1. Cell Theory 7.1 Questions of the day!
What are the seven characteristics of life?
Cells have a specific set of rules that they always follow. What do you think they are?
How can scientists determine what these rules are? What tools might they use?
How is a theory different from a hypothesis? Why would the rules for cells be called “cell theory”?

2. Cell Theory 7.1
Cells discovered by Robert Hooke in by looking at cork.
Named cells because they looked like rooms (cells).
50 years later, animal cells were found.
Robert Hooke's cells

3. Cell Theory 7.1 Brain cells
We have learned that life requires 7 characteristics in order to be considered living.
Likewise, cells have rules that they ALWAYS follow
Brain cells

4. Cell Theory 7.1 Cell Theory
Series of statements that ALL cells follow.
All organisms are made of cells.
Cells are the basic unit of organization in an organism.
All cells are derived from existing cells.

5. Cell Theory 7.1

6. Cell Theory 7.1 Microscopes Compound light microscope
Light and lenses used to magnify
1000 x is the greatest magnification
Doesn’t kill the specimen
Eye lens x objective lens = total magnification
10 X x 10X = 100X

7. Cell Theory 7.1

8. Cell Theory 7.1 Plant Cell – light microscope
Bacteria – light microscope

9. Cell Theory 7.1 Electron microscopes Use electrons to magnify
Specimens are blasted with electrons
Image projected on a screen

10. Cell Theory 7.1 Transmission electron microscope (TEM) Cells are dead
View internal structures
500,000 X greatest magnification
Scanning electron microscope (SEM)
Look at surface structures
Kills cell
250,000 X magnification

11. Cell Theory 7.1 TEM Image of a cell
SEM Image of a Tardigrade (color was added)

12. Cell Theory 7.1 Scanning tunneling electron microscope (STEM)
Doesn’t kill
Looks at atoms and DNA
STEM Image of DNA

13. Cell Theory 7.1 Cell Types There are 2 types of cells
Prokaryotic are simple (bacteria)
Eukaryotic are complex (plants and animals)
Both have similarities and important differences

14. Cell Theory 7.1 Prokaryotic and Eukaryotic Cells both have... DNA
Ribosomes/Protein
Membrane
Phospholipid bilayer (Controls what goes in and out of cell)
Follows cell theory
Form follows function – shape determined by job.

15. Cell Theory 7.1 Prokaryotic Cells Small Bacteria No Nucleus
No membrane bound organelles
Circular DNA (plasmid)
Divides through binary fission

16. Cell Theory 7.1 Eukaryotic Cells Have a Nucleus
Have membrane bound organelles
Undergoes mitosis
DNA is linear
Complex
Plants and Animals

17. Cell Theory 7.1

18. Cell Theory 7.1 CONCLUSION!
Cells allows follow the rules of cell theory
Microscopes show scientists how cells function and what small structures on organisms look like
There are 2 main cell types that have similarities but important differences.
Prokaryotic cells are simple
Eukaryotic cells are complex

19. Cell Theory 7.1
TASKS!
Draw a prokaryotic and eukaryotic cell labeling the main differences.
If you encountered an alien cell, discuss how you would tell if it was a prokaryotic or a eukaryotic cell.
What is “cell theory”? What does it state?