7th Standard Science ( Nutrition in Plants )

Nutrition in Plants

I. Fill in the blanks:
1. Green plants are called autographs since they synthesis’ their own food.

2. The food synthesized by the plants is stored as starch.

3. In photosynthesis solar energy is captured by the pigment called Chlorophyll.

4. During photosynthesis plants take in carbon dioxide and release oxygen gas.

 

II. Choose the correct answer:
1. Cuscuta is an example of parasite
(i) autotroph
(ii) parasite
(iii) saprotroph
(iv) host
 

2. Plant which traps and feeds on insects is pitcher plant 

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

3. Which part of the plant takes in carbon dioxide from the air for photosynthesis? Stomata 

(i) Root hair
(ii) Stomata
(iii) Leaf veins
(iv) Sepals

4. Plants take carbon dioxide from the atmosphere mainly through their leaves

(i) roots
(ii) stem
(iii) flowers
(iv) leaves 

 

III. Name the following:
1. A parasitic plant with yellow, slender and tubular stem.
Ans: Cuscuta

2. A plant that has both autotrophic and heterotrophic mode of nutrition.
Ans: Pitcher plant

3.The pores through which leaves exchange gases.
Ans: Stomata

 

IV. Mark 'T' if the statement is true and 'F' if it is false:   

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

2. Plants which synthesis’ their food themselves are called saprotroph. (F)

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

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

 

V. Answer the following:-

1: Why do organisms need to take food?
Ans: All living organisms require food to survive. It gives them energy to perform various activities. All activities such as playing, running, walking, studying, etc. require energy. The various components present in our food such as carbohydrates, proteins, fats, vitamins, and minerals provide energy to our body. These are also important for growth and development of the body.

2: Distinguish between a parasite and a saprotroph.
Ans:

Parasite Saprotroph	other me
The organism that grows on the body of The organism and derives nutrients from it the dead known as a parasite. Called saprotroph.	e organism that obtains nutrients from an or decaying organic matter is
Examples of parasites are Cuscuta and orchids.	Examples of saprotroph are fungi and so bacteria.

 

3: How would you test the presence of starch in leaves?
Ans: Take two healthy green potted plants of the same type. Keep one potted plant in a dark room for one or two days in order to remove all the starch from the leaves. Keep the other plant in sunlight. Now, take one leaf from each potted plant and put a few drops of iodine solution on them. Then note down the observation.
No blue black colour will be observed on the leaves of the plant kept in the dark room. This indicates the absence of starch. Blue black colour will be observed on the leaves of the plant kept in sunlight. This indicates the presence of starch.

4: Give a brief description of the process of synthesis of food in green plants.
Ans: Photosynthesis is defined as the process in which the chlorophyll-containing plant cells synthesis food in the form of
carbohydrates, using carbon dioxide and water in the presence of solar energy. Photosynthesis Sources of raw materials required for photosynthesis:

Step 1: Water is taken in from the roots of the plant and is transported to the leaves.

Step 2: Carbon dioxide from the air enters the leaves through the tiny pores called stomata and diffuses to the cells containing
chlorophyll.

Step 3: Solar energy is used to break water into hydrogen and oxygen. This hydrogen is combined with carbon dioxide to form food for the plants, which is ultimately used by the animals as well.
Thus, photosynthesis can be represented by the following equation.

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

Ans: 

 

Photosynthesis

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

Ans: By growing fruits and vegetable crops inside large greenhouses, the growth of the fruits and crops is enhanced because more sunlight is exposed to the plants because the amount of the Greenhouse Gas (Co2) is more than normal and it doesn't leave the greenhouse.

VI. Match the items given in Column I with those in Column

Chlorophyll	Bacteria
Nitrogen	Heterotrophs
Amarbel	Pitcher plant
Animals	Leaf
Insects	Parasite