Protoplast fragility due to loss of cell wall osmotic protection

Steps:

• Plant cell walls provide structural support and resist internal turgor pressure from water influx.
• Enzyme digestion removes the wall, leaving only the plasma membrane as the barrier.
• In hypotonic environments, water enters freely via osmosis without wall resistance.
• Unchecked water entry causes the membrane to burst, damaging the protoplast.

Why B is correct:

• Turgor pressure, defined as the hydrostatic pressure from water against the rigid cell wall, normally limits net water movement; without the wall, osmosis causes rapid swelling and lysis.

Why the others are wrong:

• A: Mitochondria produce ATP independently and are not directly affected by wall removal.
• C: Secretory vesicles fuse with the plasma membrane, which remains intact.
• D: Shape change results from damage but does not explain the primary cause of fragility.

Final answer: B