Protein synthesis and transport, illustration. DNA (deoxyribonucleic acid, blue helix) in the cell nucleus (left) contains genes, that code for proteins. DNA is transcribed into mRNA (messenger ribonucleic acid, yellow strands), which leaves the nucleus for the cytoplasm. There, ribosomes (blue, globular, left centre) on the endoplasmic reticulum (membranes, left) translate the mRNA to proteins. The proteins are then transported in vesicles (spheres) to the Golgi apparatus (centre) where they are modified and packaged for transport out of the cell (far right).