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10 Cards in this Set
- Front
- Back
Describe the 3 functions of the membrane at the surface of the cell.
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>Separating cell contents from the outside environment
>Controls which substances enter and leave the cell >Cell recognition and signalling |
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Describe the 3 functions of the membrane within the cell.
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>Divide cell into compartments making different functions more efficient
>Can form vesicles >Control which substances enter and leave the organelle. |
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Describe the 'fluid mosaic' structure.
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>Phospholipid molecules form a continuous fluid bilayer
>Various protein molecules are scattered through the bilayer some can move around >Glycoproteins (protein molecules have a carbohydrate part attached) >Glycolipids (phospholipid molecules have a carbohydrate part attached) >Cholesterol |
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Describe the role of cholesterol in the cell membrane.
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Cholesterol molecules fit between phospholipid tails to make the membrane more rigid/more complete so water molecules and ions cannot pass easily through the membrane.
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Describe the role of phospholipids in the cell membrane.
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Describe the role of glycolipids and glycoproteins in the cell membrane.
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>Cell signalling and recognition
>Glycoproteins can bind cells together in tissues. >Some receptor sites allow hormones to bind with the cell which causes the cell to respond in some way. |
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Outline the effects of changing temperature on membrane structure and permeability.
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Increase in temperature gives molecules more kinetic energy so they move faster. This increased movements of phospholipids makes membranes more permeable.
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Describe the role of channel proteins in the cell membrane.
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Allows the movement of molecules that are usually too large and too hydrophylic to cross the membrane.
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Describe the role of carrier proteins in the cell membrane.
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Actively moves some substances across membrane using ATP.
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Explain the term 'cell signalling'.
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One cell releases a messenger molecule, which travels to another cell where it binds to a receptor on the target cell membrane because the two have complimentary shapes, causing the target cell to respond in some way.
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