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- Lets everything in and out
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- Cell wall
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- Allows some substances through but not others
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- Cell membrane
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- Lets nothing in or out
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- Movement of molecules from an area of high concentration to an area of low concentration
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- Gaseous exchange in alveoli and leaves
- Absorption of digested food in small intestine
- Absorption of minerals by root hairs
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- Movement of water molecules from an area of high water concentration to an area of low water concentration across a semi-permeable membrane
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- Water entering root hairs
- Water being reabsorbed in nephron
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- Liquid that dissolves other substances
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- Water
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- A substance that dissolves in a solvent
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- Salt
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- The mixture of solvent and solute
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- Salt and water mixing
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- The animal cell is in a solution with same concentration as cytoplasm
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- Water moves in and out of cell at the same rate
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- The animal cell is in a solution that is more concentrated (less water) than the cytoplasm
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- Water moves out of the cell
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- The cell can shrivel up
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- Think - Hyper to get out of class - hypertonic - the water moves out of the cell
- Remember - The water will move where more water is needed
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- The animal cell is in a solution that is less concentrated (more water) than it’s cytoplasm
‣
- Water goes into cell
‣
- Cell can burst
‣
- The plant cell is in solution that has same concentration as cytoplasm
‣
- Water moves in and out of cell at same rate
‣
- The plant cell is in a solution with more concentration (less water) than cytoplasm
‣
- Water moves out of the cell
‣
- It becomes Flaccid
‣
- Plasmolysed
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- If the plant cell loses a lot of water
‣
- The plant cell is in solution of less concentration (more water) than that of the cytoplasm
‣
- Water moves into the cell
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- No
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- Due to the cell wall
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- Turgid
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- Pressure from cytoplasm and vacuole pressing against cell membrane
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- Doesn't require energy
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- Diffusion and Osmosis are passive processes
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- The movement of molecules is always from an area of high concentration of water to an area of low concentration of water
‣
- Food Preservation
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- Bacteria have a high concentration of water
- Salt has a low concentration of water
- Place salt on meat
- The water from bacteria will move by osmosis to the salt cells (because salt cells need more water)
- Therefore the bacteria cells lose their water and will shrivel up and die - preserving the meat
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- The movement of substances from areas of low concentration to areas of high concentration (against the concentration gradient)
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- No
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- Because it uses energy to move against the concentration gradient
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- Cut 2 pieces of visking tubing
- Tie one end of both
- Fill one with sucrose solution (sugar) and water
- Fill other with water
- Use weighing scales to get initial mass of both pieces of visking tubing
- Place each in separate beakers of water
- After 20 mins, remove, dry and re-weigh both pieces for final mass
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- Visking tubing with sucrose solution increased in size due to osmosis
- Final mass increased when compared to initial mass