1. Cell Theory

2. In The Beginning...
In the beginning, the majority of the population believed in the idea of spontaneous generation.
Spontaneous Generation : The belief that life can arise from inanimate objects.
However, today we know this to be false!
Why?! 2

3. But, what is the Cell Theory?
A number of different scientists were involved in establishing the Cell Theory.
Each one contributed a little more to the theory we know today.
But, what is the Cell Theory? 3

4. The Cell Theory has 3 Principles…
Principle 1: All living things are made of one or more cells.
Unicellular (made of one cell)
Multicellular (made of many cells)
HINT: IF IT HAS A CELL/CELLS, IT IS A LIVING THING. 4

5. The Cell Theory
Principle 2: Cells are the most basic unit of how an organism is built and how it functions.
(In other words..Nothing simpler than a cell has all of the characteristics of life.) T 5

6. The Cell Theory Principle 3: All cells come from pre-existing cells.
IN OTHER WORDS… All cells develop from other cells due to cell division. 6

7. Redi, Set, Go!
Francisco Redi was the first scientist to formally question spontaneous generation.
In 1638, Redi observed that maggots appeared on meat that was left out overnight.
He performed an experiment to see if rotted meat could produce maggots.

8. The Path To The Cell Theory
From there, the cell theory began to grow from the work and research of many scientists.
More was learned about cells as microscopes improved over the years. 8

9. Robert Hooke Used a light microscope to look at plant tissue.
Noticed that a piece of dead cork had tiny chambers.
Called them cells because they looked like the cells of a monastery.
Hooke's Microscope
Hooke's Drawings 9

10. Anton van Leeuwenhoek
One of the first people to use a microscope to study living things in nature.
Able to see things that no one had seen before.
First person to see the tiny organisms living in pond water. 10

11. Other Important Scientists
Matthias Schleiden
All plants are made of cells.
Theodor Schwann
All animals are made of cells.
Rudolf Virchow
Looked at how cells reproduce.
Cells come from cells that already exist. 11

12. The Classification of Cells
Now that these scientists discovered cells, they needed a way to classify(distinguish between) them.
There are two types of cells:

13. Prokaryotes vs. Eukaryotes
Eukaryotes are/have:
Big
Ribosomes
Complex
Membrane-bound organelles
A Nucleus
The nucleus houses the cell's DNA.
The nucleus is the control center of the cell.
Prokaryotes are/have:
Small
Ribosomes
Simple
Naked DNA
There isn't a need for a control center because the cell is so small!