A single cell without a brain can smell, remember, and hunt for food
The baffling intelligence of a single cell (2024)
E. coli chemotaxis reveals intelligence in its most elemental form: a cell with no brain that senses chemicals, remembers recent concentrations, and adapts across five orders of magnitude. The signaling network—CheY phosphorylation, receptor methylation, and the flagellar motor—acts as a tunable chemical computer. This deep dive explores how a bag of unthinking molecules gives rise to purposeful behavior, offering a narrow, deep slice of systems biology.
Bacterial cells can amplify signals more than 50-fold; that is to say, a 2% change in receptor occupancy can bring about a 100% change in the output of the system at the flagellar motors. This feature allows cells to sense minute changes in concentration—less than three molecules per cell volume!