chemotaxis
http://purl.obolibrary.org/obo/GO_0006935
The directed movement of a motile cell or organism, or the directed growth of a cell guided by a specific chemical concentration gradient. Movement may be towards a higher concentration (positive chemotaxis) or towards a lower concentration (negative chemotaxis). [ http://openisbn.com/search.php?q=0198506732&isbn=1/ ]
Synonyms: taxis in response to chemical stimulus