The primary component of DNA is the sequence of nucleotides, which are the building blocks of the DNA molecule. Each nucleotide comprises a sugar, a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine). The specific order of these nucleotides encodes genetic information, determining an organism's traits and functions. The structure of DNA is a double helix, where pairs of nitrogenous bases form the steps of the spiral staircase, enabling stable inheritance and replication. This molecular architecture is fundamental to genetics and cell biology.