Matching Pairs 4.4 Cell TheoryOnline version History and Basic concepts of cell theory by Susana Montealegre 1 Postulate 2 The cell is the structural unit and the _______ 2 He was the first scientist to observe live microorganisms. 3 Postulate 1: All the organisms ..... 4 He said that all cells are produced by dividing existing cells. 5 Postulate 3: All cells come from ________ 6 Scientist who observed cells in cork for the first time. He calls them celle. 7 He said that all animal tissues are composed of cells 8 I conclude after studying plant tissues that all plants are made up of cells.