The Cell

1
The Cell

• Cell tissue organ system

Section 3.1
2
Discovered in 1665

• Robert Hooke observed cork cells from a tree

3
The Cell TheorySchleiden, Schwann, Virchow

1. All living things are composed of cells
2. Cells are the basic unit of structure and
   function in living things
3. All cells come from pre-existing cells

4
Two Divisions of Cells

• Prokaryotic Cells
• Lack a true nucleus
• Microscopic single
  celled organisms,
• Bacteria
• Eukaryotic Cells
• Contain a true nucleus

5
Eukaryotes

• Evolved _at_ 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