Which cellular organelle is responsible for protein synthesis?

The ribosome is the cellular organelle specifically responsible for protein synthesis. This process begins with the translation of messenger RNA (mRNA), which carries the genetic code from DNA. Ribosomes can be found free-floating in the cytoplasm or bound to the endoplasmic reticulum, forming what is known as rough ER. Within the ribosome, transfer RNA (tRNA) molecules read the mRNA sequence and bring the corresponding amino acids together to form polypeptide chains, which then fold into functional proteins.

Understanding the role of ribosomes in protein synthesis is fundamental to molecular biology, as proteins are essential for a variety of cellular functions, including enzymatic activity, structural support, and cellular signaling. The other organelles listed do not fulfill this specific role: mitochondria are involved in energy production, the nucleus contains genetic material and regulates gene expression, and lysosomes are responsible for the breakdown of waste materials and cellular debris.