Exercise 2.2
What consequences would you predict for a plant cell if its cell wall were to become as flexible as a cell membrane?
Not cross-checked
NCERT prints no numerical answer for this exercise, so this working has not been cross-checked against the book.
The cell would lose its shape and its firmness, and the plant built from such cells would no longer stand up.
In a concentrated sugar or salt solution the whole cell would collapse inwards, like a cheek cell, instead of only its contents pulling away while the outline held (compare Fig. 2.9a and b).
In plain water the opposite failure: water would keep entering by osmosis with nothing rigid to push back, so the cell would swell and could burst.
Cells could no longer press firmly against one another, so stems would droop and leaves and flowers would go limp even when the plant had plenty of water.
The plant would have no defence left against wind and rain — which is exactly the stress the cell wall exists to resist.
Water and minerals would still get in, since the wall was already permeable; what would be lost is only the rigidity.
