7.1 The Discovery of Cells

• Cell Theory1. All organisms are

composed of one or more cells.

2. The cell is the basic unit of organisms.

3. All cells come from preexisting cells.

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7.1 The Discovery of Cells• All cells come from

one cell…they just keep dividing

• All cells contain all the genetic info. or DNA

• Some cells have special functions and use only a small part of the DNA

www.csa.com/.../stemcell/images/pluri.jpg

7.1 The Discovery of CellsTypes of Cells

– Prokaryotic• No membrane bound

organelles• No nucleus• Most unicellular

organisms

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7.1 The Discovery of Cells– Eukaryotic

• Membrane bound organelles

• Nucleus• Most multicellular (except

ameobas, yeast and some algae)

• Much larger (see pg 174)

Animal vs. Plant Cell

Note the differences!

CELLS

Prokaryotic Eukaryotic

Animal cell Plant Cell

Cell Wall• Found in plant

cells• Located outside

the Plasma membrane

• Function: protection and support

• Made of cellulose

7.2 The Plasma Membrane• Plasma Membrane:

– Flexible boundary between cells & environment

– Selectively permeable: ___– Phospholipid Bilayer– Cholesterol, Protein

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www.biology.arizona.edu/.../ graphics/bilayer.giff

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7.2 The Plasma Membrane• Fluid Mosaic Model

http://www.bio.davidson.edu/people/macampbell/111/memb-swf/membranes.swf

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7.2 The Plasma Membrane

academic.brooklyn.cuny.edu/biology/bio4fv/pag...

Nucleus• Manages and controls all cell functions

• Holds genetic information

• Nucleolus is found there– Makes ribosomes

www.palaeos.com/.../Lists/Images/nucleolus.jpg

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