1. Discovery of the Cell and Cell Theory

2. Observations of Dead Cells
Robert Hooke ( )
First to view cells (dead cork cells)
Thought that the “little boxes” looked like the rooms where monks lived (cells)

3. Observations of Living Cells
Anton van Leeuwenhoek ( )
First to observe living cells

4. Observations of Living Cells cont.
Matthias Schleiden ( )
Concluded that all plants were made of cells

5. Observations of Living Cells cont.
Theodor Schwann ( )
Concluded that all animals were made of cells

6. Observations of Living Cells cont.
Rudolf Virchow ( )
Determined that cells only come from other cells

7. The Cell Theory (putting the observations together)
All living things are composed of one or more cells.
Cells are the basic units of structure and function in an organism.
Cells come only from the reproduction of existing cells.

8. Prokaryotic vs. Eukaryotic
All cells fall into one of two categories: prokaryotic or eukaryotic
Prokaryotic cells evolved earlier in history than eukaryotic cells
Prokaryotic cells lack several of the features found in eukaryotic cells
You are eukaryotic.
Your cells have a nucleus and membrane-bound organelles.
Prokaryotic Cell
Eukaryotic Cell

9. Prokaryotes
Eukaryotes

10. Prokaryotic vs. Eukaryotic cont.
Prokaryotic Cell
Eukaryotic Cell
Cell Membrane
May be unicellular
May be multicellular
Has membrane-bound organelles
Has a membrane-bound nucleus
Contains DNA or other genetic info

11. Intro to Cell Structure
Quick Review:
Cells = basic unit of life
Unicellular: the organism is just one cell
Multicellular: the organism has lots of cells, each carries out a specific job
All cells have:
Cell membrane
Cytoplasm (with organelles)
DNA (genetic material)

12. Cell membrane
Thin barrier separating the cytoplasm and contents of the cell from the external environment.
In some cells the membrane is surrounded by a cell wall.
The cell wall is a thick, rigid structure surrounding plant and bacteria cells.

13. Inside a Cell Cytoplasm Nucleus Organelles =
space inside the cell, between the membrane and nucleus that contains a semi-liquid substance and houses the organelles.
Nucleus
spherical organelle that contains the DNA of eukaryotic cells.
Visible in most cells under a light microscope
All plant and animal cells are eukaryotic.
Organelles =
specialized structures that carry out cell functions
Most are not visible using only a light microscope

14. Onion Cells

15. Elodea Cells

16. Cheek Cells