Important Questions for CBSE Class 7 Science Chapter 1 - Nutrition in Plants

A) Very Short Answer Questions (1 Mark)

1. Fill in the blanks: 

i. The components essential for our body are called ____________. 

Ans: Nutrients 

ii. We obtain nutrients through ______________ . 

Ans: Food 

iii. Carbohydrates, _______________ and fats are important nutrients. 

Ans: Proteins 

iv.  ____________ can make their own food from simple nutrients. 

Ans: Plants/Autotrophs 

v. All animals are directly or indirectly _____________ on plants for food. 

Ans: Depend 

2.  State whether true or false. If false, correct the statement by changing the underlined word

a. Animals are the only organisms that can prepare their own food using simple substances from their surroundings. 

Ans: The given statement is false. Plants are the only organisms that can prepare their own food using simple substances from the surroundings. 

b. The intake of food by an organism is called nutrition. 

Ans: The given statement is true. 

c. Stomata absorb sunlight for photosynthesis. 

Ans: The given statement is false. Chlorophyll absorbs sunlight for photosynthesis. 

d. Insectivorous plants are autotrophic. 

Ans: The given statement is false. Insectivorous plants are partially heterotrophic. 

e.  Starch on reacting with iodine solution turns brown in color. 

Ans: The given statement is false. Starch on reacting with iodine turns blue-black in color. 

3. Define the following terms: 

a. Nutrition 

Ans: The process by which an organism receives and digests food to get the nutrients insoluble and simple forms is called Nutrition.

b. Autotrophs 

Ans: The organisms which can build their own food with the help of molecules like carbon dioxide gas and water from their surroundings with the assistance of sunlight and chlorophyll are called Autotrophs.

c. Photosynthesis 

Ans: The process by which organisms use sunlight to synthesize nutrients from carbon dioxide and water to create their own food is called Photosynthesis. In plants photosynthesis generally involves the green pigment called chlorophyll and generates oxygen as a secondary product.

d.  Host 

Ans: An organism that provides nourishment and/or shelters to some other organism is called a Host. The host supports and provides nourishment for the parasite (guest) and hence the host is negatively affected by this relationship. 

e. Parasite 

Ans: An organism that lives inside or on an organism of another species (its host) and which relies on the host for all the nutrients is called Parasite. The parasite is not able to survive without the host body.

B. Short Answer Questions (3 marks)

1. What are stomata? Explain their function. 

Ans: The tiny pores present on the underside of the leaf surface and surrounded by guard cells are called stomata. 

The functions of stomata include, 

1. Exchanging gases by the process called diffusion for photosynthesis and respiration. 

2. Transpiration of water i.e. the loss of excess water from the plant by evaporation of water from the upper surface of the leaf. 

2. How is sunlight used by the plant for photosynthesis? 

Ans: 

1. The main energy source for photosynthesis is sunlight. 

2. Sunlight is trapped by the green pigment chlorophyll which is present in all green parts of the plants including leaves. 

3. The energy of the sunlight converts water and carbon dioxide into a sugar called glucose. 

4. Glucose is used by plants for generating energy and to make other essential substances like cellulose and starch.

3. Why are some plants insectivorous? Give examples. 

Ans: 

1. Plants require nutrients like nitrogen in addition to carbohydrates for survival. 

2. In the places where there is a lack of nutrients, especially nitrogen, some plants fulfill their nitrogen requirements by digesting insects in order to absorb the necessary nitrogen. 

3. Examples of insectivorous plants include Venus flytrap, Utricularia, Drosera, Rafflesia, Pitcher plant, etc. 

4.  Explain the saprotrophic mode of nutrition with an example. 

Ans: 

1. Partial digestion of substrate outside the body and then absorbing the digested material into the body is called the saprotrophic mode of nutrition. 

2. With the saprotrophic mode of nutrition, the body releases digestive enzymes to the substrate which causes the partial breakdown of the substrate which later on gets absorbed by the body. 

3. Examples of organisms that follow a saprotrophic mode of nutrition include some detritivores such as fungi.

5. What is symbiosis? Explain with help of an example. 

Ans: Symbiosis is a relationship that exists between two organisms living in a close physical association which is mutually beneficial for both.

1. In this relationship, both organisms are equally benefited and no organism is affected by this relationship. These interactions last for a long term with the survival of both species.

2. Examples of organisms that follow symbiosis include lichen, mycorrhiza, etc.

C) Long Answer Questions (5 marks)

1. Explain how photosynthesis occurs in plants. 

Ans: 

1. The process by which organisms use sunlight to synthesize nutrients from carbon dioxide and water to create their own food is called Photosynthesis.

2. In this process, organic food like starch is synthesized by inorganic molecules like water and carbon dioxide.

3. The main energy source which is sunlight is trapped by the green pigment. 

4. Chlorophyll is present in all green parts of the plants including leaves.

5. The raw materials required are carbon dioxide and water where carbon dioxide is absorbed from the atmosphere and water is absorbed from the soil. 

6. The energy from sunlight enables a chemical reaction that converts carbon dioxide and water into glucose and oxygen. 

7. Glucose is used by plants for generating energy and to make other essential substances like cellulose and starch.

8. The overall chemical reaction during the process of photosynthesis can be represented as follows: 

$6\text{C}{{\text{O}}_{\text{2}}}\text{}+\text{}12{{\text{H}}_{\text{2}}}\text{O}\xrightarrow[\text{Chlorophyll}]{\text{Light}}{{\text{C}}_{\text{6}}}{{\text{H}}_{\text{12}}}{{\text{O}}_{\text{6}}}\text{  +  }6{{\text{O}}_{\text{2}}}\text{  }+\text{  }6{{\text{H}}_{\text{2}}}\text{O}$

$ \text{Carbon        water                    glucose      oxygen       water}   \text{dioxide} $

2. How are nutrients replenished in soil naturally? How can the nutrients be replenished artificially? 

Ans: 

1. The source of nutrients for the plants is soil. 

2. Plants receive nutrients from the soil which leads to depletion of nutrients in the soil. 

3. Plants are unable to use nitrogen gas directly from the atmosphere. Some bacteria convert nitrogen from the atmosphere into soluble compounds that can be used by plants. 

4. As they live in symbiotic association with the roots of leguminous plants, the nitrogen content is replenished in the soil by their actions. Nitrogen gets replenished in the soil naturally by using leguminous plants after cereal crops in the soil. 

5. In an artificial way, the nutrients can be replenished by using fertilizers and manure. 

3. How can we demonstrate that chlorophyll is necessary for photosynthesis?

Ans:

1. Necessity chlorophyll can be demonstrated by carrying out an experiment on a variegated leaf. 

2. Before the start of the experiment, the outline of the leaf is traced on a piece of paper and the green areas are marked. 

3. To allow the process of photosynthesis, the leaf is placed in sunlight for some hours. 

4. The leaf is then boiled in alcohol so that it gets decolorized after which the iodine solution is added to the leaf. 

5. It can be observed in response to iodine solution the green areas of the leaf turn blue-black which indicates that the starch is present. 

6. Thus, through this experiment, it can be observed that photosynthesis occurs in the green areas of the variegated leaf which shows that chlorophyll is necessary for photosynthesis. 

4. How do plants obtain nutrients other than carbohydrates? 

Ans: 

1. Plants synthesize carbohydrates using energy from sunlight to convert carbon dioxide and water to glucose and further on into starch. 

2. The nutrients other than carbohydrates are obtained directly from the soil. 

3. The nitrogen content is replenished in the soil by the action of nitrogen-fixing bacteria. Nitrogen gets replenished in the soil naturally by using leguminous plants after cereal crops in the soil. Nitrogen compounds can be replenished in artificial ways by adding fertilizers and manure to the soil. 

4. Some insectivorous plants like the pitcher plant and Venus flytrap get their nitrogen requirements fulfilled by consuming insects. In this process, the insects are trapped and digested by the plant and the nutrients are released into the body of the plant. 

Class 7 Science Chapter 1 Important Questions- Free PDF Download

This chapter helps students to understand the various factors revolving around nutrition. Students will learn about the very basic functions of plants and how they retrieve nutrition through photosynthesis and carbon dioxide. All these functions help plants to grow more healthy and also help support the living beings around them. In this chapter, we will look into various functions of the plants and how they store and use their food to their benefit. Students will learn a great deal of this subject and also the various topics Lack of practice and a solid course plan and curriculum may act as a barrier preventing you from securing good scores and to urge a radical comprehension of all the essential concepts and topics under this chapter and break the barriers, students must enjoy the continuous practice. Regular practice of Chapter 1 class 7Important Questions can help students improve, become through the concepts and topics, and be efficient during preparation or revision. This article also provides class 7 science chapter 1 extra questions that can benefit students during their preparation of the subject. 

Class 7th Science Chapter 1 Important Concepts 

In this chapter, we will look into various concepts and some of these are explained down below. 

This chapter takes an intrinsic look into how the plants and how it functions in the world by using the right nutrition. The following are some of the topics covered in this chapter-

Stomata 

These are tiny pores found on the underside of the surface of the leaf and are surrounded by guard cells. They play a vital role by exchanging gases during the process of respiration and photosynthesis which in turn causes transpiration of water through evaporation from the leaf surface. 

Importance of Sunlight 

Sunlight is present for most of the time during the day and the plants are very efficient in using this as it is the energy source for the process of photosynthesis. The green pigment known as chlorophyll traps the sunlight which is present all over the plant. This sunlight is later converted into chemical energy. 

Saprotrophic Mode 

This mode is a partial digestion mode of the substrate outside the body wherein the digested material is absorbed into the body. In this mode of digestion, the plant releases digestive enzymes into the substrate. The partially digested substrate is then absorbed by the organism. We can see this type of digestion in fungi. 

Symbiosis 

This is a process where two organisms are mutually benefited. Here in this process, both the organism involved is not going to be harmed in any way and they are equally benefited. One organism could provide nutrition whereas the other organism could do it with some kind of shelter and protection. 

Photosynthesis 

The process where green plants convert solar energy into chemical energy is known as photosynthesis. Inorganic molecules like carbon dioxide and water are used to synthesize food like starch. The process starts off with the trapping of sunlight which is done by the chlorophyll present in green plants. Raw materials such as water and carbon dioxide are the prime ingredients for photosynthesis. Water is absorbed from the soil and carbon dioxide is taken from the atmosphere. The sunlight is the catalyst here in this process which converts the carbon dioxide and water into starch and oxygen. Starch is used up by the plant whereas the oxygen is left out to the atmosphere for other organisms to utilize.

Nutrients Being Replenished in the Soil Naturally 

Plants are constantly using the nutrients found in the soil for their own purpose and this in turn leaves the soil depleted of its nutrients. Nitrogen gas which is present in the atmosphere cannot be directly used by the plants. This nitrogen gas has to first be converted into soluble compounds and this can help plants to solve the later process. So this process is done by bacteria found in the soil and an example of this is Rhizobium. Rhizobium is found in the roots of leguminous plants.

The Process of Plants Receiving Nutrients Other Than Carbohydrates 

Raw materials such as water and carbon dioxide are the prime ingredients for photosynthesis. Water is absorbed from the soil and carbon dioxide is taken from the atmosphere. The sunlight is the catalyst here in this process which converts the carbon dioxide and water into starch and oxygen. Most of the other nutrients that are needed are obtained from the soil directly and this is obtained because of the nitrogen-fixing bacteria known as Rhizobium. There are many ways to obtain the nutrients and we will explore deeper in the chapter. 

Important Questions for Class 7 Science Chapter 1

Students here will learn a number of the essential elements in this chapter 1 of class 7. This may help them in their future grades because it sets the groundwork. Constant practice of the essential questions should help students to tackle any difficult questions in their final examinations the following are class 7th science chapter 1 important questions -

• How do plants obtain nutrients other than carbohydrates?

• How can we demonstrate that chlorophyll is essential for photosynthesis?

• How are nutrients replenished in the soil naturally?

• How can nutrients be replenished in the soil artificially?

• What is symbiosis in plants? give an example.

• Explain the saprotrophic mode of nutrition in plants

• Why are some plants insectivorous? Give an example

• How is sunlight used by the plant?

• What are stomata? Explain their function.

• Differentiate between autotrophic and heterotrophic nutrition.

• Describe the role of enzymes in the digestion of food.

• What are the components of a balanced diet? Explain their importance.

• Discuss the harmful effects of malnutrition on the human body.

• What is the importance of water in the diet of organisms?

• Explain the process of respiration in plants and animals.

• How do herbivores, carnivores, and omnivores obtain nutrition?

Benefits of Nutrition in Plants Class 7 Important Questions 

Students must understand the importance of this subject and what it holds for college kids of sophistication 9. By utilizing the important questions and with a rigorous practice regime students are going to be ready to score the foremost out of their exams. These exams are often a touch difficult without the proper guidance but by using this article students are going to be ready to study in a more structured manner.

The Following are the Advantages of Chapter 2 Science Class 9 Important Questions

• It provides students with a structure with which they will study for his or her upcoming examinations.

• This is a fundamental chapter for college kids and plays an important role in upcoming grades.

• Students don’t need to worry about the relevance of these questions as they're all cross-checked and updated consistently with the newest CBSE guidelines and rules. therefore the information in this article is genuine and reliable.

• Students can use this text to use their time wisely, it helps boost their confidence after consistent practice and students can plan their preparation accordingly.

• Students can utilize and practice the important questions so that they can ace their examinations. 

Conclusion 

These essential questions on plant nutrition greatly benefit Class 7 students. This pivotal chapter serves as a foundation for middle school science, enabling students to comprehend the fundamental aspects of nutrition. Exploring topics like photosynthesis and carbon dioxide, this text empowers students to optimize their time, build confidence through consistent practice, and strategize their preparation. By familiarizing themselves with these important questions, students become aware of the chapter's diverse content and develop the skills to tackle challenging exam questions through dedicated effort.