# AP BIOLOGY

## PLANTS

### TRANSPORT IN PLANTS

 Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
The cell A has an osmotic potential of-20 bars and a pressure potential of +6 bars. What will be its water potential?
 A -14 bars B +14 bars C -20 bars D -26 bars
Explanation:

Detailed explanation-1: -w=(−20)+(+6)=−14 bars. Hence, option A-14 bars is the correct answer.

Detailed explanation-2: -Water potential () is actually determined by taking into account two factors-osmotic (or solute) potential (S) and pressure potential (P). The formula for calculating water potential is = S + P. Osmotic potential is directly proportional to the solute concentration.

Detailed explanation-3: -In case of flaccid cell, the turgor pressure becomes zero. There is no pressure exerted by the protoplast on the cell wall so the pressure potential of the cell will be zero. A cell at zero turgor has an osmotic potential equal to its water potential. Therefore, the water potential of the flaccid cell is 25 bars.

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