Here's why:

* DNA holds genetic information: DNA is a molecule that carries the instructions for building and maintaining an organism. These instructions are encoded in the sequence of its four building blocks (adenine, guanine, cytosine, and thymine).

* Genes within DNA: The DNA molecule is organized into units called genes. Each gene contains the code for a specific protein or RNA molecule. These proteins are essential for the cell's structure, function, and regulation.

* Transcription and translation: The DNA blueprint is first transcribed into RNA. This RNA molecule then serves as a template for building proteins through the process of translation.

Therefore, DNA acts as the blueprint for the cell, dictating its structure, function, and overall development.