Figure 3.

Timeline 1925–1972. Summary of the main contributions related to cell membrane discovery between the first studies on cell membrane structures and the formulation of the fluid mosaic model. The events are approximatively ordered from top to bottom from the earlier events to the most recent. Although the studies are sometimes difficult to classify, the colors of the boxes reflect some major research axes influent to this history: orange, osmotic studies; red, studies with artificial membranes; purple, electrophysiology works; dark green, direct description of membranes; pink, some transporter theories; light blue, asymmetric ion distribution debate; light green, electron microscopy studies. Although most of these contributions were highly interconnected, full lines between boxes highlight particularly important relationships and dashed lines point out to contradictory views in major controversies.