What nucleotide pairs with guanine?

Cytosine is the nucleotide that pairs with guanine in DNA. This pairing is due to complementary base pairing, where guanine and cytosine form three hydrogen bonds between them. Complementary base pairing is a fundamental property of DNA, where adenine always pairs with thymine (in DNA) or uracil (in RNA), and guanine always pairs with cytosine. This specific pairing is crucial to maintaining the stability and integrity of the DNA double helix structure and is vital for various biological processes, including DNA replication and protein synthesis.