NCERT Solutions class 7 Science 1. Nutrition in Plants Text-book Questions (Exercise)

Exercise (NCERT Text Book) Chapter -1  

Q1. – Why do organisms need to take food?

Ans – Organisms need food to

(i) Get energy to do work.

(ii) Build up body .

(iii) Repair damages in the body.

(iv) Maintain the functions of the body.

Q2. – Distinguish between a parasite and a saprotroph.

Ans. – Parasite: 

(i) It gets nutrients from host on which they live.

(ii) It lives on or in the host.

(iii) Ex: Cuscuta 

Saprotroph : -

(i) It gets nutrient from dead and decaying matter.

(ii) It lives on dead or decaying stuff.

(iii) Ex: Bacteria and fungi. 

Q3. – How would you test the presence of starch in leaves?

Ans : When iodine comes in contact with starch, a dark blue colour appears.  Testing the presence of starch in leaves, when we dropped some solution of iodine on leaves they give dark blue colour. Thus we can say there is starch in leaves.  

Q4. – Give a brief description of the process of synthesis of food in green plants.

Ans : the process of synthesis of food in green plants is called photosynthesis, in which green palnts synthesise their food using carbon dioxide and water in presence of chlorophyll and sunlight. This process takes place in leaves.  The products of photosynthesis are carbohydrate and oxygen. The equation of this process is

Q5.  – Show with the help of a sketch that the plants are the ultimate source of food.

Ans :

Q6.  – Fill in the blanks:

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

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

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

(d) During photosynthesis plants take in ______________________ and release __________________.

Ans:

(a)         Autotrophs

(b)         Starch

(c)          Chlorophyll

(d)         carbon dioxide and water, carbohydrate and oxygen.

Q7.  – Name the following:

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

Ans : cuscuta (Amarbel)

(ii) A plant that has both autotrophic and heterotrophic mode of nutrition.

Ans : Pitcher plant

(iii) The pores through which leaves exchange gases.

Ans : Stomata

Q8.  – Tick the correct answer:

(a) Amarbel 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

Q9.  – Match the items given in Column I with those in Column II:

Column I                            Column II

Chlorophyll                         Bacteria

Nitrogen                           Heterotrophs

Amarbel                           Pitcher plant

Animals                            Leaf

Insects                             Parasite

Ans :

Column I                            Column II

Chlorophyll                           Leaf

Nitrogen                             Bacteria

Amarbel                              Parasite

Animals                              Heterotrophs

Insects                               pitcher plant

Q10. – 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 themselves 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)

Ans :

(i)  F

(ii)  F

(iii) T

(iv) T

Q11. – Choose the correct option from the following:

Which part of the plant gets carbon dioxide from the air for photosynthesis.

(i) root hair (ii) stomata (iii) leaf veins (iv) sepals

Ans : (ii) stomata

Q12. – 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

Ans : (iv) leaves