Inspired by the need for effective stochastic models to describe the complex
behavior of biological motor proteins that move on linear tracks exact results
are derived for the velocity and dispersion of simple linear sequential models
(or one-dimensional random walks) with general waiting-time distributions. The
concept of ``mechanicity'' is introduced in order to conveniently quantify
departures from simple ``chemical,'' kinetic rate processes, and its
significance is briefly indicated. The results are extended to more elaborate
models that have finite side-branches and include death processes (to represent
the detachment of a motor from the track).Comment: 17 pages, 2 figure