AP BIOLOGY

Detailed explanation-1: -A nucleotide is the basic building block of nucleic acids (RNA and DNA). A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base.

Detailed explanation-2: -Phosphorus is present both in DNA and RNA as it forms the backbone of the nucleic acid. The acidic nature of nucleic acids is due to the presence of phosphoric acid. In both DNA and RNA, the phosphorus which is considered to be the backbone helps in the formation of phosphodiester bonds.

Detailed explanation-3: -Unlike DNA, RNA in biological cells is predominantly a single-stranded molecule. While DNA contains deoxyribose, RNA contains ribose, characterised by the presence of the 2′-hydroxyl group on the pentose ring (Figure 5).