Environmental Tonicity Affects Cells

by Jason Amores Sumpter
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So in our previous lesson videos, we introduce tennis ity and the direction of osmosis across a membrane. How water flows from Hypo Tonic solutions towards hyper tonic solutions. And so in this video, we're going to talk about how the environmental tennis ity effects cells, and so we're mainly going to be focusing on the outside environment that surrounds a cell. And so if the outside environment that surrounds a cell is hypo Tonic, then in this scenario water is going to enter the cells and cause the cells to swell up or enlarge like a hippo. And so you can think that Hypo Tonic environments cause cells to swell up or enlarge like ah hippo. Now, for animal cells that do not have a cell wall, they could potentially lice or burst under these conditions. And so you can think of it like a balloon If the cell is a balloon, if you blow too much air into a balloon, then it's going to expand in large or swell like ah hippo. But if you blow too much Erin into it, then it could potentially pop open. And so the same goes with cells cells, if too much water enters the cells, they could swell up too much, and if they swallowed too much, they could potentially lice or burst. And so, for animal cells that do not have cell walls, they do not prefer hype a tonic environments because they could potentially lice or burst, which could kill them. However, for plant cells that do have cell walls, the cell walls can prevent the expansion of the cell membrane. And so that means that the cell membrane is protected from licensing or bursting open with plant cell walls and so plant cell walls and plant cells. They actually prefer Hypo Tonic environments, and this is because they do not lice or burst open. And when the water enters the plant cells, it actually increases what is known as turker pressure and turker pressure is pretty much defined as the water pressure that's on the cell membrane, and this allows plants to have their upright and healthy structure. So let's take a look at our image down below to clear up some of these ideas, and we're gonna be focusing mainly on the left hand side of the image over here. And so once again, when the outside environment that is surrounding a cell is Hypo Tonic, then that could potentially cause a cell to swell up like a hippo. And so when we take a look here at this top part of the image, notice that we're showing you an animal cell and notice that it's a blood cell. And water is moving towards the inside of the cell in the hype, a tonic environment. And so notice that when water goes into the cell just like blowing air into a balloon, the cell is going to expand. But if it expands too much, it could potentially cause cell license, essentially causing the cell to burst open, killing the cell. And that's exactly what's happening right here with this animal cell and so animal cells, because they do not have cell walls, they could undergo sell license, and that could kill the cell. And so animal cells do not prefer hype. A tonic environments, however noticed down below. What we're showing is a plant in a plant cell, and plant cells have a cell wall that surrounds the cell membrane, and the cell wall prevents the expansion of the cell membrane, and so it prevents cell license And so plant cells do not have to worry about licensing in hype a tonic environments and instead plant cells. They actually prefer hype, a tonic environments, and the reason for that is because it leads to high turker pressure. Essentially, the cell membrane that is, uh, surrounding the cell here is applying pressure to the cell wall that surrounds the cell as well, and that allows the cell to the plant to take up a new, upright, healthy structure like what we see here and so once again, plants they prefer to be in Hypo Tonic environments, but animal cells, they do not like hype a tonic environments. So now let's take a look at the second type of environment. If the outside environment that is surrounding a cell is is a tonic, then in that scenario, water is going to both enter and exit the cell at equal rates. And that means that if water is going in and leaving the cell at equal rates, then the cell is not really going to change in size, and so this is actually preferred by animal cells like our blood cells. So let's take a look at our image down below here in the middle, where we're showing you the conditions where the outside environment surrounding the cell is isotonic. Uh, in this scenario, water is going to both enter cells, and water is going to leave cells at equal rates, which means that the cell is not going to change in size. And for animal cells like these red blood cells that we're showing you here, they actually prefer isotonic environments. Now, taking a look at the plant cell down below when it is in an isotonic environment, water. Once again we'll go into the cell and leave the cell at equal rates. And so the plant cell is not going to change in size. However, notice that the cell membrane here is not applying a lot of pressure to the cell wall. There are these gaps between the cell membrane and the cell wall, and so that means that there is not a really high amount of turker pressure and plants. They don't really prefer isotonic environments because it doesn't allow them to have the high turker pressure that allows them to have their upright, healthy formation. So now let's take a look at the final environment and if the outside environment that is surrounding a cell is hyper tonic and that scenario water is going to exit cells, and when water exit cells, it's almost like deflating a balloon. And so the balloon will get smaller and the cell would also get smaller and shrivel up and shrink down. And also because water is exiting, that's going to cause the cells to dehydrate. They're going to be losing water. And this is very similar to how AH hyper kid gets dehydrated. And so you can think, Hey ah, hyper kid that's jumping all up and down and never stops jumping around. They also get dehydrated, and so you can think hyper and hyper can lead to dehydration water leaving the south. So let's take a look at our image down below, over here on the right hand side, where the outside environment surrounding the cell is hyper tonic and that scenario, once again, water is going to be leaving the cell exiting the cell. And when it does that, the cell itself is going to shrivel up and shrink down and get dehydrated, just like all of these cells here so we can say that cells will be hydrate in this environment. And so this means that animal cells do not prefer hyper tonic environments because dehydration can lead to cell death now down below. Here with the plant cell were also showing the plant cell in a hyper tonic environment. And once again, water is going to be leaving the plant cell. In this scenario, and in this scenario, what you'll notice is that the cell membrane, which is right here, is not applying ah lot of pressure at all to the cell wall that surrounds it. And so there is a really low amount of turker pressure, and that will cause plants toe, lose their upright, healthy structure and begin toe wilt and die off is well. And so neither animal nor plant cells prefer hyper tonic environments because it will lead toa dehydration and low turker pressure for plants. And so, uh, what you can see here is that plant cells once again prefer Hypo tonic environments. Animal cells, uh, here prefer isotonic environments, and neither plant or animal cells prefer hyper tonic environments. And so this year concludes our lesson on how environmental tennis ity effects cells and we'll be able to get some practice applying these concepts as we move forward in our course. So I'll see you all in our next video.