Transcript The Discovery of Cells

The Discovery of
Cells
Light Microscopes
 Anton van
Leeuwenhoek
 The father of microscopy
 Used microscopes to
study microorganisms
 Used a simple light
microscope with one
lens and a light
Light Microscopes
 Compound light
microscope
 Uses several lenses
that can magnify
objects 1500x
 Expanded science
and allowed scientists
to better understand
the organization of
living organisms.
The Cell Theory
 Robert Hooke
 Observed dead cells
of oak bark with a
compound
microscope
 Named box like
structures CELLS
 Cells are the basic
units of all living
things
Robert Hooke’s original image of bark.
Matthias Schleiden
 German Scientist
 In 1830s concluded that
all plants are composed
of cells.
Theodor Schwann
 Made similar
observations
on animals
 Concluded all
animals are
made up of
cells
Rudolf Virchow
 German Pathologist
 “Every cell comes
from a cell.”
Cell Theory
3 main ideas of the Cell Theory
1. All organisms are composed of one or more
cells. Singular cell organisms and Multicellular organisms.
2. The cell is the basic structure and
organization of organisms. No matter how
large an organism, it is made up of cells.
3. All cells come from preexisting cells. A cell
divides to form two identical cells.
Electron Microscopes

Vladimir Zworykin (seated) and
James Hillier demonstrate an
early electron microscope.
 Developed in the 1940s
 Uses a beam of
electrons (not light) to
magnify items as much
as 500,000x allowing a
view inside the cell. This
occurs in a vacuum so
that electrons do not
collide with air particles
2 Types of Electron
Microscopes pg 192
 Scanning Electron
Microscope (SEM)
 Scans cells surface to
provide scientist with its 3-D
shape.
 Transmission Electron
Microscope (TEM)
 Allows scientist to study
structures inside the cell.
2 Basic Cell Types
1. Prokaryotic
– Do not have membrane-bound organelles.
Most unicellular organisms, such as bacteria.
Called prokaryotes.
Organelles are specialized structures
contained within a cell.
2. Eukaryotic
-Cells containing membrane-bound organelles.
Most multicellular organisms and are known
as eukaryotes. Some unicellular organisms
are eukaryotes.
The Nucleus
 Robert Brown
 Scottish Scientist that
observed eukaryotic
cells and noted a
prominent structure.
 Rudolf Virchow
 Concluded that this
structure was
responsible for cell
division. This
structure is what we
now call a nucleus.
Eukaryotic Cels
 Plant Cell
Eukaryotic Cells
 Animal Cell