The pyrimidine bases of DNA are cytosine and thymine. One pyrimidine combines with one purine to make up a rung of the DNA double helix. Nucleotides, the building blocks of DNA, comprise a phosphate group, a five-carbon ... More »

Cytosine, uracil and thymine are nitrogenous bases belonging to the pyrimidine group. Accompanied by the purine bases of adenine and guanine, cytosine and thymine are nitrogenous bases used to construct DNA. Uracil is a ... More » Science Chemistry Acids & Bases

Pairing of a specific purine to a specific pyrimidine is due to the structure and properties of each ring and the three-dimensional fit between complements. Purine and pyrimidine are organic, aromatic ring compounds that... More »

The rungs of the DNA ladder consist of four nitrogenous bases: adenine, thymine, cytosine and guanine. Each rung of the ladder is composed of two of the nitrogenous bases held together by hydrogen bonds. More »

Adenine, guanine, cytosine and thymine are the four chemical bases found in DNA. In a given DNA molecule, adenine always pairs with thymine, and guanine always pairs with cytosine. More »

The base pairing rules for DNA are governed by the complementary base pairs: adenine (A) with thymine (T) in an A-T pairing and cytosine (C) with guanine (G) in a C-G pairing. Conversely, thymine only binds with adenine ... More »

DNA stores information in a sequence of adenine, cytosine, guanine and thymine on a backbone of two deoxyribose molecules, which intertwine in a double helix. In nature, this information is read by RNA molecules and turn... More »