On the issue of biological receptors: fundamental data that have been forgotten or neglected

Aim. The biological action of chemical and physical factors can be carried out in three stages: (1) stimulation, (2) inhibition and (3) collapse of chemical reactions. Externally, these reactions manifest themselves as stimulation or inhibition of physiological (growth) processes or death of the biological object. There are still no convincing data on how these processes are regulated at the molecular level. Experimantal data on why some substances are biologically active while others are not in comparable doses are also absent. The structure of molecules that determine their biological activity has not been identified either. The aim of the study was to identify the specific structure of molecules that determine their biological activity based on the analysis of the steric structure of various chemical compounds. Results. After analyzing the structure of various biologically active substances (toxins, agricultural and pharmaceutical chemicals), the active hydrogen atom was identified at the N- or C-atoms in the bilateral environment by electron-withdrawing groups, as well as the presence of unsaturated bonds in aliphatic or cyclic structures, but not in aromatic cycles. Conclusions. It is concluded that such fragments of molecules determine the biological activity of chemical compounds.