DNA base pairing

A critical feature of DNA is the ability of the nucleotides to make very specific pairing.

A-T and C-G.

A is said to be complementary to T (and U) and C is complementary to G

 

The complementary nucleotides are held together by weak hydrogen (H) bonds. However, the sum of the strength of these weak bonds allows DNA to maintain its double-stranded structure. Note that there are 2 H bonds between A and T and 3 between Cand G

 

 

 

See other DNA diagrams http://www.agen.ufl.edu/~chyn/age2062/lect/lect_02/3_37.gif and http://www.agen.ufl.edu/~chyn/age2062/lect/lect_02/3_36.gif

For more information click http://www.blc.arizona.edu/Molecular_Graphics/DNA_Structure/DNA_Tutorial.HTML#Components (Scroll down in new page)

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