Gujarat Board GSEB Textbook Solutions Class 7 Science Chapter 1 Nutrition in Plants Textbook Questions and Answers, Notes Pdf.

Gujarat Board Textbook Solutions Class 7 Science Chapter 1 Nutrition in Plants

Gujarat Board Class 7 Science Nutrition in Plants Textbook Questions and Answers

Question 1.
Why do organisms take food?
Answer:
Food is needed by all organisms for many purposes:

• The main function of food is to help in growth and development of the body.
• Food provides energy for movements such as running, walking or raising our arm.
• Food is also needed for replacement and repairing damaged parts of body.
• Food gives us resistance to fight against diseases and protects us from infections.

Question 2.
Distinguish between a parasite and a saprotroph?
Answer:
Parasite:

• Parasite feeds on a living organism.
• The organism on which it feeds is called host.
• A parasite takes ready-made food from the organism on which it feeds.

Saprotrophs:

• They feed on dead and decaying organism.
• They do not feed on a living organism.
• They secrete digestive juices on the matter they live and convert it into, a solution and then absorb it.

Question 3.
How would you test the presence of starch in leaves?
Answer:
The presence of starch in leaves can be tested by Iodine test. When we remove chlorophyll from leaf by boiling it in alcohol and then put 2 drops of iodine solution, its colour changes to blue and indicates the presence of starch.

Question 4.
Give a brief description of the process of synthesis of food in green plants.
Answer:
The green plants have chlorophyll in the leaves. These leaves use CO₂ and water to make food in the presence of sunlight.

During photosynthesis oxygen is released.

Question 5.
Show with the help of a sketch that plants are the ultimate source of food.
Answer:

Sketch to show that plants are the ultimate source of food.

Question 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 absorbed by the pigment called _______.
(d) During photosynthesis plants take in _______ and release _______ gas.
Answer:
(a) autotrophs
(b) starch
(c) chlorophyll
(d) carbon dioxide, oxygen

Question 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.
Answer:
(i) Cuscuta
(ii) Insectivorous plant or Pitcher Plant
(iii) Stomata

Question 8.
Tick the correct answer:
(a) Cuscuta is an example of:
(i) autotroph
(ii) parasite
(iii) saprotroph
(iv) host
Answer:
(ii) parasite

(b) The plant which traps and feeds on insects is:
(i) cuscuta
(ii) china rose
(iii) pitcher plant
(iv) rose
Answer:
(iii) pitcher plant

Question 9.
Match the items given in Column I with those in Column II:

Answer:

Question 10.
Mark ‘T’ if the statement is true and ‘F’ if 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.
Answer:
(i) False
(ii) False
(iii) True
(iv) True

Question 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) Petals
Answer:
(ii) Stomata

Question 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

Question 13.
Why do farmers grow many fruits and vegetable crops inside large green houses? What are the advantage to the farmers?
Answer:
Growing crops inside large green houses provide required temperature for crops, prevent crops from wind, cold, insects, etc. The advantages of farming in green houses is better yield of crops and it requires less efforts of farmer.

Extended Learning – Activities And Projects

Question 1.
Project: Take a potted plant with broad leaves. Take two strips of black paper and cut out a small square in their centres. Cover a part of two leaves with these papers and secure them with paper clips (Fig. 1.4). Keep the plant in the sunlight for 2-5 days. Observe the difference in the colour of the covered and Experiment to test the uncovered the occurrence of portions on photosynthesis the leaf. Perform iodine test on this leaf.

Did the two parts show different results? Now take second leaf. Remove the strip and expose the covered part to the sunlight for 2-3 days and do the iodine test again. Describe your observations.
Answer:
The colour of the covered portion of the leaf is pale yellow while un – covered portion is green in colour. Only the uncovered part becomes blue-black on treatment with iodine solution, that shows presence of starch.

When iodine test is performed on the second leaf, after exposing the covered part to the sunlight for 2-3 day, the whole portion shows presence of starch. These observations lead us to conclude that light is necessary for photosynthesis.

Question 2.
Visit a green house if there is one near your place. Observe how they grow plants. Find out how they regulate the amount of light, water and carbon dioxide to growtheplants.
Answer:
Green house is a glass house in which plants are kept to protect them from cold weather. They are usually made in colder regions. The glass panels trap the heat from the sunlight inside the green house.

Question 3.
Try growing a sweet potato just in water. Describe your experiment and observations.
Answer:
Take a big beaker or a glass tumbler three-fourth filled with water. Put a small sweet potato in it. See that sweet potato completely dip into the water. After 4-5 days, you may observe that the sweet potato starts decaying. This show that only water is not enough for growth of plants.