Before revision: We study physical limits of chemical sensing by a single chemotactic cell with cooperative chemoreceptors on the cell surface .
After revision: Most sensory cells use cross-membrane chemoreceptors to detect chemical signals in the environment. The biochemical properties and URLanization of chemoreceptors play important roles in achieving and maintaining sensitivity and accuracy of chemical sensing. Here we investigate the effects of receptor cooperativity and adaptation on the limits of gradient sensing. We study a single cell with aggregated chemoreceptor arrays on the cell surface .