To determine which pairing fits according to Chargaff's rule, we need to understand what Chargaff's rule states. Chargaff's rule, also known as the base-pairing rule, is one of the key discoveries in molecular biology about the structure of DNA.
Chargaff's rule states that in a double-stranded DNA molecule:
1. The amount of adenine (A) is equal to the amount of thymine (T).
2. The amount of cytosine (C) is equal to the amount of guanine (G).
This rule can be summarized by saying A pairs with T and C pairs with G in DNA.
Now, let's look at the options provided:
1. [tex]\(A=T ; C=G\)[/tex]
2. [tex]\(A=C ; T=G\)[/tex]
3. [tex]\(A=G ; T=U\)[/tex]
4. [tex]\(A=U ; C=G\)[/tex]
According to Chargaff's rule:
- Adenine (A) pairs with Thymine (T)
- Cytosine (C) pairs with Guanine (G)
Among the given options, the first choice ([tex]\(A=T ; C=G\)[/tex]) is the correct one, as it matches directly with Chargaff's findings.
Therefore, the base pairing in DNA should resemble [tex]\(A=T ; C=G\)[/tex], corresponding to the first choice.
