Here's a breakdown:

* Ribosomes: These are tiny organelles found in both prokaryotic and eukaryotic cells. They act as the protein synthesis machinery, reading the genetic code from messenger RNA (mRNA) and linking amino acids together to form proteins.

* mRNA: This molecule carries the genetic code from DNA in the nucleus to the ribosomes.

* Amino acids: These are the building blocks of proteins.

So, the process of protein synthesis (also called translation) happens in the ribosomes, using the instructions from mRNA and the building blocks of amino acids.