Describe active transport. Propose a model illustrating this process.
Active transport is the opposite of passive transport, in the way that active uses ATP to transfer material through a membrane whereas passive does not. This is the movement against the concentration gradient. Because substances are moving against the grain, they need extra help, an extra push. Proteins studded throughout the membrane facilitate this process. This is an important process because it helps cells work towards equilibrium, even when the surrounding environment is not the proper tonicity for a cell to maintain equilibrium. Please see ‘Glucose and Na+/K+ Transport’ under Ch 7 for an explanation of the sodium-potassium pump which is depicted below. |
| http://www.mhhe.com/biosci/esp/2001_gbio/folder_structure/ce/m3/s5/ |
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