The Song of the Cell: An Exploration of Medicine and the New Human

by Siddhartha Mukherjee

It’s simpler, perhaps, to imagine entering and exploring the interior of a cell as an astronaut might imagine exploring an unfamiliar spacecraft. From far away, you might see the spacecraft’s/cell’s outer contours: the oblong, gray-white sphere of an oocyte, or the crimson disk of a red blood cell. As you approach the cell membrane, you might begin to see its outer layer more clearly. Bobbing on that fluid surface are proteins. Some might be receptors for signals, while others might function like molecular glue for attaching one cell to another. Some of these might be channels. If you are fortunate, you might watch a nutrient or an ion slip through the pore and into the cell. And now, you, too, might “board” the craft. You would dive through the hull—that is, into the bilayer membrane, moving rapidly through the space between the two layers, only about ten nanometers thick, or ten thousand times thinner than a strand of human hair—and emerge inside. Look around and above: now the inner lamella of the cell membrane would hang above you like the fluid surface of the ocean as seen from below. You would also see the inner parts of the proteins dangling above you, like the underbellies of buoys.