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How we discovered that all LIVING things were made of cells
Cell Theory How we discovered that all LIVING things were made of cells
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Robert Hooke – (1665) Using a microscope he saw little boxes in cork he called cells
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Cork looked like monastery cells
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Leeuwenhoek – (1673) Saw first living cells with microscope
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How did he use such a microscope?
Place specimen in water drop here Look through here Adjust here
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So stop complaining about your compound microscope
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Schleiden (1838) A Botanist Concluded all plants are made of cells
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Schwann (1839) An animal embryologist
Concluded all animals are made of cells
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Schwann Sounds like swan (animal)
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Virchow (1855) All Cells can only arise from other pre-existing cells
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Cell theory : All living things are composed of cells
Cells are alike in their basic structure and function in an organism Cells need information to survive Cells only come from reproduction of existing cells
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Why are cells so small? 1) efficiency – if surface area to volume ratio too small, substances can not pass in and out quick enough 2) specialization – different cells have different functions
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Types of cells Prokaryotes Eukaryotes
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Prokaryotic cells Prokaryote= “before nucleus”
No Nucleus or other organelles with membranes Mostly bacteria All are unicellular
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Key structures of prokaryotes
Nucleoid DNA (not enclosed) Cell wall Capsule surrounding cell Plasma membrane Cytoplasm Ribosomes Flagella (some) pili
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Eukaryotic cells Eukaryote = “true nucleus”
Have DNA contained in a nuclear membrane Have a Plasma membrane surrounding Have organelles surrounded by membranes (Golgi bodies, ER, mitochondria, lysosomes etc.) Also have ribosomes Unicellular and multi cellular types
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Eukaryotic cells = Animal and Plant
Most organelles are the same for plant and animal cells. Some differences are Animal – centrioles Plant –chloroplasts, central vacuole, cell wall
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Observation of Cells with microscope
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Basic Parts of cell Plasma Membrane Cytoplasm Nucleus
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Animal Cells Nucleus Cell membrane Cytoplasm Other organelles not
visible 400X
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Plant cells also have chloroplasts and a cell wall
Nucleus Cell wall Cell membrane Chloroplasts 1000X
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Drawing cells under microscope
Draw a neat diagram Not this like this 2-3 cells 400X Nucleus Remember: magnification and labels
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