Water Potential Formula Explained
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7 سال پیش
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This video describes how the
This video describes how the water potential formula works and can be used in biological processes.
** If there are any pictures used in this video, they are NOT MINE and I will not take credit for them. **
TRANSCRIPT:
Water potential can determine the direction in which water will flow. It’s influenced by solute concentration and pressure. Here’s the formula: water potential = solute potential plus pressure potential. So, let’s start off with pure water. Pure water has a water potential of 0, because it doesn’t have any solutes in it and we’re assuming it’s not being affected by pressure. And, we know that through osmosis, water will flow from an area of higher water potential to lower water potential. That means that if we put a cell in pure water, and the cell has a negative water potential, water will diffuse into the cell. Let’s take a look at what this means according to the formula.
It’s pretty easy to understand – solute potential tells us if there are any solutes in the solution, and pressure potential tells us if there is any pressure acting on the solution. We’ll use our cell example from before, and pretend that we’ll start off with a water potential of 0. When we put solutes inside our cell, we see that our solute potential goes down, therefore lowering water potential as a whole. Why does solute potential go down when we add solutes? Well, that’s because we know that water flows from higher to lower water potential. If we add solutes to the cell, it will cause water to flow inside the cell because there is a higher concentration of solutes inside the cell than outside. So, it would only make sense that since water is flowing from outside the cell to inside the cell, the inside of the cell would have to have lower water potential than the outside, therefore we lower the solute potential. You can also think of it this way: it lowers the potential that more solutes will go in, since there are a lot in there already.
Now on to pressure potential. Water always flows from areas of high pressure to low pressure. Think of it like squeezing a tube of toothpaste. When you apply pressure on one side of the tube, the toothpaste always goes in the opposite direction. So here, I’ve drawn a u-shaped container filled halfway with water. Now I’m going to apply pressure to one side. Naturally, the water would move to the other side of the container, since the right side now has a higher pressure, causing the water to move the opposite direction. When we apply pressure, pressure potential decreases, too. But when we lift away pressure, pressure potential goes UP. This can cause one side to have higher water potential than the other, therefore making the water go that way.
Alright, I hope that helped you better understand the water potential formula. Remember, adding solutes decreases solute potential. Adding pressure decreases pressure potential, too, but taking away pressure increases pressure potential. Finally, water always moves from higher to lower water potential and higher to lower pressure. Thanks for watching, and be sure to check out my other videos.
** If there are any pictures used in this video, they are NOT MINE and I will not take credit for them. **
TRANSCRIPT:
Water potential can determine the direction in which water will flow. It’s influenced by solute concentration and pressure. Here’s the formula: water potential = solute potential plus pressure potential. So, let’s start off with pure water. Pure water has a water potential of 0, because it doesn’t have any solutes in it and we’re assuming it’s not being affected by pressure. And, we know that through osmosis, water will flow from an area of higher water potential to lower water potential. That means that if we put a cell in pure water, and the cell has a negative water potential, water will diffuse into the cell. Let’s take a look at what this means according to the formula.
It’s pretty easy to understand – solute potential tells us if there are any solutes in the solution, and pressure potential tells us if there is any pressure acting on the solution. We’ll use our cell example from before, and pretend that we’ll start off with a water potential of 0. When we put solutes inside our cell, we see that our solute potential goes down, therefore lowering water potential as a whole. Why does solute potential go down when we add solutes? Well, that’s because we know that water flows from higher to lower water potential. If we add solutes to the cell, it will cause water to flow inside the cell because there is a higher concentration of solutes inside the cell than outside. So, it would only make sense that since water is flowing from outside the cell to inside the cell, the inside of the cell would have to have lower water potential than the outside, therefore we lower the solute potential. You can also think of it this way: it lowers the potential that more solutes will go in, since there are a lot in there already.
Now on to pressure potential. Water always flows from areas of high pressure to low pressure. Think of it like squeezing a tube of toothpaste. When you apply pressure on one side of the tube, the toothpaste always goes in the opposite direction. So here, I’ve drawn a u-shaped container filled halfway with water. Now I’m going to apply pressure to one side. Naturally, the water would move to the other side of the container, since the right side now has a higher pressure, causing the water to move the opposite direction. When we apply pressure, pressure potential decreases, too. But when we lift away pressure, pressure potential goes UP. This can cause one side to have higher water potential than the other, therefore making the water go that way.
Alright, I hope that helped you better understand the water potential formula. Remember, adding solutes decreases solute potential. Adding pressure decreases pressure potential, too, but taking away pressure increases pressure potential. Finally, water always moves from higher to lower water potential and higher to lower pressure. Thanks for watching, and be sure to check out my other videos.
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در تاریخ 1396/01/25 منتشر شده
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