The Structure of Nucleic Acids

Nucleic acids are polymers composed of smaller units called nucleotides. Each nucleotide consists of three components:

• A nitrogenous base: Adenine, guanine, cytosine, thymine, or uracil.

• A pentose sugar: Deoxyribose in DNA and ribose in RNA.

• A phosphate group: Contributes to the formation of the nucleic acid backbone.

Nucleotides are connected through phosphodiester bonds, forming a sugar-phosphate backbone. The sequence of nitrogenous bases carries the genetic information.

DNA usually consists of two complementary strands arranged in a double helix. Adenine pairs with thymine, while guanine pairs with cytosine. In RNA, uracil replaces thymine, and the molecule is generally single-stranded.