Download Part 2 = Cytology: History and Intro Info File

1. Who invented the first compound light
microscope and when?
2. Why is Robert Hooke a significant
individual in biology? When did he do his
work?
3. Why is Antonie van Leeuwenhoek
a significant individual in biology? When
did he do his work?
4. What is the Cell Theory and what does it
state?
5. What is Cell Differentiation?
Part 2:
CYTOLOGY
1. History of Cytology
a. 1590 - Dutch spectaclemakers, the Janssens, = first
version of a compound light
microscope.
b.
Robert Hooke
• In 1635, Robert Hooke
observed a thin slice of
cork using a primitive
microscope.
• Called the compartments
he saw “CELLS” = 1st
to use the term.
Cell History
• Cork cells as
diagrammed
by Robert
Hooke
Photo of Actual Cork Cells 400X
c. Anton Van Leeuwenhoek
*1675 - created an improved
microscope to observe water and
tissue samples. He called many
unicellular organisms “animalcules “
• “Father of Microbiology”= First to
observe and create figures of many
living cells of organisms previously
unseen by the unaided eye.
Van Leeuwenhoek
d. Current Tools of Cytology :
1. Compound Light Microscopes
*A type of optic microscope
* 2 lenses to magnify
* Light must pass through the specimen
*highest magnification =1500X -2000X.
2. Electron Microscopes
*uses a particle beam of electrons to
create a highly-magnified image.
*can magnify up to 1 million times
larger than actual size.
Electron Microscopes
Electron Microscope
Bacterial Cells 10,000X
Electron Microscope Image of DNA
Electron Microscope Image of
Pollen
Electron Microscope Images of
Eyelash Mites
2.Cell Differentiation=
All organisms begin as a single cell. In
multicellular organisms, cell’s become
specialized to perform specific
functions for the organism.
Fat Cells
*Muscle Cells
*Nerve Cell
*Blood Cells
RED BLOOD CELLS
A White Blood Cell
Among Red
*Reproductive Cells
Egg Cell
Sperm Cells
3. The Cell Theory
a. All living things have at least 1 cell.
b. Cells are the basic units of structure
and function in an organism.
c. Cells come only from other cells
The Myth = Spontaneous
Generation
The idea that some living things
originated from unrelated and
sometimes nonliving entities.
*first proposed by Aristotle
*first tested by Francesco Redi (1668)
Francesco Redi
In one experiment, Redi took six jars, which he divided in
two groups of three: in the first jar of each group, he
put an unknown object; in the second, a dead fish; in
the last, a raw chunk of veal. Redi took the first group
of three, and covered the tops with fine gauze so that
only air could get into it. He left the other group of jars
open. After several days, he saw maggots appear on
the objects in the open jars, on which flies had been
able to land, but not in the gauze-covered jars.
*Officially rejected after Louis Pasteur’s
experiment in 1859
*Pasteur developed the
Theory of BIOGENESIS
life comes only from preexisting life.
=
4. Types of Cells
a. Prokaryotic
* Unicellular organisms only=
Kingdom Archaebacteria
Kingdom Eubacteria
* Lack membrane-bound organelles
* Have a cell membrane, DNA,
RNA, Cytoplasm, and ribosomes
PROKARYOTIC CELLS
b.
Eukaryotic
* In Unicellular and multicellular
organisms (All Kingdoms (=4) of Domain Eukarya)
* Have membrane-bound organelles
along with a cell membrane, DNA
in a nucleus, RNA, cytoplasm, and
ribosomes.
EUKARYOTIC CELLS