Cell Theory

Cell Theory!

2.1.1: outline cell theory

The Cell Theory was developed and includes the following elements:

• Cells are the smallest units of life.
• Cells only come from pre- existing cells
• All living organisms are composed of cells

2.1.2 Discuss the evidence for the cell theory

Idea: All living things consist of cells

Evidence: Since the time of Robert Hooke, huge numbers of tissue samples from many different organisms have been examined using microscopes and have been found to consist of cells.

Idea: Cells are the smallest unit of life

Evidence: Experiments have taken place where the cell membrane is bust open and its subunits are seperated in a centrifuge, and the subunits don't survive for long by themselves.

Idea: All cells come from pre-existing cells

Evidence: Experiments can be done using materials that can sustain the growth of living cells, and if in these environments all cells are killed and no new cells enter, no cells develop from the non-living material.