Lesson: Nutrition in Plants

Question: 1

Why do organisms need to take food?

Solution:

Organisms need to take food to get energy and perform the essential life processes for survival, such as, growth and development, respiration, reproduction, excretion, and response to stimuli.

Question: 2

Distinguish between a parasite and a saprotroph.

Solution:

Question: 3

How would you test the presence of starch in leaves?

Solution:

Step 1: A fresh leaf is collected as sample.

Step 2: The leaf is then boiled in water for some minutes in order to kill the leaf cells.

Step 3: This boiled leaf is then dipped in an iodine solution.

Step 4: If the leaf colour changes to blue black when dipped in iodine; it shows the presence of starch.

Question: 4

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

Solution:

Photosynthesis is the process in which food is synthesised in plants in the presence of sunlight. Carbon dioxide is absorbed from the air through the stomata in leaves while the water is absorbed from the soil through roots. In the presence of sunlight and chlorophyll, carbon dioxide reacts with water to produce glucose (carbohydrate) and oxygen. The overall equation of photosynthesis is as follows:

 

Question: 5

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

Solution:

This food chain shows that plants are the ultimate producers and all the animals depend on them directly or indirectly.

Question: 6

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 __________________.

Solution:

(a) Autotrophs

(b) Carbohydrates (starch)

(c) Chlorophyll

(d) Carbon dioxide, oxygen

Question: 7

Name the following:

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

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

(iii) The pores through which leaves exchange gases.

Solution:

(i) Cuscuta

(ii) Pitcher plant or Venus flytrap or Sundew plant

(iii) Stomata

Question: 8

Tick the correct answer:

(a) Amarbel is an example of:

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

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

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

Solution:

(a) (ii) parasite

(b) (iii) pitcher plant  

Question: 9

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

Solution:

Chlorophyll - Leaf

Nitrogen-Bacteria

Amarbel- 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 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)

Solution:

(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) Sepals

Solution:

(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

Solution:

(iv) Leaves