How does DNA base pairing work?

1 Answer

In DNA base pairing, Adenine pairs with Thymine and Cytosine pairs with Guanine.

Explanation:

Adenine and Guanine are purines and Cytosine and Thymine are pyrimidines.

Dictated by specific Hydrogen bonding patterns, Watson and Crick base pairs allow the DNA helix to maintain a regular helical structure.

Pairing of a specific purine to a specific pyrimidine is due to the structure and properties of these bases. Matching base pairs form H - bonds. Adenine and Thymine have 2 sites where they form
H - bonds. Cytosine and Guanine have 3 sites.

Bonded together, these base pairs form the rungs of the DNA ladder or double helix.

For each of the four nitrogenous bases a specific tautomeric form must be incorporated for proper bonding, stability and attachment to the sugar phosphate backbone of DNA.