The focus of proteomics is a biological group called the proteome. The proteome is dynamic, defined as the set of proteins expressed in a specific cell, given a particular set of conditions. Within a given human proteome, the number of proteins can be as large as 2million.  Proteins themselves are macromolecules: long chains of amino acids. This amino acid chain is constructed when the cellular machinery of the ribosome translates RNA transcripts from DNA in the cell's nucleus.  The transfer of information within cells commonly follows this path, from DNA to RNA to protein.