Base Pairing
The specific hydrogen bonding between complementary nitrogenous bases in nucleic acids.
Formula / equation
A–T (2 H-bonds), G–C (3 H-bonds)
Unit
Dimensionless
In depth
A purine always pairs with a pyrimidine, keeping the helix a constant width. The three hydrogen bonds of a G–C pair make it more stable than an A–T pair, so GC-rich DNA requires a higher temperature to separate the strands.
Examples in the real world
Each strand acting as a template for the other during replication; Chargaff's finding that A equals T and G equals C.