DNA structure Flashcards
Frederick Griffith
studied bacteria that cause pneumonia
2 strains: R (rough)-harmless & S (smooth)-deadly
experiment:
heat the S strain=harmless
live R+heated S=deadly
Saw that there was a transforming factor that caused the R strain to turn into the S strain
Oswald Avery (Colin McCleod and Maclyn McCarty)
Rationalized that there are specific macromolecules in a cell
Used enzymes to destroy each type of macromolecule in the “S” strain, theorizing that the “S” would transform into an “R” strain when its factor is destroyed
Found the transforming factor to be DNA
Alfred Hershey and Martha Chase
studied bacteriophages=a viruse that attacks bacteria.
Labelled virus with radioactive isotopes: Proteins with sulfur and DNA with phosphorus
Found that DNA is the genetic information of cells
Linus Pauling
Caltech professor
Nobel Prizes: proteins & peace
Was believed to be a communist because he was against the creation of nuclear weapons
James Watson & Francis Circk
Watson: 23 yr old American
Crick: 35 yr old physical chemist
Used work of Rosalind Franklin & Maurice Wilkins
Discovered DNA: is 2 chains of monomers & has a twisted shape=double helix
Crick discovered they 2 chains were antiparallel
Irwin Chargraff
Established the Base pair rule
In a cell:
the amount of Thymine will always match the amount of adenine
the amount of Cytosine will always match the amount of guanine
Nitrogenous bases
thymine, cytosine,adenine,guanine
what holds 2 strands together
purine
2 ring shape
adenine & guanine
pyrimidine
1 ring shape
thymine & cytosine
deoxyribonucleic acid
DNA
uses sugar deoxyribose
