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

(A + G)/(C + T)= 1.0

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 guanine (G) is equal to cytosine (C). This means that the ratios of A to T and G to C are both 1:1, which is crucial for understanding the base pairing in DNA and the overall composition of nucleotides.

Nucleotide Composition

Nucleotides are the building blocks of DNA, consisting of a sugar, a phosphate group, and a nitrogenous base. In double-stranded DNA, the total percentage of purines (A and G) must equal the total percentage of pyrimidines (C and T), leading to the equation (A + G)/(C + T) = 1.0, which reflects the balance of these nucleotide types.

Double-Stranded DNA Structure

Double-stranded DNA consists of two complementary strands that wind around each other, forming a double helix. The strands are held together by hydrogen bonds between paired bases (A with T and G with C), which is essential for the stability of the DNA molecule and the accurate replication of genetic information.