Download THE CELL THEORY

11/1/2011
THE CELL THEORY
ROBERT HOOKE (1665)
English scientist.
Developed the first compound microscope.
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ROBERT HOOKE
In 1665, he used his
microscope to look at cork
cells.
Hooke coined the term “cell”
What he saw under the
microscope reminded him of
the living quarters of the
monks (cells).
ANTON VAN LEEUWENHOEK
(1674)
Dutch curtain maker
who ground lenses as a
hobby.
Improved and
perfected the
microscope.
The first to observe
living cells
(blood cells and bacteria
from his teeth.)
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MATHIAS SCHLEIDEN (1837)
German Botanist
Obser ved that all plants are made up of cells.
THEODOR SCHWANN (1837)
German Zoologist
Obser ved that all animals are made up of cells.
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RUDOLF VIRCHOW (1858)
German Doctor
The first to observe
living cells reproduce.
Deduced that animal
cells come only from
animals, plant cells
come only from plants.
ROBERT BROWN (1833)
Scottish botanist
First to see the nucleus
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THE CELL THEORY
The obser vations of these scientists led to the cell theor y.
The modern cell theor y has 3 par ts:
a.
Cells are the basic units of life
b.
All living things are made of one or more cells.
c.
All cells come from preexisting cells.
ORGANIZATION OF LIFE
Organisms can be single-celled or multicellular.
Multicellular organisms are organized into complex structures.
Multicellular organisms have specialized cells to per form a
single function.
Ex. Red blood cells carry oxygen; muscle cells provide movement.
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MOLECULES
COMBINE TO FORM
CELLS
COMBINE TO FORM
Red blood cells
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TISSUES
COMBINE TO FORM
Cardiac muscle
ORGANS
COMBINE TO FORM
Heart
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SYSTEMS
COMBINE TO FORM
Circulatory System
ORGANISMS
COMBINE TO FORM
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ECOSYSTEMS
T YPES OF CELLS
Prokaryotic cells –
primitive cells that have
little internal structure.
Eukaryotic cells – evolved
from prokaryotic cells
and contain numerous
internal structures.
Organelles – structures in the
cell responsible for carrying
out specific functions. “cell
organs ”
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PROKARYOTIC CELLS
Prokar yotic cells do not contain a nucleus or any membrane
bound organelles.
They are always single-celled organisms.
Ex. Bacteria
Ver y simple structure – cell wall and membrane surrounding
cytoplasm.
Divide by binar y fission
EUKARYOTIC CELLS
Eukar yotic cells contain a
nucleus and membranebound organelles.
Can be single-celled or
multicellular organisms.
Ex. Algae (single) or plants
(multi)
Divide by mitosis
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WHAT LIMITS CELL SIZE?
Sur face Area to Volume Ratio
As a cell increases in size, its volume increases faster than its
sur face area
WHAT LIMITS CELL SIZE?
Manage Resources:
A cell must be able to fill its volume with nutrients and empty
its volume of wastes
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WHAT LIMITS CELL SIZE?
Regulate Cell Functions (DNA Proteins)
DNA must be able to control protein production. Larger cells
would not have enough DNA to produce enough proteins for the
cell’s normal functions
ANOTHER WAY TO LOOK AT IT:
Each tiny cube
(cell) is better able
to exchange
nutrients and
wastes than the
big cube
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