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Active transport across cell membranes

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Active transport:
Requires the use of chemical energy to move substances across a membrane, against a concentration gradient.
Active transport proteins may be uniports, symports, or antiports. Review Figure 5.13

uniport symport antiport
In primary active transport, energy from the hydrolysis of ATP is used to move ions into or out of cells against their concentration gradients. The sodium-potassium pump is an important example. Review Figure 5.14
primary active transport

Secondary active transport couples the passive movement of one substance with its concentration
gradient to the movement of another substance against its concentration gradient. Energy from ATP is used indirectly to establish the concentration gradient that results in the movement of the first substance.

Secondary active transport
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