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15 Cards in this Set
- Front
- Back
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Transport mechanisms exist so that
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molecules can move across plasma
membranes |
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When they are able to move freely
molecules move from the area of |
high concentration to an area of low concentration
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molecules don’t move freely
across the plasma membrane |
Glucose is an example.
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Some molecules move easily across most cell membranes.
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like water
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two clusters of transport mechanisms
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active transport. passive transport.
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transport of molecules across a membrane requires energy
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active transport.
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does not require energy
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passive transport.
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Transport of molecules across a membrane follows the same principles as chemical reactions:
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passive movement occurs from high energy to low energy; to move in the opposite direction requires the
input of energy |
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energy of a solution depends on the solute concentration
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energy
increases as solute concentration increases |
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A chemical driving force that acts on a given substance depends only
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on the
concentration gradient of that particular substance. |
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Three types of driving forces influence the transport of molecules
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Chemical,
electrical, electrochemical. |
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Any difference in energy existing across a membrane acts as
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a driving force that tends to
push molecules in one direction of another. |
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a driving force that tends to
push molecules in one direction of another. |
concentration differences or
other factors that affect the energies of the molecules. |
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molecules move from areas of high concentration to low
concentration |
they move down their concentration gradient.
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The rate of movement varies with the
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size of the concentration gradient.
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