In DNA, what nucleotide does adenine (A) pair with?

Adenine (A) pairs with thymine (T) in DNA through two hydrogen bonds, forming a base pair that is essential for the double-helix structure of DNA. This specific pairing is crucial for DNA replication and the accurate transmission of genetic information. The complementarity between adenine and thymine ensures that the DNA strands can properly align and separate during replication, allowing for the correct copying of genetic material.

In contrast, uracil, which is found in RNA, replaces thymine in RNA structures but does not participate in DNA pairing. Guanine and cytosine pair together, but they are not the complementary base for adenine in the context of DNA. This specificity in base pairing is a fundamental concept in molecular biology, highlighting the importance of adenine's interaction with thymine.