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9/8/2013
Cell Theory
What comes to mind when you
think of the term “cell”?
Date: ___________
A Little History…
1590: Ernest
Two Dutch men
• •1939:
•Why do you
think there are
such large gaps
in this history?
invent
the
very
first
Everett
writes
• 1665:
Hooke
1830
–Robert
1855:
• 1880 – 1890:
observes
cork
under a
compound
microscope.
textbook
Biology
Scientists
andvon
coins the Louis Pasteur
• microscope
1683:
Anton
of the
Cell
discover
the(cork
cell
and Robert
term
“cell”.
Leeuwenhoek
Koch began the
Surfaceand
provides
aafter
protective
nucleus
(Dutch)
discovers
insulation
layer
study of
years ofthat
studying
propose
allfor
trees,
protecting it from bacteria.
protozoans
the
structure
and
plants
and animals
water loss,
physical
function
of
cells.
damage,
are
madeand
of pathogens).
cells
Cell Theory
• There are three tenets of the cell
theory:
– All living things are composed of one or
more cells.
– Cells are the basic units of structure
and function in living things.
– All presently existing
cells arose from
previously existing cells.
Think about this...
• Why is it important to study cells?
About the Cell
• It is the lowest level
of structure capable
of life.
• Don’t forget:
– Unicellular organisms
are made up of one cell only.
– Multicellular organisms
are made up of many cells,
like us!
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9/8/2013
Two Major Cell Types
• Prokaryotic cells
• Eukaryotic cells
Prokaryotic Cells
No nucleus
DNA is circular, floats within
cell
Eukaryotic Cells
Nucleus
DNA is arranged into
chromosomes, packaged in
nucleus
No membrane-bound
organelles
No mitochondria – usually
obtain energy from sunlight
or chemicals
Membrane-bound organelles
Contain mitochondria AND
chloroplasts – can get energy
from food and sunlight
Unicellular
Mostly multicellular, some
unicellular
Much smaller than eukaryotic Large size
Ex: BACTERIA
Ex: PLANTS & ANIMALS
BOTH have a cell membrane, DNA, cytoplasm, and ribosomes
Focus Questions
1.
2.
3.
4.
5.
6.
7.
8.
What did Robert Hooke do?
What did Anton von Leeuwenhoek do?
What are the 3 tenets of the cell theory?
What is the lowest level of structure capable of life?
What are unicellular organisms?
Multicellular organisms?
What are the two types of cells?
What are the 5 differences between prokaryotic and
eukaryotic cells?
9. Give me an example of a prokaryotic cell.
10. Give me an example of a eukaryotic cell.
11. What is similar about pro- and eukaryotes?
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