right. So, term for this type of chemical |
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| 75:47 | we usually refer to it as a . Alright. But there's other terms |
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| 75:51 | you might see come up every now then. They have varying sizes, |
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| 75:55 | structure. And what they do is gonna bind to as we said, |
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| 75:59 | receptor when I get to those last minutes, you've got to tell me |
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| 76:03 | I'll just keep talking until those poor out. They're going to see if |
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| 76:06 | gonna shut up. All right, like Yeah, that sounds good then |
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| 76:13 | start talking about. Yeah. So there's lots of different types of |
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| 76:17 | . And what I wanted to do I wanted to draw it out here |
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| 76:20 | I just I'll just go through this in the next slide and then I |
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| 76:23 | we'll just call it quits and then get to the actual receptors in the |
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| 76:26 | lecture. Right. But we can here we have like ligand gated |
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| 76:30 | Alright. So basically I have something can be bound and opens up and |
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| 76:34 | ions to go through. All So what we're doing is we're changing |
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| 76:39 | flow of ions which means we're creating current in the cell which can then |
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| 76:43 | stuff. We have g protein coupled , basically what we have is we |
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| 76:47 | a pathway a series of molecules that acting like a domino in other |
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| 76:52 | a cascade of events that can turn multiple things. Alright. And typically |
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| 76:57 | daming it for this intermediary called the protein. That's why they're called G |
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| 77:02 | coupled receptors because the receptor is coupled the g protein catalytic receptors. These |
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| 77:07 | some sort of enzymatic complex associated with . Whether they're part of the enzyme |
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| 77:12 | or the enzyme is attached to it matter. That's that's whatever the case |
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| 77:17 | be. Uh that means they can relate things or they can take off |
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| 77:22 | and when you phosphors later takeoff phosphoric on a molecule. What you're doing |
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| 77:26 | you're changing its level of activity. right. Um inter cellular receptors you |
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| 77:32 | cells that can have receptors inside the in different ways. Typically these can |
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| 77:36 | the nuclear receptors which can be found us all in the nucleus and act |
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| 77:41 | transcription factors to change gene expression. then we have these weird ones that |
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| 77:46 | never heard of before reading this text , which is strange I mean but |
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| 77:50 | you can take a receptor that actually destroyed or damaged through some sort of |
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| 77:56 | icis and then those fragments actually become which is kind of interesting. So |
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| 78:03 | all sorts of weird stuff out The general rule of signaling is uh |
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| 78:10 | off the receptor needs to be able recognize what's binding to it. That |
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| 78:14 | pretty logical. Right? Right. you match what you're attracted to once |
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| 78:18 | get bound that's gonna cause a change the shape of the receptor that then |
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| 78:22 | in some sort of internalization of the . So what we say is the |
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| 78:27 | signal turns into the inside signal. what trans deduction is. It's changing |
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| 78:31 | from one form to the other. , so it's transducer from extra to |
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| 78:37 | then you're gonna get transmission. So that means is is that that internal |
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| 78:43 | now is going to work its way a pathway to either amplify itself or |
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| 78:48 | specifically localize and activate the right defectors simply is the thing that causes the |
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| 78:58 | . Yeah, I know. And you can modulate it. How much |
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| 79:03 | are you going to change the activity the effect? Er What what mechanisms |
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| 79:06 | there in place to do that? is the ultimate change in response? |
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| 79:11 | turned on this thing ergo the cell does something different, I turned off |
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| 79:14 | thing ergo the cell does something different lastly I'm a dad. So this |
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| 79:19 | the way I'm gonna explain when you in the room and turn off the |
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| 79:21 | . You better dang well turn off light when you walk out of the |
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| 79:24 | and that's the same thing. Anything turn on, you better turn |
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| 79:27 | that's what termination is. Otherwise the keeps doing stuff it shouldn't do alright |
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| 79:32 | we come back we'll finish up this here I forgot from the orientation week |
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| 79:38 | what it |
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