In which organelle does protein synthesis occur in eukaryotic cells?

Protein synthesis in eukaryotic cells primarily occurs in the ribosomes. Ribosomes are the cellular structures that translate messenger RNA (mRNA) into polypeptide chains, which eventually fold into functional proteins. They can be found free-floating in the cytoplasm or attached to the endoplasmic reticulum, forming what is known as the rough endoplasmic reticulum.

The process begins when mRNA, which carries the genetic blueprint for a specific protein, binds to the ribosome. Transfer RNA (tRNA) then brings the corresponding amino acids to the ribosome, where they are linked together in the order specified by the mRNA sequence. This process is essential for cellular functions, as proteins play critical roles in structure, function, and regulation of the body’s tissues and organs.

While the endoplasmic reticulum and Golgi apparatus are also involved in the broader context of protein production and processing, respectively, the ribosome is specifically the site where the actual synthesis of proteins occurs. Mitochondria are primarily known for energy production and do not play a direct role in protein synthesis.