school energy&environment

The coacervates

Actually we are still a long way away from what could be defined as a living organism also because nowadays it is surrounded by a wrap called “cellular membrane”, that separates it from the outer world.
Starting from these suppositions, Oparin assumed that in the hot primitive seas organic molecules would gather in small drops, similar to the actual cells. These small drops wrapped up in water molecules are called “coacervates” (from cum acervo = gather together) and were already known before Oparin’s research. It has been proved that by placing certain proteins which bind well with it in the water, with certain temperature and acidity conditions, numerous small drops will form holding within them most of the larger molecules bound together.
This can be explained by the existence of opposite sign electric charges on the proteins, which are then attracted to one another and gather polar molecules of water on the outer surface to form a membrane around the aggregation transforming it into a small drop.
In 1958 the biochemist Sidney Walter Fox , who discovered protein precursors (proteinoids), made some proteinoids melt in hot salty water. When the solution cooled down, he noticed that there were thousands of small corpuscles similar to bacteria, that he called “microspheres”. Through the microscope he saw that the small organic substance corpuscles had a double protection membrane. This membrane is not like a cellular membrane, but in certain conditions it acts as one. In fact, when placing them in solutions at higher or lower concentrations compared to their inner liquid, they shrink or swell exactly like living cells will do in the same situation. Furthermore, the microspheres are able to keep some molecules inside and let others out. These features make the microspheres look very much like living cells.