Question

The value of TP & WP of two cells A and B are given below. (i) TP of A cell - 10 atm (ii) WP of A cell - 14 atm (iii) TP of B cell - 12 atm (iv) WP of B cell -12 atm On the basis of above data, select the wrong information in the given options. (1) Cell A is not full turgid so water may enter this cell. (2) In B cells, the value of DPD may be zero. (3) The movement of water may take place from B to A. (4) The cell A will be shrinked if the value of TP is more than WP.

Answer 1

TP is the turgor pressure which cells exert outwards against their cell walls by expanding the protoplast. WP is the water potential which is referred to as water’s potential energy.

Complete answer:
Turgor pressure is denoted by the pressure potential of cells. It can be both positive and negative. Cell a has a negative pressure which means a tension is created. This causes a decrease in total pressure of the cell and this causes the wilting of the cell. A turgor pressure is caused inside the cell due to entry of a solvent. WP is exerted against the turgor pressure. At equilibrium both turgor pressure and water pressure are equal.

Let us analyse all options to find the correct answer
Option A: Water potential is higher this means that water may enter this cell. Hence, this is an incorrect option.
Option B: DPD of cell B is 0 since the cell is at equilibrium. Hence, this is an incorrect option.
Option C: At this point the cell B is at equilibrium so the net water transport will cease. Hence, the option is correct.
Option D: This is an incorrect option.

Thus, the correct answer is Option (C) The movement of water may take place from B to A.

Additional Information:
i) Water potential of pure water is 0 bars.
ii) Turgor pressure is 0 in a flaccid cell.
iii) Nowadays DPD is denoted by water potential.

Note: The movement of water from higher concentration to lower concentration across a semipermeable membrane is called osmosis. It helps the cell to maintain its shape and turgidity.