1. Presented by Kesler Science
Cell Theory
Created by Kesler Science – More 5E lessons at KeslerScience.com
Presented by Kesler Science

2. Essential Questions: What is the cell theory?
What are similar functions of all cells?

3. Quick Action – INB Template
Cell Theory
Robert Hooke
Matthias Schleiden, Theodor Schwann, & Rudolph Virchow
Cell Theory INB Template
Cut out the Template on the solid lines
Glue outside tabs into notebook
Opens like windows
Write notes underneath window panes
What is the cell theory?
What are the 2 main types of cells?

4. Cell Theory
Cell
Smallest structural and functional unit of an organism
Usually microscopic
Contains cytoplasm and a nucleus enclosed in a membrane
Two main types of cells:
1. Prokaryotic (no nucleus)
2. Eukaryotic (has a nucleus)

5. Robert Hooke Cell Theory 1665
Observed bark of cork trees under a microscope
Thought the objects looked liked individual rooms in a monastery, which were called cells
Called his discovery cells
Did not know their true function
1665
Cork Cells

6. Anton van Leeuwenhoek Cell Theory
Developed the microscope lens to see greater magnification
First person to observe bacteria and protozoa (single-celled animal)
Observed and described red blood cells
1670

7. Mathias Schleiden Cell Theory
Concluded all plant tissues are composed of cells
Declared that the cell is the basic building block of all plant matter.
Sensed the importance of the nucleus of a cell
1838
Plant Cell

8. Theodor Schwann Cell Theory
Concluded that all animal tissues are composed of cells, too.
Collaborated with Schleiden to form a new theory in biology
1839
Animal Cell

9. Cell Theory Cell Theory
Schleiden and Schwann’s ideas became known as the cell theory.
All organisms are composed of cells.
Cells are the basic unit of life.
This theory was as important to biology as the atomic theory was to chemistry.
There was one more piece of the puzzle to cell theory. Where did these cells come from?

10. Rudolph Virchow Cell Theory
Proposed that all cells result from the division of previously existing living cells
This idea became a key piece of the modern cell theory.
1855

11. Cell Theory Modern Cell Theory All organisms are composed of cells.
Cells are the basic unit of life.
All cells come from the division of previous existing cells.

12. Quick Action – Cell Theory
That’s a lot of scientists to remember with very long names. Work with a partner and come up with some sort of device to remember the importance of each one in the development of cell theory.
Share your creative device with the class.
Robert Hooke – named the cell base observations on cork bark
Anton van Leeuwenhoek – improved the microscope and observed bacteria and one-cell animals
Mathias Schleiden – all plant tissue is made of cells
Theodor Schwann – all animal tissue is made of cells
Rudolph Virchow – all cells come from preexisting cells

13. Cell Theory Functions of Cells
Metabolism- chemical reactions inside the cell
Response – perceiving and responding to changes in the environment
Homeostasis – keeping conditions inside the organism within tolerable limits (balanced)
Metabolism
Response
Homeostasis

14. Functions of Cells (continued)
Cell Theory
Growth
Reproduction
Functions of Cells (continued)
Growth – increase in size
Reproduction – producing offspring (sexually or asexually)
Nutrition – Obtaining food to provide energy for growth
Defense – protection against enemies
Defense
Nutrition

15. Quick Action – Cell Theory
Let’s see how good you memory is. There were 7 cell functions listed on the last two slides. Have your teacher give you another peek at them and then write down as many as you can remember.

16. Check for Understanding
Can you…
Recognize that according to cell theory all organisms are composed of cells?
Recognise that cells carry on similar functions.
Clear up any confusion and answer questions.