Diagram showing the hydrogen bonds that form between the four bases in the DNA double helix. These weak forces between the bases keep the two complementary strands of DNA together and ensure that the correct bases are put in the right place during replication of the DNA molecule. A always pairs with T and C always pairs with G. Due to the fact that a C-G pair has 3 H-bonds it is stronger than an A-T pair which only has 2 H-bonds.
Credit: Pete Jeffs, Wellcome Images
This resource is part of the Post 16 genetics and genomics collection of resources.
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