A schematic representation of the decrease in concentration of extracellular harmful acetic acid molecules (HAc) and intracellular acetate ions (Ac^–) produced by an alkaline pH shift.

<p>A) Diagram to show HAc formation from Ac^– and diffusion across the cell membrane as an uncoupler. Ac^– cannot permeate the <i>E. coli</i> cell membrane. B) Release of intracellular acetate by an alkaline extracellular pH shift from 6.5 to a higher pH. Dark blue indicates higher intracellular acetate concentrations. pKa, the dissociation constant of acetic acid.