Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
14 Cards in this Set
- Front
- Back
Friedrich Miescher
|
1869 (Spain)
~finds a sticky substance inside nucleus which he calls nuclein |
|
Frederick Griffith
|
1931
~Deadly smooth vs. live rough pneumonia cells in mice...leads to the "Transforming Principle" |
|
Avery and McLeod
|
1944
~Isolate DNA in the S strain as the substance responsible for transformation (in a test tube) |
|
Hershey/ Chase
|
1952
~Perform experiment to eliminate the possibility of protein being the genetic material, using bacteriophages and radioactive tags of phosphorus and sulfur |
|
Erwin Chargaff
|
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. |
|
Wilkins and Franklin
|
194?
~use x-ray crystallography to determine that DNA is helical in shape |
|
Watson and Crick
|
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 |
|
Meselson and Stahl
|
~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. |
|
Rich and Wang
|
1979
~Discover Z-DNA (left handed spiral). Functions as regulator, possibly. |
|
Sir Archibald Garron
|
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) |
|
Beadle and Tatum
|
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. |
|
Linus Pauling/ Itano
|
1949
~Tests w/ normal and sickle cell hemoglobin (made up of polypeptides) revealed that one mutation leads to structural changes in protein. |
|
Vernon Ingram
|
195?
~One gene makes one polypeptide...a mutation leads to a defective polypeptide. |
|
Nirenberg/ Matthei
|
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 |