The main function of ribosomes is protein synthesis. Ribosomes read messenger RNA (mRNA) sequences and translate them into polypeptide chains by linking amino acids in the correct order. Proteins produced by ribosomes are essential for cell structure, function, and regulation of tissues and organs. Unlike other organelles, ribosomes do not synthesize lipids, replicate DNA, or produce energy, making their role in protein production critical for cell viability and function. Disruption in ribosomal activity can lead to severe cellular dysfunction and disease.

Reference: Molecular Biology of the Cell, Alberts et al., 6th Edition.