What is one of the main functions of DNA within a cell?

The primary function of DNA within a cell is to serve as the repository of genetic information. DNA contains the specific sequences of nucleotides that encode the instructions needed for the development, functioning, growth, and reproduction of all known living organisms and many viruses. It holds the genetic blueprint that guides the synthesis of proteins and other molecules essential for life.

The storage of genetic information is critical because it ensures that traits can be passed down from one generation to the next through processes such as reproduction. Furthermore, this stored information is transcribed into messenger RNA and then translated into proteins, which perform various functions in the cell.

The other options relate to functions that involve other cellular components or processes. For example, energy production occurs primarily in mitochondria through cellular respiration, while protein synthesis is facilitated by ribosomes and occurs after transcribing DNA into mRNA. These processes cannot occur without the foundational genetic information provided by DNA, but the main role of DNA itself is to store that genetic information.