1. KEY CONCEPT Cells are the Basic unit of life.

2. The cell theory
Many scientists contributed to the cell theory.
More was learned about cells as microscopes improved.
unifying concept of biology. .

3. The Cell theory has three principles.
All organisms are made of cells.

4. The Cell theory has three principles.
All organisms are made of cells.
All existing cells are produced by other living cells.

5. The Cell theory has three principles.
All organisms are made of cells.
All existing cells are produced by other living cells.
The cell is the most basic unit of life.

6. All cells share certain characteristics. Cells tend to be microscopic.
All cells are enclosed by a membrane.
All cells are filled with cytoplasm.
cell membrane
Bacterium
(colored SEM; magnification 8800x)
cytoplasm

7. There are two cell types:
1. eukaryotic cells
2. prokaryotic cells.

8. Eukaryotic cells have a nucleus.
cell membrane

9. Prokaryotic cells do not have a nucleus
organelles
cell membrane

10. Eukaryote have membrane bound organelles
nucleus
organelles
cell membrane

11. Prokaryotic cells do not have membrane-bound organelles.
nucleus
organelles
cell membrane
cytoplasm