IGCSE Biology Paper-1: Specimen Questions with Answers 116 - 116 of 208

Question 116




What is a description of transpiration?


Choice (4)
a.Movement of water from the roots to the leaves
b.Movement of water through the cells of the leaf
c.Loss of water vapour from the leaves and stems of a plant
d.Exchange of gases between the leaf and the atmosphere




  • Land plants absorb a large quantity of water from the soil, but only a very small fraction of water utilized in various metabolic activities by the plants. The rest amount of it, evaporates from the stem and leaves. About 98 percent of the water absorbed by land plants evaporates from the aerial parts and diffuses into the atmosphere. “The loss of water in the form of vapour from the aerial parts of a plant is called transpiration. ” Maximum transpiration occurs in Mesophytic plants.
  • It is an evaporation phenomenon, but it differs from the general process of evaporation. Evaporation is referred to the loss of water vapours from a free surface, whereas in case of transpiration of water passes through the epidermis with its cuticle or through the stomata. Transpiration maintained the atmospheric temperature.
Flow of Water

Flow of Water

Loading image