Differentiated cells have all the DNA they need, just like any other cell in the body. However, they only express a specific subset of that DNA, which is what makes them specialized for their particular function. Here's a breakdown:

* All cells have the same DNA: Every cell in your body contains the complete genetic blueprint, the same DNA, with the exception of red blood cells which lack a nucleus.

* Differentiation is about gene expression: Differentiation is the process where cells specialize. This happens because specific genes are turned on or off, controlling which proteins are produced.

* Specialized functions: Different cell types express different sets of genes, leading to the production of different proteins and thus different functions. For example, a muscle cell expresses genes for muscle proteins, while a nerve cell expresses genes for proteins involved in transmitting nerve impulses.

* DNA remains constant: The DNA itself doesn't change during differentiation. It's the pattern of gene expression that changes, allowing for the development of diverse cell types with specialized functions.

In short, differentiated cells don't need "more" DNA. They utilize the same complete set of DNA as all other cells, but they express different parts of it, leading to specialized functions.