What is the role of ribosomes in a cell?

Ribosomes play a crucial role in the process of protein synthesis, which is fundamental to cellular function and structure. They serve as the molecular machinery that translates messenger RNA (mRNA) into polypeptides, which then fold to become functional proteins. The ribosome reads the sequence of codons in the mRNA and, with the help of transfer RNA (tRNA), assembles the corresponding amino acids in the correct order to form a polypeptide chain.

This process occurs in two main stages: initiation, where the ribosome assembles around the mRNA and the first tRNA, and elongation, where amino acids are sequentially added to the growing chain until a stop codon is reached. The proteins synthesized at ribosomes are essential for numerous cellular functions, including metabolism, structure, signaling, and regulation.

Other functions mentioned, such as sites of ATP production, storage of genetic information, and regulation of cell division, are performed by other cellular components, such as mitochondria, the nucleus, and specific regulatory proteins, respectively. Thus, the primary and defining function of ribosomes is indeed the site of protein synthesis.