In Biology, structure and function are tightly linked. When considering physical properties of a biological system this link might seem obvious but when it comes to connecting structure to a biological function (like gene expression or protein activity), this link is less evident. I will present 3 biological systems where the structure of biological components are crucial for proper biological behavior: (i) Nuclear deformation during hematopoietic stem cell differentiation; (ii) RNA polymerase condensates stabilization during acid stress in E. coli; (iii) Crystal-like structure of adherent-invasive E. coli micro-colonies