Before an Escherichia coli cell divides to give two viable daughter cells, the constantly growing cell must replicate, topologically decatenate, and spatially segregate its genetic materials. These processes pose non-trivial, conceptual questions at the interface between physics and biology. In this talk, I will discuss the questions in two independent and yet related contexts. In the first part, I will focus on the spatial processes involving chromosomes, and present experimental and theoretical results to show that the bacterial chromosome behaves as a loaded entropic spring, strongly confined by a crowded environment inside the cell. The second part concerns temporal processes the cell must coordinate, and I will show that E. coli possess a very robust mechanism of growth. I will conclude with one of the long-standing questions in biology, which we physicists may view as a "causality" problem. |
