A collection of posts from a 7th grade science teacher. Enjoy.
Tuesday, August 30, 2011
Notes on the Miller Urey Experiment - On the origin of life.
Mr. S Summarizes.
SO these dudes made an experiment on some gasses and water and found that by adding electricity they could essentially create the building blocks of life. Later researchers confirmed this finding and then some finding they could produce the components of DNA from non living gasses by adding electricity.
As well researchers have found meteorites that have amino acids still in them which indicates that possibly life was brought to earth by falling meteorites. Which makes me think....where did their life evolve...still the same question.
It is also important to note that the atmosphere of early earth (4.5-3.8 billion years ago) was nothing like it is today. Humans could not have survived. There was little to NO oxygen in the atmosphere.
We know that there are single celled organisms that don't need oxygen to survive. They are called anaerobic.
adapted from http://www.blogger.com/post-create.g?blogID=673845189173946144
1950 - Tried to see if they could create life from gases and electric current.
They used molecules which were believed to represent the major components of the early Earth's atmosphere and put them into a closed system
The gases they used were methane (CH4), ammonia (NH3), hydrogen (H2), and water (H2O). Next, he ran a continuous electric current through the system, to simulate lightning storms the researchers observed that some of the carbon formed of organic compounds. More amazingly some had formed amino acids which are used to make proteins. Finally and more importantly still their experiment showed that amino acids, which are essential to cellular life, could be made easily under the conditions that scientists believed to be present on the early earth. This enormous finding inspired a multitude of further experiments.
In 1961, Juan Oro discovered that from an aqueous solution he could produce the nucleotide base, adenine. Adenine is of tremendous biological significance as an organic compound because it is one of the four bases in RNA and DNA. It is also a component of adenosine triphosphate, or ATP, which is a major energy releasing molecule in cells. Further experimentation showed that the other essential components of DNA and RNA could be created through prebiotic chemistry.
On September 28, 1969, a meteorite fell over Australia, analysis of the meteorite has shown that it is rich with amino acids. This meteorite has demonstrated that the Earth may have acquired some of its amino acids and other organic compounds by meteorite striking earth.....but then where did they get their amino acids from?
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