NCERT Solutions for Class 7 Science Chapter 1 - Nutrition In Plants

Q1. Why do organisms need to take food?

Ans: 

Organism needs food to:-

1. Survive

2. Grow

3. Gain energy

4. Damage repair

5. Maintain bodily functions

6. Other activities

Q2. Distinguish between a parasite and saprophyte.

Ans: Differences between parasites and saprophytes are as follows:

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

Ans: When starch reacts with an iodine solution, it takes on a characteristic dark blue colour. If a few drops of iodine solution are applied to a leaf and a dark blue colour develops, the existence of starch in the leaf is confirmed.

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

Ans: In green plants, the synthesis of food occurs by a process called photosynthesis. During this process, chlorophyll in the cells of the leaves uses carbon dioxide and water to synthesize carbohydrates in the presence of sunlight. The process can be represented by an equation:

• \[Carbon\:dioxide\:+\:\:Water\:\xrightarrow[Chlorophyll]{Sunlight}\:Carbohydrates\:+Oxygen\]

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During this process, oxygen is released, and the carbohydrates generated are stored as starch.

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

Ans:

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6. Fill in the blanks:

1. Green plants are called ----------- since they synthesize their own food.b. The food synthesized by the plants is stored as ---------------. 

Ans: Green plants are called autotrophs since they synthesize their own food.

2. The food synthesized by the plants is stored as ---------------. 

Ans: The food synthesized by the plants is stored as starch.

3. In photosynthesis, solar energy is captured by the pigment called------------.

Ans: In photosynthesis, solar energy is captured by the pigment called chlorophyll.

4. During photosynthesis plants take in ------------- and release -------------. 

Ans: During photosynthesis, plants take in carbon dioxide and release oxygen.

Q7. Name the following: 

1. A Parasitic plant with a yellow, slender, and tubular stem.

Ans: Cuscuta- The Cuscuta plant is classified as a parasite since it lacks chlorophyll and feeds on the host. The host loses vital nutrients as a result of this process.

2. A plant that has both autotrophic and heterotrophic modes of nutrition.

Ans: Pitcher plant - The pitcher plant is an autotrophic plant that performs photosynthesis, but it also has a partly heterotrophic method of nutrition because it grows in nitrogen-deficient soil.

3. The pores through which leaves exchange gases.

Ans: Stomata- Gases such as carbon dioxide, water vapour, and oxygen can diffuse into and out of the plant's interior tissues through stomata.

Q8. Tick the Correct Answer: 

a. Amarbel is an example of:

1. Autotroph

2. Parasite

3. Saprophyte

4. Host 

Ans: (ii) Parasite- 

Cuscuta or Dodder are other names for Amarbel. A parasite is an organism that grows on the body of another organism and feeds on its nutrition.

b. The plant which traps and feeds on insects is:

1. Cuscuta

2. China rose

3. Pitcher plant 

4. Rose 

Ans: (iii) Pitcher plant

The pitcher plant is a type of plant with trapping and digesting leaves. Medicine is made from the leaf and roots.

Q9. Match the item in given column I with those in column II.

Ans: 

Q10. Mark “T” if the statement is true and “F” if it is false:

1. Carbon dioxide is released during photosynthesis. (T/F) 

Ans: False- Oxygen is released during photosynthesis.

2. Plants that synthesize their food themselves are called saprotrophs. (T/F) 

Ans: False- Plants which synthesize their food themselves are called autotrophs. 

3. The product of photosynthesis is not a protein. (T/F)

Ans: True- The product of photosynthesis is not a protein.  

4. Solar energy is converted into chemical energy during photosynthesis. (T/F)

Ans: True- Solar energy is converted into chemical energy during photosynthesis.

Q11. Choose the Correct Option From the Following:

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

1. Root hair

2. Stomata 

3. Leaf veins

4. Sepals 

Ans: (b) Stomata get carbon dioxide from the air for photosynthesis.

Q12. Choose the correct option from the following:

Plants take carbon dioxide from the atmosphere mainly through their:

1. Roots 

2. Stem

3. Flowers

4. Leaves

Ans: (d) Plants take carbon dioxide from the atmosphere mainly through their leaves.

NCERT Solutions for Class 7 Science- Free PDF Download

Nutrition in plants Class 7 NCERT is a conceptual chapter for the students of Class 7. Vedantu provides all Class 7 Science Chapter 1 Solutions in PDF format for students to get easy access. These solutions have the entire Ch 1 Science for Class 7 covered and will help students to score better marks in Science exams.

Important Topics Covered in NCERT Solutions for Chapter 1 of Class 7 Science- Nutrition in Plants 

In Class 7 Chapter 1 Nutrition in Plants, students will learn many concepts related to plants and how they get nutrition for themselves. Other important topics that students will learn about are as follows:

NCERT Solutions for Class 7 Science Chapter 1 – Nutrition in Plants

NCERT Solutions for CBSE Class 7 Science Chapter 1 Nutrition in Plants will help the students to answer the NCERT questions in a more appropriate way  so as to score better marks in the examination. The free PDF will also allow them to access this important study resource from anywhere and anytime, which will help them build a strong foundation on the above-mentioned concepts at their convenient time. 

Therefore, students are advised to thoroughly study NCERT Solutions for CBSE Class 7 Science Chapter 1 Nutrition in Plants to aid their preparation for the exams. 

1.1 Mode of Nutrition in Plants

• Plants have the unique ability to produce their own food, setting them apart from other living beings.

• They utilize sunlight, minerals, water, and carbon dioxide present in their surroundings to prepare their food.

• The process by which plants convert these raw materials into food is known as photosynthesis.

• During photosynthesis, plants use chlorophyll, a green pigment found in their cells, to capture sunlight energy.

• The captured sunlight energy is then used to convert carbon dioxide and water into glucose, a form of sugar.

• Glucose serves as the primary source of energy for the plant's growth, development, and metabolic processes.

• Along with glucose, plants also produce oxygen as a byproduct of photosynthesis, which is released into the atmosphere.

• The minerals absorbed by plants from the soil play a crucial role in their growth, as they provide essential nutrients necessary for various cellular activities.

• These nutrients not only support plant growth but also aid in repairing damaged body parts.

• Through their autotrophic mode of nutrition, plants demonstrate their self-sufficiency in obtaining energy and nutrients from their environment.

1.2 Photosynthesis- Food Making Process in Plants

• Leaves are considered food factories in plants, synthesizing food for all parts of the plant.

• Different body parts transport raw materials to the leaves.

• Roots absorb water and minerals from the soil and transport them to the leaves through vessels.

• Stomata, tiny pores on the leaves, absorb carbon dioxide, and their opening and closing are controlled by guard cells.

• Chlorophyll, present in all leaves, is responsible for the green color and traps sunlight for photosynthesis.

• Photosynthesis is the process by which plants produce food using sunlight, carbon dioxide, and water.

• Photosynthesis is essential for maintaining life on Earth as it provides food for plants, which is the basis of the food chain.

• During photosynthesis, chlorophyll uses sunlight, water and carbon dioxide to produce carbohydrates.

• The equation for photosynthesis is : 

$\text{Carbon dioxide + water }\xrightarrow[\text{Sunlight}]{\text{Chlorophyll}}\text{ Carbohydrate + oxygen}$

• Oxygen is released as a byproduct of photosynthesis, and the carbohydrate formed is converted to starch.

• Starch in leaves indicates the occurrence of photosynthesis.

• Plants with yellow, red, or multicolored leaves also perform photosynthesis as chlorophyll is present in these leaves.

• Algae in stagnant water bodies, indicated by green slimy patches, also perform photosynthesis using chlorophyll.

• Cells, the building blocks of every living body, play various functions, including gaseous exchange during photosynthesis.

• Stomata control gaseous exchange, and their opening and closing are regulated by guard cells.

1.3 Other Modes of Nutrition in Plants

Not all plants contain chlorophyll:

• Some plants, like Cuscuta, do not have chlorophyll.

• Cuscuta is a yellow tubular plant that twines around the stems of other plants.

Heterotrophic nutrition in non-chlorophyll-containing plants:

• Plants without chlorophyll obtain their food through heterotrophic nutrition.

• They acquire nutrients from other living organisms.

Host-parasite relationship:

• Non-chlorophyll-containing plants rely on a host plant to obtain nutrients.

• When these plants deprive the host of its valuable nutrients, they are called parasites.

Plants as parasites:

• We often associate parasites with insects and animals, but plants can also be parasites.

• Non-chlorophyll-containing plants that depend on other organisms for nutrition are considered parasitic.

Insectivorous plants:

• Some plants, like the pitcher plant, have pitcher-shaped structures formed from modified leaves.

• The pitcher plant captures insects (prey) when they fall into the pitcher.

• Hairs directed downwards inside the pitcher prevent the insects from escaping.

• These plants are known as insectivorous plants as they consume insects for nutrition.

1.4 Saprotrophs

• Mushroom's Nutritional Mode: Unlike plants, mushrooms do not contain chlorophyll and cannot perform photosynthesis. Instead, they obtain their food through a process known as saprophytic nutrition. This involves secreting digestive juices and chemicals onto decaying or dead organic matter, extracting nutrients from them. Mushrooms are considered saprotrophs in this nutrition mode.

• Fungi Growth on Various Surfaces: Fungi can be found growing on different surfaces such as leather, pickles, bread, and other materials that are kept in hot and humid conditions for extended periods. These fungi thrive on the presence of moisture and organic matter, aiding in their growth and decomposition process.

• Fungi in Rainy Seasons: Rainy seasons often see an increase in the population of saprotrophic fungi. These fungi play a role in the spoilage of food and clothing during this time. Fungal spores, which can travel through the air, settle on wet surfaces and germinate, leading to fungal growth and the subsequent spoilage of items.

• Symbiotic Relationships: In certain relationships between organisms, both parties benefit from their association. One example is the close association between certain fungi and plant roots. These fungi, known as mycorrhizae, derive nutrients from the plants while providing them with nitrogen in return. This mutualistic relationship benefits both organisms involved.

• Lichens: Lichens are another example of a symbiotic relationship involving fungi. In lichens, fungi and algae coexist. The algae produce food through photosynthesis, while the fungus provides water, minerals, and a protective structure for the algae. This partnership allows both organisms to thrive in various environments.

1.5 How Nutrients are Replenished in the Soil

If plants use all the minerals and nutrients from the soil, the levels of these nutrients in the soil are supposed to go down. To replenish the nutrient content of the soil, farmers often add manures and fertilizers to the soil. In this way, the nutrients are replenished, and it will support the continued growth of plants on this soil.

In general, soils require plenty of nitrogen for their growth. After each harvest, the soil gets devoid of nitrogen. To have further plantation on these soils, farmers often grow leguminous crops that can increase the nitrogen content of the soil. These leguminous crops like pulses, grams, dal, etc. are in a symbiotic relationship with a bacteria called rhizobium, which fixes atmospheric nitrogen into the soil. The bacteria obtain food and shelter in return from the plants. Growing leguminous crops in the field reduces the need to add nitrogen-containing artificial fertilizers to the soil.

In this CBSE Class 7 Science Chapter 1 nutrition in plants, you learned about plants that are autotrophs. You also learned about different nutrition modes amongst plants like heterotrophic, saprophytic, parasitic, insectivorous and symbiotic.

Facts that Matter

• All organisms take food and utilize it to get energy for growth, maintenance and various life processes.

• Based on the mode of getting food, organisms are classified as autotrophs and heterotrophs.  

• Autotrophs prepare their own food using simple inorganic materials like carbon dioxide and water. 

• The essential requirements for photosynthesis are chlorophyll and sunlight.

• Heterotrophs are organisms that cannot make food on their own and so they depend on autotrophs directly or indirectly for food.

• Parasitic, saprophytic, insectivorous and symbiotic are the different modes of heterotrophic nutrition in plants.

• Plants like Cuscuta are parasites as they take nutrition from the host plant.

• Saprotrophs like Fungi obtain nutrition from dead and decaying organic matter. 

• Symbiotic relationship between Rhizobium and legumes helps in enriching the soil of the nitrogen that was lost.

• Leaves of the plants prepare the food so they are called the food factory of the plant.

• The important components of food are carbohydrates, fats, proteins, vitamins and minerals. 

• The Sun is the fundamental source of energy for all living organisms.

NCERT Solutions Class 7 Science Other Chapters

• Chapter 2 - Nutrition in Animals

• Chapter 3 - Fibre to Fabric

• Chapter 4 - Heat

• Chapter 5 - Acids

• Chapter 6 - Physical and Chemical Changes

• Chapter 7 - Weather

• Chapter 8 - Winds

• Chapter 9 - Soil

• Chapter 10 - Respiration in Organisms

• Chapter 11 - Transportation in Animals and Plants

• Chapter 12 - Reproduction in Plants

• Chapter 13 - Motion and Time

• Chapter 14 - Electric Current and Its Effects

• Chapter 15 - Light

• Chapter 16 - Water: A Precious Resource

• Chapter 17 - Forests: Our Lifeline

• Chapter 18 - Wastewater Story

Additional Materials for CBSE Class 7 Science 

• CBSE Class 7 Important Questions

• CBSE Class 7 Revision Notes

• CBSE Class 7 Exemplar Solutions

Key Features of NCERT Solutions for Class 7 Science Chapter 1

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