Define the term osmosis.Give details of the types of osmosis in plants.

Explanation

Osmosis(Latin:Osmos-impulse,urge)is special typ of diffusion .It represents the movement of water or solvent molecules through a selectively permeable membrane from the place of its higher concentration (high water potential)to the place of its lower concentration (low water potential).
Types of solution based on concentration:
(i)Hypertonic (hyper=High,tonic=solute):This is a strong solution (low solvent from from other solutions).
(ii)Hypotonic (Hypo=low,tonic=solute):
It refers to two solutions having same concentration.In this condition the net movement of water molecule will be zero.
The term hyper,hypo and isotonic are relative terms which can be only is comparison with another solution.
Type of osmosis:Based on the direction of movement of water or solvent in an osmotic system ,two type of osmosis can occur,they and Endosmosis and Exosmosis.
(i)Endosmosis:Endosmosis is defined as the osmotic entry of solvent into a cell or a system when it is placed in a pure water or hypotonic solution. eg:dry raisins (high solute and low solvent)placed in the water .it swells up due to turgidity .
(ii)Exosmosis:Exosmosis is defined as the osmotic withdrawal of water from a cell or system when it is placed in a hypertonic solution.Exosmosis in a plant cell leads o plasmolysis.