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14 Cards in this Set
- Front
- Back
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Friedrich Miescher
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1869 (Spain)
~finds a sticky substance inside nucleus which he calls nuclein |
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Frederick Griffith
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1931
~Deadly smooth vs. live rough pneumonia cells in mice...leads to the "Transforming Principle" |
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Avery and McLeod
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1944
~Isolate DNA in the S strain as the substance responsible for transformation (in a test tube) |
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Hershey/ Chase
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1952
~Perform experiment to eliminate the possibility of protein being the genetic material, using bacteriophages and radioactive tags of phosphorus and sulfur |
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Erwin Chargaff
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194?
~Tetranucleotide hypothesis had said that DNA was composed of repeating units; each having 4 nucleotides, complete with ATCG equally. Chargaff discovers... 1) % of ea. nitrogen base varies between species 2) Within a species, % are constant and there are 50% purines to 50% pyridimines. |
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Wilkins and Franklin
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194?
~use x-ray crystallography to determine that DNA is helical in shape |
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Watson and Crick
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1953
~discover DNA to be a double helix with sugar and phosphates making up the sides of the ladder and nitrogen bases joined by hydrogen bonds as the rungs ~complementary base pairing of purine with pyrimidine leads to correct width matching Franklin's x-ray ~paired bases can occur in any order |
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Meselson and Stahl
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~prove DNA replication to be semi-conservative meaning that each side of the old DNA becomes a template for new DNA. Therefore, in every new DNA strand, 1/2 of old exists.
~Synthesis occurs from 5' to 3' end at a rate of 500-5000 bases/minute. Synthesis occurs continuously on the leading strand. Discontinuously on the lagging strand. ~DNA polymerase begins process and checks for errors. (1/100,000 is rate of mutation). DNA ligase joins 3' to 5' pieces. |
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Rich and Wang
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1979
~Discover Z-DNA (left handed spiral). Functions as regulator, possibly. |
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Sir Archibald Garron
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Early 1900s
~Said that there was a relationship between inheritance and enzyme-related disease. ex. diabetes/ insulin, hemophilia/blood-clotting factor: must be link between genes and proteins) |
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Beadle and Tatum
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1940
~Experiment with bread mold (neurospora). Normally, the mold is capable of making all of the enzymes it needs for growth. Beadle and Tatum x-ray the spores to cause mutations in the genes and found that each mutant strain lacked one enzyme. Therefore, they conclude that each gene makes one enzyme. |
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Linus Pauling/ Itano
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1949
~Tests w/ normal and sickle cell hemoglobin (made up of polypeptides) revealed that one mutation leads to structural changes in protein. |
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Vernon Ingram
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195?
~One gene makes one polypeptide...a mutation leads to a defective polypeptide. |
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Nirenberg/ Matthei
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1961
~Crack the genetic code. ~Each 3 nitrogen bases=codon ~Each codon codes for an aminmo acid. ~Only one "start" AUG codon; 3 "stop" codons UAG, UGA, UAA ~101 other codons which code for 70 amino acids |
