The structure of DNA is a double helix' The structure aligns the phosphates on the outside of the he

1
The structure of DNA is a double helix. The
structure aligns the phosphates on the outside of
the helix while the nitrogenous bases are found
on the inside.
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Erwin Chargaff
Chargaff found Chargaffs Rule. This principle
states that, in a molecule of DNA, the number of
adenine bases will be equal to the number thymine
bases, likewise the number of cytosines will be
equivalent to the number of guanines. http//cpmc
net.columbia.edu/news/in-vivo/Vol2_Iss10_may26_03/
img/chargaff-profile.gif
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I saw before me in dark contours the beginning
of a grammar of biology. I started with the
conviction that if different DNA species
exhibited different biological activities, there
should exist chemically demonstrable differences
between deoxyribonucleic acids. Erwin
Chargaff
4
In X-ray crystallography, we obtain a
blue-print of the electron density clouds of
molecules. http//libproxy.mit.edu8062/content/v
ol299/issue5615/images/large/se1231374002.jpeg
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In X-ray crystallography, we obtain a
blue-print of the electron density clouds of
molecules. http//www.lbl.gov/Science-Articles/Ar
chive/images1/atp-density-map.jpg
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Francis Crick
Jim Watson
Watson and Crick came up with the model that the
structure of DNA was a double helix. http//caria
ri.ucr.ac.cr/claudiog/Crick_Watson.jpg
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Rosalind Franklin
Rosalind Franklin collected the x-ray diffraction
data from DNA that allowed Watson and Crick to
create their double helix DNA model. http//www.w
ellesley.edu/WomensReview/archive/2002/11/highlt.h
tml
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Maurice Wilkins
Wilkins was involved in the collection of the
x-ray diffraction data from DNA that allowed
Watson and Crick to create their double helix DNA
model. http//www.drg.de/data/wuerdigungen/Nobelp
reise/images/196220WILKINS20MEDIZIN_WEB.JPG
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The Eighth Day of Creation Horace Freeland
Judson Cold Spring Harbor Laboratory Press
(1996) The Double Helix James D.
Watson Werdenfeld Nicholson (1997)
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This is an image of the x-ray diffraction pattern
obtained from DNA. http//home.tiscalinet.ch/biog
rafien/biografien/franklin.htm
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The original model of DNA that Watson and Crick
build was composed of metal and
wire. http//www.albany.edu/achm110/bdnagroovean
dwc.htm
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Watson and Crick came up with the model that the
structure of DNA was a double helix.
It has not escaped our notice that the specific
pairing we have postulated immediately suggests a
copying mechanism for the genetic material.
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Watson gave a lecture at Cold Spring Harbor
describing the double helix model. 50 years
later an image of the lecture is still used.
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Jim Watson
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http//www.laskerfoundation.org/awards/kwood/watso
n/images/crickwatson.jpg
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Matt Meselson
Frank Stahl
The Meselson-Stahl experiment was the first to
show the semi-conservative mechanism of DNA
replication.