Q.5:- Differentiate between the following:
(a) Diffusion and Osmosis
(b) Transpiration and Evaporation
(c) Osmotic Pressure and Osmotic Potential
(d) Imbibition and Diffusion
(e) Apoplast and Symplast pathways of movement of water in plants.
(f) Guttation and Transpiration.
Answer:-
(a) Diffusion and Osmosis
Diffusion |
Osmosis
|
It is a movement of molecules from high concentration to low concentration. |
It is a movement of molecules from high concentration to low concentration through semi permeable membrane. |
It can occur in solids, liquids, and gases. |
It occurs in the liquid medium. |
It does not require any driving Force. |
It occurs in response to a driving force. |
OR
Osmosis is a type of diffusion. When diffusion happens across a semi-permeable membrane, it is called osmosis. Semi-permeable membrane is not necessary in all cases of diffusion.
(b) Transpiration and Evaporation
Transpiration |
Evaporation
|
It occurs in plants. |
It occurs from any free surface and involves living and non-living surfaces. |
It occurs mainly through the stomatal pores on plant leaves. |
It occurs through any free surface. |
It is controlled by environmental factors as well as physiological factors of plants |
It is entirely driven by environmental factors. |
OR
Evaporative loss of water from plants is called transpiration, while conversion of water into vapour at any temperature is called evaporation.
(c) Osmotic Pressure and Osmotic Potential
Osmotic Pressure |
|
It is expressed in bars with a positive sign. |
It is expressed in bars with a negative sign. |
It is a positive pressure. |
It is a negative pressure. |
Its value increases with an increase in the concentration of solute particles. |
Its value decreases with an increase in the concentration of solute particles. |
OR
The pressure which needs to be applied to prevent the inward flow of water across a semi-permeable membrane. In other words, the minimum pressure needed to negate the osmosis is called osmotic pressure. On the other hand, the ability of a solution to suck in water from across a semi-permeable membrane is called osmotic potential.
(d) Imbibition and Diffusion
Imbibition |
|
Imbibition is a special type of diffusion when water is absorbed by solids and colloids causing them to enormously increase in volume. |
Diffusion is the passive movement of particles, ions, and molecules along the concentration gradient. |
It usually involves water. |
It involves solids, liquids, and gases. |
Random movement of molecules to attain concentration equilibrium is called diffusion. When osmosis happens in a way that solids (colloids) take up water, it is called imbibition.
(e) Apoplast and Symplast pathways of movement of water in plants.