The role of ribosomes in a cell is primarily to synthesize proteins. These complex molecular machines translate messenger RNA (mRNA) into polypeptide chains, essential for cellular functions. Ribosomes can be found floating freely in the cytoplasm or attached to the endoplasmic reticulum, forming rough ER. Each ribosome comprises two subunits made of ribosomal RNA (rRNA) and protein, working together to read the sequences of mRNA and assemble the corresponding amino acids into a functional protein. This process is vital for cell growth, repair, and overall function, driving the expression of genes.