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Aim: How was the cell theory
developed?
CHARACTERISTICS OF
LIFE

Cells:

Metabolism:

Homeostasis:

Reproduction:
What instrument was vital for
scientists to discover and learn about
cells?
Light
Microscope
A light microscope can magnify objects
up to 1000 times.
This instrument allows scientists to see
larger parts of a cell (cell membrane,
nucleus, chromosomes, etc…)
Anton van Leeuwenhoek
1600’s
Spiral Bacteria
Developed simple light
microscopes that allowed him to
examine tiny things.
Human Sperm
Robert Hooke(1665)
What is this?
First Compound
Microscope
CORK CELLS
First person to
use the word
“cell”
Matthias Schleiden (1838)
ALL PLANTS ARE MADE OF
CELLS
Theodor Schwann (1838)
ALL ANIMALS ARE MADE UP OF
CELLS
Rudolf Virchow (1858)
CELLS COME FROM
PRE-EXISTING CELLS
Cell theory
 All
living things are made of
cells
 Cells are the basic unit of
structure and function
(metabolism)
 New cells come from preexisting cells
What are some problems
with the Cell Theory?
 Are
viruses living?
 Where did the first cell come
from?
 Mitochondria and Chloroplast
can reproduce on their own.
Viruses
They are not made up of cells,
but are they living?
What do you know
about viruses?
They
can make
you very sick
They can be
transmitted from
person to person
There are
different types of
viruses
HOW BIG IS A VIRUS?
Too small to be seen with a
light microscope
•They are
microscopic and
smaller than cells!
Electron Microscope
Used to view extremely
small structures inside cells
& viruses
 Utilizes an electron beam
instead of a light beam
 Can magnify up to a
million times
 Subject must be dead
and dry

How can we determine if a virus
is living or non-living?
Is it made of cells?
 Does it maintain homeostasis?
 Does it carry out metabolism?
 Does it reproduce?

Is a virus living or non
living?
Introduction to Viruses Video
What do all cells have in
common?
Cell membrane –
gives shape to the
cells and allows
things in and out.
 The cytoplasm –
the jelly like
material where all
cell parts are found

Light Microscope
 Our
microscope
has a maximum
magnification of
400x.
 Useful for viewing
larger organisms
like bacteria and
paramecium.
What happened here?
Why does a doctor stick a
swab inside your mouth?
Cultures are used to grow
bacteria. The jelly at the
bottom is called agar. Why do
we need agar to grow bacteria?
What’s the difference?
What if you want to separate a
mixture?
Use A
Centrifuge
Janet Plowe
Cell Membrane
Gives shape and controls
what comes in and out