Prokaryotic and eukaryotic ribosomes resemble each other structurally, but they are not identical. They are found in the cytoplasm of both prokaryotic and eukaryotic cells as well as in the matrix of mitochondria and the stroma of chloroplasts (plant cells). In eukaryotic cytoplasm, ribosomes are found in the cystol (liquid medium of the cytoplasm) and are bound to the endoplasmic reticulum as well as the outer membrane of the nuclear envelope. Prokaryotic ribosomes are smaller in size, contain fewer proteins, have smaller RNA molecules, and are more sensitive to different inhibitors of protein synthesis than their eukaryotic counterparts.