Cells: Structure & Function
All Living Organisms are Made Up of Units Called Cells
- Cell theory:
- All living creatures are made from 1 or more cells
- All cells are produced from previously existing cells (no spontaneous generation)
- All cells appear to be descended from the first cell which existed about 4 billion years ago
- For a species to exist its reproductive cells must be potentially immortal (no aging)
- Our bodies start from a single cell and contain about 100,000,000,000,000 (10^13) cells at maturity
There Are 2 Basic Types of Cells: Prokaryotic and Eukaryotic