The document summarizes the Cell Theory, which states that all living things are made of one or more cells, the cell is the basic unit of structure and function of living things, and all cells come from pre-existing cells. It discusses the scientists whose work contributed to the development of the Cell Theory over many years, including Hooke, van Leeuwenhoek, Schlieden, and Schwann. The document also notes that understanding the Cell Theory helps explain how tissues and organs work and can aid in curing diseases like cancer.

1. Cell Theory
Megan Stanley
BIO 122

2. “If I have seen further, it is only by
standing on the shoulders of giants”
• Isaac Newton
• Science builds
over time

3. What is a cell?

4. Types of Cells

5. Bacteria

6. Blood Cell Nerve Cell

7. Skin Cell Cancer Cell

8. Stem Cell

9. Is a theory a guess?
No, a scientific guess is a
hypothesis. A theory is fact.

10. Cell Theory
•All living things are made up of
one or more cells
•The cell is the basic unit of
structure and function
•All cells arise from pre-existing
cells

11. Who came up with the Cell
Theory?
• Many different scientists over
many years

12. Why do we care?
• To understand how tissues work
• How organs function
• Cure disease, such as cancer
• Cloning

13. The Scientific
“Giants”

14. Robert Hooke (1655)
• Coined the
term “cell”

15. Anton van Leeuwenhoek (1674)
• First compound
light microscope

16. Matthias Schlieden (1838)
All plants are
made of cells

17. Theodor Schwann (1839)
All animals are
made of cells

18. Rudolf Virchow (1839)
Cells can only
arise from pre-
existing cells

19. Bacteria Viruses
Cause disease Cause disease
Have DNA Have DNA
Replicate Replicate
Evolve Evolve
Living Nonliving
Made up of a
cell
Not made up of
a cell

20. Bacterium Virus

21. Why is bacteria considered living,
but a virus considered nonliving?
• A virus is not made up of a
cell