Which organelle is responsible for protein synthesis?

The organelle responsible for protein synthesis is ribosomes. Ribosomes play a crucial role in translating messenger RNA (mRNA) into polypeptide chains, which then fold into functional proteins. This process, known as translation, occurs in the cytoplasm, where ribosomes can either be free-floating or attached to the endoplasmic reticulum, forming what is known as rough ER.

Ribosomes consist of two subunits, which come together during protein synthesis to read the sequence of the mRNA and facilitate the addition of amino acids to the growing polypeptide chain, using transfer RNA (tRNA) to bring the correct amino acids to the ribosome. The function of ribosomes is fundamental to cellular operations, as proteins are essential for a multitude of functions within the cell, including structural roles and enzymatic activity.

The other organelles mentioned have different functions. Mitochondria primarily produce ATP through cellular respiration, the Golgi apparatus is involved in modifying, sorting, and packaging proteins and lipids for secretion or use within the cell, and lysosomes are responsible for digestion and waste removal. Therefore, ribosomes are uniquely specialized for the task of protein synthesis.