Which of the following equations are true for the percentages of nucleotides in double-stranded DNA?

(A)/(C) = (G)/(T)

Key Concepts

Chargaff's Rules

Chargaff's Rules state that in double-stranded DNA, the amount of adenine (A) is equal to thymine (T), and the amount of cytosine (C) is equal to guanine (G). This base pairing is fundamental to the structure of DNA, as A pairs with T and C pairs with G, ensuring that the percentages of these nucleotides are complementary.

Base Pairing

Base pairing refers to the specific hydrogen bonding between nucleotides in DNA. Adenine pairs with thymine through two hydrogen bonds, while cytosine pairs with guanine through three hydrogen bonds. This pairing is crucial for the stability of the DNA double helix and is the basis for the complementary nature of the two strands.

Nucleotide Composition

The nucleotide composition of DNA refers to the relative amounts of the four nucleotides: adenine, thymine, cytosine, and guanine. In double-stranded DNA, the total percentage of A and T will be equal, as will the total percentage of C and G, leading to the conclusion that the ratios of these nucleotides can be expressed in equations reflecting their complementary nature.