Like a map showing heavily traveled roads, this mathematical model of metabolic activity inside an E. coli cell shows the busiest pathway in white. Reaction pathways used less frequently by the cell are marked in red (moderate activity) and green (even less activity). Visualizations like this one may help scientists identify drug targets that block key metabolic pathways in bacteria. Courtesy of Albert-László Barabási, professor of physics at the University of Notre Dame. Featured in the January 18, 2005, issue of Biomedical Beat. High res. image (714 KB PNG)