AP BIOLOGY

Detailed explanation-1: -Both are nitrogenous bases . However, pyrimidines contain one carbon-nitrogen ring and purines contain two carbon-nitrogen rings. Adenine and guanine are purines, while thymine, cytosine, and uracil are pyrimidines. In a DNA molecule, a pyrimidine base always pairs with a purine base.

Detailed explanation-2: -The pyrimidines, cytosine and thymine are smaller structures with a single ring, while the purines, adenine and guanine, are larger and have a two-ring structure.

Detailed explanation-3: -The nitrogenous bases with two ringed structures are the purines and thus are bigger than the pyrimidines. The purines comprise of nine-membered structure with four typical nitrogen atoms. In contrast, pyrimidines have a single ring structure and are smaller than purines.

Detailed explanation-4: -They are nitrogenous bases that make up the two different nucleotides in DNA and RNA. Purines (adenine and guanine) are two-carbon nitrogen ring bases while pyrimidines (cytosine and thymine) are one-carbon nitrogen ring bases.

Detailed explanation-5: -Pyrimidines have a single ringed structure. Cytosine, thymine and uracil are examples of pyrimidine. Q. Assertion :The heterocyclic compounds in nucleic acid are the nitrogenous bases.