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 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! Jan Baptiste van Helmont

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

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

B. We used to think IV. 1750 Lazzaro Spallanzani … 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!) Louis Pasteur

Germ Theory: Ignaz & Louis In ACTION The Experiments! http://www.youtube.com/watch?v=K SLCkT2ttXQ&feature=related http://www.youtube.com/watch?v=KfcGJvlr Rks&feature=related Start 1:30 in

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…)

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

C. How did life on Earth begin? II. Blue-green algae IS 1-2 Disease Unit - Cell Biology/Germ Theory

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

Animation of Experiment

Stanley Miller

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