1. History of the Cell

2. How are these cells the same and how are they different?

3. What is a cell? A cell is the basic unit of life. A cell is a structure within a living thing that has a boundary surrounding the material inside.

4. How small is a cell?

5. How were cells discovered? Scientists were curious about what living things were made of. So they created microscopes to take a closer look at living things.

6. Who were the main people involved in the discovery of cells? Anton van Leeuwenhook Robert Hooke Robert Brown Matthias Schleiden Theodor Scwann Rudolf Virchow

7. Anton von Leeuwenhoek 1600s. First to see and describe cells. Used a simple microscope (one lens). Looked at tiny living organisms in a drop of pond water (“wee beasties”).

8. Robert Hooke 1665. First to use the term, “cells.” Used a compound microscope (2 lenses). Looked at a slice of cork (dead cells). Noted for seeing, describing, and explaining.

9. Robert Brown 1831. First to identify the nucleus. Realized that nucleus was doing something important.

10. Matthias Schleiden 1838. First to conclude that all plants are made of cells.

11. Theodor Schwann 1839. First to conclude that all animals are made of cells.

12. Rudolf Virchow 1855. Cells reproduce: that is where new cells come from. “When a cell exists, there must have been a pre-existing cell…”

13. What is the Cell Theory? 1. All living things are made of cells. (Schleiden = plants, Schwann = animals) 2. Cells are the basic units of structure and function in living things. 3. New cells are produced from existing cells. (Virchow) (Virchow)

14. Prokaryotes and Eukaryotes

15. Word origins eu….. means ‘true’ pro…. Means ‘earlier than’ karyon….. means ‘kernel’ organelle…means ‘mini-organ’

16. Cells Come in a Variety of Shapes and Sizes  Smallest= mycoplasma bacteria (0.2 µm in diameter)  Largest = Chaos chaos amoeba (1000 µm in diameter)  Most cells = 5 to 50 µm in diameter

17. ProkaryotesEukaryotes Size Usually smaller and simpler Usually larger and more complex NucleusAbsentPresent Genetic Material Not in nucleus In nucleus (separate from rest of cell) ExampleBacteria Plants, animals, fungi, protists

19. Prokaryotic Cell Parts: Bacteria