Class VII Exercise Solutions

                                                        Nutrition in plants

Que.1.Why do organisms need to take food?

Ans. The organisms need to take food to build their bodies, to grow, to repair damaged part of their bodies and to obtain the energy to carry out life processes. Food provide protection against infections.

 Que.2.Distinguish between a parasite and a saprotroph.

Ans.

PARASITES	SAPROTROPHS
Live inside the body of host and derive the food from it	Feed on dead and decay organic matter
They harm the body of host	They are cleaning agents
Ex.Cuscuta	Ex. Fungi

Que.3.how would you test the presence of starch in leaves?

Ans. The presence of starch in leaves can be tested by Iodine test. Iodine turns starch solution into blue black colour . Pour few drops of dilute iodine solution on a boiled leaf. The leaf becomes blue black in colour which proves the presence of starch in it.

Que.4.Give a brief description of the process of synthesis of food in green plants.

Ans. Plants prepare their own food by the process of photosynthesis . Leaves of the plants have green pigment called chlorophyll , which helps them to capture the energy of the sunlight. The plants synthesise their food from carbon di oxide and water in the presence of sunlight. This process is called Photosynthesis.

The reaction of Photosynthesis-

                                           Sunlight

Carbon di oxide  +  water    ------------>              Glucose + oxygen

                                           Chlorophyll

Que.5.Show with the help of a sketch that the plants are the ultimate source of food.

Ans.

                         Sun    à   Green plants    à   Herbivores   à  Carnivores

Hence carnivores and herbivores depend on green plants for food.

Que.6. Fill in the blanks-

a.Green plants are called  AUTOTROPHS  since they synthesis their own food.

b.The food synthesised by the plants is stored as .. STARCH.

c.In photosynthesis solar energy is captured by the pigment called CHLOROPHYLL

d.During photosynthesis, plants take in  Co₂  and release  O₂

Que.7.Name the following

a.A parasitic plant with yellow, slender and tubular stem----CUSCUTA (AMARBEL)

b.A plant that has both autotrophic and heterophic mode of nutrition  PITCHER PLANT (INSECTIVOROUS PLANT)

c.The pores through with leaves exchange gases.   STOMATA

Que.8 (a).Amarbel is an example of  PARASITE

          (b) The plant which traps and feeds on insects is PITCHER PLANT

                            (Remaining solutions will be posted soon…)