A. Cell Overview
Cells are the basic units of structure and function in
living things.
Chapter 1: Cell Structure and Function
Cell structure: what it is made of and how its parts are
put together
Ex: human cells form a body with a head, two arms, and two
legs (etc.)
By: Miss Murphy
Cell function: processes that enable it to stay alive
Ex: obtaining oxygen and growing
B. Microscopes
C. Cell Observation
A microscope is an instrument that makes small
objects look larger.
1590- First compound microscope
Zacharias and Hans Janssen made the first compound
microscope using a tube with lens at each end.
The invention of the microscope made it possible for
the cell to be discovered.
1660- Robert Hooke
English scientist who built a compound microscope and
observed a slice of cork
He described the cells as tiny boxes or a honeycomb
He thought that cells only existed in plants and fungi
1674- Anton van Leeuwenhoek
Used a handmade microscope to look at drops of lake
water and found many one-celled organisms
He called them “animalcules”
He also observed blood cells from fish, birds, frogs,
dogs, and humans
Therefore, it was known that cells are found in animals
as well as plants
1839- Theodor Schwann- stated that all animal tissues
are composed of cells.
1858- Rudolf Virchow- concluded that cells must start
from preexisting cells.
D. Development of the Cell Theory
Three German scientists contributed greatly to the
knowledge of cells
1838- Matthias Schleiden- concluded that all plant parts
are made of cells
“All cells come from cells”
E. Cell Theory
F. Properties of Microscopes
The 3 Basic Components of the Cell Theory are:
1. All living things are composed of cells.
Magnification- the ability to make things look larger
than they are
Convex lens- curved lens where the center is thicker
than the ends
Resolution- sharpness or clearness of an image
2. Cells are the basic units of structure and function in
living things.
3. All cells are produced from other cells.
G. Types of Microscopes
Simple light microscope- similar to a magnifying glass
and has only one lens.
Compound light microscope- Lets light pass through
an object and then through two or more lenses.
Electron Microscope- Uses beams of electrons instead
of light
Stereomicroscope- Gives a three dimensional view of
a large object. (lens for each eye)
Compound Microscope
Magnification
The total magnification is equal to the magnification
of the two lenses magnified together
Example:
Eyepiece is 10x
Objective is 40x
Total magnification is 400x
10x X 40x = 400x
Highest possible is 2000x
Microscope Parts