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Cell Biology – GERM THEORY

Integrated Science 1-2. Cell Biology – GERM THEORY. A. Cell Theory – What We Think Today. I. All life is cells II. All cells come from other cells. B. We used to think. Jan Baptiste van Helmont. Small organisms appear in non-living matter when conditions are right

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Cell Biology – GERM THEORY

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  1. Integrated Science 1-2 Cell Biology – GERM THEORY

  2. A. Cell Theory – What We Think Today I. All life is cells II. All cells come from other cells

  3. B. We used to think • Jan Baptiste • van Helmont • Small organisms appear in non-living matter when conditions are right • Spontaneous Generation: • Maggots and flies from rotten meat • Frogs from pond mud • 1600’s: Jan Baptiste van Helmont: • Mice from wheat grains placed in a sweaty shirt!

  4. B. We used to thinkIII. 1668 – Francisco Redi 1. Maggots don’t form in rotten meat if flies are kept away! flies maggots Wire screen meat

  5. B. We used to think IV. Lazzaro Spallanzani • Meat broth boiled & sealed never spoils! • Broth boiled & left open to air develops microorganisms Mold and bacteria heat heat

  6. B. We used to think IV. 1750 Lazzaro Spallanzani Louis Pasteur • … but critics claimed that a “vital principle” in air is needed for spontaneous generation, and was “destroyed” by boiling. V. 1860 – Louis Pasteur settles the matter! (you will too!)

  7. Germ Theory: The Experiments! http://www.youtube.com/watch?v=KfcGJvlrRks&feature=related Start 1:30 in Ignaz & Louis In ACTION • http://www.youtube.com/watch?v=KSLCkT2ttXQ&feature=related

  8. C. How did life on Earth begin? I. We know today that ALL life shares one Precambrian ancestor (all life uses the same genetic code.) 1. If life never starts spontaneously, how could it begin the first time?? 2. Divine creation? Extraterrestrial origin? From non-living chemicals? (we don’t know…)

  9. C. How did life on Earth begin? II. Blue-green algae ~3,500,000,000 –year old cyanobacteria (blue-green algae)

  10. C. How did life on Earth begin? II. Blue-green algae

  11. C. How did life on Earth begin? III. 1953: Stanley Miller & Harold Urey Electricity Pre-Cambrian Air H20 NH3 CH4 H2 Amino acids out! (The building blocks of proteins) Heat - Boil

  12. Animation of Experiment

  13. Stanley Miller

  14. The same mix of amino acids were found next year in the Murchison Meteorite…

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