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14 Cards in this Set
- Front
- Back
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Molecules in liquids and gases move randomly due to what? |
Their thermal kinetic energy |
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Diffusion causes particles to move _____ a _________ __________ . |
down concentration gradient |
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What is osmosis? |
The diffusion of water molecules through a partially permeable membrane, down a concentration gradient. |
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Does osmosis only work in living things and why? |
Yes because it only works in a partially permeable membrane |
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What is active transport? |
Going from a high concentration to a low concentration (uses energy) |
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Sometimes there is not a concentration gradient, or the gradient is the wrong way. What can't occur when this happens? |
Diffusion |
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Active transport can move molecules ______ a concentration gradient. This requires a source of energy. Where does the source of energy come from? |
Against Respiration |
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What does active transport involve? |
The movement of molecules across cell membranes |
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What is active transport done by? |
a 'carrier protein' that recognises the molecule that it needs to move. |
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Describe the way the carrier protein works |
The carrier protein rotates within the membrane and releases the molecule inside the cell. Then it changes shape back again, ready for the next molecule. |
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What is the carrier protein also known as? |
a 'transport protein' |
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Describe the order of active transport by the way the carrier protein works |
1. outside the cell are the molecules to be transported across the membrane. the carrier protein is in the cell membrane. 2. energy from respiration is used to change the shape of the carrier protein. 3. the molecule is released on the other side of the membrane. 4. the carrier protein goes back to its original shape. |
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How would you know if a situation would need active transport? |
whether it is moving against a concentration gradient |
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Give examples of active transport |
1. moving glucose from the blood into cells, where there is already glucose in the cell 2. in the kidney, reabsorbing glucose back into the blood, where there is already glucose in the blood 3. mineral ions in the soil being moved into the more concentrated solutions within plant cells
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