Plant

Biology

GASEOUS EXCHANGE IN PLANTS

GASEOUS EXCHANGE IN PLANTS
Oxygen is required by plants for the production of energy for cellular activities.
Carbon (IV) oxide is required as a raw material for the synthesis of complex organic substances.
Oxygen and carbon (IV) oxide are obtained from the atmosphere in the case of terrestrial plants and from the surrounding water in the case of aquatic plants.
Gaseous exchange takes place mainly through the stomata.

Biology

WATER RELATIONS IN PLANT AND ANIMAL CELLS

WATER RELATIONS IN PLANT AND ANIMAL CELLS
The medium (solution) surrounding cells or organisms is described by the terms hypotonic, hypertonic and isotonic
A solution whose solute concentration is more than that of the cell sap is said to be hypertonic

A cell placed in such a solution loses water to the surroundings by osmosis

A solution whose solute concentration is less than that of the cell sap is said to be hypotonic

A cell placed in such solution gains water from the surroundings by osmosis

A solution which has the same solute concentration as the cell sap is said to be isotonic