English: Figure 1: Cells excrete chemicals (autoinducers) into their environment to measure the population around it. Each bacteria has it’s own type of autoinducer, for a Gram-negative bacteria (like in the example) it is most commonly an Acyl Homoserine Lactone (AHL). This close contact cell-to-cell communication is essential for biofilms to form. Quorum sensing ensures this density growth by the formation of more autoinducers the higher the population. An AHL will diffuse through one cells membrane into another cells that is near by. From there, it attaches onto an activator protein and both then bind to the chromosomes in the cell. Lastly, products go through the AHL synthase to create more AHL and are secreted through the cell. The process repeats itself and grow the environments population to create the biofilm. Polysaccharides increase the pathogenicity of the biofilm and prevent the penetration of antibiotics.