Now, in eukaryotic cells, ribosomes begin to synthesize the polypeptide chain in the cytosol of aracel. And such ribosomes that are found in the cytosol and which are not attached to any organelle are known as free ribosomes. Now, if the growing polypeptide chain that is being synthesized by the free ribosome is destined to remain inside the cytoplasm of the cell, in such a case, the free ribosome will remain a free ribosome. It will not attach to any organelle inside the cell during the entire process of translation. However, if the growing polypeptide chain that is being synthesized by the free ribosome is destined to be either secreted by the cell or to be embedded into the plasma membrane of the cell, in such a case, the free ribosome as well as the growing polypeptide chain will go on to attach onto the membrane of the endoplasmic reticulum. And now the free ribosome becomes a membrane bound ribosome.