A bacterium's genome, pulled into a straight thread, is nearly 1,000 times longer than the cell from which it came. If you placed one E. coli into a gallon-sized jug with some nutrients and waited a few hours, the genomes of its descendants, placed end-to-end, would reach to the moon and back ...several times. 1 One rarely pauses to ponder how so much DNA — let alone sugars, proteins, lipids, and other molecules — can fit inside such a small vessel. A typical E. coli cell, after all, measures about one micrometer across. Its entire volume is 100 times smaller than that of a red blood cell, and about 100 million times smaller than a grain of sand. The truth is that biochemistry textbooks often depict cells as spacious places, where molecules float in secluded harmony. "But a cell looks more like a burrito," says Michael Elowitz , a biologist at Caltech. All the biochemicals are pushed together, bumping into each other.…