Nutrition in Plants class 7 Science NCERT Solutions

Nutrition in Plants class 7 Science NCERT Solutions: Nutrition in Plants is the chapter 1 from class 7 Science NCERT. Here you'll get Nutrition in Plants class 7 Science/Nutrition in Plants class 7 Science NCERT Solutions.

Nutrition in Plants class 7 Science Main Points

All organisms need food and utilise it to get energy for growth and maintenance of their body. Green plants synthesise food for themselves by the process of photosynthesis. They are autotrophs.

Plants like Cuscuta are parasites. They take food from the host plant. Plants use simple chemical substances like carbon dioxide, water and minerals for the synthesis of food. Chlorophyll, water, carbon dioxide and sunlight are the essential requirements for photosynthesis. Complex chemical substances such as carbohydrates are the products of photosynthesis.

Solar energy is absorbed by the chlorophylls present in leaves/plants. Oxygen is produced during photosynthesis. Oxygen released in photosynthesis is utilised by living organisms for their survival.

Many fungi derive nutrition from dead and decaying matter. They are saprotrophs. A few plants and all animals are dependent on others for their nutrition and are called heterotrophs.

Nutrition in Plants class 7 Science Notes

Nutrition can be defined as a process by which organisms take in the food and utilize it in order to survive. Special substances such as proteins, vitamins, carbohydrates, minerals and fats are called nutrients.

Based on the mode of nutrition organisms can be divided into two categories:

Autotrophic Organisms: They can prepare their food by themselves such as plants
Heterotrophic Organisms: They depend upon other organisms for their food such as animals

Plants prepare their food with the help of certain raw materials that they gather from their surroundings; water, carbon dioxide, sunlight, minerals, chlorophyll.

The process by which plants prepare their food by using these raw materials is called Photosynthesis.

Leaves are also known as the Food Factories of the plants as they are the places where food is prepared.

Different parts of the plants like roots gather the raw materials from the environment and then transfer them to the leaves where photosynthesis takes place.

Transportation of water and Minerals in plants - The roots of the plants absorbs the water and minerals of the soil and then transports them to the leaves via stems and branches.
Inhalation of Carbon Dioxide - There are tiny holes or pores present on the surface of the leaves called Stomata that take in the carbon dioxide present in the atmosphere.
Presences of Chlorophyll in the Leaves - A substance called Chlorophyll is present in the leaves of the plants. It is a green colour pigment. The chlorophyll not only provides green colour to the leaves but also helps in the process of photosynthesis. Chlorophyll captures the sunlight and along with other raw materials prepares the food in the leaves.

This process of photosynthesis only occurs in the daytime in the presence of Sunlight hence it is called Photosynthesis, photo means light.

Sun is called the ultimate source of energy for all living organisms

We know that the plants use solar energy to make their food. The herbivores animals depend upon the plants for their food. Carnivores animals that do not eat plants depend upon the herbivores animals. Therefore, all of the living organisms directly or indirectly receive their energy from the Sun.

Parts of a cell

The Nucleus: Every cell has a nucleus present in the centre that performs various functions of the cell.
The Cell Membrane: Every cell has an outer boundary which protects the cell called the Cell Membrane.
The cytoplasm: Every cell has a gel-like structure present in it called the Cytoplasm.
Cell organelles: These are membrane bound structures found within a cell in the cytoplasm. The cell organelles have special function associated with them. Different cell organelles found in the cell are:
Mitochondria: Produces energy for the cell
Endoplasmic Reticulum: Produces lipids and proteins in cell
Golgi apparatus: Helps in exporting materials out of cell
Lysosomes: Help in digestion in the cell

Parasitic Plants: Some plants live on another plant for their nutrition. These are called parasites. The plants on which these parasitic plants survive are called the host. For Example, cuscuta is a parasitic plant.

Insectivorous Plants: Some plants depend upon insects for the food and thus are called Insectivorous. The leaves of these plants are modified into a pitcher like structure. The top part of the leaves acts as a lid which can open and close the pitcher.

The pitcher contains hair in a downward direction which traps the insects. The pitcher on capturing the insect secretes some digestive juices which help in the digestion of the insect.

For Example, Dischidia and Nepenthes

Saprotrophs: Some organisms survive on decaying food and organisms. This mode of nutrition is called saprotrophic nutrition and the organisms that survive because of the saprotrophic nutrition are called Saprophytes.

Plants get their nutrients from the soil mainly hence there is a need to replenish the soil again with nutrients so that the plants can survive on it.

Fertilizers and manure are often used to replenish the soil with the nutrients. They contain potassium, phosphorus and nitrogen all of which are important for the plants.

A bacterium called Rhizobium is present in the soil which can convert nitrogen present in it in the form that can be consumed by the plants.

The rhizobium generally lives in the roots of the plants such as peas, beans, grams and legumes and provides nitrogen to these plants. This again is an example of a symbiotic relationship. The farmers often do not need to use fertilizers while growing such crops.

Class 7 Science Chapter 1 Nutrition in Plants Questions Answers

Exercise

1. Why do organisms take food ?

Ans: Food is needed by all organisms for many purposes:

(a) The main function of food is to help in growth.

(b) Food provides energy for movements such as running, walking or raising our arm.

(d) Food gives us resistance to fight against diseases and protects us from infections

2. Distinguish between a parasite and a saprotroph.

Ans:

Parasites

A parasite derives its nutrients from the living organism and it deprives the host of valuable nutrients. For example, Mosquito.

Saprotrophs

Saprotroph organisms take in nutrients from dead and decaying matter. For example, Fungi.

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

Ans: The presence of starch in leaves can be tested by Iodine test. When we remove chlorophyll from leaf by boiling it in alcohol and then put 2 drops of iodine solution, its colour change to blue indicates the presence of starch.

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

Ans: The green plants have chlorophyll in the leaves. The leaves use C02 and water to make food in presence of sunlight.

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

Ans:

NCERT Solutions of Nutrition in Plants class 7 Science

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 _________________.

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

Ans:

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

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

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

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.

Ans: (i) cuscuta (ii) Insectivorous plant (iii) Stomata

8. Tick the correct answer:

(a) Cuscuta is an example of:

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

Ans: Parasite

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

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

Ans: Pitcher plant

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

Ans: Column I Column II

Chlorophyll Leaf

Nitrogen Rhizobium

Cuscuta Parasite

Animals Heterotrophs

Insects Pitcher plant

NCERT Solutions for Nutrition in Plants class 7 Science

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)

Ans: (i) False (ii) False (iii) True (iv) 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: Stomata

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

Ans: Leaves

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

Ans: Farmers grow fruits and vegetable crops inside large greenhouse because it protects it from high blowing wind, and rodents. Greenhouse protects the plant from the climatic conditions of outside and it can have its own suitable temperature for the growth of plants.

The advantages of using green house to the farmers are

(i) They have control over their climatic conditions.

(ii) Free from pests, rodents and also from birds and animals so they have increased producibility.

Class 7 Science