Which structures are found in both prokaryotes and eukaryotes?

Which structures are found in both prokaryotes and eukaryotes?

• A. Nucleus
• B. Mitochondria
• C. Ribosomes
• D. Chloroplasts

Answer: (C)

Ribosomes are the protein-making machines found in all cells, so they appear in both prokaryotes and eukaryotes. In bacteria and other prokaryotes, ribosomes sit in the cytoplasm (and can be free-floating) and they’re slightly smaller (70S) than the ribosomes in eukaryotic cells (80S), which can be free or attached to the rough endoplasmic reticulum. The nucleus, mitochondria, and chloroplasts, on the other hand, are membrane-bound organelles characteristic of eukaryotic cells and are not present in prokaryotes. So the shared structure that fits both domains is the ribosome.

Ribosomes are the protein-making machines found in all cells, so they appear in both prokaryotes and eukaryotes. In bacteria and other prokaryotes, ribosomes sit in the cytoplasm (and can be free-floating) and they’re slightly smaller (70S) than the ribosomes in eukaryotic cells (80S), which can be free or attached to the rough endoplasmic reticulum. The nucleus, mitochondria, and chloroplasts, on the other hand, are membrane-bound organelles characteristic of eukaryotic cells and are not present in prokaryotes. So the shared structure that fits both domains is the ribosome.