Final answer:
DNA provides a series of genes that can be turned on or off during cellular differentiation. Transcription factors play a crucial role in determining gene expression by binding to specific genes on the DNA molecule.
Step-by-step explanation:
The role of DNA in cellular differentiation is to provide a series of genes that can be turned on or off. In order for a cell to differentiate into its specialized form and function, it needs to manipulate the genes and the proteins they code for. Transcription factors, a class of proteins, bind to specific genes on the DNA molecule and either promote or inhibit their transcription, thus determining which genes will be expressed and which ones will remain silent.