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NCERT solutions for Class 7th Science Chapter- 1 ” Nutrition In Plants”

TEXTUAL QUESTIONS

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Q.1- Why do organisms need to take food?

Ans- Organisms need to take food for growth and to get energy. Food is also needed for repairing damaged body parts and to fight against diseases.

Q.2- Distinguish between a parasite and a saprotroph.

Ans- Parasite – Organisms which derive nutrition from the body of other living organisms are called parasites. Eg. Cuscuta.

Saprotroph- Organisms which derive nutrition from dead and decaying organic matter are called saprotroph. Eg. Mushroom.

Q.3- How would you test the presence of starch in leaves?

Ans- 1) Take a potted plant and cover a leaf of potted plant with black paper.

2) Keep the plant in sunlight for 3-4 days.

3) Remove the black paper.

4) Pour 2-3 drops of Iodine solution on the portion which was wrapped in the black paper.

5) The portion of the leaf covered with black paper will not turn blue which shows the absence of starch.

6) Pour 2-3 drops of Iodine solution on the other portion of leaf.

7) The portion of leaf which was not covered with black paper turns blue which shows the presence of starch.

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

Ans- All green plants synthesise food with the process called photosynthesis. The process of preparing food from carbon dioxide and water in the presence of sunlight and chlorophyll is called photosynthesis.

The process of photosynthesis can be expressed by the following reaction :

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Q.5- Show with the help of sketch that the plants are the ultimate source of food.

Ans- Following sketch shows that the plants are the ultimate source of food-

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Q.6- Fill in the blanks-

a) Green plants are called_______ since they synthesise their own food.

b) The food synthesised by plants is stored as_____.

c) In photosynthesis solar energy is captured by the pigment called_______.

d) During photosynthesis plants take in_____ and release________.

Ans- a) autotrophs (b) starch (c) chlorophyll (d) carbon dioxide, oxygen

Q.7- Name the following :

a) A parasitic plant with yellow, slender and tubular stem.

b) A plant that has both autotrophic and heterotrophic nutrition.

c) The pores through which leaves exchange gases.

Ans- a) Cuscuta.

b) Pitcher plant.

c) Stomata.

Q.8- Tick (✓) the correct answer :

a) Amarbel is an example of –

i) autotroph

ii) parasite

iii) saprotroph

iv) host

b) The plant which traps and feeds on insects is –

i) cuscuta

ii) china rose

iii) pitcher plant

iv) rose

Ans- a) parasite. b) pitcher plant

Q.9- Match the columns given in Column I with those in Column II.

IMG 20220504 104137

Ans-

IMG 20220504 104158

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Q.10- Mark ‘T’ if the statement is true and ‘F’ is it is false.

i) Carbon dioxide is released during photosynthesis.

ii) Plants which synthesise their food themselves are called saprotrophs.

iii) The product of photosynthesis is not a protein.

iv) Solar energy is converted into chemical energy during photosynthesis.

Ans- i) F (ii) F (iii) T (iv) T

Q.11- Choose the correct option from the following :

Which part of the plant gets Carbon dioxide from air for photosynthesis?

i) Root hair

ii) Stomata

iii) Leaf veins

iv) Sepals

Ans- Stomata.

Q.12- Choose the correct option from the following :

Plants take carbon dioxide from the atmosphere mainly through their :

i) Roots

ii) stem

iii) Flowers

iv) Leaves

Ans- Leaves.