DNA's primary structure is made up of just four different bases, and its secondary structure is regular and highly stable. How can a molecule with these characteristics hold the information required to build and maintain a cell?

DNA consists of a backbone made of sugar and phosphate groups, with four nitrogenous bases (adenine, thymine, cytosine, and guanine) attached. The sequence of these bases encodes genetic information, with specific combinations determining the instructions for building proteins and regulating cellular functions.

The stability of DNA's secondary structure arises from the specific pairing of bases: adenine pairs with thymine, and cytosine pairs with guanine. This complementarity not only stabilizes the double helix but also allows for accurate replication and transcription, ensuring that genetic information is reliably passed on during cell division.

The genetic code is a set of rules that defines how sequences of bases in DNA correspond to amino acids in proteins. This code is read in triplets (codons), allowing the cell to translate the information stored in DNA into functional proteins, which are essential for maintaining cellular structure and function.