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Unformatted text preview: Active transport Moving against a concentration gradient or an electrochemical gradient requires the input of additional energy and so is called the active transport of materials. This is the only kind of transport able to move molecules against a concentration gradient. Like facilitated transport, it depends upon protein transporters in the membrane; in this process these proteins are composed of the membrane-bound enzyme, H +-ATPase. Using the typical proton pump reaction, the enzyme catalyzes the hydrolysis of ATP. In primary active transport, the energy released by the hydrolysis is used to modify the membrane protein itself, which then transports the molecule through the protein. In secondary active transport, the energy is used to pump a large quantity of H + across the membrane; as the protons flow back they carry with them other substances. Sucrose is moved in membrane; as the protons flow back they carry with them other substances....
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This note was uploaded on 11/14/2011 for the course BIO 1421 taught by Professor Farr during the Fall '08 term at Texas State.
- Fall '08
- Active Transport