AP BIOLOGY

Detailed explanation-1: -Adenine (A) and guanine (G) are purines, and cytosine (C), thymine (T), and uracil (U) are pyrimidines. These are the most important parts in the nucleic acid, and genetic information is stored in the sequence of these molecules.

Detailed explanation-2: -Examples of pyrimidines are cytosine, thymine, and uracil. Cytosine and thymine are used to make DNA and cytosine and uracil are used to make RNA.

Detailed explanation-3: -Hydrogen bonding and base stacking interactions of pyrimidines are important for stabilizing the three-dimensional structure in nucleic acids. The most important biological substituted pyrimidines are cytosine, thymine, and uracil.

Detailed explanation-4: -Purines (adenine and guanine) are two-carbon nitrogen ring bases while pyrimidines (cytosine and thymine) are one-carbon nitrogen ring bases.

Detailed explanation-5: -Thymine is a pyrimidine, which means that it is composed of a single ring consisting of 4 carbon atoms and 2 nitrogen atoms. Thymine helps stabilize nucleic acid structures. DNA is composed of two strands that twist upon each other to form a double helix.