Who proposed the cell theory and explain the theory? Also, name the scientist who expanded this theory.

Cell theory:

1. Matthias Schleiden, a German botanist, and Theodor Schwann, a British Zoologist formulated the cell theory in the mid-nineteenth century.
2. In 1838 Schleiden was the first to state that cells are building blocks of plants.
3. These discoveries led to the formulation of cell theory.
4. But the cell theory failed to explain how the new cell arises from pre-existing cells.
5. In 1855, Rudolf Virchow, a German physiologist, stated that ‘Omnis cellula e cellula' means that new cell arises from pre-existing cells.

Cell theory postulates:

1. The cell is the structural and functional unit of life.
2. All living organisms are made of cells.
3. All cells arise from pre-existing cells expanded by Rudolf Virchow in 1858.