Question

Water potential and osmotic potential of pure water are
(a) Zero and zero
(b) 100 and zero
(c) 100 and 100
(d) Zero and 100

Answer 1

Hint: Water molecules possess a particular amount of kinetic energy. The greater the concentration of water during a system, the greater is its kinetic energy or water potential. Movement of water molecules occurs from the higher energy to the lower energy in a system.

Complete step by step answer:
Water potential is the chemical potential of water, which depends on the number of water molecules within the solution. More the amount of water molecules within the solution more the water potential. By convention, the water potential of pure water is assumed to be zero, in order that the water potential of all solutions is negative. The osmotic potential is the potential due to dissolved solutes. More the number of dissolved solute particles, the more the osmotic potential. In pure water, the amount of dissolved solute particles is zero, hence the osmotic potential is zero.
The osmotic potential has important implications for several living organisms. If a living cell is surrounded by a more concentrated solution, the cell will tend to lose water to the more negative water potential of the encompassing environment. This could be the exhibition for marine organisms living in seawater and halophytic plants growing in saline environments. In the case of a plant cell, the flow of water out of the cell may eventually cause the plasma membrane to tug faraway from the cell wall, resulting in plasmolysis. Most plants, however, have the power to extend the solute inside the cell to drive the flow of water into the cell and maintain turgor.
So, the correct answer is ‘(a)cZero and zero’.

Note: The concept of water potential has proved useful in understanding and computing water movement within plants, animals, and soil. Water potential is usually expressed in potential energy per unit volume. The pressure potential during a plant cell is typically positive. In plasmolyzed cells, pressure potential is almost zero. Negative pressure potentials occur when water is pulled through an open system like a plant xylem vessel.