[en] This article describes the results of research into the effect of photolysis and photosynthesis of complex molecules on the cold dust particles that float around in the space between stars. A short description is given of how and under what circumstances, the interstellar dust particles form active centres for molecule formation. An outline is given of the attained results with analogue models in the laboratory and their astrophysical implications. 'Spin-offs', results that have no direct connection with this astrophysical investigation, are also mentioned. Recent experiments thus give room for theoretical speculations concerned with the search for the conditions that enabled life to develop on our planet. (C.F.)