What do purines bond to?

Purines bond to pyrimidines to form base pairs, which are the building blocks of DNA and RNA. Purines are nitrogenous organic compounds that are characterized by their double-ring structure. The two purines found in DNA are adenine (A) and guanine (G), while the two pyrimidines are thymine (T) and cytosine (C). In RNA, uracil (U) takes the place of thymine.

The purines and pyrimidines are held together by hydrogen bonds. Adenine always pairs with thymine (or uracil in RNA), while guanine always pairs with cytosine. This base-pairing rule ensures that the genetic information stored in DNA and RNA is accurately copied during replication and transcription.