O Levels Biology (5090)•5090/12/M/J/24

Explanation
Osmosis Without Cell Wall Support
Steps:
- Plant cells normally have rigid cell walls that prevent bursting during osmosis.
- Removing the cell wall leaves only the semi-permeable plasma membrane.
- Distilled water is hypotonic, so water enters the cell via osmosis due to higher internal solute concentration.
- The membrane cannot withstand the pressure, leading to cell rupture.
Why D is correct:
- In hypotonic solutions, osmosis drives water influx (diffusion of water across a semi-permeable membrane from low to high solute concentration), bursting wall-less cells per the osmotic pressure principle.
Why the others are wrong:
- A: Turgidity requires cell wall support; without it, bursting occurs instead of turgor.
- B: Cell membranes are selectively permeable and block large proteins from passing.
- C: Water enters (not exits) in hypotonic conditions, causing swelling.
Final answer: D
Topic: Diffusion and osmosis
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