Final answer:
Ribosomes are crucial for protein synthesis and are found in the cytoplasm of both prokaryotic and eukaryotic cells, as well as on the rough endoplasmic reticulum (and in mitochondria and chloroplasts) of eukaryotic cells.
Step-by-step explanation:
Ribosomes are essential for protein synthesis and are found in both eukaryotic and prokaryotic cells. In prokaryotes, ribosomes are located in the cytoplasm, whereas in eukaryotes, they exist both in the cytoplasm and on the surface of the rough endoplasmic reticulum. Additionally, mitochondria and chloroplasts in eukaryotic cells contain their own ribosomes, which are structurally similar to prokaryotic ribosomes. In eukaryotic cells, ribosomes can be found in the cytoplasm as well as attached to the rough endoplasmic reticulum.