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DISCOVERY OF THE
STRUCTURE OF DNA
Hank Oliver and Chelsea Peacock
Frederick Griffith


Discovered the process called transformation
Found a transforming agent that survived heat and
change a bacteria to virulent
Oswald Avery and Colleagues
Proved DNA was the
transforming compound
 Used protein-destroying
enzymes to destroy proteins,
RNA-destroying enzymes to
destroy RNA, and DNAdestroying enzymes to
destroy DNA.
 Transformation was stopped
when DNA-destroying
enzymes were used.

Alfred Hershey & Martha Chase



Performed experiment with
T2 bacteriophage
Using radiolabeled proteins
and DNA and followed
them.
Experiment proved DNA
was transforming agent
Rosalind Franklin & Raymond Gosling


Worked together to produce the first X-ray
diffraction pictures of DNA
Their picture of DNA was stolen by Watson & Crick
to determine the structure of DNA
Erwin Chargaff


The amount of cytosine equals the amount of
guanine and the amount of adenine equals the
amount of thymine.
Adenine ALWAYS pairs with Thymine; Guanine
ALWAYS pairs with Cytosine – Chargaff’s Rule
Maurice Wilkins


Studied the orientation of purines and pyrimidines
in DNA
Developed well-defined X-ray diffraction pictures
of DNA which led to Watson and Crick’s DNA
model
James Watson & Francis Crick
First to determine structure of DNA
 Double helix
 Chargaff’s Rule
 Made of sugar-phosphate backbone with bases
hydrogen bonded together holding
two strands together

References
Griffith Experiment
http://www.nature.com/scitable/topicpage/isolating-hereditary-material-frederick-griffith-oswald-avery-336
Avery Experiment
http://study-biology.wikispaces.com/DNA+and+Genetic+Information
Hershey & Chase Experiment
http://www.accessexcellence.org/RC/VL/GG/hershey.php
Rosalind Franklin’s X-ray Picture
http://biology.kenyon.edu/courses/biol63/dna-prot/xray.html
Rosalind Franklin Picture
http://askabiologist.asu.edu/Rosalind_Franklin-DNA
Raymond Gosling Picture
http://kingscollections.org/exhibitions/archives/dna/key-individuals/gosling
Image for Chargaff’s Rule
http://www.odec.ca/projects/2004/mcgo4s0/public_html/t2/dna.html
Chargaff Picture
http://sanycao-sbi4u.blogspot.com/2012/02/scientists-great-contributions.html
References
Maurice Wilkins Picture
http://scarc.library.oregonstate.edu/coll/pauling/dna/pictures/portrait-wilkinsmodel.html
Watson and Crick Picture
http://www.chemheritage.org/discover/online-resources/chemistry-in-history/themes/biomolecules/dna/watson-crickwilkins-franklin.aspx
DNA Structure
http://library.thinkquest.org/24355/data/details/media/dnastructure.html