Lesson 1 discovering the cell
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Transcript of Lesson 1 discovering the cell
LESSON #1What is so extraordinary about the organizationof living organisms?
DISCOVERING THE
CELL
The unit of life
Levels of
biological
organizatio
n
Before the 1800s
How were cells discovered?
Discovering the principles of the
microscope
In 1590, Zacharias
Janssen, a Dutch
eyeglass maker.
2 overlapped lenses
increase magnification
Anton Van Leewenhoek (1632-
1723)
Father of microbiology
First to observe living
organisms smaller than
what the human eye can
see.
Robert Hooke
Scientist
Made an improved
microscope.
First used the word
“cell” to indicate what
living beings are made
of.
What Hooke saw…
A pause
In the following
years Hooke’s
discovery didn’t
have much influence
in science.
S. XVII y XVIII
Scientists were
focused on
classifying new
species discovered
by explorers.
In the early 19th Century they had a revolutionary idea in Germany.
Living things are
made of living
units
They started studying plants and animals at a microscopic level again.
Both came up with a theory that said that all organisms come from a cell and
develop from there by the formation of new cells. CELL THEORY.
18381839
All living things are formed by one or more
cells
A cell is the smallest and simplest living
thing.
All cells come from other pre-existing cells.
All cells can function independently,
although they work together in a coordnated
way when part of an organism.
One cell can perform all living functions : nutrition,
reproduction and interrelation
How large are things really?
Microscopic objectsare meassured in:
μm = 10-3 mm
Nm = 10-6 mm
Not visible with a naked eye.
Eye resolution is 0,2 mm
If two objects are separated by a smaller distance, wewill see them as one.
Exercise 1:
If an object meassures1 mm, how manymicrometers does itmeassure? And howmany nanometers?
Exercise 2
Paramecium caudatum magnified 300 times
3.6 cm
What is the size of the
paramecium?
Could we see it with
our naked eye?
20th Century interest: The cell
1930 invention of
the Electron
Microscope:
uses electrons
instead of light.
Resolution 0,5 nm.
Allows to see cells in
detail.
Electron Microscope Images
What do you think this is? And this?