NCERT Solutions for
Class 7th Science
Chapter 1 : Nutrition in Plants
Chapter 1 : Nutrition in Plants
Exercise:
1.Why do organisms need to take food?
Answer:
Organisms need to take food to get energy and perform life process. The life process include nutrition, respiration, growth, excretion, reproduction and response to stimuli which can only be done by intake of food.
2.Distinguish between a parasite and a saprotroph.
Organisms need to take food to get energy and perform life process. The life process include nutrition, respiration, growth, excretion, reproduction and response to stimuli which can only be done by intake of food.
2.Distinguish between a parasite and a saprotroph.
Answer:
Parasite
|
Saprotroph
|
The organism that grows on the body of another organism
and derives nutrients from it is known as a parasite.
|
The organism that obtains nutrients from the dead or
decaying organic matter is called saprotroph.
|
They take the readymade food from the host.
|
They take the digested and decayed food.
|
They directly feed on living organisms for their
nutrition.
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They feed on dead and decaying organism.
|
Examples- Cuscuta and orchids.
|
Examples- Fungi and some bacteria.
|
3. How would you test the
presence of starch in leaves?
Answer:
Answer:
Steps to test the presence of starch in leaves :
|
Step 1:
A fresh leaf
is taken.
|
Step 2:
The leaf is
boiled in water for few minutes to kill the cells in the leaf.
|
Step 3:
Now, dip
this leaf in iodine solution.
|
Step 4:
The color of
the leaf will changes into blue black color when iodine is added to it which
shows the presence of starch in it.
|
4. Give a brief description of
the process of synthesis of food in green plants.
Answer:
Photosynthesis is the process synthesis of food in the plants with the help of chlorophyll and carbon dioxide in the presence of sunlight.Water and minerals present in the soil are absorbed by the roots and transported to the leaves by the vessels.Carbon dioxide from air is taken through stomata present in leaves.Leaves are the food factories of the plants which capture the energy of the sunlight with the help of chlorophyll. This energy is used to synthesize food from carbon dioxide and water.
Answer:
Photosynthesis is the process synthesis of food in the plants with the help of chlorophyll and carbon dioxide in the presence of sunlight.Water and minerals present in the soil are absorbed by the roots and transported to the leaves by the vessels.Carbon dioxide from air is taken through stomata present in leaves.Leaves are the food factories of the plants which capture the energy of the sunlight with the help of chlorophyll. This energy is used to synthesize food from carbon dioxide and water.
sunlight
Carbondioxide + Water
___________________→ Carbohydrate + Oxygen
chlorophyll
5. Show with the help of a sketch that the plants are the ultimate source of food.
Answer:
The food chain shows that the plant is the ultimate producer. Only plant can produce food and rest of other organisms are directly or indirectly dependent on it.
6. Fill in the blanks:
(a) Green plants are called ________________ since they synthesise their own food.
(b) The food synthesised by the plants is stored as _________________.
(c) In photosynthesis solar energy is captured by the pigment called ___________.
(d) During photosynthesis plants take in ______________________ and release __________________.
Answer:
(a) autotrophs
(b) starch
(c) chlorophyll .
(d) carbon dioxide & oxygen.
7. Name the following:
(i) A parasitic plant with yellow, slender and tubular stem.
(ii) A plant that has both autotrophic and heterotrophic mode of nutrition.
(iii) The pores through which leaves exchange gases.
Answer:
(i) Cuscuta (Amarbel)
(ii) Pitcher plant
(iii) Stomata
8. Tick the correct answer:
(i) Amarbel is an example of:
(a) autotroph
(b) parasite
(c) saprotrop
(d) host
(d) carbon dioxide & oxygen.
7. Name the following:
(i) A parasitic plant with yellow, slender and tubular stem.
(ii) A plant that has both autotrophic and heterotrophic mode of nutrition.
(iii) The pores through which leaves exchange gases.
Answer:
(i) Cuscuta (Amarbel)
(ii) Pitcher plant
(iii) Stomata
8. Tick the correct answer:
(i) Amarbel is an example of:
(a) autotroph
(b) parasite
(c) saprotrop
(d) host
Answer: (b) parasite
(ii) The plant which traps and feeds on insects is:
(a) Cuscuta
(b) china rose
(c) pitcher plant
(d) rose
Answer: (c) pitcher plant
9. Match the items given in Column I with those in
(ii) The plant which traps and feeds on insects is:
(a) Cuscuta
(b) china rose
(c) pitcher plant
(d) rose
Answer: (c) pitcher plant
9. Match the items given in Column I with those in
Column II:
Column
I
|
Column II
|
Chlorophyll
|
Bacteria
|
Nitrogen
|
Heterotrophs
|
Amarbel
|
Pitcher Plant
|
Animals
|
Leaf
|
Insects
|
Parasite
|
Answer:
Column I
|
Column II
|
Chlorophyll
|
Leaf
|
Nitrogen
|
Bacteria
|
Amarbel
|
Parasite
|
Heterotrophs
|
Animals
|
Insect
|
Pitcher Plant
|
10. Mark ‘T’ if the statement is true and ‘F’ if it is
false:
(i) Carbon dioxide is released during photosynthesis. (T/F)
Answer: False
(ii) Plants which synthesise their food themselves are called saprotrophs. (T/F)
(i) Carbon dioxide is released during photosynthesis. (T/F)
Answer: False
(ii) Plants which synthesise their food themselves are called saprotrophs. (T/F)
Answer: False
(iii) The product of photosynthesis is not a protein. (T/F)
Answer: True
(iv) Solar energy is converted into chemical energy during photosynthesis. (T/F)
Answer: True
11. Choose the correct option from the following:
Which part of the plant takes in carbon dioxide from the air for photosynthesis?
(i) Root hair
(ii) Stomata
(iii) Leaf veins
(iv) Sepals
Answer: (ii) Stomata
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
Answer: (iv) leaves
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
Answer: (iv) leaves