1. The Cell Theory

2. Main Questions
Where do cells fit in to the organization of living things?
What are the main ideas of the cell theory?
Describe the major differences between prokaryotes and eukaryotes.
How has the meaning of the word “cell” changed since the time of Robert Hooke?
What is the function and structure of the cell membrane and the cell wall?

3. Levels of Biological Organization

4. The Cell Theory All living things are made of one or more cells.
Cells are the basic units of structure and function for all living things.
All cells come from preexisting cells (reproduction).

5. Robert Hooke – early 1800s
First to see cells in a microscope. He examined cork cells under a microscope

7. There are two basic types of cells
Prokaryotes – earliest type of living cell, smaller than eukaryotes; no nucleus; DNA is free-floating in the cell
Eukaryotes – have a membrane enclosing their DNA (nucleus); more complex structure; larger
Organisms can be unicellular OR multicellular.

8. Prokaryotes

9. Eukaryotes

10. Cell Membrane

11. Cell Wall