Base complementarity
Definition
The specific pairing rules that govern double-stranded DNA: adenine pairs with thymine (2 hydrogen bonds) and guanine pairs with cytosine (3 hydrogen bonds). Any other combination is geometrically incompatible with the double helix. This rule is why knowing one strand's sequence immediately specifies the other strand's sequence.
Related terms
- Antiparallel orientation
- The two strands of the DNA double helix run in opposite directions: one strand reads 5' to 3', its complement reads 3'...
- Denaturation
- The separation of double-stranded DNA into two single strands by disrupting the hydrogen bonds between base pairs. In PCR, denaturation is achieved...
- Deoxyribonucleotide
- The monomer unit of DNA, consisting of a deoxyribose sugar, a phosphate group, and one of four nitrogenous bases (adenine, thymine, guanine,...
- GC content
- The proportion of base pairs in a DNA molecule that are guanine-cytosine. Because G-C pairs form three hydrogen bonds (versus two for...
- Phosphodiester backbone
- The repeating sugar-phosphate chain that forms the structural scaffold of each DNA strand. The backbone is highly charged and hydrophilic, faces outward...
Explained in
- The DNA Double Helix and Base PairingThe specific pairing rules that govern double-stranded DNA: adenine pairs with thymine (2 hydrogen bonds) and guanine pairs with cytosine (3 hydrogen bonds). A...