NCERT Class 7 Science Chapter 1 Nutrition in Plants: Notes, Solutions, Free PDF

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Class 7 Chapter 1 Nutrition in Plants

NCERT Class 7 Science Chapter 1 Nutrition in Plants teaches us the different modes of nutrition, cells, photosynthesis, and replenishment of nutrients in the soil. While learning these topics we get to know about different types of organisms, parts of cells, and multiple relationships between different components of the environment. To help you get started with these basic concepts of science, we have prepared a simplified version of the Class 7 Science chapter “Nutrition in Plants”. Also, we have tried to provide accurate answers to questions following this lesson. Keep reading!!

Download NCERT Science Class 7 Science Chapter 1 Important Questions and Answers PDF

Nutrition and Modes of Nutrition in Plants

Plants are the primary producers of food on the planet Earth. They use carbon dioxide and sunlight from the atmosphere and minerals and water from the soil to prepare food. Thus, in photosynthesis, solar energy is converted into chemical energy. 

Nutrition

The mode through which living organisms take and utilize food is called Nutrition. Here are some of the advantages of Nutrition:

  • It facilitates the growth and development of the bodies of plants and animals.
  • Also, it enables the repair of damaged organs and body parts.
  • In addition, it gives energy for the functioning of a plant and the human body. 

Autotrophic Nutrition

In this mode of nutrition, an organism makes its own food. Thus, the organisms that make their own food are called autotrophs. Examples of Autotrophs are plants as they prepare their own food using carbon dioxide, water, and sunlight. 

Heterotrophic Nutrition

In this mode of nutrition, organisms intake food prepared by autotrophs. Thus, living beings that rely on autotrophs for nutrition are called Heterotrophs. Examples of Heterotrophs are human beings and animals. 

Saprotrophic Nutrition

In this mode of nutrition, organisms depend on dead or rotting organic matter for nutrition. Therefore, organisms that intake food through this mode are called Sapotrophs. Examples of Sapotrophs include Fungi. Fungi release digestive fluids on dead and decaying organic substances that turn it into a solution. After juice secretion, they absorb nutrients from the organic matter. 

Nutrition Based on Symbiotic Relationships

In symbiotic relationships, organisms dwell together are share their food and shelter. Common examples of symbiotic relationships include fungi living in tree roots and Rhizobium bacteria. 

Here is how the symbiotic relationship between fungi living in tree roots and Rhizobium bacteria works:

  • Fungi living in tree roots: The fungus helps the tree absorb water and nutrients from the soil in exchange for the tree giving it nutrients. 
  • Rhizobium bacteria: These are found in the root nodules of leguminous plants such as moong, peas, and gram. In this relationship, the bacteria receives shelter and nutrients from the leguminous plants and in turn, the bacteria fixes nitrogen, which is essential for legumes. 
Source: Examrace

Also Read: NCERT Class 6 Science Chapter 1 Notes: Components of Food

Cells and their Parts

The tiny building blocks of plants, animals, and other organisms are known as cells. They are the fundamental unit of life. They are only visible under a microscope. Organisms made of only one cell are termed Unicellular organisms. A common example is Amoeba. Whereas, organisms made of numerous cells are called multicellular organisms. Common examples are plants and human beings. 

Cell Membrane

A thin outer layer enclosing the cell is known as the cell membrane.

Nucleus

The centrally located structure of the cell is called a nucleus. It performs most of the essential functions of a cell.

Cytoplasm

Cytoplasm refers to the jelly-like structure surrounding the nucleus of a cell. 

NCERT Class 7 Science Chapter 1 Nutrition in Plants: Cell Parts
Credit: Economic Times

Must Read: Cell Structure and Function Class 8 Notes & Questions

Photosynthesis

Photosynthesis is the process by which green plants or autotrophs convert carbon dioxide, water, and minerals into carbohydrates and oxygen in the presence of sunlight. 

Important Terms to Understand Before Learning the Photosynthesis Process

  • Stomata: Tiny pores in leaves that absorb carbon dioxide from the atmosphere are called Stomata. These are surrounded by ‘guard cells’.
  • Vessels: These are the network of passages or pipes through which water and minerals from roots to leaves. These travel from roots through the stem and branches and go up to the leaves, where photosynthesis takes place. 
  • Chlorophyll: The green pigment of leaves is known as chlorophyll. 

Photosynthesis Process

Photosynthesis usually occurs in the leaves of plants. Owing to this, leaves are known as the “food factory” of plants. 

Here is how photosynthesis takes place:

  • The stomata in leaves absorb carbon dioxide from the air.
  • Leaves require water and minerals to initiate food production. Thus, the stem transports water and minerals from the roots to the leaves.
  • Thereafter, chlorophyll in the leaves uses energy from sunrays to prepare food using water, minerals, and carbon dioxide.
  • Finally, the leaves produce oxygen and carbohydrates as byproducts of photosynthesis.

The process of photosynthesis can be depicted with the following equation:

Carbon dioxide + Water Carbohydrate + Oxygen (In the presence of Sunlight+Chlorophyll)
NCERT Class 7 Science Chapter 1 Nutrition in Plants: Photosynthesis
Credit: ResearchGate

Check out: NCERT Class 6 Science Chapter 4 Notes: Getting to Know Plants

Replenishing of Nutrients in the Soil

Here are some important concepts and facts about replenishing of nutrients in the soil: 

  • In order to produce their own nourishment as well as for other critical functions, plants collect mineral elements from the soil.
  • Regular nutrient enrichment of soils is required, including nitrogen, phosphorous, potassium, and other elements.
  • Then we may cultivate plants and maintain their health.
  • There are 17 essential nutrients for plants, 6 of which are termed macronutrients and the remaining 11 are termed micronutrients. Micronutrients are needed in extremely minute amounts, whereas macronutrients are needed in vast amounts.

Read More: Branches of Soil Science: Definition & Examples

Other Important Concepts in NCERT Class 7 Science Chapter 1: Nutrition in Plants

Let us now learn about important concepts to understand NCERT Class 7 Chapter 1 “Nutrition in Plants” in detail. 

Insectivorous Plants

Any plant that engulfs insects for food and nutrition is known as an insectivorous plant. Some examples of this plant type include Pitcher Plant and Venous Flytrap.

Here are some important properties of insectivorous plants:

  • These are green in colour.
  • These carry out photosynthesis.
  • These grow in soils that have low nitrogen content.

Cactus Plants

Here are the key properties of cactus plants:

  • These are primarily found in desert regions. Owing to the water scarcity in the desert, the leaves of cactus are modified to spines to prevent water loss. 
  • As the leaves of a cactus are modified to spines, photosynthesis cannot take place in the leaves. Thus, the green stems of cacti carry out photosynthesis. 
  • Also, green branches of cactus plants also prepare food sometimes. 

Parasites

Heterotrophic organisms that rely on other organisms for their food are called parasites. 

Here is how parasites intake food and absorb nutrients:

  • The host is the organism that the parasite attaches to.
  • The process deprives the host of the nutrients necessary for its own growth since the parasite eats them.
  • Cuscuta (Amarbel), for instance, is a non-green plant that feeds on the plant it is growing on.

Also Read: NCERT Class 6 Science Chapter 6 Notes: The Living Organisms: Characteristics and Habitats

NCERT Class 7 Science Chapter 1 Solutions: Nutrition in Plants

Let us now look at answers to writing questions in NCERT Class 7 Science Chapter 1. 

Ques 1. How do organisms take food?

Ans: Organisms need food for the following reasons:

  • It facilitates the growth and development of the bodies of plants and animals.
  • Also, it enables the repair of damaged organs and body parts.
  • In addition, it gives energy for the functioning of a plant and the human body. 

Ques 2. Distinguish between a parasite and a saprophyte

Ans: Here is the difference between a parasite and a saprophyte

ParasiteSaprophyte
A parasite lives in a host and uses it to extract food. A saprophyte takes food from dead and decaying organic matter.
Example: Cuscuta (Amarbel)Example: Fungi

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

Ans: The presence of starch in leaves can be determined through an Iodine test. This test involves first removing chlorophyll from a leaf by boiling it in alcohol. Subsequently, adding two drops of iodine solution to the leaf will cause a color change to blue, indicating the presence of starch.

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

Ans: Here is how green plants synthesize foods:

  • The stomata in leaves absorb carbon dioxide from the air.
  • Leaves require water and minerals to initiate food production. Thus, the stem transports water and minerals from the roots to the leaves.
  • Thereafter, chlorophyll in the leaves uses energy from sunrays to prepare food using water, minerals, and carbon dioxide.
  • Finally, the leaves produce oxygen and carbohydrates as byproducts of photosynthesis.

Ques 6. Fill in the blanks:

a. Green plants are known as_______________ since they synthesise their own food.

b. The food synthesized by plants is stored as ________________.

c. In photosynthesis, solar energy is absorbed by the pigment called______________.

d. During photosynthesis, plants take in_(1)____________ and release_(2)_____________ gas.

Ans:

a. Autotrophs

b. Starch 

c. Chlorophyll

d. (1) Carbon dioxide (2) Oxygen 

Ques 7. Name the following:

a. A parasitic plant with yellow, slender, and branched stem.

b. A plant that is partially autotrophic.

c. The pores through which leaves exchange gases.

Ans:

a. Cuscuta

b. Pitcher plant

c. Stomata

Ques 8. Choose the correct option from the following:

a. Cuscuta 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    

Ans:

a. (ii) Parasite

b. (iii) Pitcher Plant

Ques 9. Match the items in Column I with those in Column II

Column IColumn II
1. ChlorophyllA. Rhizobium
2. NitrogenB. Heterotrophs
3. CuscutaC. Pitcher Plant
4. AnimalsD. Leaf
5. InsectsE. Parasite

Ans:

Column IColumn II
1. ChlorophyllD. Leaf
2. NitrogenA. Rhizobium
3. CuscutaE. Parasite
4. AnimalsB. Heterotrophs
5. InsectsC. Pitcher Plant

Ques 10. Which of the following statements are True or False?

a. Carbon dioxide is released during photosynthesis.

b. Plants that synthesize their food are called saprotrophs.

c. The product of photosynthesis is not a protein.

d. Solar energy is converted into chemical energy during photosynthesis.

Ans:

a. False

b. False

c. True

d. True

Ques 11. Choose the correct option from the following:

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

a. Root hair

b. Stomata

c. Leaf veins

d. Petals

Ans: b. Stomata

Ques 12. Choose the correct option from the following:

Plants take carbon dioxide from the atmosphere mainly through their:

a. Roots

b. Stem

c. Flowers

d. Leaves

Ans: d. Leaves

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

Ans: Large greenhouses are chosen for the cultivation of fruits and vegetable crops due to their ability to shield the crops from the impact of external weather conditions while maintaining an optimal temperature for crop growth.

Here are some ways in which farmers benefit from growing fruits and vegetables in greenhouses:

  • Farmers can safeguard their crops from both diseases and unfavorable weather conditions. 
  • Additionally, greenhouses serve as protective barriers against wind and rodents, further ensuring crop well-being.

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FAQs

Q.1. What are unicellular organisms?

Ans: Organisms made of only one cell are termed Unicellular organisms. A common example is Amoeba.

Q.2. What are the different modes of nutrition?

Ans: Here are the different modes of nutrition:
– Autotrophic
-Heterotrophic
-Saprotrophic

Q.3. What are examples of legumes?

Ans: Legumes are nitrogen-rich products. Common examples are gram, pulses, and peas.

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