Most biochemical processes can be naturally described in terms of the size, e.g., number of molecules, of each species under consideration. The dynamics of such systems are then studied by analysing the variation in time of the number of molecules in each species due to the occurrence of events. Given that events occur at random, the mathematical formulation for the dynamics is that of a stochastic process. When the number of molecules is high, it seems to be plausible to describe the number of molecules by means of continuous variables whose evolution is ruled by differential equations. The goal of this talk is to present the ongoing work related to the potential mismatches between models based on differential equations and on stochastic processes.