1. Discovering Cells (p. 4)
CELLS - The cell is the basic unit of structure and function in all living things.

2. Cell
Definition – The cell is the basic unit of structure and function in all living things.

3. 2 Types of Cells Prokaryotic – no nucleus or organelles
Ex. Bacteria
Eukaryotic – have a nucleus and organelles
Ex. Plant and Animal cells

4. How do we know cells exist?
Invention of the microscope made it
possible for people to discover and
learn about cells – around 1590

5. Cell Size Most cells are too small to be seen without a microscope.
It would take 50 human cells to cover the dot on the letter i.

6. A Few Large Cells
Most cells are very small but a few are the size of the yolk of a chicken egg

7. Many Small Cells
The physical reason why most cells are so small is because cells take in food and get rid of wastes through their outer surface.
The area of a cell’s surface – compared with the cell’s volume – limits the cell’s size.

8. How do we know cells exist?
Robert Hooke – 1663
Used a compound microscope to
look at cork and called the small
structures inside the cork, cells.
Anton van Leeuwenhoek
1st person to view microorganisms.
Used a simple microscope – with one lens.

9. Robert Hooke without his wig

10. Robert Hooke’s drawing of cork cells – “small rooms”
What was important about Hooke’s work?
Answer in your book
He was the first to see the remains of cells. He gave “cells” their name.

11. Leeuwenhoek and his microscope 1632-1723
1674

12. Leevenhook’s Microscope
Very small and hard to use.
Magnification x. 
Using his simple microscope, Leeuwenhoek was able to discover the existence of single-celled organisms he called, "animalcules“ – meaning “little animals”
We call them microorganisms.
He saw animalcules in lake water, scrapings from teeth and gums and water from rain gutters

13. What did Leeuwenhoek’s observations reveal?
Answer in your book!!
living things moved and were smaller than the eye could see.

14. Mirrors…
Hooke did what?
Leeuwenhoek did what?
Teach…okay!

15. German Scientists developed the cell theory
Virchow
Schleiden
Schwann

16. What is the cell theory?
The cell theory is a widely accepted explanation of the relationship between cells and living things.

17. CELL THEORY
All living things are composed of cells Schleiden (plant cells) and Schwan (animal cells)
Cells are the basic unit of all living things.
All cells come from existing cells (Virchow).

18. To which part of the cell theory did Virchow contribute?
Book question:
All cells come from existing cells.
Show the wacky history of the cell theory
Fill out book info

19. How do microscopes work?
Some microscopes focus light through lenses to produce a magnified image, and other microscopes use beams of electrons.

20. How do Microscopes Work?
Write this…
Lenses – bend the light that passes through them -this magnifies the object

21. How do Microscopes Work?
Magni = “great” or “large
Underline all the words with that prefix in it on page 8.
Figure 3 – what are they??

22. Compound Microscope Magnification
Compound microscopes magnify an image using 2 lenses at once
One lens is fixed in the eyepiece
Second lens is chosen from a group of lenses attached to a revolving nosepiece

23. Compound Microscope Magnification
Light passes through the specimen and the lens near it
Then the 2nd lens near the eye magnifies the enlarged image even more

24. Compound Microscope Magnification
Total magnification is equal to the magnification of the two lenses multiplied together

25. Compound Microscope Magnification
Figure 4: look at picture:
1. Calculate the three total magnifications possible for this microscope
10x4=40x
10x10=100x
10x40=400x

26. Compound Microscope Magnification
2. Predict What would happen if the object on the slide were too thick for light to pass through it?
Light would not reach the lenses, so you would not see anything except darkness.

27. Resolution
Another term for sharpness of an image (write this in your book)
Better resolution shows more detail.

28. Electron Microscopes
Use a beam of electrons instead of light to produce a magnified image
Can magnify up to 10,000,000x
Image of a yellow mite and needle and thread

30. Assess your Understanding 2a
Magnification makes objects look than they really are.
larger

31. Assess your Understanding2b
The diameter of a microscope’s field of view is estimated to be .9mm. About how wide is an object that fills two thirds of the field?
.6mm

32. Assess your Understanding 2c
How are magnification and resolution different?
Magnification makes objects look larger. Resolution shows more detail.

33. Cell Organization “The Building Blocks”
Cell - the basic unit of life
Tissue - similar cells working
together
Ex. Blood, muscle, bone
Organ – a group of tissues working
Ex. Heart – made of blood, nerve, and muscle tissue
Organ System – several organs working together
Ex. Heart and blood vessels make circulatory system
Organism – Organ systems functioning to keep
organism alive
Ex. Roots, stems, and leaves help keep plant alive

34. Gigantiops destructor, a tropical ant, as seen under a scanning electron microscope.