DNA serves as the chemical basis of heredity, maintaining species identity over time. It undergoes self-duplication during cell division, transferring identical DNA strands to daughter cells.

Adenine pairs with thymine, and cytosine pairs with guanine through hydrogen bonds in DNA. RNA has a single-stranded helical structure, with messenger RNA (m-RNA), ribosomal RNA (r-RNA), and transfer RNA (t-RNA) serving different functions.

The primary structure of nucleic acids refers to the sequence of nucleotides in the chain, while the secondary structure, proposed by Watson and Crick, reveals a double-strand helix structure for DNA with complementary base pairs held by hydrogen bonds.

A nucleoside is formed by attaching a base to the 1’ position of a sugar. Nucleotides are created when a nucleoside links to phosphoric acid at the 5’-position of the sugar, and nucleotides join through phosphodiester linkages.

Chromosomes, composed of proteins and nucleic acids, carry hereditary traits. Nucleic acids, DNA and RNA, function as long chain polymers of nucleotides, playing a crucial role in transmitting inherent characteristics across generations.