In the cell, there are production lines, in this case, manufacturing new proteins of many different sorts. Messenger RNA acts as a blueprint, like a barcode. This blueprint is interpreted by machines on a production line, which are called ribosomes, to assemble the correct sequence of amino acids.

Amino acids are the building blocks used to make proteins. As in cities where products are made in factories and used within the city, so the completed proteins are often for home consumption, but others may be exported outside the cell for use elsewhere.

Some ribosomes float free in the cytosol and the proteins they make are made directly into the cytosol. Many ribosomes join together on the rough endoplasmic reticulum.

FACTORY

New goods and products are continually being manufactured from raw materials. In cities this takes place in workshops and factories. Raw materials are transformed, usually in a sequence of steps on a production line, into finished products. The process is governed by a clear set of instructions or specifications. In some cases the final products are for immediate or local use, in others they are packaged for export.