* Ribosomes: These are the sites of protein synthesis. They are complex structures made of ribosomal RNA (rRNA) and proteins. Ribosomes move along messenger RNA (mRNA) molecules, reading the genetic code and assembling amino acids into polypeptide chains.
* Endoplasmic reticulum (ER): This is a network of membranes that extends throughout the cytoplasm of eukaryotic cells. The rough endoplasmic reticulum (RER) is studded with ribosomes, which synthesize proteins that are destined for secretion, incorporation into the cell membrane, or delivery to other organelles.
So, while the actual assembly of proteins happens on ribosomes, the process of protein synthesis is often considered to occur within both the ribosomes and the ER.
