Transcript Scientists, Cell Theory and Prokaryote vs. Eukaryote

Scientists, Cell Theory
and Prokaryote vs.
Eukaryote
What is a Cell?
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Cell – Basic unit of living things.
Organisms are either:
 Unicellular – made of one cell such
as bacteria and amoebas.
OR
 Multicellular – made of many cells
such as plants and animals.
ALL LIVING THINGS :
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Are made of cells
Can reproduce
Have genetic code
Grow and develop
Obtain/use materials and energy
Respond to environment
Maintain homeostasis
Change over time
Cell Theory
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Confirmed discoveries that all scientists
believe to be true about cells:
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1. Cells are the basic unit of life.
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2. All living things are made of cells.
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3. New cells are produced from
existing cells.
Microscopes
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Light Microscope – magnifies tiny
organisms up to 1,000 times. Uses light
and lenses (we use these).
Electron Microscope – magnifies up to
a million times. Uses electrons.
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TEM – Transmission Electron Microscope –
transmits electrons through a slice of an
object. Shows internal structure.
SEM – Scanning Electron Microscope – scans
the outside of an object (shows 3-D view of
the surface).
The Discovery of Cells
before
nucleus
true
nucleus
Prokaryotes
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NO nucleus
NO organelles
ALL are unicellular
Smaller than eukaryotic cells
Forerunner to eukaryotic cells
(smaller and more simple)
DNA – single strand and circular
Ex: ALL Bacteria
Eukaryotes
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Has a nucleus with a nuclear envelope
Bigger and more complex than
prokaryotes
Have Organelles
DNA – double-stranded and forms
chromosomes (highly organized)
Can be uni- OR multicellular
Ex: animals, plants, fungi
Similarities
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Contain all four biomolecules
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Have ribosomes
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Have DNA
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Similar Metabolism
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Can be unicellular
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Have cell membranes