in this video, we're gonna do a quick refresher on Oz Moses. So you guys know that as Moses is simply a type of diffusion, and diffusion is the movement of a substance from high concentration down toe, lower concentrations of the same substance and, as Moses again is a specific type of diffusion. And so, as Moses is the diffusion of a solvent across a semi permeable membrane, or remembering that allows some substances to cross but prevents other substances from crossing. And so the solvent is usually going to be water, especially in biological systems, and osmotic pressure is the pressure that's required to prevent the flow of the solvent. And so really, osmotic pressure is a measure of the strength of osmosis. So the higher the osmotic pressure, the greater the strength of osmosis. Now, in our next video, we're going to talk about the direction of osmosis. But before we get there, it's important to note that as Moses direction depends on the tennis ity of the solution and so recall that the tennis ity refers to the relative concentrations of salutes, not solvents, that air dissolved in the solutions. And so really there are three different terms that refer to the tennis ity of a solution. And those three terms are isotonic hype, a tonic and hyper tonic. So isotonic refers to a solution that has the same solute concentration as another solution. And again, salute here is incredibly important because tennis City refers to the solute concentration, not the solvent concentration. So the next term is going to be Hypo Tonic. And so Hypo Tonic kind of sounds like Low Hypo Low. So hype Atomics Solutions have lower solute concentrations than another solution and the opposite of hype. A tonic is going to be hyper tonic. And when I think of hyper, I think of a kid that's had way too much sugar and they're just running around all over the place. And so because they've had too much sugar hyper, this is a solution that has a higher, uh, saw you concentration than another solution. And so what's really important to note is that these three terms here are words of comparison, so you could Onley use them when you're comparing one solution to another solution. So in our example below, we're going to compare the outside solution of the cell to the inside solution of the cell, which is separated by a plasma membrane. And so we're going toe label the tennis ity of the outside solution. So in our first scenario of our example, the outside solution, which is in light blue, is separated by a semi permeable membrane, and the inside solution is in the yellowish like oranges. Brownish type color here, mustard color on. We have these green salutes that air dissolved and so notice that the outside solution has a lower solute concentration than the inside solution. Because there's less green dots in, ah, certain area. And so because Thea outside solution has a lower solid concentration, it's going to be hypo tonic in comparison to the inside solution. Now, over here in the next scenario, noticed that the concentration of salutes these green dots here is exactly the same on the outside and the inside solution. So that means that the outside solution is isotonic with respect to the inside solution and then, in our final scenario over here, notice that the outside solution has a much greater solute concentration than the inside. And so because the outside has a higher solute concentration, it's going to be hyper tonic. And so again, the tennis city here is going to control the direction of osmosis. And we'll talk about the direction of osmosis in our next video, so I'll see you guys in.
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concept
Osmosis Direction
Video duration:
4m
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So now that we've reviewed Tennis City, we can talk about osmosis direction and recall that, as Moses is simply the diffusion of a solvent across a semi permeable membrane and usually that solvent is going to be water. So when we're talking about osmosis direction, we're really talking about the direction of water movement across this semi permeable membrane. And so if you tend to get confused on this, here's all you guys need to remember. Water will always move from Hypo Tonic solutions towards hyper tonic solutions, and this is true when the salutes cannot diffuse across the membrane. And so instead of the salutes, defusing the solvent or water will diffuse and water is always going to defuse towards the mawr concentrated solution, salute solution or towards the hyper tonic solution in order to dilute the salutes. Until that solution is isotonic with respect to the solution that the water traveled from. And so if we look at our example down below, notice that the water flow or the water movement is always gonna be in the same direction here, it's gonna flow from Hypo tonic solutions towards hyper tonic solutions. And so, if you can remember Hypo toe hyper. You'll be good on all of your osmosis direction questions. And so one thing that students tend not to realize is that water still moves from higher concentrations of water towards lower concentrations of water. So water still diffusing in the normal way that we think of diffusion. And so Hypo Tonic Solutions, we know, have lower solute concentrations. But they actually have higher water concentrations, and hyper tonic solutions we know have higher saw you concentrations. But they actually have lower water concentrations. And so down here, what we'll see is high. Botanic solutions have low solute concentration, but they have higher water concentrations, and hyper tonic solutions have higher solute concentrations. But they have lower water concentrations, and so water is still moving in the same direction from high concentration of water tow, low concentration of water but still from low concentration of solute, toe high concentration of solute. So it's just moving in the same direction here. And so if we apply these rules to our scenarios from above from our previous video, which we already completed here we labeled the tennis ity of the outside solution. And so we said that the outside solution in the first scenario was Hypo Tonic. So we'll put hypo on the outside. And that means, of course, that the inside is going to be hyper tonic. And so recall that water flows from hypo towards hyper so the water flow is going to go across the membrane in this direction towards the hyper tonic solution, and so water is going to flow into the cell. And if water flows into the cell, that means that the cell can expand in its size. And over here in our second scenario, we said that it is isotonic. The outside is isotonic with the inside, and so what that means is that water flow is actually going to go in both directions at an equal rate. And so it's not that there's no water movement. It set the water movement goes equally in both directions, so water's always moving across the membrane, no matter what, and then in our last scenario over here, what we said is the outside solution is hyper tonic. And of course, that means that the inside of the cell has to be hypo tonic, and so water again is gonna move from Hypo towards hyper And so it's gonna move from the hypo here towards the hyper. That means it's moving outside of the cell. And so water leaves the cell. That means that the cell could dehydrate, and it's gonna shrink up in trouble. And so we're gonna talk, Maura, about the results of osmosis in our next video. So I'll see you guys in that video.
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concept
Results of Osmosis
Video duration:
6m
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So in our last lesson video, we said the direction of osmosis is impacted by the tennis ity of the solutions, and water always flows from Hypo Tonic solutions towards hyper tonic solutions. And so the direction of osmosis will impact the results of osmosis. And that's what we're going to focus on in this video now, when cells are placed into hypo Tonic environments that causes the cells to swell up just like a hip bow. And that's because when the environment is hype, a tonic that means that the inside of the cell will be hyper tonic. And again. Water always flows from Hypo Tonic solutions towards hyper tonic solutions, so water would flow into the cell and cause the cell to swell up just like a hip bow. And so when the cells continuously swell up, that could potentially cause the cells toe lice or rupture slash burst. And that's because the membrane is expanded too much. Now, recall from your previous bio courses that sells with cell walls. Well, actually, not lice and hype a tonic solutions. And that's because the membrane expansion is prevented by the cell wall. Now, hype a tonic environments are actually preferred by plant cells, which have cell walls. And that's due to the increased Turker pressure and recall from your previous bio courses that Turker pressure is literally just the water pressure applied on the cell membrane, pushing the cell membrane up against the inside of the cell walls. And the Turker pressure is really what gives lots of plants their ability to maintain their structures. And we'll be able to see an example of Turker pressure down below in our image now with hyper tonic environments. On the other hand, that causes cells to dehydrate, just like a hyper kid would get dehydrated pretty quickly. And so over here we have an image of a crazy hyper kid that I would hate to baby sit over a weekend. And so this hyper kid is gonna get dehydrated pretty quickly, jumping around all over the place. And so hopefully that will help you guys remember that when cells were placed into hyper tonic environments that will dehydrate the cells just like a hyper kid gets dehydrated pretty quickly and so down below on the left hand side of our image. What we have our animal cells in different environments with different tennis city and on the right what? We have our plant cells with the the same scenarios. And so starting with the animal cells on the left, when again, uh, cells are placed into hypo Tonic environments, they will swell up like a hippo. And so that's because all of the water is going to be flown into the cell. And so you can see the direction of these arrows down below are pointing into the cell because water will be flowing in and again. That's because the environment is hypo tonic, and water always flows towards hyper tonic solutions. And so the inside of the cell will be hyper tonic and again that could potentially cause some cells to lice or rupture, so you can see that we have some cells. Listen here. Now, when cells are placed into hyper tonic solutions again, the cells air going to dehydrate, just like a hyper kids gets dehydrated. And that's because water is leaving the cell so you can see the direction of these arrows is leaving the cells and again. That's because the inside of the cell would be hypo tonic, and the outside of the cell is hyper tonic just like we're indicating up above. And of course, that could cause the cells to shrivel up and dehydrate and potentially die. So this is not a good environment. So essentially, what we're saying is for animal cells, uh, the hype atomic environment is not a good environment, and the hyper tonic environment is also not a good environment. And so for animal cells, it's the isotonic environment that is preferred. And that's because we have unequal rate of water flow going into the cell and out of the cell. And so again, isotonic environments are preferred by animal cells. Now, over here on the right again, we have plant cells, and we know that in Hypo Tonic environments, cells air going to swell up like a hippo. And that's again because water is flowing into the cell just like it's being indicated. And so what you'll see is that when water is flowing into the cell here, it's actually not going toe lice because plant cells have cell walls and that prevents the membrane expansion. So here what you'll see is that this hype, a tonic environment, is actually preferred by the plant cells, and you'll see that the the central vacuole here is filled up with lots and lots of water, and the cell membrane is pushed up against the inside of the cell wall. And that creates a lot of turker pressure, which is helpful for the plant to maintain their structures. Now, over here with the isotonic environment, notice that we have an equal water flow going in and out of the self. And so notice that the central vacuole is not us filled up as it is over here with the high platonic environment. And also notice that that we have these gaps here in between, uh, the, uh cell membrane and the cell wall, and that is not a preferred scenario by plant cells. So what we can do is we can place an X here to indicate that this is not really the ideal scenario for a plant cell. And then, of course, with hyper tonic environments cells they're going to dehydrate, just like a Khyber kid gets dehydrated. And that's again because the direction of water flow is leaving the cell. And so notice how shriveled up this plant cell is, and that's because it's being dehydrated. And this, again is not gonna be a good environment for the plant cell. And so moving forward, we'll be able to get some practice utilizing these concepts, so I'll see you guys in those videos.
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Problem
Problem
What is the tonicity of the outside solution in comparison to the cell?
A
Hypotonic
B
Isotonic
C
Hypertonic
D
electrotonic
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Problem
Problem
What direction will the water flow?
A
Inside → Outside
B
Outside → Inside
C
Water flows in both directions.
D
No flow of water.
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Problem
Problem
Plants become turgor when placed in this type of solution:
