1. Chapter 2.2
What are cells?

2. What are cells?
CELLS- the basic structure in living things is a cell. All living things are made up of one or more cells.
Cheek cells
Fat cells

3. DISCOVERY of CELLS:
The first person to see cells was Robert Hooke, an English scientist. He used a light microscope to look at thin slices of cork.

4. Cork is found in many plans (especially in wooden plants)
Cork is found in many plans (especially in wooden plants). The cork looks like it has many small boxes which he named “cells.” But these were “dead” cells.

5. History (con’t.)
Anton van Leeuvenhoek was the first person who saw living cells in He saw very small things swimming in the water.

6. HISTORY:
In 1838, Anton van Leeuvenhoek , said that all plants are made up of cells. In 1839, Theodor Schwann said that cell is the basic structure in animals. Rudolph Virchow studied cells, and said that cells divide to make new cells.

7. All these ideas were put into a cell theory:
All living things are made up of one or more cells
Cells are the basic unit of life
Cells come from other cells
All these ideas were put into a cell theory:

8. Checking concepts: What is the basic unit of structure in living things?

9. What did Anton van Leeuwenhoek see in a drop of pond water?.

10. Where do cells come from?

11. Review the cell theory:

12. Fill in blanks A human body is made of millions of ______.
The first person to observe and describe cells was ______________.
The dead cells that were first discovered were _____________.
The basic unit of life is _______.
Cells come from ______________.
All living things are made of __________.