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

by Siddhartha Mukherjee

You go out for dinner one evening. Perhaps in Venice, Italy—a resplendent restaurant near the Giardini, the public gardens of the city near the banks of the Bacino di San Marco. You begin with baccala manticato, the whipped salt-cod concoction that the Venetians stole from the Portuguese and appropriated into a national culinary monument. There’s a mound of toasted bread and a gigantic bowl of rigatoni to follow, and enough Chablis to fill a small canal. Perhaps you don’t realize as you walk back that a cellular cascade has been activated. Leave aside digestion for a moment. It is the metabolic cascade—and the restoration of chemical balance—that is the small miracle of cell biology that unfolds in your body as you walk back to your hotel. The carbohydrates from the bread and rigatoni are digested into sugars—ultimately, into glucose. The glucose is picked up from the intestines, absorbed into blood and moved into circulation. When the blood reaches the pancreas, it senses the spike in glucose, and sends out insulin. The insulin, in turn, moves the sugar from the blood into all the cells of your body, where it can be stored, if needed, or used for energy, as needed. The brain is the ultimate recipient of these signals: if the sugar drops too low, it reacts by sending out converse signals. Yet other hormones, secreted by different cells, send signals to release stored sugars into the blood. The stores come from liver cells, which respond, at least transiently, by releasing ...