Endosymbiotic features in eukaryotic organelles

Steps:

• Identify cell types: prokaryotic cells lack nucleus and membrane-bound organelles; eukaryotic cells have them.
• Recall organelle origins: chloroplasts and mitochondria derive from prokaryotes via endosymbiosis, retaining prokaryotic traits like 70S ribosomes and circular DNA.
• Analyze sequences: match diagram relationships to prokaryotic components in eukaryotic structures.
• Select option aligning prokaryotic ribosomes with chloroplast in plant cells.

Why A is correct:

• Chloroplasts in plant cells (eukaryotic) contain prokaryotic 70S ribosomes, per endosymbiotic theory.

Why the others are wrong:

• B: Nuclei in eukaryotic cells have linear DNA, not circular; membrane-bound ribosomes are 80S eukaryotic.
• C: Prokaryotic cells lack chloroplasts, which are eukaryotic organelles.
• D: Mitochondria in eukaryotic cells have 70S ribosomes but are not prokaryotic cells themselves.

Final answer: A