The basic tenets of the cell theory are as follows:
- All living things are made up of one or more cells.
- The cell is the structural and functional unit of all living things.
- Cells come from pre-existing cells through the process of division.
- All cells are the same in regard to chemical composition.
- All energy flow (i.e. metabolism and biochemistry) of life occurs within the cell.
The cell theory is credited to the scientists, particularly, Theodor Schwann, Matthias Jakob Schleiden, and Rudolf Virchow. Theodor Schwann, a German physiologist, stated in his writings that all living things are composed of cells and the products of cells in their structures.1 This theory was founded together with M. J. Schleiden, a German botanist. Rudolf Virchow, a German biologist and doctor, contributed to the cell theory with his tenet in Latin: "Omnis cellula e cellula", which translates to "All things arise from pre-existing cells".2 This tenet negates the theory of spontaneous generation.
1 Schwann, Theodor. (1839). Microscopic Investigations on the Accordance in the Structure and Growth of Plants and Animals. Berlin. (English translation by the Sydenham Society, 1847)
2 Robinson, Richard. "History of Biology: Cell Theory and Cell Structure". Advameg, Inc. Retrieved 17 March 2014.