Cell

1
Cell History
van Leeuwenhoek
Hooke
2
Cell History

• All life is made of cells
• Discovered after microscope invented
• 1665 Robert Hooke first observed cork (dead
  plant bark)
• Cork reminded him of tiny rooms
• He named the empty boxes cells

3
Cell Theory
Schleiden

• Three Parts
• 1) All organisms are made of cells
• 2) The cell is the most basic unit of life
• 3) Cells come from other cells
• Whats the big problem with this theory?

Schwann
Virchow
4
Cell Diversity

• Shape depends upon function
• Nerve Shape Elongated branching
• Function Sends messages to and from brain
• Red Blood Shape Disc-like shape prevents
  clogging
• Function Carries O2 throughout blood
• Skin Shape Flat broad layers overlap
• Function Covers and protects the body

5
Cell Categories

• 1) Prokaryote Cells without a nucleus and other
  membrane-bound organelles
• Oldest cells known (4 billion years old)
• Believed to have evolved first (oldest fossils)
• AKA Bacteria

6
Cell Categories

• 2) Eukaryote Cells with a nucleus membrane
  bound organelles
• More complex cells
• Evolved from prokaryotes
• Ex Protists, Fungi, Plants, Animals

7
Eukaryote Evolution

• Endosymbiosis Theory Chloroplast mitochondria
  were free-living organisms
• Both were engulfed by a larger predator cell
• Both gave the larger cell an advantage (make food
  and energy)
• Predator cell provided each protection
• Over time, these cells could not survive without
  the mitochondria chloroplast
• Evidence Mitochondria chloroplast contain own
  DNA, replicate, contain own ribosomes, make their
  own protein

8
QuickReview

• Cells shape is related to its job (function)
• Cells are the basic units of life
• Cells come from other cells

9
recap

1. Who first identified cells?
2. What was he/she examining?
3. Name the three parts to the cell theory.
4. Explain how the shape of a blood cell allows it
   to perform its job better.
5. Which category of cells contain nuclei?
6. Why are bacteria considered the oldest forms of
   life on Earth?
7. How do prokaryotes and eukaryotes differ?
8. Which organelles are associated with the
   endosymbiosis theory?
9. What evidence exists that the organelles from 8
   were once free-living?