Question

Who proposed the Cell Theory? Explain the main points of this theory as its stands today.

Answer 1

Robert Hook in 1665 first coined the term cell while observing plant cells under a microscope. In 1838, Matthias Jacob Schleiden proposed that all plant tissues are made from cells. In 1839, Theodor Schwann generalized this to all living organisms, proposing that animal tissues also are made from cells and that eggs are also cells as well, with all life starting as a single cell. Rudolf Virchow, in 1858 concluded that all cells come from preexisting cells.

The generally accepted parts of cell theory today include:

(1) All known living things are made up of one or more cells.

(2)All living cells arise from preexisting cells by division.

(3) Cell is the fundamental unit of structure and function in all living organisms

(4)The activity of an organism depends on the total activity of the independent cell.

(5)Energy flow ( metabolism and biochemistry ) occurs within the cell.

(6) Hereditary information ( DNA) is passed on from cell to cell.

(7)All cells have the same chemical composition in similar species.