Bags for Life

Creased, crumpled and odd-looking, we have trillions of these strange structures inside our bodies. These are cell membranes, biological bags that keep life-giving chemicals safe – and volatile ones separate – inside our cells. Each grey-coloured membrane pictured here (in a computer simulation) is being tugged about by red-coloured structural proteins attached to its surface. The proteins curve the membrane slightly, like poles embedded in the lining of a tent, pulling it into shape. These computer simulations show a variety of membrane shapes produced simply by increasing the number of virtual protein ‘poles’ and watching how their tug o’ war with the membrane resolves itself. As more proteins are attached (from top left to bottom right, here), the squirming membranes settle in different ways – even forming tube shapes similar to those found inside our cells (bottom right), where they have evolved to pipe chemicals from place to place.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

Website

• John Ipsen
• MEMPHYS-Center for Biomembrane Physics, University of Southern Denmark, Denmark
• Copyright Elsevier 2013
• Published in Biophysical Journal, 104(5): 1118-1028