If you are a student and studying in class 7 or getting preparation for different exam please read the questions and answers and I hope you will get benefit from it. In this article I have covered all the questions with satisfied answers below. If you read the article you need not to go anywhere else to solve the problems of this chapter.
1. Why do organisms take food?
Answer: All living organisms take food to get essential nutrients like proteins, carbohydrates, vitamins fats and minerals dissolved in waters which are very essential for building their bodies, to grow, to repair damaged parts of their bodies and provide the energy to carry out life processes.
2. Distinguish between a parasite and a saprotroph.
Answer: The organisms can’t synthesise their own foods or nutrients and depend on their host are called parasite. Example, cuscuta. Whereas the organisms absorb the nutrients from dead and decaying matter are called saprotroph. Example, fungi.
3. How would you test the presence of starch in leaves?
Answer: We can test the starch in leaves by the Iodine test. First of all boil few green leaves in water with few drops of alcohol then wash the leaves carefully and pour few drops of iodine solution on leaves and you would observe the colour change to blue that indicates the presence of startch.
4. Give a brief description of the process of synthesis of food in green plants.
The process of preparing or synthesis food in leaves or other part green plants is called photosynthesis which mainly occurs in green leaves. We know that the leaves have a green pigment called chlorophyll which helps leaves to capture the energy coming from sunlight. Leaves use that energy to prepare food from carbon dioxide and water. In the process of photosynthesis the chlorophyll, sunlight, carbon dioxide and water are essential components. It is a unique process on the earth. The solar energy is captured by the green leaves and stored in the plant in the form of food.
5. Show with the help of a sketch that plants are the ultimate source of food.
Step 1: Only plants can prepare their own food itself with the help of energy and others peripherals carbon dioxide and water. That is why plants are Autotrophs or producers
Step 2: Saprotrophs are allow depend on death and decay bodies both of autotrophs and heterotrophs
Step 3: heterotrophs Heterotrophs both Herbivores and carnivores depend on plants
6. Fill in the planks:
a. Green plants are called Autotrophs since they synthesise their own food.
b. The food synthesized by plants is stored as Starch.
c. In photosynthesis solar energy is absorbed by pigment called Chlorophyll.
d. During photosynthesis plants take in Carbon Dioxide and release oxygen.
7. Name the following:
(i) A parasitic plant with yellow, slender and branched stem.
(ii) A plant that is partially autotrophic.
(iii) The pores through which leaves exchange gases.
8. Tick the correct answer:
a. Cuscuta 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
9. Match the items given in column I with those in column II:
Column I Column II
Cuscuta Pitcher plant
Column I Column II
Insects 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)
(ii) Plants which synthesise their food are called saprotrophs. (T/F)
(iii) The product of photosynthesis is not a protein. (T/F)
(iv) Solar energy is converted into chemical energy during photosynthesis. (T/F)
11. Choose the correct option from the following:
Which of part of the plant takes in carbon dioxide from the air for photosynthesis?
(i) Root of hair (ii) Stomata (iii) Leaf veins (iv) Petals
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
13. Why do farmers grow many fruits and vegetable crops inside large green house? What are the advantages to the farmers?
Answer: Farmers grow many fruits and vegetable crop s inside large green house to protect their own foods and surplus send, for money or help, to city or in the area where foods do not produce. It also use in drought areas to for filling the scarcity of foods. There have many other reason for this purpose.
Farmers always crops a large area the same grain because they get many advantages from it like irrigation, ploughing, sowing seed, and maintaining, harvesting and labour wage.