1. Write everything that is BLACK
Section 3-1 “Cells”
Write everything that is BLACK

2. KEY CONCEPT: Cells are the Basic unit of life.

3. Many scientists contributed to the cell theory.
The cell theory grew out of the work of many scientists and improvements in the microscope.
Many scientists contributed to the cell theory.

4. The Cell Theory:
1. All organisms are made of cells

5. 2. All existing cells are produced by other living cells

6. 3. The cell is the most basic unit of life

7. 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

8. There are two cell types: 1. Eukaryotic cells: Have a nucleus
Have membrane bound organelles
Usually multi-cellular
Example:
plants, animals
nucleus
organelles
cell membrane

9. 2. Prokaryotic cells:
Do not have a nucleus
Do not have membrane-bound organelles
Usually single-celled
Example: bacteria
cell membrane
cytoplasm