Adenine pairs with thymine and guanine with cytosine through hydrogen bonds.
Practise Biochemistry, Environment & Industry All Biochemistry, Environment & Industry topics
Base pairing is the specific hydrogen bonding between complementary nucleobases. Adenine pairs with thymine, or with uracil in RNA, through two hydrogen bonds, and guanine pairs with cytosine through three. Each pair always consists of one purine and one pyrimidine, so the width of the double helix stays uniform along its length. Because the pairing is complementary, one strand specifies the sequence of the other, which is the basis for copying DNA during replication and for transcription into RNA. G-C pairs contribute more to helix stability than A-T pairs because of their third hydrogen bond.
Key ideas: Adenine pairs with thymine (two hydrogen bonds) and guanine with cytosine (three), in RNA A pairs with U. A purine always pairs with a pyrimidine so the helix width stays constant. Higher G plus C content gives a higher melting temperature, which matters for PCR primer design.
Common mistakes and connections: A common mistake is to pair A with C or to claim that G-C pairs are covalent. Purines are A and G (two rings), pyrimidines are C, T, U (one ring). Mismatch errors are what repair enzymes check. Links to Chargaff rules, replication fidelity and hybridization.
Approximate DNA melting temperature rises with GC content because G-C pairs have three hydrogen bonds against two for A-T. The interactive lesson shows this as a live animation or chart.
A DNA sequence rich in G and C melts at a higher temperature than one rich in A and T.
Adenine pairs with thymine and guanine with cytosine through hydrogen bonds.
Base Pairing is a intermediate topic in Biochemistry, Environment & Industry. It builds on the vocabulary of beginner topics in this area.
Study these earlier topics in Biochemistry, Environment & Industry first: Cholesterol, DNA Structure, RNA Types.
The next topics in Biochemistry, Environment & Industry are DNA Replication and Transcription and Translation.
Yes. The interactive lesson includes a self-check question on Base Pairing, and the Biochemistry, Environment & Industry quiz draws on every topic in this area.
Base Pairing is topic 25 of 127 in Biochemistry, Environment & Industry.
Browse all 127 topics in Biochemistry, Environment & Industry