The shape of the red blood cell shown in the figure is determined exclusively bit its elastic energy. No biological specificities are required. Image attributed to Helmut Strey.
Fluorescence microscopy is widely used to image and observe the cytoskeleton, which consists of various proteins that form filamentous structures in the cell. In this mammalian cell, actin filaments that form a mesh around the edges of the cell are stained red, and the microtubules that are centrally bundled are stained blue.
A 3 um square electron microscope image of the cell wall in a living mustard plant seedling. The cellulose fibers organize into a dense mesh that is oriented perpendicular to the stem of the plant. Little is known about how plants make cellulose, which is the most abundant polymer on earth. Image credit, Tobias Baskin.
We use biophysical methods to study the mechanics and dynamics of cells and their various structural and functional subunits, such as the cytoskeleton. Concepts taken from soft-matter physics are used to understand and explain cellular processes.