Absorption by bacterial cells: interaction between receptor sites and the effect of fluid motion.

The absorption of some species X by a bacterial cell depends (i) on the concentration of receptors for species X and (ii) on the state of motion of the surrounding medium. The latter problem is particularly interesting, since without any restriction on the type of fluid, details of the flow field or kind of cell, an explicit expression for the increase in uptake is obtained. To study the interaction between neighboring receptor sites we concentrate on the limit of small area fraction. The result obtained correlates quite well with experimental data.