 The cell theory, first developed in 1839 by Schleiden and Schwann, states that all organisms are composed of one or more cells; all cells come from preexisting cells; and cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.There are two types of cells, eukaryotic and prokaryotic.Prokaryotic cells are usually singletons, while eukaryotic cells are usually found in multicellular organisms.