Osmosis
- Created by: Meeeeeeeeee
- Created on: 10-04-13 20:30
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- Osmosis
- What Is It?
- Type of diffusion
- Movement of water molecules across a partially permeable membrane.
- Goes from a high concentration to a low concentration.
- Partially Permeable Membrane
- Membrane with very small holes
- Only let's tiny molecules such as water pass through.
- Big molecules can't pass through (e.g. Sucrose)
- What Happens?
- Water molecules pass both ways through the membrane. This is because they move about randomly all the time.
- More water molecules on one side so steady net flow of water in to the region with fewer water molecules.
- The stronger the solution becomes more dilute as the water is trying to "even up" the concentration of the solutions on both sides of the membrane.
- What Happens In Cells?
- Tissue fluid surrounds the cells in the body.
- Tissue fluid will usually have a different concentration to the fluid inside the cells. This means water will move in to or out of the cell.
- If the cell is short of water it is more concentrated which means the outside is more dilute so water will go in to the cell.
- This makes the cell increase in size.
- If the cell has lots of water it is more dilute which means the outside is more concentrated so water will be drawn out of the cell.
- This makes the cell decrease in size.
- Other Information
- Tissue fluid is water with oxygen, glucose and stuff dissolved in it. It is squeezed out of the blood capillaries to supply the cells with everything they need.
- An experiment you can do to show osmosis is cut up potato cylinders and measure them and put some in a beaker of pure water and some in a beaker with a lot of sugar mixed with water. Leave it for about half an hour and measure them again.
- The one in pure water should have increased in size and the one in the sugar solution should have decreased in size.
- What Is It?
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