The invention is an automated multiple-purpose, integrated laboratory system comprising interchangeable modular elements for the construction and measurement of biological assays. The functions of the modular elements may include multiwell platform handling, chemical reagent or cell management, volumetric transfer of liquids for assay construction or for recovery of reaction products for analysis, incubation under controlled environmental conditions, measurement of spectrometric signals originating from the assays, processing and analysis of the resulting spectrometric data, and other functions. The modular elements are arranged around a number of robotic elements that deliver plates to different modular elements, transfer plates to groups of modules served by a different robotic element, or other actions necessary in plate handling. Liquid transfer to and from multiwell platforms, necessary for assay construction or for the initiation of physiological events in cells, is partitioned among different modules specialized for transferring nanoliter or smaller volume quantities of chemical concentrates, or microliter quantities of assay reagents, cells, media and other assay constituents. Applications of this invention include the quantitation and analysis of the expression of multiple genes in cells, measurement of multi-gene expression kinetics, analysis of activation or suppression of multiple signal transduction pathways, screening chemical compounds for modulatory effects on multi-gene expression or on signal transduction pathways or on other biochemical networks of cells, or other analytical biological or biochemical assays.