All
living things are made
of one or
more
CELLS.
Some organisms consist of ONE cell
while others have MANY cells.
Regardless of the
number of cells, living
things must carry on all
the life PROCESSES.
This cell is in the
process of cell
REPRODUCTION.
MICROSCOPE was very important to
the discovery of cells.
It was not until the
mid-1600’s that
microscopes were
used to examine
the parts of living
things.

ROBERT HOOKE who examined thin
slices of CORK and other plant tissues.
He found that they
contained BOXLIKE
structures which he
called CELLS.

…DEAD cells.
He never
observed the
cells of living
things.
POND water using a
very powerful singlelens microscope.
Leeuwenhoek also
observed human
BLOOD cells and
BACTERIA which are
the smallest kinds of
cells.

1824 – Henry Dutrochet
 Proposed
that
all living things
were made
from cells.

1831 – Robert Brown

Observed and
named the NUCLEUS

1838 – Matthias
Schleiden

1839 – Theodor
Schwann

Developed the
theory that all plants
contained cells.

Proposed that all
animals contained
cells.


1839 – Johannes
Purkinje
Used the term
“protoplasm” to refer
to the jelly-like
material in a cell.

1855 – Rudolf Virchow

Stated that all living
cells came from other
cells.

1861 – Max Schultze

1861 – Felix Dujardin

Defined “protoplasm”
as the physical basis
of life.

Recognized the
existence of onecelled organisms.
They were also
able to describe
the events of cell
DIVISION in which
one cell splits to
form TWO cells.

The Cell Theory states that….
› All organisms are made of ONE or more CELLS
› All cells carry on LIFE ACTIVITIES
› New cells ARISE only from other LIVING cells
by the process of CELL DIVISION.

The first cell could not have come from a
pre-existing cell.

Although viruses can carry on many life
processes, they DO NOT contain cells

Mitochondria and chloroplasts contain
their own DNA and can reproduce within
a cell.