Timeline of Events
The Cell and The Cell Theory
Chapter 4: Structure and Function
of Cells
Microscopes
- The first compound
microscope was invented
by Zacharias Janssen in
Middleburg, Holland,
around the year 1595.
- A compound microscope
has two lenses.
Jansen’s Microscope
Jansen’s Microscope
• The Janssen microscope
was capable of
magnifying images
approximately three times
when fully closed and up
to ten times when
extended to the maximum.
Light Microscopes
• In 1665, Robert Hooke
looked at a thin slice of
cork from the bark of a
cork oak tree.
• He described “a great
many little boxes” that
reminded him of cubicles
or “cells”.
Robert Hooke’s Drawing
Robert Hooke’s Microscope and
Drawing
Cells
• The “little boxes” that
Hooke observed were the
remains of dead plant
cells.
• Hooke coined the word
“cells” for the structures he
saw under the microscope.
1673 Anton Van Leeuwenhoek
• In 1673, Van Leeuwenhoek
was the first person to view
living cells.
• He called the organisms
“animalcules”.
• We now call them protists.
Anton van Leeuwenhoek
1827 Karl von Baer
• In 1827 Karl
von Baer
discovered
the
mammalian
egg.
• This meant
that animals
had cells.
Plant and Animal Kingdoms
• In the 1800’s all organisms were
placed into only two kingdomsthe Plant Kingdom and the
Animal Kingdom.
• 1838: German Botanist Matthias
Schleiden concluded that all
plants are composed of cells.
• In 1839: German Zoologist
Theodor Schwann concluded
that all animals are composed
of cells.
All organisms are composed of
cells.
• Schleiden’s and Schwann’s
conclusion led to the first
statement of THE CELL
THEORY.
• All Living things are
composed of cells.
Rudolf Virchow 1855
• In 1855, Rudolf Virchow had
evidence that cells came from
other cells.
• This was an astonishing
statement since in the mid1800’s, the controversy over
spontaneous generation had
grown fierce.
• Spontaneous generation states
that life can simply “appear”.
The Cell Theory
• All living things are
composed of cells.
(Schleiden and Schwann)
• Cells are the basic unit of
structure and function in
an organism.
• Cells come from the
reproduction of existing
cells. (Virchow)
The first cell structures- organelles
• 1857 Kolliker describes
mitochondria in muscle.
• Mitochondria are structures
inside of cells where
cellular respiration takes
place.
• Organelles are cellular
structures that perform
specific functions.
Mitochondria inside of cells
1897 Camillo Golgi
• In 1897, Camillo Golgi
discovers the Golgi
Apparatus.
• The Golgi Apparatus is an
organelle that is called the
“packaging plant”.
Electron Microscopes
• Electron microscopes
contributed to our
knowledge of cells.
• E. Ruska made the first
image producing electron
microscope in 1933 and
used it to take pictures of
gold and copper surfaces.
Improving Technology
• Improving technology has
allowed scientists to unlock
the secrets of the cell.
• There are two major types
of electron microscope:
the transmission electron
microscope (TEM) and the
scanning electron
microscope (SEM)
1964 Palade
• In 1964 George Palade
published his work on the
network of membraneous
organelles in cells of the
guinea pig pancreas.
• This network included the
rough endoplasmic
reticulum, smooth
endoplasmic reticulum, the
Golgi Apparatus, and
lysosomes.
1996 - Cloning
• 1996 Researchers in
Scotland clone a sheep
from the adult sheep cell.
2004
• Tissue engineering used to
grow new skin and bone
for transplant.
Timeline of Events
Use this Power Point to create a
timeline.
Microscopes helped biologists
clarify our definition of life.
• All living things:
– Consist of organized parts.
– Obtain energy from their
surroundings.
– Perform chemical reactions.
– Change with time
– Respond to their
environment
– Reproduce
The End