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DOUBLE HELIX DNA PDF
DOUBLE HELIX DNA SERIES

Watson, "The Double Helix: A Personal Account of the Discovery of the Structure of DNA". James Watson wrote a personal account of his famous discovery and the people involved: James D. Watson, Crick and Wilkins received the Nobel Prize for Physiology or Medicine in 1962.

DOUBLE HELIX DNA PDF

To view the PDF on this page, you will need Adobe Reader. Their 900-word paper, published in Nature, concluded, famously, "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material."

The two strands of the double helix run in opposite directions.

The nucleotide bases use hydrogen bonds to pair specifically, with an A always opposing a T, and a C always opposing a G.

Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups. A DNA molecule is made up of two linked strands that wind around each other to resemble a twisted ladder in a helix-like shape.

DNA is a double helix, with the sugar and phosphate parts of nucleotides forming the two strands of the helix, and the nucleotide bases pointing into the helix and stacking on top of each other. Double helix, as related to genomics, is a term used to describe the physical structure of DNA.

Their model revealed the following important properties: Watson and Crick used paper cutouts of the bases and metal scraps from a machine shop to come up with their own model. Others quickly realized that the model was chemically flawed. While Watson and Crick were still working on their model, Pauling published a paper suggesting a triple-helical structure for DNA. They were competing with Linus Pauling, who had earlier discovered the alpha-helical structure of some protein molecules. Watson and Crick raced to find the structure before anyone else.

X-ray diffraction patterns, obtained by Rosalind Franklin and Maurice Wilkins, revealed great symmetry and consistency in the structure of DNA and gave important clues about its dimensions.

In the DNA of any given type of cell, the amount of adenine approximately equals the amount of thymine, while the amount of cytosine approximately equals the amount of guanine.

Phoebus Levene had determined these chemical characteristics.

DOUBLE HELIX DNA SERIES

Nucleotides are linked in series into a chain, with phosphate and sugar groups alternating. DNA is made of nucleotides, chemical building blocks made of three parts: a phosphate group that is linked to a deoxyribose sugar, which is in turn linked to one of four nitrogenous bases - adenine (A), cytosine (C), guanine (G), or thymine (T).By the time Watson and Crick turned their attention to solving the chemical structure of DNA, DNA was known to have the following attributes: Francis Crick and James Watson described the double helix structure of DNA.