Ribosomes are found in prokaryotic and eukaryotic cells; in mitochondria, chloroplasts and bacteria. Those found in prokaryotes are generally smaller than those in eukaryotes. Ribosomes in mitochondria and chloroplasts are similar in size to those in bacteria.

Do prokaryotes and eukaryotes have ribosomes?

All ribosomes (in both eukaryotic and prokaryotic cells) are made of two subunits — one larger and one smaller. In eukaryotes, these pieces are identified by scientists as the 60-S and 40-S subunits. In prokaryotes, the ribosomes are made of slightly smaller subunits, called 50-S and 30-S.

Why do eukaryotes have 80S ribosomes?

Eukaryotic ribosomes are also known as 80S ribosomes, referring to their sedimentation coefficients in Svedberg units, because they sediment faster than the prokaryotic (70S) ribosomes. ... Both subunits contain dozens of ribosomal proteins arranged on a scaffold composed of ribosomal RNA (rRNA).