Nutrition in Plants

Chapter 1

 1. Why do organisms take food?

Ans: Organisms take food to get nutrients in there body .


2. Distinguish between a parasite and a saprotroph.

Ans: Parasite get their nutrition from another organism, whereas saprotroph get their nutrition from dead and decaying organic debris .


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

Ans: The presence of starch in leaves can be tested by the Iodine test.


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

Ans: Green plants manufacture their own food through a fascinating process called photosynthesis. Here's a simplified breakdown:

  1. Ingredients: Plants gather water from the soil through their roots and carbon dioxide from the air through tiny pores on their leaves called stomata. Sunlight serves as the energy source. Finally, plants contain a green pigment called chlorophyll, crucial for capturing sunlight.

  2. Light Capture: Chlorophyll acts like a solar panel, absorbing specific wavelengths of sunlight and converting this light energy into a usable form of chemical energy.

  3. Water Splitting: Using the captured energy, the plant splits water molecules into hydrogen and oxygen. The oxygen is released back into the atmosphere as a byproduct.

  4. Food Building: With the help of enzymes, the plant uses the hydrogen from water and the carbon dioxide from the air to build glucose, a simple sugar which is the primary form of food for the plant.

  5. Food Distribution: The glucose is then transported throughout the plant to provide energy and fuel growth.


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

6. Fill in the blanks:

(a) Green plants are called __________ since they synthesise their own food.

Ans: Autotrophs .


(b) The food synthesized by plants is stored as _________.

Ans: Starch .


(c) In photosynthesis solar energy is absorbed by the pigment called ___________.

Ans: Chlorophyll .


(d) During photosynthesis plants take in ___________ and release ________ gas.

Ans: Carbon dioxide and Oxygen .


7. Name the following:

(i) A parasitic plant with yellow, slender and branched stem.

Ans: Cuscuta plant .

(ii) A plant that is partially autotrophic.

Ans: Pitcher plant .

(iii) The pores through which leaves exchange gases.

Ans: Stomata .

8. Tick the correct answer:

(a) Cuscuta is an example of:

(i) autotroph (ii) parasite (iii) saprotroph (iv) host

Ans: (ii) parasite .

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

(i) Cuscuta (ii) china rose (iv) pitcher plant (iv) rose

Ans: (iv) pitcher plant .


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

   Column I                      Column II

1.Chlorophyll              a)  Rhizobium

2.Nitrogen                    b) Heterotrophs

3.Cuscuta                      c) Pitcher plants 

4.Animals                      d) Leaf

5.Insects                        e) Parasite

Ans: 1. Chlorophyll = d) Leaf 

          2. Nitrogen = a) Rhizobium

         3. Cuscuta =    e) Parasite

         4.  Animals = b) Heterotrophs

         5.  Insects  =   C) Pitcher plants


10. Mark T if the statement is true and F if it is false: 

(1) Carbon dioxide is released during photosynthesis. (T/F) 

Ans: False .

(2)Plants which synthesize their food are called saprotrophs. (T/F) 

Ans: False .

(3) The product of photosynthesis is not a protein. (T/F) 

Ans: True .

(4) Solar energy is converted into chemical energy during photosynthesis.(T/F) 

Ans: 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) Petals

Ans: (ii) Stomata .


(12) Choose the correct option from the following: 

        Plants take carbon dioxide from the atmosphere mainly through their: 

        (i)  Roots (ii) Steam (iii) Flowers (iv) Leaves 

Ans: (iv) Leaves 


 13. Why do farmers grow many fruits and vegetable crops inside inside large green houses? What are the advantages to the farmers?

Ans:        Farmers cultivate fruits and vegetables inside greenhouses for several reasons, all of which offer significant advantages:

  • Controlled Environment: Greenhouses act like giant shields, protecting crops from the whims of nature. Farmers can regulate factors like temperature, humidity, and even light levels to create ideal growing conditions for specific plants, regardless of the outdoor climate. This allows them to grow crops that wouldn't normally thrive in their region or even grow them year-round.

  • Pest and Disease Protection: The physical barrier of the greenhouse keeps out many destructive pests like insects, rodents, and birds that can damage crops. Additionally, controlling the environment within the greenhouse helps limit the spread of diseases that might plague outdoor crops.

  • Increased Yield and Quality: By providing optimal growing conditions, greenhouses can significantly boost the yield of fruits and vegetables. This translates to more produce per square foot of growing space. Additionally, the controlled environment minimizes damage from pests and diseases, leading to higher quality produce.

  • Off-Season Production: Greenhouses allow farmers to extend their growing season or even grow crops year-round. This enables them to supply fresh produce to consumers even when it wouldn't be available outdoors due to seasonal limitations.

Overall, greenhouses offer farmers a powerful tool to increase their production, improve crop quality, and extend their growing seasons. This leads to greater profits and a more reliable supply of fresh fruits and vegetables for consumers.


Type by Jyotishna Hazarika