Final answer:
Adenine (A) pairs with thymine (T) forming two hydrogen bonds, while guanine (G) pairs with cytosine (C) to form three hydrogen bonds. These pairings are fundamental to the structure and function of DNA as per Chargaff's rules.
Step-by-step explanation:
In complementary base pairing within DNA, adenine (A) forms two hydrogen bonds with thymine (T), and guanine (G) forms three hydrogen bonds with cytosine (C). This bonding is crucial for the structural stability of the DNA double helix. Each type of base pairing forms a similar shape that is key to the efficient replication and function of DNA.
Chargaff's rules also support the concept of complementary base pairing, indicating that the amount of adenine and thymine is the same, as is the amount of guanine and cytosine in DNA. This consistency is due to the specific pairing through hydrogen bonds, where adenine pairs exclusively with thymine, and guanine with cytosine, further reinforcing the precision of the DNA structure and its replication.