Mrs. Stewart
Central Magnet School
Honors Biology
 Robert
Hooke
 Used an “early” Light Microscope to
observe dead “cells” in bark of a Cork
Oak tree
He coined the
term “cells”
because he
described what
he saw as “many
little boxes”
that reminded
him of the
cubicles, or
cells, where
monks live.
 Anton
Van
Leeuwenhoek

Made microscopes
– able to grind
lenses to increase
magnification to
10x Hooke’s
microscope
First to observe
living cells


Spyrogyra genus –
type of algae
Termed them
Animalcules
(protists)
 All
living organisms are composed of one or
more cells


Matthias Schleiden – plants
Theodor Schwann – animals
 Cells
are the basic units of structure and
function in an organism
 Cells
come only from the reproduction of
existing cells

Rudolf Virchow
 Microscopes
are why scientists were able
to stop speculating and start observing
and exploring the “unseen” world of living
and non-living things.
 Microscopes helped scientists clarify our
definition of life
 Consist
of cells
 Cells display organization
 Obtain and use energy to perform chemical
reactions (metabolism)
 Change through time (adapt)
 Respond to their environment/stimulus
 Reproduce
 Growth and development
 Homeostasis
 Shape

Cell shapes
reflect the
different
functions
of cells
 Size

A few cells are large enough to be seen by the
“naked” eye
 Surface
size.


area-to-volume ratio determines cell
All materials needed by the cell must enter
and exit through the surface (cell
membrane/wall)
 Nutrients come in
 Wastes are excreted out
As a cell becomes larger, the volume increases
more than the surface area. There is a point
where there is not enough surface area to
sustain transport in/out of necessary materials
to keep up with volume of cell.

Prokaryotes





Smaller
No nucleus, but a
nucleoid
DNA is in one circular
chromosome
No plasma membrane
No membrane bound
organelles
Pro = NO

Eukaryotes






Larger
Nucleus
Plasma membrane
Membrane bound
organelles
Organelles carry out life
processes within cell
DNA in multiple
chromosomes within
nucleus
Eu = DO
 Cell
wall
 Large central vacuole
 plastids