Question
Sort nucleoid, nucleolus, lysosome, mitochondria, ribosomes, plasma membrane, and flagella into Prokaryotic cells only, Eukaryotic cells only, or Both prokaryotic and eukaryotic cells.
Correct classification
Prokaryotic cells only
- Nucleoid — the non-membrane-bound region that contains the main bacterial chromosome.
Eukaryotic cells only
- Nucleolus — a specialized region inside the nucleus where ribosomal RNA is made and ribosomal subunits begin to assemble.
- Lysosome — a membrane-bound digestive compartment found in the standard animal-cell model.
- Mitochondria — membrane-bound organelles that carry out major steps of aerobic cellular respiration in most eukaryotes.
Both prokaryotic and eukaryotic cells
- Ribosomes — both cell types translate messenger RNA into protein, although their cytosolic ribosomes differ in size and composition.
- Plasma membrane — every cell uses a selectively permeable boundary to separate its interior from the environment.
- Flagella — flagellated members occur in both groups, but prokaryotic and eukaryotic flagella are built differently and move by different mechanisms.
The fastest distinction is the presence of a membrane-bound nucleus and other membrane-bound organelles: those features identify a eukaryotic cell, while DNA in a nucleoid identifies a prokaryotic cell.
Evidence boundary
The bins describe whether a structure occurs within each broad cell type, not whether every member has it. Prokaryotic and eukaryotic flagella are structurally different, and specialized eukaryotic cells or lineages may lack some otherwise characteristic organelles.
Sources
These references support the concepts and methods used in the explanation above.