Question

Briefly describe the cell theory.

Answer 1

Schleiden and Schwann together formulated the cell theory (1838 - 39). This theory, however, did not explain how new cells were formed. Rudolf Virchow (1855) first explained that cells divided and new cells are formed from pre-existing cells (Omnis cellula-e cellula). He modified the hypothesis of Schleiden and Schwann to give the cell theory a final shape. Cell theory as understood today is

1. All living organisms are composed of cells and products of cells.
2. All cells arise from pre-existing cells.