What is the structure of a DNA molecule?

The structure of a DNA molecule is characterized by its double helix formation, which consists of two long strands of nucleotides twisted around each other. Each nucleotide is made up of a phosphate group, a sugar (deoxyribose in the case of DNA), and a nitrogenous base (adenine, thymine, cytosine, or guanine).

In the double helix, the sugar and phosphate groups form the backbone, while the nitrogenous bases extend inward, paired in a specific manner—adenine with thymine and cytosine with guanine—thereby forming the rungs of the spiral ladder. This unique structure not only allows for the stability of the DNA molecule but also facilitates accurate replication and transcription processes vital for cellular function and heredity.

This configuration is crucial for numerous biological processes, including but not limited to the preservation of genetic information and the regulation of gene expression, indicating the important role this structure plays within a cell.