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16 Cards in this Set
- Front
- Back
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What is osmosis? |
The movement of water from an area of high water potential to an area of low water potential, down a water potential gradient, through a partially permeable membrane, across the phospholipid bilayer or via channel proteins. |
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How would you describe an area of high water potential? |
Lots of free water molecules with little solute |
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How would you describe an area of low water potential? |
Fewer free water molecules with lots of solvent |
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What are channel proteins also known as? |
Aquaporins |
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What are the 4 key osmosis facts? |
A water potential gradient is required It can occur through the phospholipid bilayer or channel proteins because water is small and polar. Water potential is measured in kilopascals Pure water is 0KPa and adding solutes to water makes the water potential lower |
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Which molecules can diffuse via osmosis? |
Only water molecules |
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Which is the highest water potential? |
0 KPa |
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What happens as you go down from 0 KPa and into negative numbers? |
As you go down, water potential gets lower. |
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What is a solution? |
A solute + water = a solution |
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What is a hypertonic solution? |
A solution with a lower water potential due to less free water molecules than in the cell |
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What is an isotonic solution? |
A solution with the same water potential as the cell. Therefore, there's no net movement of water molecules |
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What is a hypotonic solution? |
A solution with a higher water potential than in the cell. There are more free water molecules than in the cell. |
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What happens to an animal cell in a hypertonic solution? |
Water moves out of the cell causing it to shrink and become wrinkled. It is crenated |
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What happens to a plant cell in a hypertonic solution? |
Water moves out of the cell, so the cell membrane pulls away from the cell wall as water leaves. It is plasmolysed |
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What happens to an animal cell in a hypotonic solution? |
Water moves into the cell and it bursts. It is haemolysed |
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What happens to a plant cell in a hypotonic solution?
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Water moves into the cell and it becomes turgid. The cell wall prevents it from bursting as the membrane pushes against the wall. |
