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Which four bases are used to build DNA?

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biology; microscope — Biology A researcher using a microscope to examine a specimen in the laboratory.

DNA is built using four nitrogen-containing bases, which are categorized as either purines or pyrimidines. These bases are:12

Adenine (A): A purine12
Guanine (G): A purine12
Cytosine (C): A pyrimidine12
Thymine (T): A pyrimidine12

Within the DNA molecule, these bases form complementary pairs—adenine always pairs with thymine, and guanine always pairs with cytosine—held together by hydrogen bonds. This specific pairing is fundamental to the structure of the double helix and the transmission of genetic information. While RNA also utilizes adenine, guanine, and cytosine, it uses uracil instead of thymine.2341