The biological process wherein messenger RNA (mRNA) is decoded to produce a specific polypeptide occurs in two primary locations within eukaryotic cells. These locations are the cytoplasm, specifically on free ribosomes, and the endoplasmic reticulum, when ribosomes are bound to its surface. Polypeptide synthesis, irrespective of location, uses the mRNA sequence as a template, transferring RNA (tRNA) to deliver corresponding amino acids, which are then linked together to form the polypeptide chain.
The spatial separation of these locations reflects the diverse destinations of the newly synthesized proteins. Cytoplasmic synthesis generally produces proteins destined for use within the cell, like enzymes and structural proteins. Proteins produced on the endoplasmic reticulum are often destined for secretion outside the cell, insertion into the cell membrane, or for localization within organelles such as the Golgi apparatus and lysosomes. This division of labor optimizes cellular function by ensuring efficient protein targeting and prevents potential interference between different protein classes.
