Deterministic and stochastic modelling of biochemical processes - an introduction and open problems Tomas Vejchodsky Abstract: This talk introduces basic ideas of mathematical models of dynamical chemical systems. We will compare the deterministic and stochastic models and show that they can provide even qualitatively different predictions. This research is motivated by biochemical processes in living cells, where concentrations of certain chemical species are extremely low (units of molecules). This causes strong manifestation of stochastic effects and invalidity of deterministic models. Subsequent parts of the talk will discuss more advanced mathematical tools for stochastic modelling of biochemical systems. We will discuss the central difficulty, which is the size and complexity of biochemical networks of intra-cellular mechanisms. We will mention reduction of these large models. We show that solution of the stationary chemical master equation is equivalent to finding the null-space of a large sparse matrix. We will comment on the accuracy and boundary conditions for chemical Fokker-Planck equation, and we will explain the need for solving high-dimensional partial differential equations and an approach how to achieve it.