1. Cell tissue organ system
The Cell
Cell tissue organ system
Section 3.1

2. Discovered in 1665
Robert Hooke observed cork cells from a tree

3. The Cell Theory Schleiden, Schwann, & Virchow
All living things are composed of cells
Cells are the basic unit of structure and function in living things
All cells come from pre-existing cells

4. Two Divisions of Cells Prokaryotic Cells Eukaryotic Cells
Lack a true nucleus
Microscopic single celled organisms,
Bacteria
Eukaryotic Cells
Contain a true nucleus

5. Eukaryotes Evolved @ 2 billion years ago
atmosphere needed to contain oxygen

6. Prokaryotic Eukaryotic No nucleus Small No membrane bound organelles
Single circular DNA that is in direct contact with the rest of the cell
True Nucleus
10,000 times larger
Membrane bound organelles
DNA enclosed within nucleus