Group translocator, definition

Definite structural requirements relating to activity (33, 34, 35, 55, 57, 58), translocation (56), and biodegradability (41) appear to exist for certain chemical groups of surfactants. Whether these also influence herbicide persistence in plants and roots requires further study. 

In the actual state of our knowledge we should carefully avoid the application of the definition of active transport, given below, to any translocation of a chemical group or radical from a donor to an acceptor. More appropriately, we should consider some of the relationships established between an organism and its surroundings For instance, how does a frog, sitting in tap-water, keep its interior of different ionic composition (Na and a ) from the outside medium ... 

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