Ribosomes are organelles found in both prokaryotic and eukaryotic cells. They are like mini machines that synthesize all the proteins in the cell. In any single animal cell, there can be as many as 10 million ribosomes! The ribosomes form the manufacturing department of the cell.
In the nucleus, a sequence of DNA that codes for a specific protein is copied onto an intermediate molecule called messenger RNA (mRNA). The mRNA molecule carries this information to the ribosome, and its sequence determines the order of amino acids in a polypeptide chain. The ribosome synthesizes this polypeptide chain, which eventually folds to become a protein. In animal cells, ribosomes can be found freely in a cell’s cytoplasm or attached to the endoplasmic reticulum.