Cell Theory
Section 3.1
1
Vocab and Main Concept
• Cell Theory (p. 71) – Very important concept!
– Know all parts
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•
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Cytoplasm (p. 72)
Organelle (p. 72)
Prokaryotic cell (p. 72)
Eukaryotic cell (p. 72)
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A
Neuron
Scalded Skin
Cell
White Blood Cell
Red Blood Cells, normal
and sickle cell
Chagas Disease
Myocardial cells through a
light microscope
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Cell Theory
• The cell theory grew out of the work of many
scientists and improvements in the
microscope.
• These are some of the names associated with
the development of Cell Theory.
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Cell Theory – First Microscope
The development of the
microscope opened our minds to a
world that until then, was
unimagined. We suddenly were
seeing strange, living, things in our
water, our food, and throughout
our environment.
This is the first compound microscope,
credited to Zacharias Jansen, a teenager
at the time. Some give an assist to
Hans, his father.
The microscope’s invention was in
1590 and could have been given to
a number of men – including the
inventor of the telescope (Hans
Lipershey). At the time, Holland
was the center of science.
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Cell Theory – Antony van Leeuwenhoek
• He discovered bacteria, free-living and
parasitic microscopic protists, sperm cells,
blood cells, microscopic nematodes and
rotifers, and much more.
– http://www.ucmp.berkeley.edu/history/leeuwenh
oek.html
Leeuwenhoek even wrote a paper about his
observations on the plaque between his own
teeth. Began by grinding lenses for his own
microscope.
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Cell Theory – The Basics
• Cell theory is a unifying concept in biology –
including germ theory, genetics, and evolutionary
theory.
• The principles of cell theory are three fold:
1. All organisms are made of cells.
2. All existing cells are produced by other living
cells.
3. The cell is the most basic unit of life as the atom is
the most basic unit of matter.
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Cell Theory
A Euglena – you can see the
flagellate and chloroplasts
The mitotic division of a cell
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Two types of cells
• There are two cell types: eukaryotic cells and
prokaryotic cells.
• Eukaryotic cells have a nucleus and membrane
bound organelles (you are made up of
eukaryotic cells).
• Prokaryotic cells do not have membrane
bound organelles and have no nucleus.
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DNA of Prokaryotes
• Prokaryotes are bacteria and other very simple organisms like
archea.
• The DNA of prokaryotes is in a DNA ring in organism’s
cytoplasm since it has no nucleus.
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DNA of Eukaryotes
• The massive difference between eukaryotes
and prokaryotes is the nucleus.
• The nucleus is where the DNA is – it never
ever leaves the nucleus!
• Eukaryotes also have membrane bound
organelles – prokaryotes do not.
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DNA of Eukaryotes
cell membrane
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Entrance/Exit Ticket
• What are the three parts to cell theory? You
must commit these to memory.
• Why is cell theory important (give 2
reasons)?
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