cell discovery & cell theory. it all started with an invention…. the first microscope...
TRANSCRIPT
It all started with an invention….
The first microscope– Zacharias Jansen, 1595,
Middleburg, Holland– It launched great leaps
in Astronomy and Biology.
– Some of the first great observations with it were made by…
Robert Hooke (1635-1703)
– Designed microscopes– Discovered and documented
the first “cells” in 1665• Named them after the cells in
which a monk sleeps.
From: http://www.ucmp.berkeley.edu/history/hooke.html
Robert Hooke (1635-1703)
Hooke’s drawing of a flea from: http://www.rod.beavon.clara.net/micro1.htm
From the Museum of Natural History website:http://www.natmedmuse.afip.org/explore/micro/hooke.html http://micro.magnet.fsu.edu/optics/timeline/people/hooke.html
Released book of detailed drawings and observations: Micrographia, 1665
Hooke had a life-long rivalry with Sir Isaac Newton. Newton worked hard to destroy his reputation during and after his death. Much of Hooke’s work was destroyed – even his gravesite is still unknown.
Antony van Leeuwenhoek (1632-1723)
A tradesman from Holland who became fascinated with Hooke’s book Discovered bacteria, free-living protists, sperm cells, blood cells, nematodes, etc. Became an expert lens grinder and made
over 500 simple microscopes Acute eyesight and lens grinding skill let him
build microscopes that were capable of 200X magnification
Cell Theory
1838 Mattias Schleiden stated that all plant tissues consisted of cells
1839 Theodore Schwann stated that all animal tissues consisted of cells
Each conjectured that there was a nucleus 1858 Rudolf Virchow combined the two ideas
and added that all cells come from pre-existing cells, formulating the Cell Theory
Rudolf Virchow 1858
Cell Theory All living things are
composed of one or more cells
In organisms, cells are the basic units of structure and function.
All cells are produced only from existing cells.
Modern Microscopes Some of the light microscopes here are capable of
1000x magnification.– That is about the limit of a light microscope’s magnification
without losing clarity (called Resolving Power).• Due to the width of visible light’s wavelength
The electron microscope was introduced in the 1950s and uses the wavelength of electrons to increase the resolving power by 100x. – Approx. 100,000x magnification!!– Cell Biology advanced rapidly as cellular organelles were
clearly seen for the first time.
Transmission Electron Microscope (TEM) magnifies a slice of a sample. (Rabbit trachea cilia)
Scanning Electron Microscope (SEM) shows 3D image of the Rabbit trachea cilia
Modern Microscopes