[Campbell Biology P.1042] According to the 'Gas Exchange' section, what direct effect does th... | Practice Question

According to the 'Gas Exchange' section, what direct effect does the uptake of K+ by guard cells have on the cell?

  • A: It causes the guard cells to shrink, leading to stoma closure.
  • B: It triggers an osmotic influx of water, changing cell shape and bowing the guard cells outward.
  • C: It directly causes the guard cells to actively pump out H2O.
  • D: It generates a voltage that drives outward movement of H+.

Explanation

The text explicitly states: 'This uptake of K+ by guard cells triggers an osmotic influx of water that changes cell shape, bowing the guard cells outward and thereby opening the stoma.'