ABSTRACT
Directed and purposeful movement is one of the properties we most closely associate with living organisms. Even organisms that appear immotile to the naked eye, such as green plants, are very busy on the cellular level, exhibiting rapid directed movements of organelles such as chloroplasts and segregation of chromosomes during cell division. One fascinating feature of the motors found in cells is their structural and functional diversity. Nevertheless, many different kinds of motors share similar fundamental physical mechanisms, so analysis of one motor can frequently shed light on the functioning of other motors that are evolutionarily unrelated and are used for distinct biological purposes. One of the most important and familiar classes of molecular motors are those associated with the cytoskeleton, specifically with micro-tubules and actin filaments. Another example of the action of translational motors is provided by active filamentous structures in cells, which embody a subtle coupling between beam-bending dynamics and translational, force-generating motors.
