Modeling the Soft Geometry of Biological Membranes: From the Endoplasmic Reticulum to Red Blood Cell Shapes

Ranjan Mukhopadhyay

Physics, Clark University

The surface of a cell or intracellular organelle is formed by a biological membrane and often the beautiful and complex shapes of cells and organelles are determined by its membrane energetics. Examples include the rest shapes of a red blood cell and the variety of shapes of the endoplasmic reticulum and the Golgi apparatus. In this talk we will explore the physical mechanisms that underlie membrane shapes and how these shapes can be modeled mathematically. We will establish the role of membrane elasticity in determining these shapes and discuss the mechanisms for generating curvature. For red blood cells, I will present results on computed shapes that are in striking agreement with experimentally observed shapes under a variety of conditions. We will also discuss the coupling between membrane shape and membrane architecture and the biological role of such coupling.