What are the base pairs in DNA structure?

In the structure of DNA, the base pairs are formed through specific pairings of nitrogenous bases, which are adenine (A), thymine (T), cytosine (C), and guanine (G). Adenine pairs exclusively with thymine, while cytosine pairs with guanine.

The pairing can be summarized as follows: A aligns with T, and C aligns with G, forming strong hydrogen bonds that stabilize the DNA double helix.

The correct answer points out that adenine pairs with thymine, which is the proper pairing in DNA, and it also notes guanine pairing with cytosine. The mention of (U), or uracil, is relevant only in RNA, where uracil replaces thymine; thus, it should not be included in a description of DNA base pairing. This indicates a clear understanding of the fundamental principles of DNA structure and differentiation between DNA and RNA base pairing.