Cell, Cell is the structural and functional unit of life. This means that it is the smallest thing that can carry out all the activities of life. The branch of biology which deals with the study of cell is called cell biology. Discovery of cell:- Contribution of scientists in the discovery of cell.ROBERT HOOK:- In 1665 Robert Hook first discovered the cell. He described his discovery in his famous book 'Micro Graphiya'. Rober Hook named the cell as cell is the empty space bounded by a thick wall. He obsreved from his own microscope the a piece of bottle cork. There were many small empty spaces Robert named these spaces as cells. Lorenze Occan: In 1805 MR lorenze occan said every living organism orginate from the cell.Jean Baptis-De-Lamark :- In 1809 Mr Lamark said living organism no body can have life constituients of cellular tissue.Robert Brown:- In 1831 Mr Robert Brown discovered the Nucleaus in the cell. This changed the idea of Mr Robert Hook that cell is the empty space.