Question

Osmosis is the movement of water molecules from the solution with lower solute concentration (hypotonic solution) to the solution with higher solute concentration (hypertonic solution) through a selectively-permeable membrane. The movement takes place due to the osmotic gradient created by difference in concentration of the solutions on both sides of the membrane and the end result is a state where osmotic equilibrium is reached wherein movement of the fluid ceases.
(a) What is the importance of osmosis in daily life ? Give four examples.
(b) Is it useful for plants ?

CBSE Class IX Science SA 2 (3 Marks)

Answer 1

(a) (1) Osmosis also plays an important role in the body. It helps in the transfer of water and various nutrients between blood and the fluid of cells.

(2) When your hands are immersed in dishwater for a long time, your skin looks bloated. This is an effect of osmosis.

(3) When you pour salt onto a slug, water diffuses and slug shrinks as a result of osmosis.

(4) When you cook food and put sauce in the liquid part of your dish, some part of the solute moves inside the solid part of the food you are cooking. The solid part could be an egg, piece of meat, but the sauce is made of solute and not water, so it will move into the food.

(5) Reverse osmosis is a type of osmosis that is used to convert sewage water into clean drinking water.          

(b) Yes, it is useful for plants

Answer 2

osmosis is a biological process in which the movement of molecules from low concentration to high concentration through a semi permeable membrane