Lesson #2

How were cells discovered?

Prof. Beatriz Duro SEK Ciudalcampo International School

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…

Cells

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.

Mathias Schleiden

Botanic

Proved that all fragments of plants

have the cells described by Hooke.

Theodor Schwann

zoologist

Proved that all fragments of

animals also have cells.

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

The Cell TheoryLate 19th C.

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

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?

VIDEO

HOMEWORK

Draw, label and describe organelle functions.

HOMEWORK