Shared Eukaryotic Organelle Structures

Steps:

• Identify common features: Both human (animal) and plant cells are eukaryotes with mitochondria.
• Recall ribosomal types: Eukaryotic cytoplasm has 80S ribosomes, but mitochondria in both contain 70S ribosomes.
• Eliminate plant-specific traits: Plasmodesmata connect plant cells; tonoplast surrounds plant vacuoles.
• Rule out animal-specific traits: Cilia are motile structures mainly in animal cells.

Why A is correct:

• 70S ribosomes are present in the mitochondria of all eukaryotic cells, including human and plant cells, as defined by mitochondrial protein synthesis machinery.

Why the others are wrong:

• B: Cilia are found primarily in animal cells for motility, absent in most plant cells.
• C: Plasmodesmata are channels unique to plant cell walls for intercellular communication.
• D: Tonoplast is the membrane of the central vacuole, exclusive to plant cells.

Final answer: A