How can cells count? Robustness in self-assembly pathways

Cells are characterised by different kinds of structures, organelles, each of them with a specific function. In some cases, in order to perform its task, an organelle needs to have some precise features, lika a location, or shape, size and requires to be present in an exact number. Some of these features can't be directly encoded in DNA itself and they are controlled by other means. The present work addresses the poorly understood problem of how cells can count. More precisely, what mechanisms are used by the cell in order to control and constrain the number of structures it needs. In order to do so, this thesis starts by considering the flagellum, a structure that allows the cell to move in its environment, and analyses its self-assembly pathway traying to figure out what the purpose of each step of the process is in making the "counting mechanism" robust to initial resources number variations and stochastic fluctuations.