Transcript Hooke to bacteria ppt

In the
beginning…….
1665—Robert Hooke, British scientist, looked
at a thin slice of cork using a primitive
microscope
 “little boxes” reminded him of monastery cells,
so he named what he saw CELLS
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10 years later…..
Antoine Von Leeuwenhoek
(Dutch linen merchant)
discovered “tiny animals” in
supposedly clean pond water,
using a scope that he designed--we now call these organisms:
___________
 Was first to discover that there
were tiny swimming cells
(sperm) in semen
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~ 160 years later three Germans
arrived at several conclusions….
1838—Schleiden proclaimed, after much
research, that cells are in all parts of
plants
 1839—Schwann announced that animals
have cells in all their parts
 1858—Virchow reported that cells only
come from other living cells—yes, people
used to believe in abiogenesis!
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CELL THEORY
All living things are composed of 1 or more cells
 Cells are the basic units of structure & function
in organisms
 Cells are produced only from existing cells
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Common characteristics of all cells
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Cell/plasma membrane —separates the cell’s
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Cytoplasm—everything inside the cell, minus the
insides from its environment; regulates what comes
in/leaves the cell, which maintains HOMEOSTASIS—
balance between the inside/outside of cell
genetic material
Cytosol—fluid part of the cytoplasm
 Ribosomes—structures on which proteins are made;
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composed of RNA and proteins; very tiny—didn’t even
know they were in cells until electron microscopes
“discovered” them ~ 1940’s
Short history of cells
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First/oldest cells are
prokaryotes (before kernel)
single-celled organisms (ie
bacteria) that do not have
membrane-bound
compartments w/in the cell
Very tiny (1-15 µ)
Genetic material is a single,
circular strand that floats
inside the cell
Only living organisms for our
planet’s first 2 billion years
Endosymbiosis
Theory
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Theory about how more
complex cells came about
One prokaryote either
invaded or was engulfed by
another prokaryote
Neither cell died—they lived
and benefited from each
other
When they reproduced they
both split and stayed
together, making 2 cells each
with another cell inside
Cell inside either became the
nucleus or the
mitochondria…..more on
those later
Bacteria
3 shapes: coccus, bacillus, spirillum
 Coccus—round
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Diplococcus—attached pairs
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Streptococcus—attached long chains
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Staphylococcus—grape-like bunches
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BACTERIA, cont.
Bacillus—rod shaped
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Diplobacillus—2
attached
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Streptobacillus—
long chains
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BACTERIA, AGAIN
Spirillum—3 distinct
shapes
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Vibrio—comma
shaped
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Spirillum—thick,
rigid spiral
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Spirochete—thin,
flexible spiral
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Bacteria…cont.
Pathogens—disease causing bacteria; how
many diseases can you name??
 Colony—visible group of microorganisms
derived from one individual
 Shape: circular, lobate, rhizoids
 Elevation: flat, raised, convex, fuzzy
 Color: surprisingly varied
 Matte vs Shiny
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