Proto-metabolism in artificial life (IMAGE) University of Groningen Caption The stacks of rings catalyse the conversion of the basic building blocks into new three- and four-membered rings which are needed for the growth of stacks of six-membered rings (self-replication). Credit Otto Lab, University of Groningen Usage Restrictions With credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.