NCERT Solutions for Class 8 Science Chapter 2- Microorganisms Friend and Foe

NCERT Solutions for Class 8 Science Chapter 2 provides a complete understanding of the topics covered in Microorganisms: Friend and Foe. Our NCERT Solutions are carefully drafted in an interactive manner so that your fundamentals about Chapter 2 become clear and you can use them to learn more advanced topics in higher Classes.

Some important concepts covered in this Chapter include microorganisms, uses of microorganisms, harmful microorganisms, microorganisms in humans, microorganisms in animals, microorganisms in plants, food preservation, nitrogen fixation and nitrogen cycle. Class 8 Science Microorganisms: Friend and Foe consists of a total of 9 questions.

Microorganisms: Friend and Foe is prepared to keep in mind the present syllabus covered in NCERT Science Book. They are handy and concise. NCERT Solutions for Class 8th Science Chapter 2 – Microorganisms: Friend and Foe are the best study material for quick revision and provide you with enough practice during the examinations enabling you to score well.

NCERT Class 8 Science Chapter 2 – Microorganisms: Friend and Foe- Important Topics

This Chapter comprises many important concepts from an exam point of view. Some of the concepts covered in NCERT Solutions Class 8 Science Chapter 2  are as follows.

  • Microorganisms

This part of the CBSE NCERT Class 8 Chapter 2 tells you that microorganisms or microbes are very small to be seen with naked eyes and are divided into four major categories: bacteria, fungi, protozoa and algae. Further, it tells about the special microscopic organisms called Viruses, which need other living cells to reproduce. This part also discusses the shape, appearance and diseases caused by these microorganisms. 

  • Where do Microorganisms Live

This part of the NCERT Solutions for Class 8 Science Chapter 2- Microorganisms Friend and Foe mentions the habitats of microorganisms that are either single-celled or multicellular. Microorganisms can live in extreme conditions of temperature; within bodies of humans and animals; with or without oxygen; and alone or in colonies. 

  • Microorganisms and Us

This part of the Chapter tells you how some microorganisms are friendly, and some are harmful to humans.

  • Microorganisms

This section teaches you that microorganisms aid in preparing food items like bread and curd, some help in increasing the soil fertility and some help in decomposing the organic wastes.

  • Curd and Bread

This portion of the Chapter elaborates about how bacterium Lactobacillus converts milk to curd, and some other bacteria are involved in making cheese pickles and many other food items. It also tells you that yeast is used in making bakery products because the carbon dioxide produced during their rapid growth inside the dough creates bubbles and allows the dough to become fluffy.

  • Uses of Microorganisms

This part of the CBSE NCERT Class 8 Science Chapter 2 tells you that the process of conversion of sugar to alcohol by yeast is known as fermentation which finds use in large scale production of wine, alcohol and vinegar. It cites a medicinal use of microorganisms. It tells you that antibiotics and vaccines are manufactured by growing specific microorganisms and are used to treat a variety of diseases. 

  • Soil Fertility

Microbes are called biological nitrogen fixers and have the ability to convert atmospheric nitrogen to some chemicals which get mixed with soil and increase the nutrient content of soil hence increasing its fertility. 

  • The environment

This section teaches you about how the conversion of waste organic matter to smaller substances is one of the very important tasks done by microbes. This helps in cleaning the environment. In the absence of microbes, our earth would have been a big pile of garbage.

  • Harmful Microorganisms

This part of the Chapter tells us about the microorganisms which cause harm to humans and animals by causing diseases (pathogens) and by spoiling clothing, leather etc. 

    • Microorganisms in Humans

This subtopic deals with names of some common diseases caused by pathogens, names of pathogens causing the disease, mode of transmission of such diseases and ways to prevent the disease.

    • Microorganisms in Animals

Microorganisms cause diseases in animals also. Anthrax caused by bacteria is one of the deadliest of them. 

    • Microorganisms in Plants

This portion tells you about some common plant diseases caused by microbes, the names of microbes causing the disease and also gives images to understand the characteristics of the disease.

    • Poisoning 

Microorganisms grow in a food item and spoil them by producing toxic chemicals making the food unfit for consumption. Such food makes people ill when consumed. 

  • Food Preservation

This part of the NCERT Solutions for Class 8 Science Chapter 2-Microorganisms: Friend and Foe deals with methods used commonly to preserve the cooked food and avoid the growth of microorganisms and hence spoiling of food. Some of the methods of food preservation have been mentioned below.

    • Food preservation with chemicals

Chemicals such as sodium benzoate and sodium metabisulphite, known as preservatives, are added to food in order to check the growth of microorganisms. 

    1. Oil and Vinegar – Oil and vinegar cut off the oxygen supply to microorganisms causing them to die. 
    2. Cold Treatments – Sudden cooling and heating cycles of milk known as pasteurization prevents the growth of microbes.
    3. Packing – Airtight or vacuum packing of food items cut oxygen supply. This hampers the growth of microbes. 

Some other methods of Preservation of food are preservation by common salt and preservation by sugar which work on the principle of reducing moisture from food units so that the growth of microbes is hampered. 

  • Nitrogen Fixation

Microorganisms residing in the root nodules of leguminous plants and some bacteria and blue-green algae present in the soil can fix nitrogen from the air into the soil and convert into nitrogenous compounds, thereby increasing the soil fertility.

  • Nitrogen Cycle

This portion of the NCERT Class 8 Science Chapter 2 tells you about the nitrogen cycle. It tells you how nitrogen in the earth is utilized by plants and animals for their growth and then how it finally enters into the atmosphere due to microbial activity. 

Class 8 Science Microorganisms: Friend and Foe:  Exercise Discussion

NCERT Solutions for Class 8 Science Chapter 2 – Microorganisms: Friend and Foe provide comprehensive solutions for the questions asked.  CBSE NCERT Class 8 Science Chapter 2 contains a total of 9 questions which cover the entire Chapter properly.

The solutions of NCERT Class 8 Science Chapter 2 have been prepared in a clear and crisp manner to make the learning process easy and quick. The components of questions asked in NCERT CBSE Class 8 Science Chapter 2 are given below –

  • Question 1 to 3 asks you to fill in the blank, choose the right option and match the right options, respectively. They are based on memory skills. 
  • Question no. 4 to 8 asks you to reproduce and rewrite the concepts and facts learnt about microorganisms in this Chapter.
  • Question no. 9 asks you about antibiotics and the right way to use them.

All the above questions have been solved in NCERT Solutions for Class 8 Science Chapter 2 – Microorganisms: Friend and Foe using the best solving methods in a step by step and easy to understand manner.