Robert Hooke of England looks through a microscope at a sliver of cork. He notices what he calls cells or pores. He believes the cells contained the noble juices or fibrous threads of the tree when it.
Anton van Leeuwenhoek discovers unicellular organisms.
Matthias J. Schleiden of Germany published a cell theory as applied to plants.
Theodor Schwann of Germany published cell theory as applied to animals.
Rudolph Virchow proposes that all cells come from other cells.
John Gurdon used nuclear transplantation to clone an African Clawed Frog; first cloning of a vertebrate using a nucleus from a fully differentiated adult cell.
Lynn Margulis proposed the endosymbiotic theory, that the eukaryotic cell is a symbiotic union of primitive prokaryotic cells.
Yamanaka worked out how to turn mature cells in mice into stem cells by introducing a few genes. Yamanaka's 'induced pluripotent stem cells' removed the need to use live human embryos to create versatile stem cells.