Dr. Paas undergraduated at the Tel-Aviv University (focusing on biochemistry). Then, he graduated at the Weizmann Institute of Science, Rehovot, Israel, where he earned a MSc degree for the work on the complement system (Dept. of Immunology), and a PhD degree for the work on brain ionotropic glutamate receptors (with Prof. Vivian I. Teichberg, Dept. of Neurobiology). Dr. Paas spent four years as a postdoctoral fellow in the laboratory of Prof. Jean-Pierre Changeux, Pasteur Institute, Paris, France and then got a position of Maitre de Conference (assistant professor) from the College de France. During his stay in France, Dr. Paas focused on structural studies of Cys-loop receptors, particularly the acetylcholine receptor. Following his return to Israel and after spending approximately a year as a visiting scientist at the Sackler School of Medicine, Tel-Aviv University (with Prof. Bernard Attali), Dr. Paas joined the Bar-Ilan University where he established a laboratory for Biophysics, Pharmacology and Structure of Ion Channels and serves as a senior lecturer. Major research achievements: 1. Identification and localization of an extracellular guanine nucleotide-binding site in brain ionotropic glutamate receptors. 2. Identification of all the amino acids that comprise the neurotransmitter-binding pocket of an ionotropic glutamate receptor. 3. Probing the closed and open pore conformations and the gating motions of the pore-lining helices of a Cys-loop receptor. 4. Identification and characterization of the mechanism of chloride selection by an invertebrate Cys-loop receptor that responds to glutamate. 5. Organization of acetylcholine receptor molecules in three-dimensional micrometer-sized crystals that are now being used as a source of seeds for epitaxial growth of larger crystals.