Which feature is typical of prokaryotic cells?

• A. They possess a defined nucleus.
• B. They are enclosed by a cell wall and lack a nucleus and membrane-bound organelles.
• C. They are multicellular organisms with complex organ systems.
• D. They lack ribosomes.

Answer: (B)

Prokaryotic cells are characterized by not having a defined nucleus or any membrane-bound organelles. Their genetic material sits in a nucleoid region rather than inside a nucleus, and they carry out basic cellular processes without internal membranes surrounding organelles. They often have a cell wall that helps give shape and protection, and they contain ribosomes for protein synthesis (these ribosomes are not enclosed by membranes). This combination—no nucleus or membrane-bound organelles, with a cell wall present in many examples—fits prokaryotes like bacteria and archaea, setting them apart from eukaryotic cells that do have a nucleus and various membrane-bound organelles.