Cells decipher and integrate conflicting signals using complex molecular interaction networks to make an appropriate cell-fate decision. A key challenge of molecular systems biology is to understand how the dynamical behaviour of cells emerges due to the non-linear interactions within biological networks and to predict the fate of cells in response to perturbations. In order to study the network dynamics, we develop mathematical models of biological networks involved in the regulation of various cellular processes. The main goal is to integrate diverse data sets (biochemical and high-throughput) to generate mechanistic insights and novel hypothesis regarding complex cellular processes and human diseases. At Oxford, we have combined mathematical modelling with experiments to study the cell division regulatory network that controls the phase transitions of mitosis and meiosis. These studies have revealed the underlying design principle: the activator and the inhibitor of each transition are locked in multiple feedback loops to create a bistable (‘toggle’) switch. A bistable switch ensures an irreversible commitment to move forward through mitosis/meiosis and it opposes the re-activation of the checkpoint. It also serves as a control mechanism in meiosis to restrict the number of cell division cycles to two. In this talk, I wil