1. Genetic Information Storage: DNA acts as the blueprint of life, containing the instructions for building and maintaining an organism. It stores the genetic code, which determines traits like eye color, hair type, and susceptibility to certain diseases. This information is passed down from parents to offspring.

2. Protein Synthesis: DNA provides the instructions for building proteins, which are the workhorses of the cell. This process involves transcription (copying DNA into RNA) and translation (using RNA to assemble amino acids into proteins). Proteins carry out a vast array of functions, from building structures to facilitating chemical reactions.

3. Cellular Replication: DNA replicates itself during cell division, ensuring that each new cell receives a complete set of genetic information. This process is essential for growth, development, and repair in living organisms.

These three roles are interconnected and fundamental to life as we know it.