We consider three problems from applied mathematics and numerical computations, motivated by interactions with physicians and biologists. The first problem bases on the mathematical Canham-Helfrich model for red blood cells, membranes and vesicles, and its numerical resolution involves the level-set method and the eikonal equation. The second problem deals with surface PDEs, for the development of biological tissues by a continuum modeling. A concrete application to the embryogenesis is presented: it bases on a Stokes-like problem on arbitrarily complex closed surfaces. The third problem considers a continuum model for liquid foams: it involves complex fluid mechanics, combining viscous, plastic and elastic effects together, in an elastoviscoplastic fluid model. All these three problems are presented with few words on the domain of application and examples of numerical computations and comparisons with physical observations.