Who and when proposed cell theory. What are salient features of it? (AS 1)

i. In 1838, Matthias Schleiden, a German botanist, examined that plants are made up of cells.

ii. Theodore Schwann (1839), a British Zoologist, examined that animals are also made up of cells.

iii. Later on, Rudolf Virchow (1855) explains that cells arise from pre-existing cell through the process of division. He modified the hypothesis of Schleiden and Schwann to give the cell theory a final shape.

iv. Cell theory as understood today is based on two basic features:

(i) All living organisms are composed of cells and product of cell.

(ii) All cells arise from pre-existing cells.