One way of modelling the stochastic as well as the diffusive aspect of the problem is by explicitly modelling the diffusion and interactions of the individual molecules contained in the system. Such spatial simulations have been performed by Franks etal. to study the synaptic cleft using their software M-Cell [10]. Also, recent simulations by Lipkow etal. have successfully modelled the individual molecules and their diffusion to show the presence of a protein concentration gradient in the motor response in Escherichia coli using their software SmolDyn [17,18]. Another way is to discretise space on a lattice and to use extensions of the Gillespie algorithm such as in SmartCell [11,19] and MesoRD [20,21].