Here's a breakdown:

* DNA in the nucleus contains the genetic code for building proteins.

* This code is transcribed into messenger RNA (mRNA).

* mRNA travels out of the nucleus to the ribosomes, which are like protein factories.

* Ribosomes read the mRNA code and assemble amino acids into a specific protein chain.

So, while DNA provides the blueprint and the nucleus is where the blueprint is stored, the actual construction of proteins happens on the ribosomes.