The transfer and subsequent metabolism of lysophosphatidylcholine between subcellular compartments were studied in vitro by embedding membranes in alginate beads. After several experiments to validate the process, it was demonstrated that lysophosphatidylcholine was transferred from microsomes embedded in alginate beads to immobilized chloroplasts, that this transfer involved the partition of this molecule, and that the imported lysophosphatidylcholine was further used as substrate for phosphatidylcholine biosynthesis. More generally, the technique used makes it possible to avoid any cross-contamination between compartments, to evidence a transfer of molecules, and to study the metabolism of the imported molecules in the acceptor compartment.