Structure of DNA
Legend:
Illustration of the double helical structure of the DNA
molecule.
The structure of DNA is illustrated by a right handed double helix, with
about 10 nucleotide pairs per helical turn. Each spiral strand, composed
of a sugar phosphate backbone and attached bases, is connected to a complementary
strand by hydrogen bonding (non- covalent) between paired bases, adenine
(A) with thymine (T) and guanine (G) with cytosine (C).
Adenine and thymine are connected by two hydrogen bonds (non-covalent) while
guanine and cytosine are connected by three.
This structure was first described by James Watson and Francis Crick
in 1953.
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