Transcript The Cell Theory – a timeline

The Cell Theory
A Timeline
With permission: bujols via Slide Share
Late 1500’s
Late 1500’s
• Hans and Zacharias
Janssen
• Dutch lens grinders,
father and son
• produced first
compound microscope
(2 lenses)
Robert Hooke ( 1665)
• Used light microscope
to look at thin slices
of plant tissues -- cork
• Looked empty, like
monk’s chamber
• Called tiny chambers
“cells”
Anton von Leeuwenhoek (1673)
• Looked at pond water
organisms
• First to see living
microscopic organisms.
• Made careful sketches.
Matthias Schleiden -- 1838
• German Botanist
(studied plants)
• Viewed plant parts
under a microscope
• Discovered that plant
parts are made of cells
• He concluded:
“All plants are
made of cells.”
Theodore Schwann -- 1839
• German scientist who
studied animals zoologist
• Saw that all animals he
studied were cellular so
concluded:
“All animals are
made of cells.”
Rudolf Virchow - 1855
• German physician
who studied cell
reproduction
• “Where a
cell exists,
there must
have been a
preexisting
cell.”
Cells
• A cell is the smallest unit that can perform
all the functions necessary for life.
• All living things are made up of cells.
• Some living things are made up of only
one cell (single cellular).
• Other living things are made up of many
cells (multicellular).
The Cell Theory
• All living things are composed of one
or more cells.
• The cell is the basic unit of life in all
living things.
• New cells are produced from existing
cells.
Cell Similarities
• Cells come in many shapes and sizes with different
duties but …
• All are surrounded with a cell membrane
• All cells have hereditary material (DNA)
• All have cytoplasm and organelles. Cytoplasm
is the fluid within a cell which provides a safe
environment for the organelles. Organelles are
the structures within the cell that have specific
duties to make the cell a functioning unit.
Two Types of Cells
• Eukaryotic
• Are complex and of different types.
• Have a nucleus and many organelles.
• Contain more DNA due to different jobs
within the cell. DNA is linear (in a line).
• Possess a cell membrane or a cell wall.
• All living things other than bacteria.
Two Types of Cells
• Prokaryotic
• Contain no nucleus.
• Have no membrane
covered organelles,
but do have
ribosomes to make
protein.
• Possess circular
DNA.
• Are bacteria.