Important Questions Class 7 Science Chapter 1

Important Questions Class 7 Science Chapter 1 – Nutrition in Plants

Food is essential for all living organisms as it supplies vital nutrients like carbohydrates, proteins, fats, vitamins and minerals required to grow and nourish cells to fight diseases and contribute to the overall development of a healthy body . Class 7 Science Chapter 1 about “Nutrition in Plants” introduces the importance of nutrients and the various modes of nutrition in plants. Plants are called autotrophs because of their ability to produce their food.

There are many interesting concepts to learn about how nutrition in plants occurs through a unique process called photosynthesis. Plants use simple chemical substances like carbon dioxide, water and minerals in the presence of sunlight to synthesise food in the form of complex carbohydrates, which will then be consumed by heterotrophs directly or indirectly. Plants are considered the ultimate source of food for all herbivores and omnivores.

Through this chapter, you will also learn the importance of solar energy for the process of photosynthesis as well as other modes of nutrition in plants that cannot make their food due to the absence of chlorophyll, the structure of cells, Saprotrophs, and how nutrients are replenished in the soil.

Extramarks is one of the most trusted online learning platforms for Class 1 to Class 12 students which wants to create a strong foundation for future studies across all streams. Students can understand the concepts easily by referring to our NCERT solutions, CBSE revision notes, CBSE sample papers and other study materials developed by the experienced Science faculty appointed by the Extramarks. 

It’s important to regularly review the topics and solve multiple problems to understand the concepts introduced in this chapter better. The Extramarks team understands the importance of students revising the chapter by solving questions. Hence, our team of Science professors have prepared Science Class 7 Chapter 1 Important Questions for students to revise the chapter thoroughly by solving questions, especially the ones that have the highest probability of being asked in the examinations. Students registered with Extramarks will find step-by-step solutions to each question to revise core concepts covered in the chapter quickly. 

Important Questions Class 7 Science Chapter 1 – With Solutions

To score well in the examinations, students must choose accurate and appropriate study material to learn and understand the concepts. Practising questions is a form of active learning and a highly effective study method for students to revise and clear their concepts. A team of expert Science professors at Extramarks has gathered Chapter 1 Class 7 Science Important Questions from various sources like NCERT textbook, NCERT Exemplar, past years’ examination papers, etc. Detailed and easy-to-understand solutions to each question are provided to clarify the concepts for students. 

Students can register on the Extramarks’ website and access the complete list of solutions to chapter-wise questions.

Below given list consists of a few Important Questions Class 7 Science Chapter 1 with solutions:

Question 1. An iodine test is done to test the presence of

 (a) Protein

 (b) Fat

 (c) Vitamin

 (d) Starch

Answer 1: (d) Starch

Explanation: The iodine test determines the presence of carbohydrates known as starch in leaves. 

The steps for the iodine test are as below:

1. Take a potted plant.
2. Take a strip of black paper and cut out a small square in the centre.
3. Cover a part of the leaf with this black paper and keep the plant in sunlight for 2-5 days.
4. Uncover the leaf and pour a few drops of iodine solution on both portions.
5. The portion exposed to sunlight will change the colour to blue-black; on the other hand, the portion covered by the black paper will show no colour change.

Conclusion: Leaves cannot carry out photosynthesis without sunlight, that means that no starch can be found on the area where photosynthesis hasn’t occured. Starch reacts to iodine and changes the colour to blue-black only in the parts of leaves which are exposed to sunlight.

Question 2. Organisms that prepare food for themselves using simple, naturally available raw materials are referred to as 

 (a) Heterotrophs

 (b) Autotrophs

 (c) Parasites

 (d) Saprophytes

Answer 2: (b) Autotrophs

Explanation: Autotrophs are organisms that can synthesise their food through photosynthesis using water, carbon dioxide, and minerals in the soil.                             

Question 3. Tick the correct answer 

 (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

Answer 3: 

(a) ii 

(b) iii

Explanation: 

(a) Cuscuta plants are a type of parasite. They have a wiry branched structure climbing around the other tree (host tree). These plants cannot synthesise food due to the absence of chlorophyll in the leaf, so they depend on the host tree for food. 

(b) Pitcher plants are insectivorous plants as they feed on insects. Insectivorous plants trap insects because they grow in thin soil poor in nutrients. To fulfil the nutrition requirement, they eat insects.

Question 4. The term that is used for the mode of nutrition in yeast, mushroom and bread mould is

 (a) Autotrophic

 (b) Insectivorous

 (c) Saprophytic

 (d) Parasitic.

Answer 4: (c) Saprophytic

Explanation: Yeast, mushroom, and bread mould are fungi that develop on dead and decaying organic matter and absorb the nutrients from there. This is called saprotrophic nutrition. Fungi also grow on things exposed to hot and humid weather for a long time.

Question 5. Choose the correct answer from the following options

Plants take carbon dioxide from the air mainly through their:

 (a) Roots

 (b) Stem 

 (c) Flowers 

 (d) Leaves

Answer 5: (d) Leaves

Explanation: Leaves are the vital part of plants where food is processed using all the raw materials, including solar energy, carbon dioxide, water and other minerals. Leaves take carbon dioxide from the air through tiny pores called stomata.

Question 6. Which of the following statements is/are correct?

 (i) All green plants can prepare their food.

 (ii) Most animals are autotrophs.

 (iii) Carbon dioxide is not required for photosynthesis.

 (iv) Oxygen is liberated during photosynthesis.

 Choose the correct answer from the options below:

  (a) (i) and (iv) 

  (b) (ii) only

  (c) (ii) and (iii) 

  (d) (i) and (ii)

Answer 6: (a) (i) and (iv)

Explanation: Plants are autotrophs. They synthesise their food through the photosynthesis process. During photosynthesis, chlorophyll cells(green pigment) of the leaves in the presence of sunlight use carbon dioxide and water to prepare food in the form of carbohydrates and release oxygen into the air.

Question 7. A thin outer boundary surrounding the cell is called

 (a) Cell membrane

 (b) Chlorophyll

 (c) Nucleus membrane

 (d) Cytoplasm

Answer 7: (a) Cell membrane

Explanation: All living organisms are made up of cells, tissues(group of cells), and organs(group of tissues). Cells are the minor microscopic units enclosed by the thin membrane called the cell membrane. Within the cell, there is a nucleus that is located centrally and is a jelly-like substance called cytoplasm.

Question 8. When we observe the lower surface of a leaf through a magnifying lens, we see numerous small openings. Which of the following is the term given to such openings?

(a) Stomata

(b) Lamina

(c) Midrib

(d) Veins

Answer 8: (a) Stomata

Explanation: Stomata are the tiny pores or cells in the epidermis of tree leaves, stems, and other organs. Stomata are covered by the guard cells. 

Question 9. Living organisms need food as:

(a) It provides energy

(b) It helps in the growth and repair of cells

(c) It protects our body from various diseases

(d) All of these

Answer 9: (d) All of these

Explanation: Living organisms require various nutrients, including protein, carbohydrates, vitamins, and fats, for the average body to function. Food contains these essential nutrients. Hence, food is vital for the survival of all living organisms.

Question 10. During photosynthesis:

 (а) Solar energy is converted into chemical energy

 (b) Solar energy is converted into mechanical energy

 (c) Chemical energy is converted into mechanical energy

 (d) Bioenergy is converted into chemical energy

Answer 10: (a) Solar energy is converted into chemical energy.

Explanation: Photosynthesis is a unique process carried out by the leaves of plants. Chlorophyll is a green pigment in the leaves that absorbs solar energy and uses it to produce food from carbon dioxide and water. 

Question 11. Unscramble the following to form terms related to modes of nutrition

 (a) RASPAEIT

 (b) ROPEHYTSAP

 (c) TOROPHAUT

 (d) SIBIOMSYS

Answer 11:  

(a) PARASITE 

(b) SAPROPHYTE 

(c) AUTOTROPH 

(d) SYMBIOSIS

Question 12. Name the following

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

 (b) a partially autotrophic plant.

 (c) The pores through which leave exchange gases.

Answer 12: 

 (a) Cuscuta 

 (b) Pitcher plant  

 (c) Stomata

Question 13. Mark’ True’ if the statement is true and ‘False’ if it is false

 (a) Oxygen is released during photosynthesis.

 (b) Plants which synthesise their food are called saprotrophs. 

 (c) The product of photosynthesis is not a protein. 

 (d) Solar energy is converted into mechanical energy during photosynthesis.

Answer 13:

 (a) True 

 (b) False 

 (c) True 

 (d) False

Question 14. Nitrogen is an essential nutrient for plant growth. But farmers who cultivate pulse crops like green gram, Bengal gram, black gram, etc., do not use nitrogenous fertilisers during cultivation. Why?

Answer 14: Farmers who cultivate pulse crops like green gram, Bengal gram, black gram, etc., do not use nitrogenous fertilisers during cultivation because these crops derive nitrogen naturally from the rhizobium bacteria present in the root cells of the plant.

Question 15. Match the items given in Column I with those in Column II

Answer 15: The matched items are given in the below table:

Question 16. Give the equation of the photosynthesis process.

Answer 16:  The equation of the photosynthesis process for producing food in plants is

                                                                        sunlight

          Carbon dioxide + Water ——————-> Carbohydrate Oxygen     

                                                       Chlorophyll

Question 17. Distinguish between a parasite and a saprotroph

Answer 17:        

Question 18. Define the following terms: Nutrition, Autotrophs

Answer 18: 

Nutrition: The process of taking in food, digesting and using its simple and soluble forms for growth, metabolism, and repair.

Autotrophs: Living organisms that can synthesise their food using solar energy, minerals and water from the soil, and carbon dioxide from the air through a unique process called photosynthesis.

Question 19. Photosynthesis requires chlorophyll and a few other raw materials. Add the missing raw materials to the list given below.

Water, minerals, _____________, ______________.

Answer 19: Solar energy, Carbon dioxide

Question 20. A goat eats away all the leaves of a small plant (balsam). However, in a few days, new leaves could be seen sprouting in the plant again. How did the plant survive without leaves?

Answer 20: Plants have food stored in roots and stems. In the absence of leaves, plants use this stored food to survive until the new leaves are grown.

Question 21. Define symbiosis? Explain with an example

Answer 21: Symbiosis is the relationship between two organisms living together to share nutrients and shelter.

For example, The fungi living inside the plant’s roots get nutrients from the plant, and in turn, the fungus provides water and specific nutrients to the plant.

Question 22. Why do farmers grow many fruits and vegetable crops inside large greenhouses? What are the advantages to the farmers?

Answer 22: Farmers grow fruits and vegetables inside large greenhouses to enhance growth and provide suitable crop temperatures. 

A few advantages of growing crops in the greenhouse are:

1. Protecting crops from external climatic conditions.
2. It protects crops from rodents, birds and animals.
3. Farmers have plenty of crops. This helps farmers with storage.

Question 23. What is the Saprotrophic mode of nutrition? Explain it with two examples?

Answer 23: In the saprotrophic mode of nutrition, organisms obtain their nutrition from dead and decaying matter. This kind of nutrition is similar to the heterotrophic mode of nutrition.

Example 1: Bread Mould: Mould is a fungus germinating on rotting bread. These fungi create tiny spores and eventually grow as a mould to absorb nutrients like sugar and carbohydrates from the bread.

Example 2: Some of the nitrogen-fixing bacteria present in the roots of plants are also considered saprophytic as they can convert the molecular nitrogen into fixed nitrogen like Ammonia.

Question 24. If left in the open after a few days, the wheat dough emits a foul smell and becomes unfit for use. Give a reason.

Answer 24: Saprophytic organisms like yeast and fungus germinate and grow on the wheat dough when left uncovered or open for a few days. These organisms break down the Carbohydrates present in the wheat dough into simple components, leaving the dough with a foul smell and unfit to use.

Question 25. Show with the help of a sketch that plants are the ultimate source of food.

Answer 25:

Question 26. Fill in the blanks

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

       (b) During photosynthesis plants take in ______________________ and release

             __________________ gas.

       (c) The green pigments called ____________ absorb solar energy during the photosynthesis process.

       (d) The food produced by plants is stored in the form of _________________.

Answer 26:  

 (a) Autotroph

 (b) Carbon dioxide, Oxygen 

 (c) Chlorophyll 

 (d) Starch

Question 27. Sunlight, chlorophyll, carbon dioxide, water and minerals are raw materials essential for photosynthesis. Do you know where they are available? Fill in the blanks with the appropriate raw materials:

(a) Available in the plant : _______________

(b) Available in the soil : _______________, _______________

(c) Available in the air : _______________

(d) Available during day : _______________

Answer 27:

 (a) chlorophyll 

 (b) water, minerals 

 (c) carbon dioxide 

 (d) Sunlight

Question 28. Give a brief description of the process of synthesis of food in green plants through a diagram.

Answer 28: Plants synthesise their food through a process called photosynthesis. Leaves are the food factory of the plants. During photosynthesis, the green pigment called chlorophyll in the leaves in the presence of sunlight uses carbon dioxide, water and minerals from the soil to produce carbohydrates and release oxygen to the atmosphere. The below diagram shows the photosynthesis process.

Question 29. Match the organisms in Column I with their mode of nutrition given in Column II.

Answer 29: The matched organisms with their mode of nutrition are given below:                    

Question 30. Can you give me a name? Solve each of the following riddles by writing the name of the organism and its mode of nutrition. One riddle is solved to help you.

(a) I am tall, but I cannot move. I am green and can prepare my food..

(b) I live in water; people keep me in an aquarium and feed me.  

(c) I am small, and I can fly. I disturb your sleep, bite you and suck your blood which is my food.

(d) I am white and soft. I grow well in the rainy season. People pluck me from the ground and cook me. I absorb nutrients from decomposed dead parts of plants and animals in the soil.

Answer 30: 

(a) Tree, autotroph.

(b) Fish, heterotroph 

(c) Mosquito, parasite 

(d) Mushroom, saprophyte

Question 31. Spot as many organisms as possible in the puzzle given in Figure 1.2 by encircling them as shown. Write the names on a sheet of paper and categorise them into autotrophs and heterotrophs. Classify the heterotrophs into herbivores, carnivores, omnivores and saprophytes.

Answer 31 :

Autotrophs – Rose, Mango, Bhindi, Carrot, Banyan, Tulsi, Ginger, Yam

Herbivores – Elephant, Cow, Rabbit, Bee

Heterotrophs –Ant, Tiger, Fox, Mice, Owl, Crow, Cow, Rabbit, Beef, Fish, Elephant

Carnivores – Fox, Tiger

Omnivores – Ant, Owl, Crow, Fish, Mice

Saprophytes – Mushroom, Yeast

Benefits of Solving Important Questions Class 7 Science Chapter 1

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Few of the benefits of referring to Important Questions Class 7 Science Chapter 1 are:

• The questions are collated by referring to various genuine sources, including NCERT textbooks, NCERT Exemplar books, past years’ question papers and other sources. So students will get a complete variety of all the questions.
• By practising these advanced level questions from the Important Questions Class 7 Science Chapter 1, students can thoroughly brush up on the concepts. This would also help them analyse their shortcomings and overcome them before facing the school final examinations.
• The question and answers follow the latest CBSE syllabus and NCERT guidelines. Our solutions are prepared by experienced professors so that students can fully rely on our study materials.

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