The Cell and Cell Theory

1. The Cell and Cell Theory Robert Hooke Louis Pasteur

2. Teachers – Before viewing the slide show, right click on the document below. Go to “Document Object” and select “Open”. Print out worksheet and have students complete while viewing the PowerPoint.

3. History In the early 1600’s, around the same time as the pilgrims were coming to America, the art of glassmaking was greatly improving. By the middle of the 1600’s a new invention called the microscope was created using two glass lenses and a light.

4. Robert Hooke looks at a piece of cork In 1665 Robert Hooke used a microscope to look at a thin slice of cork. This is what he saw. What does it look like to you?

5. What are those little rooms? To Robert Hooke those little boxes looked like tiny rooms. He called these tiny rooms “Cells.”

6. Where else can we find cells? If you were Robert Hooke’s assistant, where would you tell him to look next?

7. He looked at other trees’ bark. Guess what he found. He found Cells He looked at leaves. Guess what he found. He found Cells

8. He looked at his hair…He looked at his skin…He looked at a rock… He found Cells He found Cells He did not find Cells

9. He looked at some metal…He looked at some water…He looked at a cat’s blood…He looked at a piece of wood... He did not find Cells He did not find Cells He found Cells He found Cells

10. Why did he find cells in some places but not in others? 1. All living things have cells.

11. Not only do all living things have cells, but they are made of cells. What’s the difference? You all have a nose but are you made of noses?

12. 2. The cell is the smallest living thing that can perform all the functions of life. • It grows, develops, and dies • Uses energy • Needs water • Responds to changes in its environment • Gives off waste • Reproduces

13. Science Headline NewsYear 1850 Scientists prove that Maggots come from dead meat… Dr. Scientist proved that maggots come from dead meat. After leaving meat out in his laboratory Dr. Scientist noticed that small maggots were found crawling out of the meat. Dr. Scientist said this proves maggots come from meat.

14. Do you believe that maggots come from meat? Louis Pasteur did not believe this. How could he prove Dr. Scientist wrong?

15. Pasteur’s experiment Pasteur covered up some meat and left it out. Do you think maggots would be found inside his meat? No.

16. Pasteur concluded that fly’s were landing on the meat and laying eggs on the meat. When the eggs hatched the maggots came out. 3. Cells come from other cells from the same species.

17. Summary • The cell theory consists of three basic points: • All living things are made of cells. • The cell is the smallest living thing that can perform all the functions of life. • All cells must come from preexisting cells.