Which base always pairs with adenine in DNA?

In DNA, adenine specifically pairs with thymine through two hydrogen bonds, which is critical for the structure and stability of the DNA double helix. This base pairing is a key aspect of the complementary nature of the DNA strands, meaning that each base on one strand corresponds to a specific base on the complementary strand.

The reason thymine pairs with adenine is due to the specific molecular structure of these bases, allowing for the formation of stable hydrogen bonds, which help maintain the integrity of the DNA molecule during replication and transcription processes. This complementary base-pairing mechanism is essential for accurate DNA replication and expression of genetic information. Other bases such as guanine and cytosine pair with each other, while uracil, which is found in RNA, does not participate in DNA base pairing.