History of Cells
What is a Cell?
Cell
• A cell has all the items necessary to carry out life’s
activities.
• Every living thing has at least one cell.
• Need a microscope b/c smaller than a period at the
end of a sentence.
Ex. Chicken egg
What does a cell
look alike?
Human red and white blood cells
Human embryo
Mitosis – Cell Division
White cells moving to
attack
A human nerve cell
Human liver cells
Cancer cells in a human liver
Volvox – a protist
Euglena – plant-like
protist
Amoeba
Paramecium –
a protist
Animal-like protist
The largest cell – what is it?
So, who are the
important people in
history and
discovery of cells
Hans and Zacharias Janssen
•Dutch lens grinders, father and son
•produced first compound microscope (2 lenses)
Robert Hooke
• Discovered cells in 1665
• English scientist
• Wasn’t even looking for cells! He was trying to impress other
scientists.
• Made a slide of Cork tree & looked at it with a simple microscope.
• looked at a thin slice of cork (oak cork) through a compound
microscope
• observed tiny, hollow, roomlike structures
• called these structures 'cells' because they
reminded him of the rooms that monks lived in
• only saw the outer walls (cell walls)
because cork cells are not alive
The 1st Cell
• Looked like 100’s of little boxes or honeycomb
• Hooke named them cells, which means “little rooms” in Latin.
• Hooke thought
cells were only in
plants & fungi b/c
they have cell walls.
Anton van Leeuwenhoek
• Dutch fabric merchant and amateur scientist
• 1673
• looked at blood, rainwater, scrapings from teeth through a
simple microscope (1 lens)
• observed living cells; called some 'animalcules' which means
“little animals.”
• some of the small 'animalcules' are now called bacteria
Humans & dogs have
flatter blood cells.
Fish, birds, & frogs
have oval shaped
blood cells.
Matthias Schleiden
• German botanist
• 1838, 2 centuries later, realized that all living things
had cells by looking at plants.
• viewed plant parts under a microscope
• discovered that plant parts
are made of cells
“Hmmm…do all the
parts of a plant have
cells?”
Theodor Schwann
•
•
•
•
1839
German
Found that all animals have cells
Co-wrote the Cell Theory w/ Rudolf Virchow.
“Animals are full of
cells!”
Rudolph Virchow
•(1855)
•German doctor, anthropologist, public health
activist, pathologist, pre-historian, biologist
and politician.
•stated that all living cells come only from
other living cells
•He is referred to as the "Father of
Pathology".
Other important dates:
1830 – Joseph Jackson Lister – invent
prototype for the compound microscope
1932 – Frits Zernike invented the phasecontrast microscope. The phase-contrast
microscope that allowed for the study of
colorless and transparent biological
materials
1931 – Ernst Ruska and Max Knoll invented
the electron microscope. Electron
microscope make it possible to view objects
as small as the diameter of an atom.
1981 – Gerd Binnig and Heinrich Rohrer
invented the scanning tunneling
microscope. The scanning tunneling
microscope that gives three-dimensional
images of objects down to the atomic level.
Lynn Margulis
• Theory-believes that onecelled organisms gave rise to
the cells we have today.
• Her theory is that 1.2 billion
years old larger cells began
eating smaller cells
Ex. White blood cells and
other cells
• But, some small cells resisted
and changed the larger cell.
Robert Brown
•Around 1833 reported the discovery of the nucleus.
•Brown was a naturalist who visited the "colonies of
Australia" from 1801 through 1805, where he
cataloged and described over 1,700 new species of
plants.
The Cell Theory
The modern tenets of the Cell Theory include:
1. all known living things are made up of cells.
2. the cell is structural & functional unit of all living
things.
3. all cells come from pre-existing cells by division.
(Spontaneous Generation does not occur).
4. cells contains hereditary information which is
passed from cell to cell during cell division.
5. All cells are basically the same in chemical
composition.
6. all energy flow (metabolism & biochemistry) of life
occurs within cells.
2 Types of Cells
Prokaryotic
Cells
• No nucleus
• No membrane covering the
organelles
• Circular DNA
• Bacteria
Eukaryotic
Cells
• Nucleus
• Membrane covering the
organelles
• Linear DNA
• Are all other cells
Hereditary Material
• DNA- deoxyribonucleic acid
• Controls all the cells activities
• Contains the info. for making new cells.