The site of protein synthesis in the cell is the ribosomes.
Ribosomes are complex structures made of ribosomal RNA and proteins. They can be found floating freely in the cytoplasm or attached to the endoplasmic reticulum, forming what is known as rough ER. During protein synthesis, ribosomes translate messenger RNA (mRNA) into amino acid sequences, effectively assembling proteins based on the genetic instructions carried by the mRNA. This process is crucial for the growth, repair, and maintenance of cells and is a fundamental aspect of cellular function.