Singer and Nicolson (1972) proposed the structure of cell membrane that was widely accepted and called as fluid mosaic model which states that fluid, native lipids, helps in the movement of protein within the membrane.
Schleiden and Schwann (1839) observed thin outer layer in cells called plasma membrane and proposed cell theory. Camillo Golgi (1898) discovered the Golgi apparatus. Robert Brown (1831) discovered the nucleus in the cell which was later termed as chromatin by Flemming.