NCERT Solutions for Class 7 Science Chapter 1 Nutrition in Plants

NCERT Solutions for Class 7 Science Chapter 1 Nutrition in Plants

Exercise

Question 1. Why do organisms take food?

Answer:- All organism need to take food to get energy for their growth, development and maintenance.

 

Question 2. Distinguish between a parasite and a saprotroph.

Answer:- 

Parasites

Saprophytes

Parasites live on or in a host and get its food at the expense of its host

Acquire nutrients from dead and decaying matter

Example: Tapeworm, roundworm

Example: Mushrooms, Fungi

 

 

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

Answer:- Iodine testing can be used to determine whether or not leaves contain starch. Add two drops of iodine solution to the leaf, the colour changes to blue, indicating the presence of starch.

 

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

Answer:-  Chlorophyll is found in the leaves of green plants. In the presence of sunlight, the leaves produce food using CO2 and water.

 

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

Answer:-

 

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) Green plants are called autotrophs since they synthesise their own food.

(b) The food synthesised by plants is stored as starch.

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

(d) During photosynthesis plants take in carbon dioxide and  release oxygen gas.

 

 

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). 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   (iv) pitcher plant   (iv) rose

Answer:- (iv) pitcher plant   

 

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

 Column I

Column II

Chlorophyll

Rhizobium

Nitrogen

Heterotrophs

Cuscuta

Pitcher plant

Animals

Leaf

Insects

Parasite

 

Answer:-

Column I

Column II

Chlorophyll

Leaf

Nitrogen

Rhizobium

Cuscuta

Parasite

Animals

Heterotrophs

Insects

Pitcher plant

 

 

Question  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)

Answer:-

  1. False
  2. False
  • True
  1. 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 advantages to the farmers?

Answer:- Green house provide favourable climatic conditions like suitable temperature for these crops. Advantages to farmers while growing fruits and vegetable crops inside greenhouses are:-

  1. The crops grow well.
  2. It protects crops against pathogens and bad climatic conditions.
  • It protects crops from the wind and rodents