1. Pg. 43 Origin of Life Where did life come from?
What was Pasteur’s contribution?
How did life arise in the first place?

2. Pasteur's Experiment
Louis Pasteur, the notable French scientist, accepted the challenge to re-create the experiment and leave the system open to air. He subsequently designed several bottles with S-curved necks that were oriented downward so gravity would prevent access by airborne foreign materials. He placed a nutrient-enriched broth in one of the goose-neck bottles, boiled the broth inside the bottle, and observed no life in the jar for one year. He then broke off the top of the bottle, exposing it more directly to the air, and noted life-forms in the broth within days. He noted that as long as dust and other airborne particles were trapped in the S-shaped neck of the bottle, no life was created until this obstacle was removed. He reasoned that the contamination came from life-forms in the air. Pasteur finally convinced the learned world that even if exposed to air, life did not arise from nonlife.
Read more: Origin of Life: Spontaneous Generation | Infoplease.com 

3. Miller-Urey Experiment
Miller and Urey, two scientists from the University of Chicago believed the ancient atmosphere to be very different than the present day atmosphere.

4. Miller-Urey Experiment
Key Point #1: The ancient atmosphere consisted of CH4, NH3, CO, CO2, N2, and H2O, but lacked free O2.
What provided energy for the reactions?

5. Miller-Urey Experiment: The origin of life on this planet
Key Point #2: The Miller-Urey experiment demonstrated the abiotic synthesis of organic compounds.
Water (H2O), methane (CH4),  ammonia (NH3), and hydrogen (H2) were all sealed inside a sterile array of glass tubes and flasks connected in a loop, with one flask half-full of liquid water and another flask containing a pair of electrodes.
Historical note: Originally, Miller reported that 11 amino acids were formed. After his death in 2007, the Professor Jeffrey Bada, himself Miller's student, inherited the original equipment from the experiment when Miller died in Based on sealed vials from the original experiment, scientists have been able to show that although successful, Miller was never able to find out, with the equipment available to him, the full extent of the experiment's success.

6. Experimental Design: The origin of life on this planet
The liquid water was heated to induce evaporation, sparks were fired between the electrodes to simulate lightning through the atmosphere and water vapor, and then the atmosphere was cooled again so that the water could condense and trickle back into the first flask in a continuous cycle.
Key Point #3: Lightning was the originally source of energy
Point out that 1953 Stanley used methane (CH4), ammonia (NH3), water (H2O), and hydrogen (H2). This was a reducing atmosphere which favored the “building” of molecules. Since 1953, the evidence indicates that the atmosphere contained water (H2O), carbon dioxide (CO2), nitrogen (N2). This a “neutral” atmosphere. When repeated with these gases, organic molecules were formed although different from the original results and in differing amounts, but still demonstrating the plausibility of this crucial first step in the origin of life. It is assumed that near active volcanoes, the atmosphere was reducing and could have contributed to the formation of organic molecules.

7. Experimental Design: The origin of life on this planet
Within a day, the mixture had turned pink in color, and at the end of two weeks of continuous operation, Miller and Urey observed that as much as 10–15% of the carbon within the system was now in the form of organic compounds.

8. Experimental Design: The origin of life on this planet
Two percent of the carbon had formed amino acids that are used to make proteins in living cells, with glycine as the most abundant. Nucleic acids were not formed within the reaction. But the common 20 amino acids were formed, in various concentrations.
Key Point #4: Amino acids, the building blocks of life were formed
23 amino acids exist, but only 20 are commonly found in living systems.