How would the number of lysosomes in a pupa be expected to change with age? Give a reason.

• A. Falls, increases, then falls; lysosomes linked to tissue breakdown
• B. Increases continuously
• C. Remains constant
• D. Decreases continuously

Answer: (A)

Lysosomes are the cell’s digestive organelles, delivering hydrolytic enzymes to break down and recycle old cellular material. In a pupa, metamorphosis involves staged tissue remodeling: larval tissues are degraded to supply materials for forming adult tissues, and this remodeling happens in waves.

At the start of pupation, lysosome numbers may drop as the system shifts from preparing larval tissues to initiating the remodeling process. Then, as dramatic tissue breakdown and recycling ramp up, lysosome production or activity increases, leading to more lysosomes. Later, once most remodeling is complete and adult tissues are taking shape, the demand for lysosome-driven digestion lessens, so lysosome numbers decline again.

This pattern—an initial fall, followed by a rise during active remodeling, and then a fall again as remodeling winds down—fits the lifecycle of pupal metamorphosis where lysosomes are closely tied to the timing of tissue breakdown.