What are the base pairs in DNA?

The base pairs in DNA consist of specific combinations of nucleotides that are held together by hydrogen bonds, forming the structure of the DNA double helix. The two primary types of nucleotides involved are adenine (A), thymine (T), cytosine (C), and guanine (G). In DNA, adenine pairs exclusively with thymine, and cytosine pairs exclusively with guanine. This specific pairing is crucial for the fidelity of DNA replication and the accurate transmission of genetic information.

Adenine and thymine form two hydrogen bonds, while cytosine and guanine form three hydrogen bonds, contributing to the overall stability of the DNA molecule. The complementary nature of these pairs ensures that the genetic code is preserved during cellular processes such as replication and transcription.

Therefore, the correct answer identifies the established complementary base pairing: adenine with thymine and cytosine with guanine, making it an essential concept in molecular biology.